NOAA Technical Memorandum NMFS-NWFSC-5

Seasonal Changes in the Intertidal and Subtidal Macrobenthic Invertebrate Community Structure in Baker Bay Lower Columbia River Estuary

Toshio Furota 1 and Robert L Emmett

National Marine Fisheries Service Northwest Fisheries Science Center Coastal Zone and Estuarine Studies Division 2725 Montlake Blvd E Seattle WA 98112

1 Present address Toho University Faculty of Science Mlyania 2-2-1 Funabashi Chiba 274 Japan

January 1993

us DEPARTMENT OF COMMERCE Barbara Hackman Franklin Secretary

National Oceanic and Atmospheric Administration John A Knauss Administrator

National Marine Fisheries Service WIlliam W Fox Jr Assistant Administrator for Fisheries

This document is available to the public through

National Technical Information Service US Department of Commerce 5285 Port Royal Road Springfield VA 22161

iii

ABSTRACT

Macrobenthic invertebrates and sedLments at 1 subtidal and 10 intertidal

stations along a transect in Baker Bay of the lower Columbia River estuary

were sampled monthly from November 1980 to October 1981 Water column

temperatures and salinities were also recorded at the subtidal station The

intertidal community consisted primarily of estuarine species whereas the

subtidal community had additional marine species Marine species declined in

abundance after the interstitial salinity minimum (June) indicating the

important role of salinity in determining benthic community structure

Filamentous algae tide pools and eelgrasses (Zostera spp) were also

important factors determining macrobenthic invertebrate community structure

By altering sedLment characteristics Zostera spp had a positive effect on

deposit feeders and a negative effect on the sand-dwelling amphipod

Eohaustorius estuaris

v

CONTENTS

Page

INTRODUCTION 1

METHODS bullbull 2

Study Site

Sampling Procedure

2

2

RESULTS AND DISCUSSION 6

Water Temperature and Salinity

Sediment Characteristics

6

6

Benthic Invertebrates bull bull bull bull 10

Efficiency of Sampling Method 10

Vertical Distribution Along the Tidal Gradient

Seasonal Changes

Intertidal Community

17

17

17

Subtidal Community

Effect of Salinity on the Benthic Community bull

Effect of Vegetation on the Benthic Community bull

18

19

19

Filamentous Algae

Ee1grasses

CONCLUSIONS

19

22

26

ACKNOWLEDGMENTS bull 27

CITATIONS bull bull bull bull 29

APPENDIX TABLE 33

INTRODUCTION

Changes in the faunal communities of estuaries are caused by physical

chemical and biological processes One of the most important physical

factors determining the benthic fauna is salinity (Boesh 1977) In intertidal

areas where physical conditions are extreme distinct vertical distributions

of benthic fauna have been observed (Brady 1943 Wells and Roberts 1980)

Furthermore benthic infauna diversity and density are affected by vegetative

growth particularly of eelgrass (Zostera spp) which increases sediment

stability and interrupts the movement of burrowing animals (Orth 1977 Ringold

1979) bull

For much of the year the Columbia River estuary is characterized by low

salinity due to large inputs of fresh water Salinity is highest during late

summer-early fall at the river mouth where surface salinity ranges from 58 to

305~ Lowest salinity occurs in early summer as a result of snowmelt from

the headwaters (Neal 1972) Large tidal fluctuations (gt30 m) result in

extensive tidal flats in the estuary

The benthic macrofauna in the Columbia River estuary has been well

studied (Haertel and Osterberg 1967 Higley and Holton 1975 Sanborn 1975

Higley et ale 1976 Higley and Holton 1978 Higley et ale 1979 Durkin and

Emmett 1980 Durkin et ale 1981 Jones 1984) Major components of the benthic

macrofauna include the amphipods Corophiumsa~onispound spinicorne and

Eohaustorius estuaris the polychaetes Neanthes limnicola and Hobsonia

florida and the bivalve Macoma balthica

The objectives of this study were to determine the influences of

seasonal changes in salinity and the presence of intertidal vegetation on the

macrobenthic community and to describe the vertical changes in the benthic

fauna along a tidal gradient on an intertidal-subtidal flat in Baker Bay

Columbia River estuary

2

METHODS

Study Site

Baker Bay is located on the north side of the lower Columbia River

estuary and has broad tidal flats consisting mainly of fine sand (Durkin and

Emmett 1980) Eleven stations were sampled along a transect that extended

from the mean high water level to the bottom of the adjacent boat channel at

the northwest corner of Baker Bay (Fig 1) Figure 2 depicts a cross section

of the study site and shows station locations and the sediment characteristics

of each station as observed in February 1981

At Stations 1 and 2 three-square bullrush (Scirpus americanus)

surrounded the sandy flats that were sampled During late summer to early

fall filamentous algal mats consisting of blue green algae (Lyngbya spp)

and a chrysophyte of the genus Vaucheria densely covered the sediment

surfaces of some areas at these stations

Stations 1 through 10 were exposed during extremely low water Patches

of the eelgrasses Zostera japonica (on the upper intertidal area Stations 3shy

7) and~ marina (on the lower intertidal area Stations 7-10) grew from July

through October Stations 4 through 7 had ripple marks on the sediment surface

indicating relatively frequent wave disturbances

Station 11 which was located at the bottom of the adjacent boat channel

(subtidal) was about 4 m deep at mean low water

Sampling Procedure

At each station three benthic invertebrate samples and one sediment

core (10 em deep by 5 em in diameter) were taken monthly from November 1980 to

October 1981 (see Appendix) usually during the second negative tide series

Intertidal stations were sampled for invertebrates using a 506 em2 (10 em

deep) metal frame At the subtidal site (and lower intertidal sites) a

506-em2 Ekman-Birge sediment sampler was used The Ekman-Birge sampler was

handled directly by scuba divers except at Station 11 where it was operated

from a research boat using a messenger weight During the last 2 months

however this sampler was operated directly by divers at Station 11 (less ship

3

Oregon

Figure 1--Benthic invertebrate and sediment sampling sites in Baker Bay Columbia River estuary November 1980 to October 1981

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

This document is available to the public through

National Technical Information Service US Department of Commerce 5285 Port Royal Road Springfield VA 22161

iii

ABSTRACT

Macrobenthic invertebrates and sedLments at 1 subtidal and 10 intertidal

stations along a transect in Baker Bay of the lower Columbia River estuary

were sampled monthly from November 1980 to October 1981 Water column

temperatures and salinities were also recorded at the subtidal station The

intertidal community consisted primarily of estuarine species whereas the

subtidal community had additional marine species Marine species declined in

abundance after the interstitial salinity minimum (June) indicating the

important role of salinity in determining benthic community structure

Filamentous algae tide pools and eelgrasses (Zostera spp) were also

important factors determining macrobenthic invertebrate community structure

By altering sedLment characteristics Zostera spp had a positive effect on

deposit feeders and a negative effect on the sand-dwelling amphipod

Eohaustorius estuaris

v

CONTENTS

Page

INTRODUCTION 1

METHODS bullbull 2

Study Site

Sampling Procedure

2

2

RESULTS AND DISCUSSION 6

Water Temperature and Salinity

Sediment Characteristics

6

6

Benthic Invertebrates bull bull bull bull 10

Efficiency of Sampling Method 10

Vertical Distribution Along the Tidal Gradient

Seasonal Changes

Intertidal Community

17

17

17

Subtidal Community

Effect of Salinity on the Benthic Community bull

Effect of Vegetation on the Benthic Community bull

18

19

19

Filamentous Algae

Ee1grasses

CONCLUSIONS

19

22

26

ACKNOWLEDGMENTS bull 27

CITATIONS bull bull bull bull 29

APPENDIX TABLE 33

INTRODUCTION

Changes in the faunal communities of estuaries are caused by physical

chemical and biological processes One of the most important physical

factors determining the benthic fauna is salinity (Boesh 1977) In intertidal

areas where physical conditions are extreme distinct vertical distributions

of benthic fauna have been observed (Brady 1943 Wells and Roberts 1980)

Furthermore benthic infauna diversity and density are affected by vegetative

growth particularly of eelgrass (Zostera spp) which increases sediment

stability and interrupts the movement of burrowing animals (Orth 1977 Ringold

1979) bull

For much of the year the Columbia River estuary is characterized by low

salinity due to large inputs of fresh water Salinity is highest during late

summer-early fall at the river mouth where surface salinity ranges from 58 to

305~ Lowest salinity occurs in early summer as a result of snowmelt from

the headwaters (Neal 1972) Large tidal fluctuations (gt30 m) result in

extensive tidal flats in the estuary

The benthic macrofauna in the Columbia River estuary has been well

studied (Haertel and Osterberg 1967 Higley and Holton 1975 Sanborn 1975

Higley et ale 1976 Higley and Holton 1978 Higley et ale 1979 Durkin and

Emmett 1980 Durkin et ale 1981 Jones 1984) Major components of the benthic

macrofauna include the amphipods Corophiumsa~onispound spinicorne and

Eohaustorius estuaris the polychaetes Neanthes limnicola and Hobsonia

florida and the bivalve Macoma balthica

The objectives of this study were to determine the influences of

seasonal changes in salinity and the presence of intertidal vegetation on the

macrobenthic community and to describe the vertical changes in the benthic

fauna along a tidal gradient on an intertidal-subtidal flat in Baker Bay

Columbia River estuary

2

METHODS

Study Site

Baker Bay is located on the north side of the lower Columbia River

estuary and has broad tidal flats consisting mainly of fine sand (Durkin and

Emmett 1980) Eleven stations were sampled along a transect that extended

from the mean high water level to the bottom of the adjacent boat channel at

the northwest corner of Baker Bay (Fig 1) Figure 2 depicts a cross section

of the study site and shows station locations and the sediment characteristics

of each station as observed in February 1981

At Stations 1 and 2 three-square bullrush (Scirpus americanus)

surrounded the sandy flats that were sampled During late summer to early

fall filamentous algal mats consisting of blue green algae (Lyngbya spp)

and a chrysophyte of the genus Vaucheria densely covered the sediment

surfaces of some areas at these stations

Stations 1 through 10 were exposed during extremely low water Patches

of the eelgrasses Zostera japonica (on the upper intertidal area Stations 3shy

7) and~ marina (on the lower intertidal area Stations 7-10) grew from July

through October Stations 4 through 7 had ripple marks on the sediment surface

indicating relatively frequent wave disturbances

Station 11 which was located at the bottom of the adjacent boat channel

(subtidal) was about 4 m deep at mean low water

Sampling Procedure

At each station three benthic invertebrate samples and one sediment

core (10 em deep by 5 em in diameter) were taken monthly from November 1980 to

October 1981 (see Appendix) usually during the second negative tide series

Intertidal stations were sampled for invertebrates using a 506 em2 (10 em

deep) metal frame At the subtidal site (and lower intertidal sites) a

506-em2 Ekman-Birge sediment sampler was used The Ekman-Birge sampler was

handled directly by scuba divers except at Station 11 where it was operated

from a research boat using a messenger weight During the last 2 months

however this sampler was operated directly by divers at Station 11 (less ship

3

Oregon

Figure 1--Benthic invertebrate and sediment sampling sites in Baker Bay Columbia River estuary November 1980 to October 1981

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

iii

ABSTRACT

Macrobenthic invertebrates and sedLments at 1 subtidal and 10 intertidal

stations along a transect in Baker Bay of the lower Columbia River estuary

were sampled monthly from November 1980 to October 1981 Water column

temperatures and salinities were also recorded at the subtidal station The

intertidal community consisted primarily of estuarine species whereas the

subtidal community had additional marine species Marine species declined in

abundance after the interstitial salinity minimum (June) indicating the

important role of salinity in determining benthic community structure

Filamentous algae tide pools and eelgrasses (Zostera spp) were also

important factors determining macrobenthic invertebrate community structure

By altering sedLment characteristics Zostera spp had a positive effect on

deposit feeders and a negative effect on the sand-dwelling amphipod

Eohaustorius estuaris

v

CONTENTS

Page

INTRODUCTION 1

METHODS bullbull 2

Study Site

Sampling Procedure

2

2

RESULTS AND DISCUSSION 6

Water Temperature and Salinity

Sediment Characteristics

6

6

Benthic Invertebrates bull bull bull bull 10

Efficiency of Sampling Method 10

Vertical Distribution Along the Tidal Gradient

Seasonal Changes

Intertidal Community

17

17

17

Subtidal Community

Effect of Salinity on the Benthic Community bull

Effect of Vegetation on the Benthic Community bull

18

19

19

Filamentous Algae

Ee1grasses

CONCLUSIONS

19

22

26

ACKNOWLEDGMENTS bull 27

CITATIONS bull bull bull bull 29

APPENDIX TABLE 33

INTRODUCTION

Changes in the faunal communities of estuaries are caused by physical

chemical and biological processes One of the most important physical

factors determining the benthic fauna is salinity (Boesh 1977) In intertidal

areas where physical conditions are extreme distinct vertical distributions

of benthic fauna have been observed (Brady 1943 Wells and Roberts 1980)

Furthermore benthic infauna diversity and density are affected by vegetative

growth particularly of eelgrass (Zostera spp) which increases sediment

stability and interrupts the movement of burrowing animals (Orth 1977 Ringold

1979) bull

For much of the year the Columbia River estuary is characterized by low

salinity due to large inputs of fresh water Salinity is highest during late

summer-early fall at the river mouth where surface salinity ranges from 58 to

305~ Lowest salinity occurs in early summer as a result of snowmelt from

the headwaters (Neal 1972) Large tidal fluctuations (gt30 m) result in

extensive tidal flats in the estuary

The benthic macrofauna in the Columbia River estuary has been well

studied (Haertel and Osterberg 1967 Higley and Holton 1975 Sanborn 1975

Higley et ale 1976 Higley and Holton 1978 Higley et ale 1979 Durkin and

Emmett 1980 Durkin et ale 1981 Jones 1984) Major components of the benthic

macrofauna include the amphipods Corophiumsa~onispound spinicorne and

Eohaustorius estuaris the polychaetes Neanthes limnicola and Hobsonia

florida and the bivalve Macoma balthica

The objectives of this study were to determine the influences of

seasonal changes in salinity and the presence of intertidal vegetation on the

macrobenthic community and to describe the vertical changes in the benthic

fauna along a tidal gradient on an intertidal-subtidal flat in Baker Bay

Columbia River estuary

2

METHODS

Study Site

Baker Bay is located on the north side of the lower Columbia River

estuary and has broad tidal flats consisting mainly of fine sand (Durkin and

Emmett 1980) Eleven stations were sampled along a transect that extended

from the mean high water level to the bottom of the adjacent boat channel at

the northwest corner of Baker Bay (Fig 1) Figure 2 depicts a cross section

of the study site and shows station locations and the sediment characteristics

of each station as observed in February 1981

At Stations 1 and 2 three-square bullrush (Scirpus americanus)

surrounded the sandy flats that were sampled During late summer to early

fall filamentous algal mats consisting of blue green algae (Lyngbya spp)

and a chrysophyte of the genus Vaucheria densely covered the sediment

surfaces of some areas at these stations

Stations 1 through 10 were exposed during extremely low water Patches

of the eelgrasses Zostera japonica (on the upper intertidal area Stations 3shy

7) and~ marina (on the lower intertidal area Stations 7-10) grew from July

through October Stations 4 through 7 had ripple marks on the sediment surface

indicating relatively frequent wave disturbances

Station 11 which was located at the bottom of the adjacent boat channel

(subtidal) was about 4 m deep at mean low water

Sampling Procedure

At each station three benthic invertebrate samples and one sediment

core (10 em deep by 5 em in diameter) were taken monthly from November 1980 to

October 1981 (see Appendix) usually during the second negative tide series

Intertidal stations were sampled for invertebrates using a 506 em2 (10 em

deep) metal frame At the subtidal site (and lower intertidal sites) a

506-em2 Ekman-Birge sediment sampler was used The Ekman-Birge sampler was

handled directly by scuba divers except at Station 11 where it was operated

from a research boat using a messenger weight During the last 2 months

however this sampler was operated directly by divers at Station 11 (less ship

3

Oregon

Figure 1--Benthic invertebrate and sediment sampling sites in Baker Bay Columbia River estuary November 1980 to October 1981

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

v

CONTENTS

Page

INTRODUCTION 1

METHODS bullbull 2

Study Site

Sampling Procedure

2

2

RESULTS AND DISCUSSION 6

Water Temperature and Salinity

Sediment Characteristics

6

6

Benthic Invertebrates bull bull bull bull 10

Efficiency of Sampling Method 10

Vertical Distribution Along the Tidal Gradient

Seasonal Changes

Intertidal Community

17

17

17

Subtidal Community

Effect of Salinity on the Benthic Community bull

Effect of Vegetation on the Benthic Community bull

18

19

19

Filamentous Algae

Ee1grasses

CONCLUSIONS

19

22

26

ACKNOWLEDGMENTS bull 27

CITATIONS bull bull bull bull 29

APPENDIX TABLE 33

INTRODUCTION

Changes in the faunal communities of estuaries are caused by physical

chemical and biological processes One of the most important physical

factors determining the benthic fauna is salinity (Boesh 1977) In intertidal

areas where physical conditions are extreme distinct vertical distributions

of benthic fauna have been observed (Brady 1943 Wells and Roberts 1980)

Furthermore benthic infauna diversity and density are affected by vegetative

growth particularly of eelgrass (Zostera spp) which increases sediment

stability and interrupts the movement of burrowing animals (Orth 1977 Ringold

1979) bull

For much of the year the Columbia River estuary is characterized by low

salinity due to large inputs of fresh water Salinity is highest during late

summer-early fall at the river mouth where surface salinity ranges from 58 to

305~ Lowest salinity occurs in early summer as a result of snowmelt from

the headwaters (Neal 1972) Large tidal fluctuations (gt30 m) result in

extensive tidal flats in the estuary

The benthic macrofauna in the Columbia River estuary has been well

studied (Haertel and Osterberg 1967 Higley and Holton 1975 Sanborn 1975

Higley et ale 1976 Higley and Holton 1978 Higley et ale 1979 Durkin and

Emmett 1980 Durkin et ale 1981 Jones 1984) Major components of the benthic

macrofauna include the amphipods Corophiumsa~onispound spinicorne and

Eohaustorius estuaris the polychaetes Neanthes limnicola and Hobsonia

florida and the bivalve Macoma balthica

The objectives of this study were to determine the influences of

seasonal changes in salinity and the presence of intertidal vegetation on the

macrobenthic community and to describe the vertical changes in the benthic

fauna along a tidal gradient on an intertidal-subtidal flat in Baker Bay

Columbia River estuary

2

METHODS

Study Site

Baker Bay is located on the north side of the lower Columbia River

estuary and has broad tidal flats consisting mainly of fine sand (Durkin and

Emmett 1980) Eleven stations were sampled along a transect that extended

from the mean high water level to the bottom of the adjacent boat channel at

the northwest corner of Baker Bay (Fig 1) Figure 2 depicts a cross section

of the study site and shows station locations and the sediment characteristics

of each station as observed in February 1981

At Stations 1 and 2 three-square bullrush (Scirpus americanus)

surrounded the sandy flats that were sampled During late summer to early

fall filamentous algal mats consisting of blue green algae (Lyngbya spp)

and a chrysophyte of the genus Vaucheria densely covered the sediment

surfaces of some areas at these stations

Stations 1 through 10 were exposed during extremely low water Patches

of the eelgrasses Zostera japonica (on the upper intertidal area Stations 3shy

7) and~ marina (on the lower intertidal area Stations 7-10) grew from July

through October Stations 4 through 7 had ripple marks on the sediment surface

indicating relatively frequent wave disturbances

Station 11 which was located at the bottom of the adjacent boat channel

(subtidal) was about 4 m deep at mean low water

Sampling Procedure

At each station three benthic invertebrate samples and one sediment

core (10 em deep by 5 em in diameter) were taken monthly from November 1980 to

October 1981 (see Appendix) usually during the second negative tide series

Intertidal stations were sampled for invertebrates using a 506 em2 (10 em

deep) metal frame At the subtidal site (and lower intertidal sites) a

506-em2 Ekman-Birge sediment sampler was used The Ekman-Birge sampler was

handled directly by scuba divers except at Station 11 where it was operated

from a research boat using a messenger weight During the last 2 months

however this sampler was operated directly by divers at Station 11 (less ship

3

Oregon

Figure 1--Benthic invertebrate and sediment sampling sites in Baker Bay Columbia River estuary November 1980 to October 1981

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

INTRODUCTION

Changes in the faunal communities of estuaries are caused by physical

chemical and biological processes One of the most important physical

factors determining the benthic fauna is salinity (Boesh 1977) In intertidal

areas where physical conditions are extreme distinct vertical distributions

of benthic fauna have been observed (Brady 1943 Wells and Roberts 1980)

Furthermore benthic infauna diversity and density are affected by vegetative

growth particularly of eelgrass (Zostera spp) which increases sediment

stability and interrupts the movement of burrowing animals (Orth 1977 Ringold

1979) bull

For much of the year the Columbia River estuary is characterized by low

salinity due to large inputs of fresh water Salinity is highest during late

summer-early fall at the river mouth where surface salinity ranges from 58 to

305~ Lowest salinity occurs in early summer as a result of snowmelt from

the headwaters (Neal 1972) Large tidal fluctuations (gt30 m) result in

extensive tidal flats in the estuary

The benthic macrofauna in the Columbia River estuary has been well

studied (Haertel and Osterberg 1967 Higley and Holton 1975 Sanborn 1975

Higley et ale 1976 Higley and Holton 1978 Higley et ale 1979 Durkin and

Emmett 1980 Durkin et ale 1981 Jones 1984) Major components of the benthic

macrofauna include the amphipods Corophiumsa~onispound spinicorne and

Eohaustorius estuaris the polychaetes Neanthes limnicola and Hobsonia

florida and the bivalve Macoma balthica

The objectives of this study were to determine the influences of

seasonal changes in salinity and the presence of intertidal vegetation on the

macrobenthic community and to describe the vertical changes in the benthic

fauna along a tidal gradient on an intertidal-subtidal flat in Baker Bay

Columbia River estuary

2

METHODS

Study Site

Baker Bay is located on the north side of the lower Columbia River

estuary and has broad tidal flats consisting mainly of fine sand (Durkin and

Emmett 1980) Eleven stations were sampled along a transect that extended

from the mean high water level to the bottom of the adjacent boat channel at

the northwest corner of Baker Bay (Fig 1) Figure 2 depicts a cross section

of the study site and shows station locations and the sediment characteristics

of each station as observed in February 1981

At Stations 1 and 2 three-square bullrush (Scirpus americanus)

surrounded the sandy flats that were sampled During late summer to early

fall filamentous algal mats consisting of blue green algae (Lyngbya spp)

and a chrysophyte of the genus Vaucheria densely covered the sediment

surfaces of some areas at these stations

Stations 1 through 10 were exposed during extremely low water Patches

of the eelgrasses Zostera japonica (on the upper intertidal area Stations 3shy

7) and~ marina (on the lower intertidal area Stations 7-10) grew from July

through October Stations 4 through 7 had ripple marks on the sediment surface

indicating relatively frequent wave disturbances

Station 11 which was located at the bottom of the adjacent boat channel

(subtidal) was about 4 m deep at mean low water

Sampling Procedure

At each station three benthic invertebrate samples and one sediment

core (10 em deep by 5 em in diameter) were taken monthly from November 1980 to

October 1981 (see Appendix) usually during the second negative tide series

Intertidal stations were sampled for invertebrates using a 506 em2 (10 em

deep) metal frame At the subtidal site (and lower intertidal sites) a

506-em2 Ekman-Birge sediment sampler was used The Ekman-Birge sampler was

handled directly by scuba divers except at Station 11 where it was operated

from a research boat using a messenger weight During the last 2 months

however this sampler was operated directly by divers at Station 11 (less ship

3

Oregon

Figure 1--Benthic invertebrate and sediment sampling sites in Baker Bay Columbia River estuary November 1980 to October 1981

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

2

METHODS

Study Site

Baker Bay is located on the north side of the lower Columbia River

estuary and has broad tidal flats consisting mainly of fine sand (Durkin and

Emmett 1980) Eleven stations were sampled along a transect that extended

from the mean high water level to the bottom of the adjacent boat channel at

the northwest corner of Baker Bay (Fig 1) Figure 2 depicts a cross section

of the study site and shows station locations and the sediment characteristics

of each station as observed in February 1981

At Stations 1 and 2 three-square bullrush (Scirpus americanus)

surrounded the sandy flats that were sampled During late summer to early

fall filamentous algal mats consisting of blue green algae (Lyngbya spp)

and a chrysophyte of the genus Vaucheria densely covered the sediment

surfaces of some areas at these stations

Stations 1 through 10 were exposed during extremely low water Patches

of the eelgrasses Zostera japonica (on the upper intertidal area Stations 3shy

7) and~ marina (on the lower intertidal area Stations 7-10) grew from July

through October Stations 4 through 7 had ripple marks on the sediment surface

indicating relatively frequent wave disturbances

Station 11 which was located at the bottom of the adjacent boat channel

(subtidal) was about 4 m deep at mean low water

Sampling Procedure

At each station three benthic invertebrate samples and one sediment

core (10 em deep by 5 em in diameter) were taken monthly from November 1980 to

October 1981 (see Appendix) usually during the second negative tide series

Intertidal stations were sampled for invertebrates using a 506 em2 (10 em

deep) metal frame At the subtidal site (and lower intertidal sites) a

506-em2 Ekman-Birge sediment sampler was used The Ekman-Birge sampler was

handled directly by scuba divers except at Station 11 where it was operated

from a research boat using a messenger weight During the last 2 months

however this sampler was operated directly by divers at Station 11 (less ship

3

Oregon

Figure 1--Benthic invertebrate and sediment sampling sites in Baker Bay Columbia River estuary November 1980 to October 1981

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

3

Oregon

Figure 1--Benthic invertebrate and sediment sampling sites in Baker Bay Columbia River estuary November 1980 to October 1981

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

Particle size (mm)

20deg St 6 St7 st 8 stg Stl0 Stl1 10

05~ 025)===rshy0125 )

0063 lt0063

EHW 3 - MHW

2 - MTL

1 - MLW

0-1- MLLWParticle o-- - ELW csize (mm)

tmiddot20 I St 1 10 051 27

o~~Jf===~- It==bull 30063 lt0063

I ---- ---- I It o 50 100 (m) ------

o 100m

~

Figure 2--A cross section of the study site in Baker Bay Columbia River estuary showing station locations and sediment characteristics observed in February 1981 Tidal levels are EHW - Extre~e High Water MHW = Mean High Water MTL - Mean Tidal Level MLW - Mean Low Water MLLW - Mean Lower Low Water and ELW - Extreme Low Water

-) ~I ~ a ~ ~ ~ ~ ~ ~

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

5

traffic reduced the hazards for divers) Invertebrate samples were placed in

a sieve box and washed through a 0595 mm (No 30) screen Samples were then

fixed in a 4 formaldehyde solution containing Rose-bengal (a protein stain)

During October 1981 two stations (Stations 3 and 7) were sampled to a

depth of 20 em These sediments were divided into top (0 to 10 em) and bottom

(10 to 20 em) portions and analyzed separately to identify the efficiency of

the sampling method

Samples for benthic invertebrate analysis were rinsed of formaldehyde

and invertebrates were then picked from the sample separated by species or

major taxonomic groups and counted Wet weights of the invertebrates were

determined to the nearest OOOL 9 at Toho University Chiba Japan using a

Sartorius1 2355 balance The weights of some invertebrates were not obtained

because they were damaged during transport from the United States to Japan

Sediment composition for the February 1981 samples was determined by

sieving the sediment through a set of sieves (20 10 05 025 0125 and

0063 mm) and then weighing each pre-weighed seive Interstitial salinities

were determined by drawing water from the core sediment using an aspirator

with a Millipore HA filter a silver nitrate method was then used to measure

salinity (Strickland and Parsons 1968) At Station 11 (subtidal boat

channel) water temperature and salinity were measured monthly at 1-m

intervals (surface to bottom) using a Beckman Model RS53 salinometer and

probe

Differences between benthic invertebrate densities in samples from

stations with and without eelgrass were tested for statistical significance

using either a Chi-square test (no zeros in the data) or a Mann-Whitney test

(some zeros in the data)

YReference to trade names does not imply endorsement by the National Marine Fisheries Service NOAA

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

6

RESULTS AND DISCUSSION

Water Temperature and Salinity

Water column temperatures at Station 11 ranged from 60degC in January to

177degC in August (Table 1) Vertical changes in temperatures varied little

throughout the year

Water column salinities tended to be lower during late winter to early

summer with the lowest salinity 35~ occurring near the surface in

February (Table 2) The highest salinity 224~ was recorded at 5 m in

December Though salinity tended to increase with water depth vertical

differences in salinity were not great suggesting that water in the study

area was well mixed

Throughout the year interstitial salinities were lower at the

intertidal sites than at the subtidal site (Table 3) Intertidal interstitial

salinities were lowest during the spring and early summer with the lowest

levels occurring in late June laquo20~) Sanders et al (1965) showed that in

an Atlantic coast estuary interstitial salinities remained relatively

constant even though overlying water salinities varied diurnally In Baker

Bay however low interstitial salinities occurred in June as a result of the

large input of fresh water from the Columbia River that consistently overlaid

the tidal flat during this period

Seasonal fluctuations of subtidal interstitial salinities were

relatively small but followed a pattern similar to that of the intertidal

stations

Sediment Characteristics

The sediment of the tidal flat (Stations 1 through 9) consisted

primarily of medium (0500 rom ~ 0250 rom in diameter) and fine sand (0250 rom

~ 0125 rom in diameter) (Fig 2) Subtidal sediment was composed primarily

of fine sand with some silt and clay laquo 0063 rom in diameter) at Station 10

and very fine sand (0125 rom ~063 rom in diameter) and silt-clay at

Station 11

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

Table 1--Monthly (1980-81) water column temperatures (OC) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 89 85 61 73 89 110 128 162 172 177 152 123

1 89 85 61 71 89 middot110 125 162 172 177 153 123

2 90 85 61 69 90 110 126 161 172 177 154 122

3 89 88 60 68 90 110 125 161 170 177 154 122

4 - 88 60 69 89 110 126 161 168 176 153 122

5 91 61 91 126 161 168 176 155 121 J

bull Temperatures not taken because of reduced water depth

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

Table 2--Monthly (1980-1981) water column salinities (ppt) at Station 11 (subtidal channel site) in Baker Bay Columbia River estuary

1980 1981

(m)

Depth Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

0 72 120 70 35 79 77 59 60 78 107 120 99

1 73 121 70 35 79 78 59 60 77 107 121 100

2 73 131 71 38 80 79 63 60 77 107 123 104

3 79 178 71 42 84 80 66 60 94 109 124 107

4 - 211 71 59 86 83 70 62 110 109 124 113

5 224 77 103 82 68 119 112 124 11 9 co

Salinities not taken because of reduced water depth

~ ~ ~ ~ ~ ~ ~ ~ a ~ ~

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

Table 3--Monthly (1980-81) salinities (ppt) of interstitial waters in intertidal (stations 1-10) and subtidal (Station 11) sediments collected in Baker Bay Columbia River estuary

1980 1981

Station Nov Dec Jan reb Mar Apr Hay Jun Jul Aug Sep Oct

1

2

3

4

5

6

7

8

9

10

11

-bull

90

90

138

88

88

82

155

65

62

90

65

99

73

62

62

62

78

65

81

74

90

37

37

42

60

98

70

65

65

77

76

60

62

70

67

96

20

19

17

15

17

15

41

44

37

72

72

76

70

72

72

74

82

78

74

109

155

108

111

108

103

106

91

95

95

111

154

167

139

123

153

170

158

109

110

109

155

112

114

102

103

104

113

102

100

104

162

D

bull Salinity not determined

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

10

Benthic Invertebrates

Thirty-seven different benthic invertebrates were identified (Table 4)

The polychaetes Neanthes limnicola and Hobsonia florida the bivalve Macgma

balthica and the amphipods Corophium salmonis and Eohaustorius estuaris were

abundant in the study area throughout the year (Figs 3 4) Gravimetrically

H balthica was the dominant species in the intertidal community followed by

H limnicola These two species comprised more than 90 of the total weight

of the middle-low intertidal community (Fig 4) At the subtidal site

H balthica was the most important species numerically and gravimetrically

followed by the spionid polychaete Pseudgpolydra kempi (Fig 5)

In a previous Baker Bay study Higley and Holton (1978) found

oligochaetes and H balthica abundant in the bay as a whole with the

haustorid amphipod E estuaris and the capitellid polychaete Medigmastus

califgrniensis abundant only in shallow and deep habitats respectively In a

nearby intertidal mudflat in Baker Bay Jones (1984) observed that Macgma

balthica and the polychaetes a flgrida and ~ ~ were the dominant members

of the benthic community followed by oligochaetes and the polychaete H

Itmnicgla Oligochaetes were not abundant in our study This may be related

to sieve sizes Higley and Holton (1978) used 0425 mm screens Jones (1984)

used 0125 mm screens and we used 0595 mm screens

Efficiency gf Sampling Hethgd

Holton et ale (1984) reported that benthic invertebrates in Baker Bay

were most abundant in the top 10 em of the sediment Similarly our analysis

showed that a 10-em depth sample was sufficient to describe the macrobenthic

community at our stUdy site although several species would be slightly

underestimated (Table 5) For example while sampling we observed many adult

soft-shell clams Hya arenaria in the lower intertidal areas However

because they lived more that 20 em below the sediment surface we did not

sample this species quantitatively Thus estimations of these undersampled

species were excluded from our analysis

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

11

Table 4--Invertebrate taxa found in an intertidal-subtidal area in Baker Bay Columbia River estuary November 1980 through October 1981

Phylum Platyhelminthes Class Turbellaria

Phylum Nemertea

Phylum Aschelminthes Class Nematoda

Phylum Annelida Class Polychaeta

Subclass Errantia Family Phyllodocidae

Eteone dBatae Eteone light

Family Nereidae Neanthes IimnicQla

Family Goniadidae Glycinde polygnatha

Family Glyceridae Hem1podus bopealis

Subclass Sedentaria Family Ampharetidae

Hobsona flgrida Family Spionidae

Pseudgpglydgra kempi Pglydgn Hgni Pyggspig elegans

Family Capitellidae HetergmAstus filifgrmis

Family Sabellidae Hanayunkia aestuarina

Phylum Arthropoda Class Crustacea

Subclass Cirripedia Order Thoracica

Family Balanidae Balanus sp

Subclass Malacostraca Superorder Peracaridae

Order Mysidacea Family Mysidae

Ne~sis mergedi Order Cumacea

Family Leuconidae HemHeuggn sp

Order Tanaidacea

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

12

Table 4--(Continued)

Family Tanaidae Pancolus californiensis

Order Isopoda Suborder Flabellifera

Family Sphaeromatidae Gnor~osphaeroma lutea

Suborder Valvifera Family Idoteidae

Saduria entomon Order Amphipoda

Suborder Gammaridea Family Eohaustoriidae

Eohaustorius estuaris Family Gammaridae

Eogammarus oclairi Eogammarus confervicolus

Family Corophiidae Corophium salmonis Corophium spinicorne

Superorder Eucarida Order Decapoda

Suborder Natantia Family Crangonidae

Crangon franciscorum Suborder Reptantia

Family Cancridae Cancer magister

Class Insecta Order Diptera

Family Chironomidae Family Dolichopodidae Family Ephydridae

Phylum Mollusca Class Gastropoda

Order Sacoglossa Class Bivalvia

Order Mytiloida Family Mytilidae

Mytilus edulis Order Veneroida

Family Cardiidae Clinocardium nuttallii

Family Tellinidae Macoma balthica

Order Myoida Family Myidae

Mya arenaria

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

13

10 ElW

11

A Numberm2 10 500 February

amp1 1Ao 13 EHW -E

2 ltgt0 cI Mlta 2 11 1i

8 bull

1I

0 ~ IIULLW

ELW

Ji I poundII I E

a

laquo I I 1 I

1I(I c CD I ~

e co s co 0

i i i i I8 6 ~ UJ t jmiddotif ~~ II

CD~ ~

B Numberm2 August10 IlOO

3 EHW 1amp1 1110

2 2 -E 1

1- U1ta bull3

5 c a 1

bullc bull 2 ~ I MLLW10 bull

I ElW 100 ELW

I I I

~ c i

j II i t 0

1 I I

JQ

t poundI t

11

Ji I(

ti 0

J i 8 is II I J I

I i I I~

~ cf

Figure 3--Tidal elevation distributions (in number~) of macrobenthic invertebrates alonq a transect in Baker Bay Columbia River estuary A) February 1981 and B) August 1981

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

14

J J A s o

B200

150

E CJI

100 l-X Cl

w ~

Iampi 50

o N o J F M A M

MONTH

Mb Macoma balthica

N I Nean hes limni cola

Ebullbullbull Eohauslorius esluaris

HI Hobsonia florida

Oth Others

J J A s o

A 7

6

5

E 4

0

gt Ishy 3 (I)

z w c

2

1

o

NI

Mb

H f Ee

Cs

Pe

Ed

Pk

Oth

N o J

Neanlhes Iimnicola

Macoma belillica

Hobsonia florida

Eohauslorius esluaris

Corophium salmonis

Pygospio eegans

Eleone dilalae

Pseudopolydora kempi

Others

F M A M

shy

Figure 4--Monthly changes (1980-81) in the densities (A) and weights (B) of macrobenthic invertebrates on middle-low sites (Stations 3-10) in Baker Bay Columbia River estuary

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

Mb Macoma ballhiclI

Pk PseudopolYdOra IcempA 5 H I Hobmiddotsonia florida

Hs

Oth 4

-N

E 30 gt

2U)

z III Q

1

o N D J F M A M J J 5 o

B 200

Mb Macoma ballhica

Oth Other

150

shyE lit

100

0 ~

III ~

50

~ ~-0

0 ~

MONTH

15

Figure 5--Monthly chanqes (1980-81) in the densities (A) and weiqhts (B) of macrobenthic invertebrates at a subtidal site (Station 11) in Baker Bay Columbia River estuary

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

16

Table 5--Vertical distributions of benthic animals on a tidal flat in Baker Bay Columbia River estuary in October 1981

Upper intertidal Middle intertidal (Station 3) (Station 7)

Depth (em) below sediment surface 0-10 10-20 0-10 10-20

Turbellaria 9684- (0079)b 4486 (0099) 593 (0040) 00 (0000)

Nemertea 00 (0000) 00 (0000) 395 (0791) 00 (0000)

Eteone dilatae 6521 (2352) 791 (0059) 00 (0000)

Neanthes limnicola 47628 (62925) 593 (0099) 23518 (40988) 593 (1 304)

Hobsonia florida 56719 (1312) 1186 (0356) 33597 (5277) 395 (0138)

Pseudopolvdora kempi 197 (0059) 00 (0000) 395 (0138) 00 (0000)

Polydora ligni 00 (0000) 00 (0000) 198 (+) 00 (0000)

Pygospio elegans 1186 (0020) 00 (0000) 198 (0079) 00 (0000)

Heteromastus filiformis 00 (0000) 00 (0000) 198 (0079) 00 (0000)

Bnorimosphaeroma lutea 198 (0020) 00 (0000) 00 (0000) 00 (0000)

Eohaustorius estuaris 593 (0277) 00 (0000) 691 7 (251) 593 (0138)

Eogammarus oclairi 593 (0059) 197 (+) 00 (0000) 593 (+)

Eoqammarus confervicolus5933 (0099) 988 (+) 3755 (1008) 198 (+)

Eogammarus spp (juveniles) 1384 (0020) 00 (0000) 00 (0000) 00 (0000)

Corophium salmonis 78854 (8834) 8893 (0119) 5138 (0573) 198 (+)

pound spinicorne 5138 (1047) 1186 (0020) 1383 (0040) 00 (0000)

Chironomidae 2372 (0099) 197(+) 00 (0000) 00 (0000)

Macoma balthica 10671 (521818) 198(12964) 9881(203656) 395 (26028)

222331 (599020)18122(13657) 8695~255179) 2965 (27608)TOTAL

bull numberm2

b weight (g) 1m2

c + _ weight less than 0020 9

17

Vertical Distribution Along the Tidal Gradient

The vertical distributions of abundant benthic invertebrates along the

tidal gradient in winter (February 1981) and summer (August 1981) were similar

(Fig 3) suggesting that the distribution patterns did not change throughout

the year In the upper two stations (Stations 1 and 2) insect larvae

(Dolichopodida and Chironomidae) were dominant their distributions were

restricted to this area Most other invertebrates were distributed below this

zone showing a clear zonal separation from the insect larvae especially in

summer Neanthes limnicola and~ florida were also abundant in the upper

tidal zone if tide pools existed This agrees with Lewis (1961) who showed

that physical conditions such as desiccation are important factors

determining the upper limit of intertidal animals on rocky shores

The densities of Pygospio elegans ~ florida and pound sa1monis were low

in the middle tidal zone (Stations 5 through 8) where ripple marks on the

sediment surface indicated that the substrate was relatively unstable In

contrast to polychaetes the amphipod Zohaustorius estuaris was relatively

abundant on this unstable sediment Pseudopolydora kempi was one of the most

important members of the intertidal flat community in Baker Bay (Jones 1984)

and was often abundant from the low tidal zone to the subtidal bottom where

the sediment had a high silt-clay content This suggests that the stability

of the sediment surface plays an important role in determining the species

composition and abundance of intertidal invertebrates

Seasonal Changes

Intertidal Community--Numerically dominant species throughout the year

in the intertidal community were~ limnicola ~ florida ~ estuaris

Macoma balthica and pound salmonis (Fig 4) Peak densities were related to

recruitment and were observed in May for ~ balthica June for~ estuaris

June and August through October for pound sa1monis July for ~ limnicola and

July and October for~ florida These population peaks coincided closely

with peaks found in another Baker Bay intertidal flat with the exception of

M balthica and~ estuaris (Jones 1984) Zohaustorius estuaris was not

present in the other flat where ~ balthica spat settled in late summer or

18

early fall (Jones 1984) The reason for the different seasons of spat

settlement on the two flats is unknown Also of note the decreases in

densities of two spionid polychaetes Pygospio elegans and Pseudopolydora

kempi coincided with the decline of interstitial salinities (Fig 4)

More than 90 of the weight of the intertidal benthic community through

the year consisted of ~ balthica and~ limnicola The community weight of

~ balthica increased during wa~er seasons (spring to fall) even after its

population numbers had decreased in summer This suggests the increase was

related to individual growth

The intertidal community biomass increased gradually during this study

with a max~urn in the final month October 1981 Because observations were

not made during the following winter it is not known whether the community

weight declined to the level observed in the previous winter

Subtidal Community--Macoma balthica was the most numerous species for 8

months from May to October and accounted for the largest portion of the

community biomass throughout the year at the subtidal site (Fig 5) Total

biomass of M balthica increased in late summer and early fall Because there

were increases in both number and individual weights of M balthica at the

subtidal site it is unclear whether the increases in total weight resulted

more from growth or recruitment

At the subtidal station Pseudopolydora kempi was abundant until the

interstitial salinity min~um of 72~ occurred in June The ~ kempi

population recovered in September but dropped again in numbers in October

perhaps due to predation or disturbance of the bottom by crabs and fishes

(Virnstein 1977) The subtidal station is located in a channel known to have

high densities of Dungeness crabs Cancer magister (McCabe et al 1986)

Jones (1984) observed a sharp peak in the density of ~ kempi in a mudflat in

Baker Bay in August 1981 In contrast to ~ kempi densities of ~ florida

increased in June (Fig 5) The cumacean of the genus Hemileucon was

relatively more abundant in winter through spring

19

Effect of Salinity on the Benthic Community

By identifying their preferred habitat invertebrates collected in this

study can be classified into three categories 1) species of unknown salinity

preferences 2) estuarine species or 3) marine species (Banse and Hobson

1974 Sanborn 1975 Smith and Carlton 1975 Higley and Holton 1978 Bousfield

1979) (Table 6) In the intertidal benthic community estuarine species were

dominant throughout the year except for October (Fig 6) Marine species were

an important component from November until June when interstitial salinities

reached a minimum and apparently reduced their numbers Recovery of the

marine species took about 4 months During the recovery period the intertidal

community was composed almost entirely of estuarine species and those with

unknown salinity preferences In October high densities of chironomid larvae

(unknown salinity preferences) at the upper intertidal stations (1 and 2)

contributed almost half of the total community densities (Fig 6)

Marine species were relatively more abundant in the subtidal community

especially during winter and spring before the June salinity decline After

the salinity minimum occurred the population density of marine species

remained low throughout the summer recovering at least temporarily in

September The recovery of the marine species in the subtidal area occurred

earlier than on the intertidal flat This suggests that salinity (average and

minimum) was an important factor affecting the population density of the

marine species at the study area However densities of marine species also

declined in October due primarily to lower densities of ~ kempi With just

one years data it is not possible to determine unequivocally that the

seasonal salinity decline regulated marine species abundances Nevertheless

the dramatic decline in marine species densities after the salinity minimum

strongly suggests a cause-and-effect relationship

Effect of Vegetation on the Benthic Community

Filamentous Algae

Filamentous algae were first observed covering the sediment at the upper

intertidal sites in January They formed dense green mats in May and remained

20

Table 6--List of benthic invertebrates and distributional areas on intertidal-subtidal sediments in the Baker Bay Columbia River estuary (1980-81) Dotted lines show distribution of nominally freshwater species (commonly found in salinity of 00 ppt) estuarine species (commonly found in salinity ranging from 00 to 250 ppt) and marine species (commonly found at salinities greater than 250 ppt) bull

Fresh ------------~ ------------- Brackish Marine --------- ---------- ---------~ ---------shy

Unknown Sa1inity Estuarine Species Karine Species Preferances

Turbellaria Eteone HIJbt1 Eteone d1latae

Nemertea Neanthes l1mn1cola Glycinde polygnatba

Balanus sp Hobsonh flodda Hemipodus borea11s

Cumacea Polydora HIJD1

Chironomidae HemHeucon sp PseudQPolydpra kemp1

Dolichopodidae Neomvs1s mercedis Heteromastus f111fQrm1s

Ephydridae Eobaustorius estuar1s EOlJammarus ocla1r1

Sacoqlossa Eogammarus conferyicQlus Cancer malJ1ster

Corgph1um salmon1s Cl1nocard1um nuttal111

Corgph1um sp1n 1cQrne HYa arenada

GnQrimpspbaergma ~

CranlJQn franciscorum

Macgma baltbiga

MytHus eduHs

21

12

18

16A tntertida1 14

12 8 ~ 10 ~

8 ~10 ~ 5

6 -caE (I) 8

40 ~6 2 ~ 0 middoten 4c C1)

o 2

0 M A M J J A S 0N 0 J F

B Subtida1

7 ~

E 6 o 5 -4~ middoten 3 c ~ 2

1

o N o J F M A M J J A s o

MONTH

_ Unknown salinity praferance species tJ Estuarine species _ Marine special

shy

Figure 6-- Seasonal changes (1980-81) of the macrobenthic invertebrate communities (defined by salinity preferences) and interstitial salinities at intertidal stations (A) and at a subtidal station (B) in Baker Bay Columbia River estuary Salinity means and ranges for intertidal stations represented by points within capped vertical lines

22

until at least October Insect larvae (Chironomidae and Dolichopodidae) and

the sabellid polychaete Manayunkia aestuarina were abundarit with the

occurrence of the agal mat However the agal filaments reduced the effective

size of the sieving screen and without the agal mat a considerable number of

these invertebrates could have passed through the 0595 mm screen It is

unclear whether the presence of the algal mat provided habitat for the insect

larvae and the sabellid polychaete

A sacoglossan gastropod occurred with the filamentous algae starting in

August and showed a maximum density of 1680m2 in October This gastropod

feeds on algae and stores their chloroplasts in its cerata Some Sacoglossa

feed on the chrysophyte Vaucheria (Smith and Carlton 1975) one of the major

components of the filamentous algal mat suggesting that the algal mat

provides habitat and food for this gastropod

Lewis (1961) suggested that the upper distribution limit of intertidal

animals is determined by their physiological tolerance to desiccation

Despite the capillary effect of the algae filaments which prevents

desiccation of the sediment surface the abundance of most benthic animals

except insects was lower in the algal mat zone in late summer (Table 7) The

filamentous algal mat may under certain conditions eliminate some of the

invertebrates that live below the sediment surface perhaps by preventing

feeding activity or reducing dissolved oxygen The presence of a shallow tide

pool at Station 2 apparently elevated the upper limits of some intertidal

animals (Table 8)

Eelgrasses

The eelgrasses Zostera japoniga and Z marina formed patchy beds on the

tidal flat during the summer Eelgrass beds increase sediment stability

resulting in high infaunal diversity and density (Orth 1977) but the rhizomes

of Zostera spp physically hinder the movement of burrowing organisms (Ringold

1979) The amphipods Eogammarus gonferyigolus and CorQphium spinigorne tended

to be more abundant at stations with eelgrasses (Table 9) suggesting that

eelgras~ provides substratum for these epiphytic amphipods The polychaetes

23

Table 7--The mean number of benthic invertebrates per r at two upper intertidal stations (Stations 1 and 2) in Baker Bay Columbia River estuary during February (no sgal mat) and August (with agal mat) 1981

February August

(No agal mat) (With agal mat)

Stations 1 2 1 2

Species Mean

nuinberm2

Mean number 1m2

Mean number1m2

Mean number1m2

Turbellaria 00 00 00 198

Polychaeta itllS2nll d11iltilll Hllilnthlla UIIID1cglil eglXddegZiI 11gn1 exggag1g 1I1DQilna Hgbsgn1i1 flgdda

461 66 00 00

132

2305 5402

66 9552 5995

00 00 00 00 00

00 922 00 00 00

Crustacea Gngz1mgaghilllzoma lutllil ighiluatsaz1ua 118tLlilz1a ijgAIIImA zua gCbid ijgQilrntIUl ZLla cgnfllcz1cglLla Cgzggh1um ulmgn1s Cgzggh1um sg1n1cgznll

132 329 00 00 00 00

132 1713

659 5402

33137 132

00 00 00 00 00 00 00 00 00 00 00 00

Insecta Dolichopodidae Chironomidae

1120 922

725 51186

264 7971 725 158432

Bivalvia MaCcmJil billth1ca 00 264 00 00

Gastropoda Sacogloaaa 00 00 00 395

Total 3162 116670 989 16791 8

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

18

early fall (Jones 1984) The reason for the different seasons of spat

settlement on the two flats is unknown Also of note the decreases in

densities of two spionid polychaetes Pygospio elegans and Pseudopolydora

kempi coincided with the decline of interstitial salinities (Fig 4)

More than 90 of the weight of the intertidal benthic community through

the year consisted of ~ balthica and~ limnicola The community weight of

~ balthica increased during wa~er seasons (spring to fall) even after its

population numbers had decreased in summer This suggests the increase was

related to individual growth

The intertidal community biomass increased gradually during this study

with a max~urn in the final month October 1981 Because observations were

not made during the following winter it is not known whether the community

weight declined to the level observed in the previous winter

Subtidal Community--Macoma balthica was the most numerous species for 8

months from May to October and accounted for the largest portion of the

community biomass throughout the year at the subtidal site (Fig 5) Total

biomass of M balthica increased in late summer and early fall Because there

were increases in both number and individual weights of M balthica at the

subtidal site it is unclear whether the increases in total weight resulted

more from growth or recruitment

At the subtidal station Pseudopolydora kempi was abundant until the

interstitial salinity min~um of 72~ occurred in June The ~ kempi

population recovered in September but dropped again in numbers in October

perhaps due to predation or disturbance of the bottom by crabs and fishes

(Virnstein 1977) The subtidal station is located in a channel known to have

high densities of Dungeness crabs Cancer magister (McCabe et al 1986)

Jones (1984) observed a sharp peak in the density of ~ kempi in a mudflat in

Baker Bay in August 1981 In contrast to ~ kempi densities of ~ florida

increased in June (Fig 5) The cumacean of the genus Hemileucon was

relatively more abundant in winter through spring

19

Effect of Salinity on the Benthic Community

By identifying their preferred habitat invertebrates collected in this

study can be classified into three categories 1) species of unknown salinity

preferences 2) estuarine species or 3) marine species (Banse and Hobson

1974 Sanborn 1975 Smith and Carlton 1975 Higley and Holton 1978 Bousfield

1979) (Table 6) In the intertidal benthic community estuarine species were

dominant throughout the year except for October (Fig 6) Marine species were

an important component from November until June when interstitial salinities

reached a minimum and apparently reduced their numbers Recovery of the

marine species took about 4 months During the recovery period the intertidal

community was composed almost entirely of estuarine species and those with

unknown salinity preferences In October high densities of chironomid larvae

(unknown salinity preferences) at the upper intertidal stations (1 and 2)

contributed almost half of the total community densities (Fig 6)

Marine species were relatively more abundant in the subtidal community

especially during winter and spring before the June salinity decline After

the salinity minimum occurred the population density of marine species

remained low throughout the summer recovering at least temporarily in

September The recovery of the marine species in the subtidal area occurred

earlier than on the intertidal flat This suggests that salinity (average and

minimum) was an important factor affecting the population density of the

marine species at the study area However densities of marine species also

declined in October due primarily to lower densities of ~ kempi With just

one years data it is not possible to determine unequivocally that the

seasonal salinity decline regulated marine species abundances Nevertheless

the dramatic decline in marine species densities after the salinity minimum

strongly suggests a cause-and-effect relationship

Effect of Vegetation on the Benthic Community

Filamentous Algae

Filamentous algae were first observed covering the sediment at the upper

intertidal sites in January They formed dense green mats in May and remained

20

Table 6--List of benthic invertebrates and distributional areas on intertidal-subtidal sediments in the Baker Bay Columbia River estuary (1980-81) Dotted lines show distribution of nominally freshwater species (commonly found in salinity of 00 ppt) estuarine species (commonly found in salinity ranging from 00 to 250 ppt) and marine species (commonly found at salinities greater than 250 ppt) bull

Fresh ------------~ ------------- Brackish Marine --------- ---------- ---------~ ---------shy

Unknown Sa1inity Estuarine Species Karine Species Preferances

Turbellaria Eteone HIJbt1 Eteone d1latae

Nemertea Neanthes l1mn1cola Glycinde polygnatba

Balanus sp Hobsonh flodda Hemipodus borea11s

Cumacea Polydora HIJD1

Chironomidae HemHeucon sp PseudQPolydpra kemp1

Dolichopodidae Neomvs1s mercedis Heteromastus f111fQrm1s

Ephydridae Eobaustorius estuar1s EOlJammarus ocla1r1

Sacoqlossa Eogammarus conferyicQlus Cancer malJ1ster

Corgph1um salmon1s Cl1nocard1um nuttal111

Corgph1um sp1n 1cQrne HYa arenada

GnQrimpspbaergma ~

CranlJQn franciscorum

Macgma baltbiga

MytHus eduHs

21

12

18

16A tntertida1 14

12 8 ~ 10 ~

8 ~10 ~ 5

6 -caE (I) 8

40 ~6 2 ~ 0 middoten 4c C1)

o 2

0 M A M J J A S 0N 0 J F

B Subtida1

7 ~

E 6 o 5 -4~ middoten 3 c ~ 2

1

o N o J F M A M J J A s o

MONTH

_ Unknown salinity praferance species tJ Estuarine species _ Marine special

shy

Figure 6-- Seasonal changes (1980-81) of the macrobenthic invertebrate communities (defined by salinity preferences) and interstitial salinities at intertidal stations (A) and at a subtidal station (B) in Baker Bay Columbia River estuary Salinity means and ranges for intertidal stations represented by points within capped vertical lines

22

until at least October Insect larvae (Chironomidae and Dolichopodidae) and

the sabellid polychaete Manayunkia aestuarina were abundarit with the

occurrence of the agal mat However the agal filaments reduced the effective

size of the sieving screen and without the agal mat a considerable number of

these invertebrates could have passed through the 0595 mm screen It is

unclear whether the presence of the algal mat provided habitat for the insect

larvae and the sabellid polychaete

A sacoglossan gastropod occurred with the filamentous algae starting in

August and showed a maximum density of 1680m2 in October This gastropod

feeds on algae and stores their chloroplasts in its cerata Some Sacoglossa

feed on the chrysophyte Vaucheria (Smith and Carlton 1975) one of the major

components of the filamentous algal mat suggesting that the algal mat

provides habitat and food for this gastropod

Lewis (1961) suggested that the upper distribution limit of intertidal

animals is determined by their physiological tolerance to desiccation

Despite the capillary effect of the algae filaments which prevents

desiccation of the sediment surface the abundance of most benthic animals

except insects was lower in the algal mat zone in late summer (Table 7) The

filamentous algal mat may under certain conditions eliminate some of the

invertebrates that live below the sediment surface perhaps by preventing

feeding activity or reducing dissolved oxygen The presence of a shallow tide

pool at Station 2 apparently elevated the upper limits of some intertidal

animals (Table 8)

Eelgrasses

The eelgrasses Zostera japoniga and Z marina formed patchy beds on the

tidal flat during the summer Eelgrass beds increase sediment stability

resulting in high infaunal diversity and density (Orth 1977) but the rhizomes

of Zostera spp physically hinder the movement of burrowing organisms (Ringold

1979) The amphipods Eogammarus gonferyigolus and CorQphium spinigorne tended

to be more abundant at stations with eelgrasses (Table 9) suggesting that

eelgras~ provides substratum for these epiphytic amphipods The polychaetes

23

Table 7--The mean number of benthic invertebrates per r at two upper intertidal stations (Stations 1 and 2) in Baker Bay Columbia River estuary during February (no sgal mat) and August (with agal mat) 1981

February August

(No agal mat) (With agal mat)

Stations 1 2 1 2

Species Mean

nuinberm2

Mean number 1m2

Mean number1m2

Mean number1m2

Turbellaria 00 00 00 198

Polychaeta itllS2nll d11iltilll Hllilnthlla UIIID1cglil eglXddegZiI 11gn1 exggag1g 1I1DQilna Hgbsgn1i1 flgdda

461 66 00 00

132

2305 5402

66 9552 5995

00 00 00 00 00

00 922 00 00 00

Crustacea Gngz1mgaghilllzoma lutllil ighiluatsaz1ua 118tLlilz1a ijgAIIImA zua gCbid ijgQilrntIUl ZLla cgnfllcz1cglLla Cgzggh1um ulmgn1s Cgzggh1um sg1n1cgznll

132 329 00 00 00 00

132 1713

659 5402

33137 132

00 00 00 00 00 00 00 00 00 00 00 00

Insecta Dolichopodidae Chironomidae

1120 922

725 51186

264 7971 725 158432

Bivalvia MaCcmJil billth1ca 00 264 00 00

Gastropoda Sacogloaaa 00 00 00 395

Total 3162 116670 989 16791 8

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

19

Effect of Salinity on the Benthic Community

By identifying their preferred habitat invertebrates collected in this

study can be classified into three categories 1) species of unknown salinity

preferences 2) estuarine species or 3) marine species (Banse and Hobson

1974 Sanborn 1975 Smith and Carlton 1975 Higley and Holton 1978 Bousfield

1979) (Table 6) In the intertidal benthic community estuarine species were

dominant throughout the year except for October (Fig 6) Marine species were

an important component from November until June when interstitial salinities

reached a minimum and apparently reduced their numbers Recovery of the

marine species took about 4 months During the recovery period the intertidal

community was composed almost entirely of estuarine species and those with

unknown salinity preferences In October high densities of chironomid larvae

(unknown salinity preferences) at the upper intertidal stations (1 and 2)

contributed almost half of the total community densities (Fig 6)

Marine species were relatively more abundant in the subtidal community

especially during winter and spring before the June salinity decline After

the salinity minimum occurred the population density of marine species

remained low throughout the summer recovering at least temporarily in

September The recovery of the marine species in the subtidal area occurred

earlier than on the intertidal flat This suggests that salinity (average and

minimum) was an important factor affecting the population density of the

marine species at the study area However densities of marine species also

declined in October due primarily to lower densities of ~ kempi With just

one years data it is not possible to determine unequivocally that the

seasonal salinity decline regulated marine species abundances Nevertheless

the dramatic decline in marine species densities after the salinity minimum

strongly suggests a cause-and-effect relationship

Effect of Vegetation on the Benthic Community

Filamentous Algae

Filamentous algae were first observed covering the sediment at the upper

intertidal sites in January They formed dense green mats in May and remained

20

Table 6--List of benthic invertebrates and distributional areas on intertidal-subtidal sediments in the Baker Bay Columbia River estuary (1980-81) Dotted lines show distribution of nominally freshwater species (commonly found in salinity of 00 ppt) estuarine species (commonly found in salinity ranging from 00 to 250 ppt) and marine species (commonly found at salinities greater than 250 ppt) bull

Fresh ------------~ ------------- Brackish Marine --------- ---------- ---------~ ---------shy

Unknown Sa1inity Estuarine Species Karine Species Preferances

Turbellaria Eteone HIJbt1 Eteone d1latae

Nemertea Neanthes l1mn1cola Glycinde polygnatba

Balanus sp Hobsonh flodda Hemipodus borea11s

Cumacea Polydora HIJD1

Chironomidae HemHeucon sp PseudQPolydpra kemp1

Dolichopodidae Neomvs1s mercedis Heteromastus f111fQrm1s

Ephydridae Eobaustorius estuar1s EOlJammarus ocla1r1

Sacoqlossa Eogammarus conferyicQlus Cancer malJ1ster

Corgph1um salmon1s Cl1nocard1um nuttal111

Corgph1um sp1n 1cQrne HYa arenada

GnQrimpspbaergma ~

CranlJQn franciscorum

Macgma baltbiga

MytHus eduHs

21

12

18

16A tntertida1 14

12 8 ~ 10 ~

8 ~10 ~ 5

6 -caE (I) 8

40 ~6 2 ~ 0 middoten 4c C1)

o 2

0 M A M J J A S 0N 0 J F

B Subtida1

7 ~

E 6 o 5 -4~ middoten 3 c ~ 2

1

o N o J F M A M J J A s o

MONTH

_ Unknown salinity praferance species tJ Estuarine species _ Marine special

shy

Figure 6-- Seasonal changes (1980-81) of the macrobenthic invertebrate communities (defined by salinity preferences) and interstitial salinities at intertidal stations (A) and at a subtidal station (B) in Baker Bay Columbia River estuary Salinity means and ranges for intertidal stations represented by points within capped vertical lines

22

until at least October Insect larvae (Chironomidae and Dolichopodidae) and

the sabellid polychaete Manayunkia aestuarina were abundarit with the

occurrence of the agal mat However the agal filaments reduced the effective

size of the sieving screen and without the agal mat a considerable number of

these invertebrates could have passed through the 0595 mm screen It is

unclear whether the presence of the algal mat provided habitat for the insect

larvae and the sabellid polychaete

A sacoglossan gastropod occurred with the filamentous algae starting in

August and showed a maximum density of 1680m2 in October This gastropod

feeds on algae and stores their chloroplasts in its cerata Some Sacoglossa

feed on the chrysophyte Vaucheria (Smith and Carlton 1975) one of the major

components of the filamentous algal mat suggesting that the algal mat

provides habitat and food for this gastropod

Lewis (1961) suggested that the upper distribution limit of intertidal

animals is determined by their physiological tolerance to desiccation

Despite the capillary effect of the algae filaments which prevents

desiccation of the sediment surface the abundance of most benthic animals

except insects was lower in the algal mat zone in late summer (Table 7) The

filamentous algal mat may under certain conditions eliminate some of the

invertebrates that live below the sediment surface perhaps by preventing

feeding activity or reducing dissolved oxygen The presence of a shallow tide

pool at Station 2 apparently elevated the upper limits of some intertidal

animals (Table 8)

Eelgrasses

The eelgrasses Zostera japoniga and Z marina formed patchy beds on the

tidal flat during the summer Eelgrass beds increase sediment stability

resulting in high infaunal diversity and density (Orth 1977) but the rhizomes

of Zostera spp physically hinder the movement of burrowing organisms (Ringold

1979) The amphipods Eogammarus gonferyigolus and CorQphium spinigorne tended

to be more abundant at stations with eelgrasses (Table 9) suggesting that

eelgras~ provides substratum for these epiphytic amphipods The polychaetes

23

Table 7--The mean number of benthic invertebrates per r at two upper intertidal stations (Stations 1 and 2) in Baker Bay Columbia River estuary during February (no sgal mat) and August (with agal mat) 1981

February August

(No agal mat) (With agal mat)

Stations 1 2 1 2

Species Mean

nuinberm2

Mean number 1m2

Mean number1m2

Mean number1m2

Turbellaria 00 00 00 198

Polychaeta itllS2nll d11iltilll Hllilnthlla UIIID1cglil eglXddegZiI 11gn1 exggag1g 1I1DQilna Hgbsgn1i1 flgdda

461 66 00 00

132

2305 5402

66 9552 5995

00 00 00 00 00

00 922 00 00 00

Crustacea Gngz1mgaghilllzoma lutllil ighiluatsaz1ua 118tLlilz1a ijgAIIImA zua gCbid ijgQilrntIUl ZLla cgnfllcz1cglLla Cgzggh1um ulmgn1s Cgzggh1um sg1n1cgznll

132 329 00 00 00 00

132 1713

659 5402

33137 132

00 00 00 00 00 00 00 00 00 00 00 00

Insecta Dolichopodidae Chironomidae

1120 922

725 51186

264 7971 725 158432

Bivalvia MaCcmJil billth1ca 00 264 00 00

Gastropoda Sacogloaaa 00 00 00 395

Total 3162 116670 989 16791 8

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

20

Table 6--List of benthic invertebrates and distributional areas on intertidal-subtidal sediments in the Baker Bay Columbia River estuary (1980-81) Dotted lines show distribution of nominally freshwater species (commonly found in salinity of 00 ppt) estuarine species (commonly found in salinity ranging from 00 to 250 ppt) and marine species (commonly found at salinities greater than 250 ppt) bull

Fresh ------------~ ------------- Brackish Marine --------- ---------- ---------~ ---------shy

Unknown Sa1inity Estuarine Species Karine Species Preferances

Turbellaria Eteone HIJbt1 Eteone d1latae

Nemertea Neanthes l1mn1cola Glycinde polygnatba

Balanus sp Hobsonh flodda Hemipodus borea11s

Cumacea Polydora HIJD1

Chironomidae HemHeucon sp PseudQPolydpra kemp1

Dolichopodidae Neomvs1s mercedis Heteromastus f111fQrm1s

Ephydridae Eobaustorius estuar1s EOlJammarus ocla1r1

Sacoqlossa Eogammarus conferyicQlus Cancer malJ1ster

Corgph1um salmon1s Cl1nocard1um nuttal111

Corgph1um sp1n 1cQrne HYa arenada

GnQrimpspbaergma ~

CranlJQn franciscorum

Macgma baltbiga

MytHus eduHs

21

12

18

16A tntertida1 14

12 8 ~ 10 ~

8 ~10 ~ 5

6 -caE (I) 8

40 ~6 2 ~ 0 middoten 4c C1)

o 2

0 M A M J J A S 0N 0 J F

B Subtida1

7 ~

E 6 o 5 -4~ middoten 3 c ~ 2

1

o N o J F M A M J J A s o

MONTH

_ Unknown salinity praferance species tJ Estuarine species _ Marine special

shy

Figure 6-- Seasonal changes (1980-81) of the macrobenthic invertebrate communities (defined by salinity preferences) and interstitial salinities at intertidal stations (A) and at a subtidal station (B) in Baker Bay Columbia River estuary Salinity means and ranges for intertidal stations represented by points within capped vertical lines

22

until at least October Insect larvae (Chironomidae and Dolichopodidae) and

the sabellid polychaete Manayunkia aestuarina were abundarit with the

occurrence of the agal mat However the agal filaments reduced the effective

size of the sieving screen and without the agal mat a considerable number of

these invertebrates could have passed through the 0595 mm screen It is

unclear whether the presence of the algal mat provided habitat for the insect

larvae and the sabellid polychaete

A sacoglossan gastropod occurred with the filamentous algae starting in

August and showed a maximum density of 1680m2 in October This gastropod

feeds on algae and stores their chloroplasts in its cerata Some Sacoglossa

feed on the chrysophyte Vaucheria (Smith and Carlton 1975) one of the major

components of the filamentous algal mat suggesting that the algal mat

provides habitat and food for this gastropod

Lewis (1961) suggested that the upper distribution limit of intertidal

animals is determined by their physiological tolerance to desiccation

Despite the capillary effect of the algae filaments which prevents

desiccation of the sediment surface the abundance of most benthic animals

except insects was lower in the algal mat zone in late summer (Table 7) The

filamentous algal mat may under certain conditions eliminate some of the

invertebrates that live below the sediment surface perhaps by preventing

feeding activity or reducing dissolved oxygen The presence of a shallow tide

pool at Station 2 apparently elevated the upper limits of some intertidal

animals (Table 8)

Eelgrasses

The eelgrasses Zostera japoniga and Z marina formed patchy beds on the

tidal flat during the summer Eelgrass beds increase sediment stability

resulting in high infaunal diversity and density (Orth 1977) but the rhizomes

of Zostera spp physically hinder the movement of burrowing organisms (Ringold

1979) The amphipods Eogammarus gonferyigolus and CorQphium spinigorne tended

to be more abundant at stations with eelgrasses (Table 9) suggesting that

eelgras~ provides substratum for these epiphytic amphipods The polychaetes

23

Table 7--The mean number of benthic invertebrates per r at two upper intertidal stations (Stations 1 and 2) in Baker Bay Columbia River estuary during February (no sgal mat) and August (with agal mat) 1981

February August

(No agal mat) (With agal mat)

Stations 1 2 1 2

Species Mean

nuinberm2

Mean number 1m2

Mean number1m2

Mean number1m2

Turbellaria 00 00 00 198

Polychaeta itllS2nll d11iltilll Hllilnthlla UIIID1cglil eglXddegZiI 11gn1 exggag1g 1I1DQilna Hgbsgn1i1 flgdda

461 66 00 00

132

2305 5402

66 9552 5995

00 00 00 00 00

00 922 00 00 00

Crustacea Gngz1mgaghilllzoma lutllil ighiluatsaz1ua 118tLlilz1a ijgAIIImA zua gCbid ijgQilrntIUl ZLla cgnfllcz1cglLla Cgzggh1um ulmgn1s Cgzggh1um sg1n1cgznll

132 329 00 00 00 00

132 1713

659 5402

33137 132

00 00 00 00 00 00 00 00 00 00 00 00

Insecta Dolichopodidae Chironomidae

1120 922

725 51186

264 7971 725 158432

Bivalvia MaCcmJil billth1ca 00 264 00 00

Gastropoda Sacogloaaa 00 00 00 395

Total 3162 116670 989 16791 8

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

21

12

18

16A tntertida1 14

12 8 ~ 10 ~

8 ~10 ~ 5

6 -caE (I) 8

40 ~6 2 ~ 0 middoten 4c C1)

o 2

0 M A M J J A S 0N 0 J F

B Subtida1

7 ~

E 6 o 5 -4~ middoten 3 c ~ 2

1

o N o J F M A M J J A s o

MONTH

_ Unknown salinity praferance species tJ Estuarine species _ Marine special

shy

Figure 6-- Seasonal changes (1980-81) of the macrobenthic invertebrate communities (defined by salinity preferences) and interstitial salinities at intertidal stations (A) and at a subtidal station (B) in Baker Bay Columbia River estuary Salinity means and ranges for intertidal stations represented by points within capped vertical lines

22

until at least October Insect larvae (Chironomidae and Dolichopodidae) and

the sabellid polychaete Manayunkia aestuarina were abundarit with the

occurrence of the agal mat However the agal filaments reduced the effective

size of the sieving screen and without the agal mat a considerable number of

these invertebrates could have passed through the 0595 mm screen It is

unclear whether the presence of the algal mat provided habitat for the insect

larvae and the sabellid polychaete

A sacoglossan gastropod occurred with the filamentous algae starting in

August and showed a maximum density of 1680m2 in October This gastropod

feeds on algae and stores their chloroplasts in its cerata Some Sacoglossa

feed on the chrysophyte Vaucheria (Smith and Carlton 1975) one of the major

components of the filamentous algal mat suggesting that the algal mat

provides habitat and food for this gastropod

Lewis (1961) suggested that the upper distribution limit of intertidal

animals is determined by their physiological tolerance to desiccation

Despite the capillary effect of the algae filaments which prevents

desiccation of the sediment surface the abundance of most benthic animals

except insects was lower in the algal mat zone in late summer (Table 7) The

filamentous algal mat may under certain conditions eliminate some of the

invertebrates that live below the sediment surface perhaps by preventing

feeding activity or reducing dissolved oxygen The presence of a shallow tide

pool at Station 2 apparently elevated the upper limits of some intertidal

animals (Table 8)

Eelgrasses

The eelgrasses Zostera japoniga and Z marina formed patchy beds on the

tidal flat during the summer Eelgrass beds increase sediment stability

resulting in high infaunal diversity and density (Orth 1977) but the rhizomes

of Zostera spp physically hinder the movement of burrowing organisms (Ringold

1979) The amphipods Eogammarus gonferyigolus and CorQphium spinigorne tended

to be more abundant at stations with eelgrasses (Table 9) suggesting that

eelgras~ provides substratum for these epiphytic amphipods The polychaetes

23

Table 7--The mean number of benthic invertebrates per r at two upper intertidal stations (Stations 1 and 2) in Baker Bay Columbia River estuary during February (no sgal mat) and August (with agal mat) 1981

February August

(No agal mat) (With agal mat)

Stations 1 2 1 2

Species Mean

nuinberm2

Mean number 1m2

Mean number1m2

Mean number1m2

Turbellaria 00 00 00 198

Polychaeta itllS2nll d11iltilll Hllilnthlla UIIID1cglil eglXddegZiI 11gn1 exggag1g 1I1DQilna Hgbsgn1i1 flgdda

461 66 00 00

132

2305 5402

66 9552 5995

00 00 00 00 00

00 922 00 00 00

Crustacea Gngz1mgaghilllzoma lutllil ighiluatsaz1ua 118tLlilz1a ijgAIIImA zua gCbid ijgQilrntIUl ZLla cgnfllcz1cglLla Cgzggh1um ulmgn1s Cgzggh1um sg1n1cgznll

132 329 00 00 00 00

132 1713

659 5402

33137 132

00 00 00 00 00 00 00 00 00 00 00 00

Insecta Dolichopodidae Chironomidae

1120 922

725 51186

264 7971 725 158432

Bivalvia MaCcmJil billth1ca 00 264 00 00

Gastropoda Sacogloaaa 00 00 00 395

Total 3162 116670 989 16791 8

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

22

until at least October Insect larvae (Chironomidae and Dolichopodidae) and

the sabellid polychaete Manayunkia aestuarina were abundarit with the

occurrence of the agal mat However the agal filaments reduced the effective

size of the sieving screen and without the agal mat a considerable number of

these invertebrates could have passed through the 0595 mm screen It is

unclear whether the presence of the algal mat provided habitat for the insect

larvae and the sabellid polychaete

A sacoglossan gastropod occurred with the filamentous algae starting in

August and showed a maximum density of 1680m2 in October This gastropod

feeds on algae and stores their chloroplasts in its cerata Some Sacoglossa

feed on the chrysophyte Vaucheria (Smith and Carlton 1975) one of the major

components of the filamentous algal mat suggesting that the algal mat

provides habitat and food for this gastropod

Lewis (1961) suggested that the upper distribution limit of intertidal

animals is determined by their physiological tolerance to desiccation

Despite the capillary effect of the algae filaments which prevents

desiccation of the sediment surface the abundance of most benthic animals

except insects was lower in the algal mat zone in late summer (Table 7) The

filamentous algal mat may under certain conditions eliminate some of the

invertebrates that live below the sediment surface perhaps by preventing

feeding activity or reducing dissolved oxygen The presence of a shallow tide

pool at Station 2 apparently elevated the upper limits of some intertidal

animals (Table 8)

Eelgrasses

The eelgrasses Zostera japoniga and Z marina formed patchy beds on the

tidal flat during the summer Eelgrass beds increase sediment stability

resulting in high infaunal diversity and density (Orth 1977) but the rhizomes

of Zostera spp physically hinder the movement of burrowing organisms (Ringold

1979) The amphipods Eogammarus gonferyigolus and CorQphium spinigorne tended

to be more abundant at stations with eelgrasses (Table 9) suggesting that

eelgras~ provides substratum for these epiphytic amphipods The polychaetes

23

Table 7--The mean number of benthic invertebrates per r at two upper intertidal stations (Stations 1 and 2) in Baker Bay Columbia River estuary during February (no sgal mat) and August (with agal mat) 1981

February August

(No agal mat) (With agal mat)

Stations 1 2 1 2

Species Mean

nuinberm2

Mean number 1m2

Mean number1m2

Mean number1m2

Turbellaria 00 00 00 198

Polychaeta itllS2nll d11iltilll Hllilnthlla UIIID1cglil eglXddegZiI 11gn1 exggag1g 1I1DQilna Hgbsgn1i1 flgdda

461 66 00 00

132

2305 5402

66 9552 5995

00 00 00 00 00

00 922 00 00 00

Crustacea Gngz1mgaghilllzoma lutllil ighiluatsaz1ua 118tLlilz1a ijgAIIImA zua gCbid ijgQilrntIUl ZLla cgnfllcz1cglLla Cgzggh1um ulmgn1s Cgzggh1um sg1n1cgznll

132 329 00 00 00 00

132 1713

659 5402

33137 132

00 00 00 00 00 00 00 00 00 00 00 00

Insecta Dolichopodidae Chironomidae

1120 922

725 51186

264 7971 725 158432

Bivalvia MaCcmJil billth1ca 00 264 00 00

Gastropoda Sacogloaaa 00 00 00 395

Total 3162 116670 989 16791 8

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

23

Table 7--The mean number of benthic invertebrates per r at two upper intertidal stations (Stations 1 and 2) in Baker Bay Columbia River estuary during February (no sgal mat) and August (with agal mat) 1981

February August

(No agal mat) (With agal mat)

Stations 1 2 1 2

Species Mean

nuinberm2

Mean number 1m2

Mean number1m2

Mean number1m2

Turbellaria 00 00 00 198

Polychaeta itllS2nll d11iltilll Hllilnthlla UIIID1cglil eglXddegZiI 11gn1 exggag1g 1I1DQilna Hgbsgn1i1 flgdda

461 66 00 00

132

2305 5402

66 9552 5995

00 00 00 00 00

00 922 00 00 00

Crustacea Gngz1mgaghilllzoma lutllil ighiluatsaz1ua 118tLlilz1a ijgAIIImA zua gCbid ijgQilrntIUl ZLla cgnfllcz1cglLla Cgzggh1um ulmgn1s Cgzggh1um sg1n1cgznll

132 329 00 00 00 00

132 1713

659 5402

33137 132

00 00 00 00 00 00 00 00 00 00 00 00

Insecta Dolichopodidae Chironomidae

1120 922

725 51186

264 7971 725 158432

Bivalvia MaCcmJil billth1ca 00 264 00 00

Gastropoda Sacogloaaa 00 00 00 395

Total 3162 116670 989 16791 8

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

24

Table 8--Influence of a tide pool and agal mat on the abundance of intertidal invertebrates at a high intertidal flat (Station 2) in Baker Bay Columbia River estuary september 1981

Abundance

Numberm2

Inside tide pool OUtside tide pool Inside tide pool Taxon covered by agal mat covered by agal mat no agal mat

Turbellaria 395 00 1186

Neanthes limnicola 4791 00 22727

Pygospio elegans 00 00 198

Hobsonia florida 593 00 26877

Corophiwn salmonis 395 00 593

Chironomidae 181028 326285 18577

Dolichopodidae 10672 1976 593

Ephydridae 14427 33597 00

Sacoglossa 2372 198 00

MaCQma baltb1cA 00 00 988

Total 214673 362056 71739

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

25

Table 9--The abundance of major macrobenthic invertebrate species on a tidal flat with and without eelgrass in Baker Bay Columbia River estuary August 1981

Species Eel-

grass 3 4 Sta5

tion 6 7 8

Neanthes limnicola No Yes

90middot 104b

45 94

44 101

31 95

61 86

41 32

Hobsonia florida No Yes

333 347

14 88

5 163

7 15

13 22

40 61

Eogammarus confervicolus No Yes

2 18

1 2

0 16

0 3

0 9

0 0

Coroehium salmonis No Yes

123 115

7 4

6 43

3 2

6 8

12 17

Coroehium seinicorne No Yes

1 6

0 0

0 35

0 3

0 5

0 1

Eohaustorius estuaris No Yes

6 0

110 62

63 30

136 17

15 18

11 16

Macoma balthica No Yes

26 36

34 36

20 29

21 28

22 26

20 29

TotalC No Yes

620 677

217 291

176 479

198 166

118 177

125 159

bull Mean number contained in two 506 cm2 samples (Samples A and B See Appendix Table) bull

b Number contained in one 506 ~ sample (Sample C) C Includes all species collected Significant difference Mann-Whitney P lt 005

Highly significant difference Chi-squareP lt 0001

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

26

lie limnicola and~ florida were more abundant in eelgrass beds than outside

the beds between Stations 4 and 6 The positive effect of Zostera spp beds

on these surface-feeding polychaetes is probably related to increased sediment

stability However the gammarid amphipod Eohaustorius estuaris which

prefers unstable sediment (Bosworth 1973) was less abundant on the zostera

sppbeds

CONCLUSIONS

The macrobenthic community structure in a fine-sand tidal flat and

adjacent muddy subtidal site in Baker Bay showed few seasonal changes in

species composition The intertidal community consisted mainly of estuarine

species such as ~ balthica lie limnicola pound sa~onis ~ florida and~

estuaris which were abundant throughout the year Marine species such as ~

kempi tended to increase in population densities from the intertidal to

subtidal sites and declined in abundance after the June salinity minimum

This indicates that a seasonal reduction in salinity is probably an important

factor maintaining the community structure of an estuarine-species dominated

intertidal-subtidal benthos This reduction was caused by the large spring

freshet of the Columbia River

Two zones of benthic invertebrate communities were observed in the tidal

flat The first was an high upper tidal zone (Stations 1 and 2) dominated by

insect larvae (Chironomidae and Dolichopodidae) A filamentous algal mat

covered the sediment surface here during summer The second zone was the

middle-lower tidal zone Here the surface deposit feeders such as ~

balthica lie limnicola and~ florida were abundant on the relatively stable

sediments of the lower tidal areas and on eelgrass beds in the middle tidal

level The sand-dwelling amphipod~ estuaris was abundant in the unstable

sediments of this middle tidal level

At the subtidal site ~ balthica was the dominant species while

~ kempi was more abundant here than at the other sites The reduced

densities of estuarine species in the subtidal site may be related to

salinity sediment texture and perhaps intense fish or crab predation

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

27

Our results suggest that one of the most important factors determining

the macrobenthic animal community structure in the Columbia~River estuary is

salinity A1so increased sediment stability and Zostera spp have a positive

effect on densities of deposit feeders and a negative effect on the densities

of ~ estuaris

ACKNOWLEDGMENTS

We would like to give special thanks to Bill Muir for his help in

sampling and George McCabe Jr for his review of this paper

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

29

CITATIONS

Banse K and K D Hobson 1974 Benthic errantiate polychaetes of

British Columbia and Washington Fish Res Board Can Bull No 185

111 p

Boesh D F 1977 A new look at the distribution of benthos along the

estuarine gradient In B C Coull (editor) Ecology of marine benthos

p 245-266 Univ South Carolina Press Columbia SC

Bosworth W S 1973 Three new species of Eohaustorius (Amphipoda

Haustoriidae) from the Oregon coast Crustae 25(3) 253-260

Bousfield E L 1979 The amphipod superfamily Gammaroidea in the

northeastern Pacific region systematics and distributional ecology

Bull Biol Soc Wash 3297-357

Brady F 1943 The distribution of the fauna of some intertidal sands

and muds on the Northumberland coast J Anim Eco1 12 27-41

Durkin J T T C Coley It Verner andR L Bmmett 1981 Anaquatic

species evaluation at rour selr scouring sites in the Columbia River

estuary Report to US Army Corps of Engineers contract DACW57-79-Fshy

0145 46 p Available Northwest Fish Sci Cent 2725 Mont1ake Blvd

E Seattle WA 98112

Durkin J T and R L Emmett 1980 Benthic invertebrates water quality

and substrate texture in Baker Bay Youngs Bay and adjacent areas of

the Columbia River estuary Report to US Fish and Wi1cllife Service

contract 14-16-009-77-939 Available Northwest Fish Sci Cent 2725

Mont1ake Blvd E Seattle WA 98112

30

Haertel L and C Osterberg 1967 Ecology of zooplankton benthos and

fishes in the Columbia River estuary Ecology 48459-472

Higley D L and R L Holton 1975 Biological baseline data Youngs Bay

Oregon 1974 Final report 11 Nov through 30 Apr 1975 Oregon State

Univ 91 p Available Oceanography Dept Oregon State Univ

Corvallis OR 97331

Higley D L and R L Holton 1978 A grab-sample study of benthic

invertebrates of the Columbia River estuary Supplemental data report 1

Nov 1975 through 29 Feb 1976 Oregon State Univ 27 p Available

Oceanography Dept Oregon State Univ Corvallis OR 97331

Higley D L R L Holton and P D Komar 1976 Analysis of benthic

infauna community and sed~entation patterns of a proposed fill site and

nearby regions in the Columbia River estuary Oregon State Univ 78 p

Available Oceanography Dept Oregon State Univ Corvallis OR 97331

Higley D L J B Morgen and R L Holton 1979 Biological baseline and

fluoride effects data for Youngs Bay Oregon 1974-1975 Supplemental

final report 1 Nov through 30 May 1975 Oregon State Univ 133 p

Available Oceanography Dept Oregon State Univ Corvallis OR 97331

Holton R L D L Higley M A Brzezinski K K Jones and S L Wilson

1984 Benthic infauna of the Columbia River estuary Columbia River

Estuary Data Development Program CREST Astoria OR 179 p plus

appendices

Jones K K 1984 Annual secondary production and community dynamics

of benthic infauna in a Columbia River estuary mudflat MS Thesis

Oregon State Univ Corvallis OR 63 p

31

Lewis J R 1961 The littoral zone on rocky shores a biological and

physical entity Oikos 12280-301

McCabe G T Jr R L Emmett T C Coley and R J McConnell 1986

Distribution abundance and size-class structure of Dungeness crabs in

the Columbia River estuary Final report to US Army Corps of

Engineers contact DACW57-84-F-0178 57 p Available Northwest Fish

Sci Cent 2725 Montlake Blvd E Seattle WA 98112

Neal v T 1972 Physical aspects of the Columbia River and its estuary

1n A T Pruter and D L Alverson (editors) The Columbia River Estuary

and Adjacent Ocean Waters p 19-40 Univ Wash Press Seattle WA

Orth R J 1977 The importance of sed~ent stability in seagrass

communities In B C Coull (editor) Zcology of marine benthos p

281-300 Univ South Carolina Press Columbia SC

Ringold R 1979 Burrowing root mat density and the distribution of

fiddler crabs in the eastern United States J Exp Mar Biol Ecol

3611-21

Sanborn H R 1975 Benthic infauna observed at five sites of the Columbia

River from August 1973 to July 1974 Final Rep to U S Army Corps of

Engineers and Columbia River Program Office 19 p Northwest Fish Sci

Cent 2725 Montlake Blvd Z Seattle WA 98112

Sanders H L P C Manogelsoorf and G R Hampson 1965 Salinity and

faunal distribution in the Pocasset River Massachusetts L~ol

Oceanogr 10216-229

32

Smith R I and J T Carlton (editors) 1975 Lights manual Intertidal

invertebrates of the central California coast Univ Calif Press

Berkeley CA 716 p bull

I

Strickland J D H and T R Parsons 1968 A practical handbook of

seawater analysis Fish Res Board Can Bull No 167 311 p

Virnstein R W 1977 The importance of predation by crabs and fishes on

benthic infauna in Chesapeake Bay Ecology 581199-1217

Wells F E and D Roberts 1980 Molluscan assemblages on an intertidal

sandflat in Princess Royal Harbour Western Australia Aust J Mar

Freshwater Res 31499-507

t M tit 1 t

33

Appendix Table--Numbers and weight (g) of benthic invertebrates collected at 11 sites in Baker Bay Columbia River estuarf November 1980 October 1981

Station la_hI Date lIov_r 1110

31AI 17

181 leI 4IAI 17

181 leI $IAI 17

IBI leI AI17 IBI leI

IaaoD rUIIUlUUIIA 110

Wt I

0002 7

0003 + 4

0002 2

0001

0003

0003

0001

13 000$

I 0004

$ 0003

4 0002

-TKA 110 Wt

4 OOot

7 11013

)

0004 2

000) 1

0011

POLYCIIAamplA Bteone d1l tae 110

Wt 11

0031 23

00$7 17

0037 2

0003 4- 0004

1 0001

3 0003

I 0007

2 0003

enthe l1n1ao1 110 Wt

111 LUI

10$ 1UI

112 1201

100 0412

112 0$0$

1 0410

27 020

32 0ll5

U 0410

)$ OllO

)7 0110

Ii 0170

Peudopo1ydora kelOp1 110 Wt

3 0001

2 0004

3 0011

1 0001

4 0003

2 0002

2 +

1 0002

Po1ydora 119111

Pygop1o elegana

110 Wt

110 Wt

n 0075

11 0044

5 0025

17 0005 bull0001

4 0001

2 +

3 0003

7 0002

2 0001

bull0002 2 + +

Heterobullbulltu r111rora1

HObaon1 r1or1d

110 Wt

110 Wt

271 0$1

2 0015

183 04)3

0012

$ 0004

4 0002

3 000

I 0014

1 0003

3 000

)

0002 3

0002

CRUSlACBA Bohautor1ubull bullbullturf 110

Wt 2

0004

00)4 72

0U7 21

0124 21

0112 31

0119 105

0110 U

0041 02 34

00 4

0ll7

Bogru canrerv1ao1u 110 Wt

1 0004

Coroph1u a1an1 110 Wt

323 0)04

143 0146

20 0011

3 0005

2 0001 + +

1 0002

3 0002

Coroph1u p1n1aorne 110 Wt

2 000)

8IVALVIAcoa ba1 th1ca 110 Wt

14 1111

21 4141

10 0611

11 2031

1S 120)7

21 73

12 1417

11 01$

13 0237

11 1073

13 241

22 1 712

34

Appendix Table--Continued

atat-lon la_lo) 7111) IB) IC) 1111) IB) Ie) 1111) IB) IC) 10111) IB) IC) Date Woveaber 10 24 24 24 24

Taxon TllllllampLLAIUA 110 3 amp 5 3 1 2

Itt + 0001 0001 0002 0002 0002 0002

HllUnA 110 1 Itt 0005

POLYCRAITA Bton diltbullbull 110 2 5 2 4 2 I 3 3 2

Itt 0004 0005 0001 0003 0004 0005 0004 0003

MbullbullnUes l111111col 110 52 10 93 112 75 7amp 12 17 91 9 10 1amp Itt 0500 1125 0545 07amp1 0401 0340 0532 0451 0790 0066 0555 0144

Gayclnde polygnstb 110 1 Itt 0013

Peudopolydor ku 110 6 7 2 14 5 11 21 13 35 10 36 16 Itt 0007 0027 0002 0049 0031 0041 0057 0038 0106 0020 0049 0034

Polydora l1gnl 110 1 1 19 7 12 10 14 12 Itt 0001 0001 0143 0038 0050 - 0016 0032

Pygosplo elegn 110 3 1 6 6 7 2 lit 0001 - bull 0002 0001 0004 0001

Hobsonl tlorId 110 5 9 5 13 6 3 3 4 12 21 10 Itt 0001 0005 0004 0005 0002 0003 0063 0023 0004 0026 00411 0039

cRVSTACampA Hea11eucon ap 110

Itt

Bohutorlus eturl 110 12 10 14 9 3 2 1 Itt 0060 - 0013 0057 0014 0013 0007

Bogru oellrl 110 1 1 Itt 0001 0001

Bogsbullbullrus contervlcolus 110 4 1 Itt - 0004

CoropUwo 1_1 110 1 1 1 Itt 0002 0001

CoropllU11 p1nlcorne 110 2 3 Itt - 0002 0003

crngon trnelscorUII 110 1 Itt 0073

BIVALVIA Cl1noerdlU11 nuttllil 110 1

Itt bull 0003

_ NIltb1e 110 27 34 ZI 15 22 17 37 32 45 42 n 51 Itt 0294 1595 1110 1047 1143 0535 14411 0754 1671 4211 1636 4440

Y srenrI 110 1 1 2 20 31 U Itt 0111 0001 0002 - 0117 0051 0127

~

It

bull bull

Appendix Table--Continued

atation Ca_le) llCA) CB) ce) Date lo-r 10 24

Taxon TllJlBampLIARIA 10 1 1 5

ft 0001 0001 0003

POLYCIIAEIA Neanthe 1lanIcoJ 10 1 1

ft 0010 0001bull Glyc1nde polygnaeha 10 1 1

ft 0012 0002

Pudopolydora kMpJ 10 10 1l 61 ft 0106 oon 0214

Polydora 11 10 21 4bullft 004 0012 OOot

Pygopl0 elegan 10 ft

Heeeraaeu fJ1Jfor1 10 1 1 ft 0013 0011

Habtlon1a flodda 10 23 2 ft 0025 0003

CRUSIACEA HaJleuCOll ap 10 4 4

ft 0001 0001

BIVALVIA HaCOlN NIl tb1ca 10 52 11

ft 2343 0110 0514

lIIya arenada 10 10 6 ft oon 0005 oon

35

31

Lewis J R 1961 The littoral zone on rocky shores a biological and

physical entity Oikos 12280-301

McCabe G T Jr R L Emmett T C Coley and R J McConnell 1986

Distribution abundance and size-class structure of Dungeness crabs in

the Columbia River estuary Final report to US Army Corps of

Engineers contact DACW57-84-F-0178 57 p Available Northwest Fish

Sci Cent 2725 Montlake Blvd E Seattle WA 98112

Neal v T 1972 Physical aspects of the Columbia River and its estuary

1n A T Pruter and D L Alverson (editors) The Columbia River Estuary

and Adjacent Ocean Waters p 19-40 Univ Wash Press Seattle WA

Orth R J 1977 The importance of sed~ent stability in seagrass

communities In B C Coull (editor) Zcology of marine benthos p

281-300 Univ South Carolina Press Columbia SC

Ringold R 1979 Burrowing root mat density and the distribution of

fiddler crabs in the eastern United States J Exp Mar Biol Ecol

3611-21

Sanborn H R 1975 Benthic infauna observed at five sites of the Columbia

River from August 1973 to July 1974 Final Rep to U S Army Corps of

Engineers and Columbia River Program Office 19 p Northwest Fish Sci

Cent 2725 Montlake Blvd Z Seattle WA 98112

Sanders H L P C Manogelsoorf and G R Hampson 1965 Salinity and

faunal distribution in the Pocasset River Massachusetts L~ol

Oceanogr 10216-229

32

Smith R I and J T Carlton (editors) 1975 Lights manual Intertidal

invertebrates of the central California coast Univ Calif Press

Berkeley CA 716 p bull

I

Strickland J D H and T R Parsons 1968 A practical handbook of

seawater analysis Fish Res Board Can Bull No 167 311 p

Virnstein R W 1977 The importance of predation by crabs and fishes on

benthic infauna in Chesapeake Bay Ecology 581199-1217

Wells F E and D Roberts 1980 Molluscan assemblages on an intertidal

sandflat in Princess Royal Harbour Western Australia Aust J Mar

Freshwater Res 31499-507

t M tit 1 t

33

Appendix Table--Numbers and weight (g) of benthic invertebrates collected at 11 sites in Baker Bay Columbia River estuarf November 1980 October 1981

Station la_hI Date lIov_r 1110

31AI 17

181 leI 4IAI 17

181 leI $IAI 17

IBI leI AI17 IBI leI

IaaoD rUIIUlUUIIA 110

Wt I

0002 7

0003 + 4

0002 2

0001

0003

0003

0001

13 000$

I 0004

$ 0003

4 0002

-TKA 110 Wt

4 OOot

7 11013

)

0004 2

000) 1

0011

POLYCIIAamplA Bteone d1l tae 110

Wt 11

0031 23

00$7 17

0037 2

0003 4- 0004

1 0001

3 0003

I 0007

2 0003

enthe l1n1ao1 110 Wt

111 LUI

10$ 1UI

112 1201

100 0412

112 0$0$

1 0410

27 020

32 0ll5

U 0410

)$ OllO

)7 0110

Ii 0170

Peudopo1ydora kelOp1 110 Wt

3 0001

2 0004

3 0011

1 0001

4 0003

2 0002

2 +

1 0002

Po1ydora 119111

Pygop1o elegana

110 Wt

110 Wt

n 0075

11 0044

5 0025

17 0005 bull0001

4 0001

2 +

3 0003

7 0002

2 0001

bull0002 2 + +

Heterobullbulltu r111rora1

HObaon1 r1or1d

110 Wt

110 Wt

271 0$1

2 0015

183 04)3

0012

$ 0004

4 0002

3 000

I 0014

1 0003

3 000

)

0002 3

0002

CRUSlACBA Bohautor1ubull bullbullturf 110

Wt 2

0004

00)4 72

0U7 21

0124 21

0112 31

0119 105

0110 U

0041 02 34

00 4

0ll7

Bogru canrerv1ao1u 110 Wt

1 0004

Coroph1u a1an1 110 Wt

323 0)04

143 0146

20 0011

3 0005

2 0001 + +

1 0002

3 0002

Coroph1u p1n1aorne 110 Wt

2 000)

8IVALVIAcoa ba1 th1ca 110 Wt

14 1111

21 4141

10 0611

11 2031

1S 120)7

21 73

12 1417

11 01$

13 0237

11 1073

13 241

22 1 712

34

Appendix Table--Continued

atat-lon la_lo) 7111) IB) IC) 1111) IB) Ie) 1111) IB) IC) 10111) IB) IC) Date Woveaber 10 24 24 24 24

Taxon TllllllampLLAIUA 110 3 amp 5 3 1 2

Itt + 0001 0001 0002 0002 0002 0002

HllUnA 110 1 Itt 0005

POLYCRAITA Bton diltbullbull 110 2 5 2 4 2 I 3 3 2

Itt 0004 0005 0001 0003 0004 0005 0004 0003

MbullbullnUes l111111col 110 52 10 93 112 75 7amp 12 17 91 9 10 1amp Itt 0500 1125 0545 07amp1 0401 0340 0532 0451 0790 0066 0555 0144

Gayclnde polygnstb 110 1 Itt 0013

Peudopolydor ku 110 6 7 2 14 5 11 21 13 35 10 36 16 Itt 0007 0027 0002 0049 0031 0041 0057 0038 0106 0020 0049 0034

Polydora l1gnl 110 1 1 19 7 12 10 14 12 Itt 0001 0001 0143 0038 0050 - 0016 0032

Pygosplo elegn 110 3 1 6 6 7 2 lit 0001 - bull 0002 0001 0004 0001

Hobsonl tlorId 110 5 9 5 13 6 3 3 4 12 21 10 Itt 0001 0005 0004 0005 0002 0003 0063 0023 0004 0026 00411 0039

cRVSTACampA Hea11eucon ap 110

Itt

Bohutorlus eturl 110 12 10 14 9 3 2 1 Itt 0060 - 0013 0057 0014 0013 0007

Bogru oellrl 110 1 1 Itt 0001 0001

Bogsbullbullrus contervlcolus 110 4 1 Itt - 0004

CoropUwo 1_1 110 1 1 1 Itt 0002 0001

CoropllU11 p1nlcorne 110 2 3 Itt - 0002 0003

crngon trnelscorUII 110 1 Itt 0073

BIVALVIA Cl1noerdlU11 nuttllil 110 1

Itt bull 0003

_ NIltb1e 110 27 34 ZI 15 22 17 37 32 45 42 n 51 Itt 0294 1595 1110 1047 1143 0535 14411 0754 1671 4211 1636 4440

Y srenrI 110 1 1 2 20 31 U Itt 0111 0001 0002 - 0117 0051 0127

~

It

bull bull

Appendix Table--Continued

atation Ca_le) llCA) CB) ce) Date lo-r 10 24

Taxon TllJlBampLIARIA 10 1 1 5

ft 0001 0001 0003

POLYCIIAEIA Neanthe 1lanIcoJ 10 1 1

ft 0010 0001bull Glyc1nde polygnaeha 10 1 1

ft 0012 0002

Pudopolydora kMpJ 10 10 1l 61 ft 0106 oon 0214

Polydora 11 10 21 4bullft 004 0012 OOot

Pygopl0 elegan 10 ft

Heeeraaeu fJ1Jfor1 10 1 1 ft 0013 0011

Habtlon1a flodda 10 23 2 ft 0025 0003

CRUSIACEA HaJleuCOll ap 10 4 4

ft 0001 0001

BIVALVIA HaCOlN NIl tb1ca 10 52 11

ft 2343 0110 0514

lIIya arenada 10 10 6 ft oon 0005 oon

35

32

Smith R I and J T Carlton (editors) 1975 Lights manual Intertidal

invertebrates of the central California coast Univ Calif Press

Berkeley CA 716 p bull

I

Strickland J D H and T R Parsons 1968 A practical handbook of

seawater analysis Fish Res Board Can Bull No 167 311 p

Virnstein R W 1977 The importance of predation by crabs and fishes on

benthic infauna in Chesapeake Bay Ecology 581199-1217

Wells F E and D Roberts 1980 Molluscan assemblages on an intertidal

sandflat in Princess Royal Harbour Western Australia Aust J Mar

Freshwater Res 31499-507

t M tit 1 t

33

Appendix Table--Numbers and weight (g) of benthic invertebrates collected at 11 sites in Baker Bay Columbia River estuarf November 1980 October 1981

Station la_hI Date lIov_r 1110

31AI 17

181 leI 4IAI 17

181 leI $IAI 17

IBI leI AI17 IBI leI

IaaoD rUIIUlUUIIA 110

Wt I

0002 7

0003 + 4

0002 2

0001

0003

0003

0001

13 000$

I 0004

$ 0003

4 0002

-TKA 110 Wt

4 OOot

7 11013

)

0004 2

000) 1

0011

POLYCIIAamplA Bteone d1l tae 110

Wt 11

0031 23

00$7 17

0037 2

0003 4- 0004

1 0001

3 0003

I 0007

2 0003

enthe l1n1ao1 110 Wt

111 LUI

10$ 1UI

112 1201

100 0412

112 0$0$

1 0410

27 020

32 0ll5

U 0410

)$ OllO

)7 0110

Ii 0170

Peudopo1ydora kelOp1 110 Wt

3 0001

2 0004

3 0011

1 0001

4 0003

2 0002

2 +

1 0002

Po1ydora 119111

Pygop1o elegana

110 Wt

110 Wt

n 0075

11 0044

5 0025

17 0005 bull0001

4 0001

2 +

3 0003

7 0002

2 0001

bull0002 2 + +

Heterobullbulltu r111rora1

HObaon1 r1or1d

110 Wt

110 Wt

271 0$1

2 0015

183 04)3

0012

$ 0004

4 0002

3 000

I 0014

1 0003

3 000

)

0002 3

0002

CRUSlACBA Bohautor1ubull bullbullturf 110

Wt 2

0004

00)4 72

0U7 21

0124 21

0112 31

0119 105

0110 U

0041 02 34

00 4

0ll7

Bogru canrerv1ao1u 110 Wt

1 0004

Coroph1u a1an1 110 Wt

323 0)04

143 0146

20 0011

3 0005

2 0001 + +

1 0002

3 0002

Coroph1u p1n1aorne 110 Wt

2 000)

8IVALVIAcoa ba1 th1ca 110 Wt

14 1111

21 4141

10 0611

11 2031

1S 120)7

21 73

12 1417

11 01$

13 0237

11 1073

13 241

22 1 712

34

Appendix Table--Continued

atat-lon la_lo) 7111) IB) IC) 1111) IB) Ie) 1111) IB) IC) 10111) IB) IC) Date Woveaber 10 24 24 24 24

Taxon TllllllampLLAIUA 110 3 amp 5 3 1 2

Itt + 0001 0001 0002 0002 0002 0002

HllUnA 110 1 Itt 0005

POLYCRAITA Bton diltbullbull 110 2 5 2 4 2 I 3 3 2

Itt 0004 0005 0001 0003 0004 0005 0004 0003

MbullbullnUes l111111col 110 52 10 93 112 75 7amp 12 17 91 9 10 1amp Itt 0500 1125 0545 07amp1 0401 0340 0532 0451 0790 0066 0555 0144

Gayclnde polygnstb 110 1 Itt 0013

Peudopolydor ku 110 6 7 2 14 5 11 21 13 35 10 36 16 Itt 0007 0027 0002 0049 0031 0041 0057 0038 0106 0020 0049 0034

Polydora l1gnl 110 1 1 19 7 12 10 14 12 Itt 0001 0001 0143 0038 0050 - 0016 0032

Pygosplo elegn 110 3 1 6 6 7 2 lit 0001 - bull 0002 0001 0004 0001

Hobsonl tlorId 110 5 9 5 13 6 3 3 4 12 21 10 Itt 0001 0005 0004 0005 0002 0003 0063 0023 0004 0026 00411 0039

cRVSTACampA Hea11eucon ap 110

Itt

Bohutorlus eturl 110 12 10 14 9 3 2 1 Itt 0060 - 0013 0057 0014 0013 0007

Bogru oellrl 110 1 1 Itt 0001 0001

Bogsbullbullrus contervlcolus 110 4 1 Itt - 0004

CoropUwo 1_1 110 1 1 1 Itt 0002 0001

CoropllU11 p1nlcorne 110 2 3 Itt - 0002 0003

crngon trnelscorUII 110 1 Itt 0073

BIVALVIA Cl1noerdlU11 nuttllil 110 1

Itt bull 0003

_ NIltb1e 110 27 34 ZI 15 22 17 37 32 45 42 n 51 Itt 0294 1595 1110 1047 1143 0535 14411 0754 1671 4211 1636 4440

Y srenrI 110 1 1 2 20 31 U Itt 0111 0001 0002 - 0117 0051 0127

~

It

bull bull

Appendix Table--Continued

atation Ca_le) llCA) CB) ce) Date lo-r 10 24

Taxon TllJlBampLIARIA 10 1 1 5

ft 0001 0001 0003

POLYCIIAEIA Neanthe 1lanIcoJ 10 1 1

ft 0010 0001bull Glyc1nde polygnaeha 10 1 1

ft 0012 0002

Pudopolydora kMpJ 10 10 1l 61 ft 0106 oon 0214

Polydora 11 10 21 4bullft 004 0012 OOot

Pygopl0 elegan 10 ft

Heeeraaeu fJ1Jfor1 10 1 1 ft 0013 0011

Habtlon1a flodda 10 23 2 ft 0025 0003

CRUSIACEA HaJleuCOll ap 10 4 4

ft 0001 0001

BIVALVIA HaCOlN NIl tb1ca 10 52 11

ft 2343 0110 0514

lIIya arenada 10 10 6 ft oon 0005 oon

35

33

Appendix Table--Numbers and weight (g) of benthic invertebrates collected at 11 sites in Baker Bay Columbia River estuarf November 1980 October 1981

Station la_hI Date lIov_r 1110

31AI 17

181 leI 4IAI 17

181 leI $IAI 17

IBI leI AI17 IBI leI

IaaoD rUIIUlUUIIA 110

Wt I

0002 7

0003 + 4

0002 2

0001

0003

0003

0001

13 000$

I 0004

$ 0003

4 0002

-TKA 110 Wt

4 OOot

7 11013

)

0004 2

000) 1

0011

POLYCIIAamplA Bteone d1l tae 110

Wt 11

0031 23

00$7 17

0037 2

0003 4- 0004

1 0001

3 0003

I 0007

2 0003

enthe l1n1ao1 110 Wt

111 LUI

10$ 1UI

112 1201

100 0412

112 0$0$

1 0410

27 020

32 0ll5

U 0410

)$ OllO

)7 0110

Ii 0170

Peudopo1ydora kelOp1 110 Wt

3 0001

2 0004

3 0011

1 0001

4 0003

2 0002

2 +

1 0002

Po1ydora 119111

Pygop1o elegana

110 Wt

110 Wt

n 0075

11 0044

5 0025

17 0005 bull0001

4 0001

2 +

3 0003

7 0002

2 0001

bull0002 2 + +

Heterobullbulltu r111rora1

HObaon1 r1or1d

110 Wt

110 Wt

271 0$1

2 0015

183 04)3

0012

$ 0004

4 0002

3 000

I 0014

1 0003

3 000

)

0002 3

0002

CRUSlACBA Bohautor1ubull bullbullturf 110

Wt 2

0004

00)4 72

0U7 21

0124 21

0112 31

0119 105

0110 U

0041 02 34

00 4

0ll7

Bogru canrerv1ao1u 110 Wt

1 0004

Coroph1u a1an1 110 Wt

323 0)04

143 0146

20 0011

3 0005

2 0001 + +

1 0002

3 0002

Coroph1u p1n1aorne 110 Wt

2 000)

8IVALVIAcoa ba1 th1ca 110 Wt

14 1111

21 4141

10 0611

11 2031

1S 120)7

21 73

12 1417

11 01$

13 0237

11 1073

13 241

22 1 712

34

Appendix Table--Continued

atat-lon la_lo) 7111) IB) IC) 1111) IB) Ie) 1111) IB) IC) 10111) IB) IC) Date Woveaber 10 24 24 24 24

Taxon TllllllampLLAIUA 110 3 amp 5 3 1 2

Itt + 0001 0001 0002 0002 0002 0002

HllUnA 110 1 Itt 0005

POLYCRAITA Bton diltbullbull 110 2 5 2 4 2 I 3 3 2

Itt 0004 0005 0001 0003 0004 0005 0004 0003

MbullbullnUes l111111col 110 52 10 93 112 75 7amp 12 17 91 9 10 1amp Itt 0500 1125 0545 07amp1 0401 0340 0532 0451 0790 0066 0555 0144

Gayclnde polygnstb 110 1 Itt 0013

Peudopolydor ku 110 6 7 2 14 5 11 21 13 35 10 36 16 Itt 0007 0027 0002 0049 0031 0041 0057 0038 0106 0020 0049 0034

Polydora l1gnl 110 1 1 19 7 12 10 14 12 Itt 0001 0001 0143 0038 0050 - 0016 0032

Pygosplo elegn 110 3 1 6 6 7 2 lit 0001 - bull 0002 0001 0004 0001

Hobsonl tlorId 110 5 9 5 13 6 3 3 4 12 21 10 Itt 0001 0005 0004 0005 0002 0003 0063 0023 0004 0026 00411 0039

cRVSTACampA Hea11eucon ap 110

Itt

Bohutorlus eturl 110 12 10 14 9 3 2 1 Itt 0060 - 0013 0057 0014 0013 0007

Bogru oellrl 110 1 1 Itt 0001 0001

Bogsbullbullrus contervlcolus 110 4 1 Itt - 0004

CoropUwo 1_1 110 1 1 1 Itt 0002 0001

CoropllU11 p1nlcorne 110 2 3 Itt - 0002 0003

crngon trnelscorUII 110 1 Itt 0073

BIVALVIA Cl1noerdlU11 nuttllil 110 1

Itt bull 0003

_ NIltb1e 110 27 34 ZI 15 22 17 37 32 45 42 n 51 Itt 0294 1595 1110 1047 1143 0535 14411 0754 1671 4211 1636 4440

Y srenrI 110 1 1 2 20 31 U Itt 0111 0001 0002 - 0117 0051 0127

~

It

bull bull

Appendix Table--Continued

atation Ca_le) llCA) CB) ce) Date lo-r 10 24

Taxon TllJlBampLIARIA 10 1 1 5

ft 0001 0001 0003

POLYCIIAEIA Neanthe 1lanIcoJ 10 1 1

ft 0010 0001bull Glyc1nde polygnaeha 10 1 1

ft 0012 0002

Pudopolydora kMpJ 10 10 1l 61 ft 0106 oon 0214

Polydora 11 10 21 4bullft 004 0012 OOot

Pygopl0 elegan 10 ft

Heeeraaeu fJ1Jfor1 10 1 1 ft 0013 0011

Habtlon1a flodda 10 23 2 ft 0025 0003

CRUSIACEA HaJleuCOll ap 10 4 4

ft 0001 0001

BIVALVIA HaCOlN NIl tb1ca 10 52 11

ft 2343 0110 0514

lIIya arenada 10 10 6 ft oon 0005 oon

35

34

Appendix Table--Continued

atat-lon la_lo) 7111) IB) IC) 1111) IB) Ie) 1111) IB) IC) 10111) IB) IC) Date Woveaber 10 24 24 24 24

Taxon TllllllampLLAIUA 110 3 amp 5 3 1 2

Itt + 0001 0001 0002 0002 0002 0002

HllUnA 110 1 Itt 0005

POLYCRAITA Bton diltbullbull 110 2 5 2 4 2 I 3 3 2

Itt 0004 0005 0001 0003 0004 0005 0004 0003

MbullbullnUes l111111col 110 52 10 93 112 75 7amp 12 17 91 9 10 1amp Itt 0500 1125 0545 07amp1 0401 0340 0532 0451 0790 0066 0555 0144

Gayclnde polygnstb 110 1 Itt 0013

Peudopolydor ku 110 6 7 2 14 5 11 21 13 35 10 36 16 Itt 0007 0027 0002 0049 0031 0041 0057 0038 0106 0020 0049 0034

Polydora l1gnl 110 1 1 19 7 12 10 14 12 Itt 0001 0001 0143 0038 0050 - 0016 0032

Pygosplo elegn 110 3 1 6 6 7 2 lit 0001 - bull 0002 0001 0004 0001

Hobsonl tlorId 110 5 9 5 13 6 3 3 4 12 21 10 Itt 0001 0005 0004 0005 0002 0003 0063 0023 0004 0026 00411 0039

cRVSTACampA Hea11eucon ap 110

Itt

Bohutorlus eturl 110 12 10 14 9 3 2 1 Itt 0060 - 0013 0057 0014 0013 0007

Bogru oellrl 110 1 1 Itt 0001 0001

Bogsbullbullrus contervlcolus 110 4 1 Itt - 0004

CoropUwo 1_1 110 1 1 1 Itt 0002 0001

CoropllU11 p1nlcorne 110 2 3 Itt - 0002 0003

crngon trnelscorUII 110 1 Itt 0073

BIVALVIA Cl1noerdlU11 nuttllil 110 1

Itt bull 0003

_ NIltb1e 110 27 34 ZI 15 22 17 37 32 45 42 n 51 Itt 0294 1595 1110 1047 1143 0535 14411 0754 1671 4211 1636 4440

Y srenrI 110 1 1 2 20 31 U Itt 0111 0001 0002 - 0117 0051 0127

~

It

bull bull

Appendix Table--Continued

atation Ca_le) llCA) CB) ce) Date lo-r 10 24

Taxon TllJlBampLIARIA 10 1 1 5

ft 0001 0001 0003

POLYCIIAEIA Neanthe 1lanIcoJ 10 1 1

ft 0010 0001bull Glyc1nde polygnaeha 10 1 1

ft 0012 0002

Pudopolydora kMpJ 10 10 1l 61 ft 0106 oon 0214

Polydora 11 10 21 4bullft 004 0012 OOot

Pygopl0 elegan 10 ft

Heeeraaeu fJ1Jfor1 10 1 1 ft 0013 0011

Habtlon1a flodda 10 23 2 ft 0025 0003

CRUSIACEA HaJleuCOll ap 10 4 4

ft 0001 0001

BIVALVIA HaCOlN NIl tb1ca 10 52 11

ft 2343 0110 0514

lIIya arenada 10 10 6 ft oon 0005 oon

35

bull bull

Appendix Table--Continued

atation Ca_le) llCA) CB) ce) Date lo-r 10 24

Taxon TllJlBampLIARIA 10 1 1 5

ft 0001 0001 0003

POLYCIIAEIA Neanthe 1lanIcoJ 10 1 1

ft 0010 0001bull Glyc1nde polygnaeha 10 1 1

ft 0012 0002

Pudopolydora kMpJ 10 10 1l 61 ft 0106 oon 0214

Polydora 11 10 21 4bullft 004 0012 OOot

Pygopl0 elegan 10 ft

Heeeraaeu fJ1Jfor1 10 1 1 ft 0013 0011

Habtlon1a flodda 10 23 2 ft 0025 0003

CRUSIACEA HaJleuCOll ap 10 4 4

ft 0001 0001

BIVALVIA HaCOlN NIl tb1ca 10 52 11

ft 2343 0110 0514

lIIya arenada 10 10 6 ft oon 0005 oon

35

~

~

~

36

Appendix Table--Continued

~a~10n la_l) Da~ De-r ala

31) 11

IB) Ie) 41) 17

IB) Ie) 51) 17

IB) Ie) 61A) 11

IB) Ie)

Taxon lUllllampLLAIIIA

1IIUIEJtfU

0 22 Irt 0001

0 bullIrt +

7 0004

3 +

bull0002

bull 2

0001 2 bull+ 0002

+

11 0002

3 +

30 0011

2 +

3 0002

3 +

3 0001

+

0003

2 +

P01yeIlAllTA BtOII dilatbullbull 0 11

Irt 0066 11

0001 16

0012 bull0002 6

000

0012 bull0003

2 0002

5 0003

1 0001

5 0007

1 0001

BtOII HghU

Sntbe ItnJcol

No Irt

No Irt 0376

115 1530

31 00

12 0622

73 0520

1 0001

7 0311

32 0112

25 0117

40 0271

14 0146

27 0015

23 0037

eudopolydor k~ 0 Irt

1 0002

3 0002

2 2- 0003 1

0003 2

0002 2

0003 1 +

2 0001

1 0002

olydora Hpj 0 Irt

1 0002

2 0002

YVOIpIO lgne No 125 Irt 0057

2a 0011

55 0025

bull 10 0003

I 0003 + + + +

Bobaonl florid bull0 103 Irt oon

101 0012

70 0051 bull0006

6 0015

5 001

3 1 0003

1 0002

1 0002

CltUSTAcv Bobuetorlubull turie

Bog~ru oclair1

0 1 Irt 0003

0 Irt

Ii 0662

1 0002

75 0503

36 0236

13 003

56 0121

50 0111

42 0121

n 03ll

0133

Bogru confrvlcolue 0 Irt

1 0001

1 0010

1 0001

1 0002

Cor~ua el8Onle 0 Irt

a 0001

15 0012

131 00

2 0001

3 0003

2 0005

IMRCTA Dol1chopocl1da

Ch1ronoa1clae

0 Irt

0 Irt

I +

1 0001

I 0005

BIVALVIA _ baltblc No

Irt 21

0160 3

0663 11

2716 32

5nl 31

7754 31

6165 13

1113 10

0731 7

05 l1015 21 11

5541 0112

37

Appendix Table--Continued

acat-lon (bullbullJaplDate _1190

7(AI 17

(8) (e) I(AI 22

(8) (e) 9(A) 22

(8) Ie) lOlA) 22

(8) (e)

Taxon TVJIIIKI1AIIIA Bo

lit - 5 0001

3 0001

_TEA Bo lit

1 0004

POLTeHAJTA Bteone Ultbullbull Bo

lit bull 2

0003 1

0001 1

0001 4

0003 2

0003

nth l1n1eol Bo lit

n 0305

47 0311 onl

U 0245

103 0770

31 0321

37 03

U 0171

34 0136

9 0100

12 Oln

21 0432

ullopolydor Irn Bo lit

1 0001

6- 6 0003

17 0030

0007

15 002

at 0057

13 oon

17 005

14 0011

16 0026

It 0011

olytlor l19111 Bo lit

4 - 0032 22

OUI 23

OOtO 11

0056 26

00 11

OOat 37

0053

ygop1o lgn Bo lit bull

4 0002

t 0001

Hetorotu f1l1fora1 Bo lit

1 OOO~

4 0Ot1

1 0003

1 0011

Robeon1 flor111 Bo lit

2 0004

1 0002

4 0012

0005 7

0013 I

0033 11

OOU bull0012 11

0061 5

0007 25

0056

CltVTACampA -1lo_

Bohoutor1u oturI

Bo lit

Bo ~ 3 000

0030

bull 2

0001 3

0018 4

OOlt 1

0003 2

000 3

0004 1

0005

Bogru oclirl Bo lit

1 0001

Eog_ru conforvlcolu Bo lit

1 0002

3 000

5 OOU

1 0002

1 0013

Bo9rubullbullp lyo_1

or pp Bo lit

2 0004

CoroplIua bullbulll_l Bo lit

1 0002

3 0003

2 0001

1 0003

3 0004

2 0002

Coropll pInlcorftO Bo lit

2 0001

11 0007

8IVALVIA YUlue Hulie

eoIia belWca

Bo lit lit

16 2134

24 1344

21 1236

31 3672

20 0835

14 1170

24 2211

2l 16

22 131

34 3377

3 0011

60 3274

60 4025

Y ronrl Bo lit

1 0021

1 0001

3 0037

34 0154 0060

50 07

8

38

Appendix Table--Continuedbull

bull ~U10n Ca_le llCA CB ce Dat De_r 1110 22

Taxon POLYCIlAltTA Bton l1ght1 No

lit bull Qlyc1nd polygnatha No 1

lit 000

lbullbulludopolydora rnpj No 31 4 0 lit 0127 OUI 030

lolydoro l1gn1 No 1 2 lit 0002 0004

Heter08tu r111rrat No 1 lit 0011

CRV~ACBA HuleuCDII p No 10lit 0002 0001

Crongon fronc1corua No 1 lit 0002

BIVALVIA Haeoaa bal th1cI No S 11 10

lit 0332 0713 0274

Yo arnar1a No 4 5 lit 0004 0009

~

bull

37

Appendix Table--Continued

acat-lon (bullbullJaplDate _1190

7(AI 17

(8) (e) I(AI 22

(8) (e) 9(A) 22

(8) Ie) lOlA) 22

(8) (e)

Taxon TVJIIIKI1AIIIA Bo

lit - 5 0001

3 0001

_TEA Bo lit

1 0004

POLTeHAJTA Bteone Ultbullbull Bo

lit bull 2

0003 1

0001 1

0001 4

0003 2

0003

nth l1n1eol Bo lit

n 0305

47 0311 onl

U 0245

103 0770

31 0321

37 03

U 0171

34 0136

9 0100

12 Oln

21 0432

ullopolydor Irn Bo lit

1 0001

6- 6 0003

17 0030

0007

15 002

at 0057

13 oon

17 005

14 0011

16 0026

It 0011

olytlor l19111 Bo lit

4 - 0032 22

OUI 23

OOtO 11

0056 26

00 11

OOat 37

0053

ygop1o lgn Bo lit bull

4 0002

t 0001

Hetorotu f1l1fora1 Bo lit

1 OOO~

4 0Ot1

1 0003

1 0011

Robeon1 flor111 Bo lit

2 0004

1 0002

4 0012

0005 7

0013 I

0033 11

OOU bull0012 11

0061 5

0007 25

0056

CltVTACampA -1lo_

Bohoutor1u oturI

Bo lit

Bo ~ 3 000

0030

bull 2

0001 3

0018 4

OOlt 1

0003 2

000 3

0004 1

0005

Bogru oclirl Bo lit

1 0001

Eog_ru conforvlcolu Bo lit

1 0002

3 000

5 OOU

1 0002

1 0013

Bo9rubullbullp lyo_1

or pp Bo lit

2 0004

CoroplIua bullbulll_l Bo lit

1 0002

3 0003

2 0001

1 0003

3 0004

2 0002

Coropll pInlcorftO Bo lit

2 0001

11 0007

8IVALVIA YUlue Hulie

eoIia belWca

Bo lit lit

16 2134

24 1344

21 1236

31 3672

20 0835

14 1170

24 2211

2l 16

22 131

34 3377

3 0011

60 3274

60 4025

Y ronrl Bo lit

1 0021

1 0001

3 0037

34 0154 0060

50 07

8

38

Appendix Table--Continuedbull

bull ~U10n Ca_le llCA CB ce Dat De_r 1110 22

Taxon POLYCIlAltTA Bton l1ght1 No

lit bull Qlyc1nd polygnatha No 1

lit 000

lbullbulludopolydora rnpj No 31 4 0 lit 0127 OUI 030

lolydoro l1gn1 No 1 2 lit 0002 0004

Heter08tu r111rrat No 1 lit 0011

CRV~ACBA HuleuCDII p No 10lit 0002 0001

Crongon fronc1corua No 1 lit 0002

BIVALVIA Haeoaa bal th1cI No S 11 10

lit 0332 0713 0274

Yo arnar1a No 4 5 lit 0004 0009

~

bull

8

38

Appendix Table--Continuedbull

bull ~U10n Ca_le llCA CB ce Dat De_r 1110 22

Taxon POLYCIlAltTA Bton l1ght1 No

lit bull Qlyc1nd polygnatha No 1

lit 000

lbullbulludopolydora rnpj No 31 4 0 lit 0127 OUI 030

lolydoro l1gn1 No 1 2 lit 0002 0004

Heter08tu r111rrat No 1 lit 0011

CRV~ACBA HuleuCDII p No 10lit 0002 0001

Crongon fronc1corua No 1 lit 0002

BIVALVIA Haeoaa bal th1cI No S 11 10

lit 0332 0713 0274

Yo arnar1a No 4 5 lit 0004 0009

~

bull

39

Appendix Table--Continued

SUio Ca_l) Date Jaary all

2CA) 12

CB) ce) 3CA) 12

CB) ce) 4CA) 12

CB) ce) 5CA) 12

CB) ce)

laaon TVJtBSLlAIUA Ko

ft 21

0005 125

0050 55

0044 41

0010 II

0003 31

0012 bull0001 bull0001

0002 bull0003 7

0003

_TampA Ko ft

2 0003

2 0003

2 0003

2 0005

1 0024

1 0003

POLYCIIAIITA Staon dilato Ko

ft bull 5

0025 5

0010 4

0003 10

0030 21

0072 21

0051 7

0012 II

0012 15

0024 3

0002 3

0002 5

000

bullbullbullnthe llnlcola Ko ft

30 0amp3amp

23 0412

1amp OUO

t5 lUl

It 1425

12 0313

70 00

70 07

amp7 0410

30 0305

30 0M2

32 0357

Pdopolydor k-p1

pygop1o lgn

Ko ft

Ko ft

It 00amp0

234 0143

llO 0070

15 0011

bull III

0117 74

0017 5

0002 3

0001

1 0003

2 0005

Hcrtu flllforat Ko ft

1 0003

1 0003

Hobsonl florlda Ko ft

lU 001l

103 0230

71 0415

122 041

10 0300

35 0131 bull0004

5 OOll

5 0014

1 0005

1 0005

2 0003

eRUSTACampA Gnorlphar lutbullbull Ko

ft 1

0007

Bobtoriubullbullbullturi Ko ft

5 0025

1 0005

amp 0041

1 000amp

amp 0031

amp 0034

30 0207

45 0215

amp0 0351

107 0210

U oon

amp3 015

Boga_ru ocldrl Ko ft

1 0010

4 0025

Bog_ru confrvlcolu Ko ft

10 0027

72 01

177 0451

4 0004 bull

2

Bog_ru ap or app Cyounq)

Corophiua bullbulllon1

Ko ft

Ko ft

21l 03

21 0021

175 0251

I 0001

155 0201

11 0012

000amp

12 000

2 0002

1 0002

1 0001

1 1 0001

Crangon frncicorva Ko ft

1 0031

IKSICTA Delichopodi Ko

ft 3

000 1

0002 1

0003

ChironoaJ Ko ft

104 0051

112 00amp7

14 0041

2 0003 bull

BIVALVIA _ bel thfca Ko ft

3 0045

1 0015

2t 2411

34 250

20 34n

34 5527

2 2714

32 2275

10 1

0120

5 0323

Myo ornori Ko ft

1bull

1 0003

1 0003

Appendix Table--Continued

l~a~10 (1) I (A) (B) (e) 7(A) (B) (e) I(A) (B) (e) (A) (B) (e) Da~ January nil 12 12 U U

bullbullOD ~LLARIA 0 2

ft 0001 bull bull _IM 0 2 2 1 1 1

ft bull 0023 0001 0004 0001 0003

aLYCIIAIilA

toano cUJtbullbull 0 1 3 1 1 1 1 2 2 7 7 I ft 0002 0002 0003 0001 0003 0001 0001 0002 0001 0011 0011

___nth JJnIaoJ 0 15 23 12 40 JI n 11 15 31 31 t2 ft Oltt 0211 0051 0111 0101 0412 0211 0713 05ot 04 0011 0tl3

bullbulludopoJ)dor hIIp1 0 1 1 1 1 10 I 13 35 t2 41 ft 0002 0002 0003 0002 0022 0013 0022 0111 0120 0110

0 olJldor JIgn1 2 I bullft 0015 0025 oon 0015

ytJOIp1o J~n 0 4 3 4 2 3 2 ft 0002 0003 bull 0002 0001 0001 bull

Htrtu ~IJI~or1 0 2 ft 0043

H~oni ~Jorid 0 1 2 1 1 1 15 11 3 21 22 25 ft - 0003 0002 0002 bull 0014 OOtl 000l 0031 0012 0053

CIlVIIACKA IIooayd _rcocU 0 1

middotft 0024

s-1Juaon p 0 1 1 ft bull bull

bull Dbutoriu turI 0 II n 11 14 7 1 2 2 1 ft bull 0211 02 0142 0015 0011 0032 0004 0003 0013 0005

bull 1I9_ru con~rvIaoJubullbull0 3 1 1 4 ft - 000l

Co~u bullbullJonI 0 1 1 1 3 ft 0004 0001 0001 0003

CoropII bullp1n1CDn1 0 I 2 ft 0005

BIVALVIA _ bdthIw 0 11 1amp 10 20 15 II n 41 34 n 21

ft bull 131 03 0 1011 00 02 1 3302 1732 2435 30tt 141

ffy bull ronrI 0 1 2 10 4 000l bullft 0001 000 0032 OOtl

40

bull

~

41

Appendix Table--Continued

lOCAl 2

bull I

oon

22 0011

bull0021

1 0003

4 0004

21 2114

24 0035

eBI

5 0003

19 012

55 00344

4 0001

3 0211

34 0041

bull 2

0001

3 2113

2 0042

eCI

2 0003

5 0021

11 000

3 0005

3 0055

32 0121

1 0002

bull

ltIi 2513

52 1000

11 CAl CBI eCI 2

1 1 0001 0001

1 1 0002 0001

1 2 0001 0003

1 3 0007 0041

II 12 0373 0371 0477

1 1 0002 0003

5

bull 3

0003 0005

li 52 71 0011 0011 0032

1 2 0001 0021

2 0005

1 2 0002 0001

1 0001

1 bull0001

-2 0001

1

31 iZ 37 307 437 4101

5 2 4 0004 - 0030

Station C_leI Date Jn~ nil

Taxon ~IA

POLYCllAamprA teone dHt

Nentbe lianicola

Glyeinde polygntb

Peeudopolydor tu

Polydor Hgn1

PY9o~o Ilegn

Hltroetu tilitoral

Hoboni tlorid

CRUarACU H-1leucon ap

Bohutoriubullbullbullturi

bull og ru oeliri

Eogru contervicolu Mo lit

Coraphiv bullbull1an1 0 ft

Coroplliv ~nicortll 0

Wo ft

0 ft

0 ft

0 ft

0 ft

Wo ft

0 ft

Wo lit bull

Wo ft

amp0 lit

amp0 lit bull

Mo lit

IMSECTA Chlrolu_ldbullbull

BIVALVIA Ifyell u eeluH

_ bIIltbi

My erenede

ft

amp0 ft

Wo ft

0 ft

0 ft

Appendix Table--Continued

l~a~10 (1) I (A) (B) (e) 7(A) (B) (e) I(A) (B) (e) (A) (B) (e) Da~ January nil 12 12 U U

bullbullOD ~LLARIA 0 2

ft 0001 bull bull _IM 0 2 2 1 1 1

ft bull 0023 0001 0004 0001 0003

aLYCIIAIilA

toano cUJtbullbull 0 1 3 1 1 1 1 2 2 7 7 I ft 0002 0002 0003 0001 0003 0001 0001 0002 0001 0011 0011

___nth JJnIaoJ 0 15 23 12 40 JI n 11 15 31 31 t2 ft Oltt 0211 0051 0111 0101 0412 0211 0713 05ot 04 0011 0tl3

bullbulludopoJ)dor hIIp1 0 1 1 1 1 10 I 13 35 t2 41 ft 0002 0002 0003 0002 0022 0013 0022 0111 0120 0110

0 olJldor JIgn1 2 I bullft 0015 0025 oon 0015

ytJOIp1o J~n 0 4 3 4 2 3 2 ft 0002 0003 bull 0002 0001 0001 bull

Htrtu ~IJI~or1 0 2 ft 0043

H~oni ~Jorid 0 1 2 1 1 1 15 11 3 21 22 25 ft - 0003 0002 0002 bull 0014 OOtl 000l 0031 0012 0053

CIlVIIACKA IIooayd _rcocU 0 1

middotft 0024

s-1Juaon p 0 1 1 ft bull bull

bull Dbutoriu turI 0 II n 11 14 7 1 2 2 1 ft bull 0211 02 0142 0015 0011 0032 0004 0003 0013 0005

bull 1I9_ru con~rvIaoJubullbull0 3 1 1 4 ft - 000l

Co~u bullbullJonI 0 1 1 1 3 ft 0004 0001 0001 0003

CoropII bullp1n1CDn1 0 I 2 ft 0005

BIVALVIA _ bdthIw 0 11 1amp 10 20 15 II n 41 34 n 21

ft bull 131 03 0 1011 00 02 1 3302 1732 2435 30tt 141

ffy bull ronrI 0 1 2 10 4 000l bullft 0001 000 0032 OOtl

40

bull

~

41

Appendix Table--Continued

lOCAl 2

bull I

oon

22 0011

bull0021

1 0003

4 0004

21 2114

24 0035

eBI

5 0003

19 012

55 00344

4 0001

3 0211

34 0041

bull 2

0001

3 2113

2 0042

eCI

2 0003

5 0021

11 000

3 0005

3 0055

32 0121

1 0002

bull

ltIi 2513

52 1000

11 CAl CBI eCI 2

1 1 0001 0001

1 1 0002 0001

1 2 0001 0003

1 3 0007 0041

II 12 0373 0371 0477

1 1 0002 0003

5

bull 3

0003 0005

li 52 71 0011 0011 0032

1 2 0001 0021

2 0005

1 2 0002 0001

1 0001

1 bull0001

-2 0001

1

31 iZ 37 307 437 4101

5 2 4 0004 - 0030

Station C_leI Date Jn~ nil

Taxon ~IA

POLYCllAamprA teone dHt

Nentbe lianicola

Glyeinde polygntb

Peeudopolydor tu

Polydor Hgn1

PY9o~o Ilegn

Hltroetu tilitoral

Hoboni tlorid

CRUarACU H-1leucon ap

Bohutoriubullbullbullturi

bull og ru oeliri

Eogru contervicolu Mo lit

Coraphiv bullbull1an1 0 ft

Coroplliv ~nicortll 0

Wo ft

0 ft

0 ft

0 ft

0 ft

Wo ft

0 ft

Wo lit bull

Wo ft

amp0 lit

amp0 lit bull

Mo lit

IMSECTA Chlrolu_ldbullbull

BIVALVIA Ifyell u eeluH

_ bIIltbi

My erenede

ft

amp0 ft

Wo ft

0 ft

0 ft

41

Appendix Table--Continued

lOCAl 2

bull I

oon

22 0011

bull0021

1 0003

4 0004

21 2114

24 0035

eBI

5 0003

19 012

55 00344

4 0001

3 0211

34 0041

bull 2

0001

3 2113

2 0042

eCI

2 0003

5 0021

11 000

3 0005

3 0055

32 0121

1 0002

bull

ltIi 2513

52 1000

11 CAl CBI eCI 2

1 1 0001 0001

1 1 0002 0001

1 2 0001 0003

1 3 0007 0041

II 12 0373 0371 0477

1 1 0002 0003

5

bull 3

0003 0005

li 52 71 0011 0011 0032

1 2 0001 0021

2 0005

1 2 0002 0001

1 0001

1 bull0001

-2 0001

1

31 iZ 37 307 437 4101

5 2 4 0004 - 0030

Station C_leI Date Jn~ nil

Taxon ~IA

POLYCllAamprA teone dHt

Nentbe lianicola

Glyeinde polygntb

Peeudopolydor tu

Polydor Hgn1

PY9o~o Ilegn

Hltroetu tilitoral

Hoboni tlorid

CRUarACU H-1leucon ap

Bohutoriubullbullbullturi

bull og ru oeliri

Eogru contervicolu Mo lit

Coraphiv bullbull1an1 0 ft

Coroplliv ~nicortll 0

Wo ft

0 ft

0 ft

0 ft

0 ft

Wo ft

0 ft

Wo lit bull

Wo ft

amp0 lit

amp0 lit bull

Mo lit

IMSECTA Chlrolu_ldbullbull

BIVALVIA Ifyell u eeluH

_ bIIltbi

My erenede

ft

amp0 ft

Wo ft

0 ft

0 ft

42

Appendix Table--Continued

Bcaclon Cal Dac rebruary 111

lCA 21

ca ce 2CA 10

ca ce 3eA 10

ca ce 4CA 10

ca ce

Taxon lIIIUIampLLARIA 80

Irt 4

bull 0002 ]5

0022

DDDZ -]

DDDZ 2

0004 4

0001 26

DDOl 10

0004

_rEA 80 Irt

]

0021 ]

000 2

DDDt 5

DDn 1

0002 ]

0003

POLyeHAETABton cUlta 80

Irt 1

DDOl 4

0010 2

0002 7

00]5 11

0124 10

003

001

5 0004

12 00]0

15 DDU

11 0075

20 DDn

anthbullbull 11Jlnicola 80 Irt

1 20 DUD

51 0452

4 0144

54 0246

55 0324

It 0161

76 1410

62 1111

14 1126

Paudopolydora bap1 80 Irt

1 0001

1 000]

Polydora 11gn1 80 Irt

1 0001

Pygop1o lgan 80 Irt

U 0024

It 0026

1 000]

4 0002

Z bull

5 0002 0035 115

0021 I]

001]

BoMon1a flodda 80 Irt

U bull 0041

Sf 011]

]

000 1

000l 2

0007 ]2

0211 022 12 0111 022

CRVaTACP HIII11_ ap 80

Irt 2

0001

Gnorlopbaroaa lut 80 Irt

1 0011

1 2 0041

Bohautor1ubullbullbulltuari 80 Irt

2 0012

]

OOU 5

00]5 I

0055 1]

0012 21

Oltt 54

0310 41

0214 1 4

000 0026 1

OOOt

Bogru oclairi 80 Irt

1 0002

7 0071

2 0010

Boga_ru confrv1colu 80 Irt

22 001

] 016]

24 010]

1 0003 1

0001

CoropbjUli azonJ 80 Irt

216 0412

liD 0262

67 1 005 000l

27 It 0021 0011

]4 0022

CoropbI bull p1nIcom 80 Irt

2 000]

IIISKCTA Dol1chopocUcIa liD

Irt

001

I 0015

]

0011 5

0011 2

0010 4

0017

eh1rono1c1a 80 Irt

12 0005

2 0001

126 000

57 00l

5t4 0526

4 2 000] 0002

BIVALVIA 1Ia baltlUca 80

Irt 2

002 1

0415 34

+ 1271 ]0

641 1]

541] 41 41

bullbull0 260 2

15

Ifya aranada liD Irt

1 0001

bull

-t

-t

bull

43

Appendix Table--Continued

8tatl_ Ca_le Date February 1111

5CA 10

CB cel aCA 10

CBI ce 7CA 10

CB ce ICA 27

CB ce)

Txon --LLIUIIA KO

ft 3

0002 4

0001 bull 1

0001

_lampA Ko ft

2 000

1 0001

2 0003

4 0018

POLYClIAIlTA Be dilaea Ko

ft 2

0005 1

0004 4

0010 3

0002 1

0002 1

0001 1

0001 2

0003 1

0003 bull 1

0002

bullbullathbullbull l111111eola KO ft

23 24- 0377 41

0113 24

0170 23

0257 22

0252 70

1001 51

0571 ltII

0522 33

0427 41

04 ltIt

1062

Pbullbulludopolydora Itbullbull KO ft

4bull

2 0005

4 0004

1 0001

3 0007

2 0003

12 003

35 0120

1t 0055

Polydora 119111 KO lit

1 0001

PygoJdo lgan Ko lit bull

2 0001

1 0001 bull

2 0001

1 0001

3 0001 bull

Hobaonia florida Ko lit

2 0006

1 0002

3 0006

1 0003

2 0003

5 0001

5 0011

10 000

OUBTACampA HlI1lueon ap Ko

lit bull bull 1bull

Saduribull bull neOllOJl Ko lit

1 Oll

Eahautor1ubullbullaeuar1 Ko lit

IS 0211

ltIt 0166

22 OOU

31 oon

70 0251

5 0340

4 0023

2 OOOl

5 0024

2 0013

Eoga_aru confrv1eolu Ko lit

3 0001

Coroph1u bullbulll8OD1 Ko lit bull

1 0001

1bull

BIVALVIA IfyUlu Hul1 Ko

lit 1

oooa

Ifa- bdtb1ca Ko lit bull

11 1103

17 2371

II 3136

II 1H2

17 271

17 1141

13 157

lI2 1700

18 123

53 13

42 2141

5$ 1375

Ifya arenar1a KO ft

1 0003

2 0004

~ -------------~~--------

44

Appendix Table--Continued

SUlon (Plel 11111 (81 (el 10(111 (81 (el 11(111 (81 (el Dat February Ull 27 27 27

Taxon POLyeHAZTABtoono d1lltlo No 1 1 4 2 3 5 2

ft 0002 0002 0002 0005 0014 0005

Btoono J1ght1 No 1 ft 0001

olntho H 1cola No 41 44 51 13 2 2 1 ft 0541 0654 0554 0115 0161 0001 0013 0014

Hoa1podu boroa11 No 1 1 1 ft 0007 0011 000

Psoudopolydon kap1 No 7 11 11 I 21 31 33 31 12 ft 0001 0016 0045 0003 0021 0045 0001 0101 0311

Polydora Hgn1 No 3 3 3 4 1 1 ft 0010 0013 000 OOlD 0004 0004

Pyvosp1o ologln No 4 ft 0001bull

Hotoraatu f111forai No 1 1 1 1 1 ft 0001 0001 0027 0003 0005

Hobon1a flor1dl No 21 20 32 1 2 ft 0032 0017 000 0044 0053 0004 0003

cJlVaTACZA IIooayd _readi No

ft

Holdloucon Ip No 21 21 11 ft 0010 0001

Gftortophlora lutoa No 1 2 ft 0004 0012

Eohautor1us bullbulltulr1 No 4 1 2 1 ft 0014 0003 0005 0002

Boga_ru ocla1ri No 1 1 1 ft 0001 0001 0045

Boga_ru confrv1colu No 1 3 ft 0003 0005

Coroph1u a~1 No 2 2 1 3 1 ft bull 000 0001 0001 0005 0002

Coropl1p1n1corno No ft bull

Cancer g1stor No 1 ft 0132

BIVALVIA fryt1lu odul1 No

ft bull Hacaa balthica No 37 33 40 51 60 51 3t 41 51

ft 5264 2tOl 4221 4610 2 3257 1101 3191 4tll

fryl Ironaria No 2 53 55 34 1 6 ft 0033 0120 0200 0543 0001bull

~

~

43

Appendix Table--Continued

8tatl_ Ca_le Date February 1111

5CA 10

CB cel aCA 10

CBI ce 7CA 10

CB ce ICA 27

CB ce)

Txon --LLIUIIA KO

ft 3

0002 4

0001 bull 1

0001

_lampA Ko ft

2 000

1 0001

2 0003

4 0018

POLYClIAIlTA Be dilaea Ko

ft 2

0005 1

0004 4

0010 3

0002 1

0002 1

0001 1

0001 2

0003 1

0003 bull 1

0002

bullbullathbullbull l111111eola KO ft

23 24- 0377 41

0113 24

0170 23

0257 22

0252 70

1001 51

0571 ltII

0522 33

0427 41

04 ltIt

1062

Pbullbulludopolydora Itbullbull KO ft

4bull

2 0005

4 0004

1 0001

3 0007

2 0003

12 003

35 0120

1t 0055

Polydora 119111 KO lit

1 0001

PygoJdo lgan Ko lit bull

2 0001

1 0001 bull

2 0001

1 0001

3 0001 bull

Hobaonia florida Ko lit

2 0006

1 0002

3 0006

1 0003

2 0003

5 0001

5 0011

10 000

OUBTACampA HlI1lueon ap Ko

lit bull bull 1bull

Saduribull bull neOllOJl Ko lit

1 Oll

Eahautor1ubullbullaeuar1 Ko lit

IS 0211

ltIt 0166

22 OOU

31 oon

70 0251

5 0340

4 0023

2 OOOl

5 0024

2 0013

Eoga_aru confrv1eolu Ko lit

3 0001

Coroph1u bullbulll8OD1 Ko lit bull

1 0001

1bull

BIVALVIA IfyUlu Hul1 Ko

lit 1

oooa

Ifa- bdtb1ca Ko lit bull

11 1103

17 2371

II 3136

II 1H2

17 271

17 1141

13 157

lI2 1700

18 123

53 13

42 2141

5$ 1375

Ifya arenar1a KO ft

1 0003

2 0004

~ -------------~~--------

44

Appendix Table--Continued

SUlon (Plel 11111 (81 (el 10(111 (81 (el 11(111 (81 (el Dat February Ull 27 27 27

Taxon POLyeHAZTABtoono d1lltlo No 1 1 4 2 3 5 2

ft 0002 0002 0002 0005 0014 0005

Btoono J1ght1 No 1 ft 0001

olntho H 1cola No 41 44 51 13 2 2 1 ft 0541 0654 0554 0115 0161 0001 0013 0014

Hoa1podu boroa11 No 1 1 1 ft 0007 0011 000

Psoudopolydon kap1 No 7 11 11 I 21 31 33 31 12 ft 0001 0016 0045 0003 0021 0045 0001 0101 0311

Polydora Hgn1 No 3 3 3 4 1 1 ft 0010 0013 000 OOlD 0004 0004

Pyvosp1o ologln No 4 ft 0001bull

Hotoraatu f111forai No 1 1 1 1 1 ft 0001 0001 0027 0003 0005

Hobon1a flor1dl No 21 20 32 1 2 ft 0032 0017 000 0044 0053 0004 0003

cJlVaTACZA IIooayd _readi No

ft

Holdloucon Ip No 21 21 11 ft 0010 0001

Gftortophlora lutoa No 1 2 ft 0004 0012

Eohautor1us bullbulltulr1 No 4 1 2 1 ft 0014 0003 0005 0002

Boga_ru ocla1ri No 1 1 1 ft 0001 0001 0045

Boga_ru confrv1colu No 1 3 ft 0003 0005

Coroph1u a~1 No 2 2 1 3 1 ft bull 000 0001 0001 0005 0002

Coropl1p1n1corno No ft bull

Cancer g1stor No 1 ft 0132

BIVALVIA fryt1lu odul1 No

ft bull Hacaa balthica No 37 33 40 51 60 51 3t 41 51

ft 5264 2tOl 4221 4610 2 3257 1101 3191 4tll

fryl Ironaria No 2 53 55 34 1 6 ft 0033 0120 0200 0543 0001bull

~

~

~ -------------~~--------

44

Appendix Table--Continued

SUlon (Plel 11111 (81 (el 10(111 (81 (el 11(111 (81 (el Dat February Ull 27 27 27

Taxon POLyeHAZTABtoono d1lltlo No 1 1 4 2 3 5 2

ft 0002 0002 0002 0005 0014 0005

Btoono J1ght1 No 1 ft 0001

olntho H 1cola No 41 44 51 13 2 2 1 ft 0541 0654 0554 0115 0161 0001 0013 0014

Hoa1podu boroa11 No 1 1 1 ft 0007 0011 000

Psoudopolydon kap1 No 7 11 11 I 21 31 33 31 12 ft 0001 0016 0045 0003 0021 0045 0001 0101 0311

Polydora Hgn1 No 3 3 3 4 1 1 ft 0010 0013 000 OOlD 0004 0004

Pyvosp1o ologln No 4 ft 0001bull

Hotoraatu f111forai No 1 1 1 1 1 ft 0001 0001 0027 0003 0005

Hobon1a flor1dl No 21 20 32 1 2 ft 0032 0017 000 0044 0053 0004 0003

cJlVaTACZA IIooayd _readi No

ft

Holdloucon Ip No 21 21 11 ft 0010 0001

Gftortophlora lutoa No 1 2 ft 0004 0012

Eohautor1us bullbulltulr1 No 4 1 2 1 ft 0014 0003 0005 0002

Boga_ru ocla1ri No 1 1 1 ft 0001 0001 0045

Boga_ru confrv1colu No 1 3 ft 0003 0005

Coroph1u a~1 No 2 2 1 3 1 ft bull 000 0001 0001 0005 0002

Coropl1p1n1corno No ft bull

Cancer g1stor No 1 ft 0132

BIVALVIA fryt1lu odul1 No

ft bull Hacaa balthica No 37 33 40 51 60 51 3t 41 51

ft 5264 2tOl 4221 4610 2 3257 1101 3191 4tll

fryl Ironaria No 2 53 55 34 1 6 ft 0033 0120 0200 0543 0001bull

~

~

45

Appendix Table--Continued

Station (a_1e) Date llarclgt 1111

2 (AI 13

la) (e) 3(A) 13

(a) Ie) 4 (A) 13

(a) (e) 5IA) 13

ca) ce)

on 71IJIIIamplLIIIIIA

_ftA

0 ft

0 ft

3 0001

1 0002

1 +

5 0002

10 0004

1 +

+

+ + 1 +

12 10 0004 0003

2 3 - 0012

P01YClUlltTA Bt_ tUlataa

Nantb Itn1cola

bullbulludopolydora kep1

0 ft bull

0 ft

0 ft

II 004

3 00

20 0011

2 0010

11 oon

22 04

0011

33 1025

16 oon

III 1

1 0038

21 1142

1 0003

6D 0551

0013

53 042

0014

0511

2 0003

3 000

20 0311

3 0003

21 0210

1 0002

53 0121

1)9o~0 lvan 0 ft

n 0015

11 0005

U 0011

4 0001

111 0021

40 OOot

4 0001

0002

2 +

1 + +

1 +

Hobaon1a tlor1da 0 ft

14 0010

1 +

21 0253

31 0013

11 012

15 0240

3 000

1 0006

1 0003

4 0011

eRUSTACampA Hnoilucon ap

Bohautor1ubullbullbulltuar1

0 ft

0 ft

21 01

31 0255

6 0033

1 0006

4Ii6 0542

54 03

22 0101

2 0001

33 0111

30 0011

+

3D 0011

JIo9a_rua contrv1colubullbull0

ft I

+ 0001 4

0002 2 2

0001

0002

Coropl1 aJoft1 0 ft

5 0001 +

1 0003

12 000

55 0041

16 0012

3 0006

1 0002

3 0004

1bullbullECTA Do1ic1gtopod1dbullbull 0

ft 2

000 1

000 1

0005 3

0006 I

000

Ch1ronca1dbullbull 0 ft

5 0040

61 0050

40 0021

23 0010

10 0004

10 0001

aIVA1VIA blaltll1a 0

ft 4

O36a 2

021 1

oooa 36

3023 4261 10

1 bullbull 36

1541 33 36

111a 10400 31

0156 11

2553 11

4013

46

Appendix Table--Continued

atatioD 1__10) Dato reb 1n

51A) IB) 13

Ie) 71A) 13

IB) Ie) IIA) 2amp

IB) Ie) A) 2amp

IB) Ie)

Ifbullbullon TUlUlliLLAIIIA

_ftA

0 1ft

0 1ft

2 bull 0001

2 0010

2 0002

2 0011

bull 1 bull

POLYCIIAIlA Bteono cUlot 0

1ft bull 2 3

0005 0004 4

0002 1 2

0002 0003 1 2 2

0002 0002 0002

bullbullontho l1n1colo 0 1ft

U Oto

2 07

7 0121

5 0507

0 135

50 121

44 07

2 0727

30 42 0lt4 0512

32 013

34 0

bullbulludopolydoro karp 0 1ft

1 0002 bull

1 0002

4 0011

1 0007

2 15 - 0042

0027 10

0012

olydoro Hpj 0 1ft

1 0004

4 0015

4 002amp

1 0007

Y908Jdo lgon

Bobaon10 ~lor1do

0 1ft

0 1ft

5 0001

4 0012

3 bull 1

0001

4 0001

1 0002

2 bull 1

0002 4

0016

1 bull 3

000

bull 0005

2 bull

0005

3 0001

11 0031

11 002

CIlUalACKA IIea1l_ op 0

1ft

BoIIoutodubullbullbulltuod 0 1ft

bull 72

0250 50

OOlt 40

0150 bull0035 15

0050 15

0015 1

0016 1

000 1

0005 2

0005 4

0031 4

002

Bog_rubull ~orv1colubullbull0 1ft bull

3 0005

CDrGFb1U8 olan1 0 1ft

1 0002

1 0002

1 0002

2 0005

3 0004

2 0003

CorGFb1Jdn1corn 0 1ft

2 0004

Crongon op 0 1ft

3 0007

BIVALVIA _belW 0

1ft 17

113 21

1 2

3151 2

2715 33

3000 3

17 34

0 12

22 32

0451 105

2lt7 70

32amp0 5

2

Yo ornor10 0 1ft

1 0212

1 0001

1 0002

4 0041 bull

bull

lit

bull

47

Appendix Table--Continued

ltaloft C_~Da ch 11 lOCAl

21 CBI lei lllAI

2 IBI cel

Taxon POLyellAlTA Bton tUlata No

ft I

+ 0014 4

0001 Z

0003

N bull tbea 1111111coJa No ft

12 11 01 0170

13 2 0117 0004

1 0002

Hea1podua boreall No ft

1 0011

Paudopolydora ku No ft

n 11 0012 0021

11 5 0027 003

10 0301

0 0230

Po1ydora 119111 No ft

2 1 000 0005

2 1 0010 0006

1 0011

1 0004

PygoapJo elg No ft

2 7 + 0003

3 001

Heteraatua f111foraia No ft

1 2 0003 0045

1 2 0012 0003

3 0004

Ho~onla flor1da No ft

10 10 0041 0032

3 OOU 0005

3 0005

2 0002

cJlU8TACampA He11eucon p No

ft II

+ 0005 32

0010 5

0002

Bohauator1ua eatuar1a No ft

1 0004

1 0003

2 0001

Bogru conferv1colubullbull0 ft

1 0002

Coropb1u aalaOll1 No ft

1 0002

3 0007

BIVALVIA Ifytllu Hul1a No

ft 1

0002 1

0001 2

0001

_ 1M1tb1ca No ft

n 155

71 6213

59 3026

13 525

15 2715

11 5121

Ifya arenar1a No ft

21 0113

21 0136

22 0186 +

3 0011

0024

48

Appendix Table--Continued

atation 18_1) 21A) IB) IC) 31A) IB) IC) 41A) IB) Ie) 51A) IB) IC) Date April Ill 10 10 10 10

Taxon TIlllllELLAJlIA No 3 5 3 12

lit 0001 0003 + + + 0002 + 0006 +

JlBllEATEA No 1 1 1 lit 000 0007 0004

POLYCIlAllTA Btone diltbullbull No 10 2 14 2 5 3 3 3 5 5

lit 0021 + 0002 0043 0027 000$ 0010 0004 0003 0006 0005 0004

Mbullbullnth 11n1col No 3 12 31 54 51 4amp 52 40 11 lit 0077 0154 0102 1254 0713 05 0614 0543 0410 1amp32 OUO

bullbulludopolydor kellp1 No 1 1 lit 0003 0004

Nopl0 1glI No I 1 20 II 2 60 1 5 2 3 5 lit 0002 + 0004 0024 0020 0014 + 0001 bull 0001 0001

Robaon1 florid No 14 2 30 11 45 50 1 2 1 3 6 1 lit 0145 0001 02amp1 011t OOtl 0160 0004 0007 0004 001 0042 0004

CRU8TACEA Rndlucon 8p No 1

lit bull 0001 bull bull bull BGbutorlubullbullbulltur1 No 16 3 25 31 44 22 34 55

lit 0112 0009 0131 01 0160 00amp1 0107 0232

Bogru oclairi No 1 lit 0001

EDg_ru confrv1colu No 1 1 2 5 1 lit 0001 0001 000 0026 bull

Coroph1ua bullbull18OnI8 No Ii 56 124 31 I 3 1 Nt 0002 bull 0123 0242 0076 0015 0001 0003

Coroph1ua plnlcorn No 2 lit bull

_ri No 1 lit 0001

IN8ECTA Dolichopodi No 3 3 3 2

lit 0017 0011 0014 0001

Chirona1 No 349 112 30 7 7 1 lit 0293 0153 0017 0003 0004 bull

BIVALVIA lflcoae bdtllic No 3 16 31 45 40 63 40 41 30

lit 0042 0473 0 1371 bullbull 350 3410 7245 2010 53 1333

bull

~

bull

46

Appendix Table--Continued

atatioD 1__10) Dato reb 1n

51A) IB) 13

Ie) 71A) 13

IB) Ie) IIA) 2amp

IB) Ie) A) 2amp

IB) Ie)

Ifbullbullon TUlUlliLLAIIIA

_ftA

0 1ft

0 1ft

2 bull 0001

2 0010

2 0002

2 0011

bull 1 bull

POLYCIIAIlA Bteono cUlot 0

1ft bull 2 3

0005 0004 4

0002 1 2

0002 0003 1 2 2

0002 0002 0002

bullbullontho l1n1colo 0 1ft

U Oto

2 07

7 0121

5 0507

0 135

50 121

44 07

2 0727

30 42 0lt4 0512

32 013

34 0

bullbulludopolydoro karp 0 1ft

1 0002 bull

1 0002

4 0011

1 0007

2 15 - 0042

0027 10

0012

olydoro Hpj 0 1ft

1 0004

4 0015

4 002amp

1 0007

Y908Jdo lgon

Bobaon10 ~lor1do

0 1ft

0 1ft

5 0001

4 0012

3 bull 1

0001

4 0001

1 0002

2 bull 1

0002 4

0016

1 bull 3

000

bull 0005

2 bull

0005

3 0001

11 0031

11 002

CIlUalACKA IIea1l_ op 0

1ft

BoIIoutodubullbullbulltuod 0 1ft

bull 72

0250 50

OOlt 40

0150 bull0035 15

0050 15

0015 1

0016 1

000 1

0005 2

0005 4

0031 4

002

Bog_rubull ~orv1colubullbull0 1ft bull

3 0005

CDrGFb1U8 olan1 0 1ft

1 0002

1 0002

1 0002

2 0005

3 0004

2 0003

CorGFb1Jdn1corn 0 1ft

2 0004

Crongon op 0 1ft

3 0007

BIVALVIA _belW 0

1ft 17

113 21

1 2

3151 2

2715 33

3000 3

17 34

0 12

22 32

0451 105

2lt7 70

32amp0 5

2

Yo ornor10 0 1ft

1 0212

1 0001

1 0002

4 0041 bull

bull

lit

bull

47

Appendix Table--Continued

ltaloft C_~Da ch 11 lOCAl

21 CBI lei lllAI

2 IBI cel

Taxon POLyellAlTA Bton tUlata No

ft I

+ 0014 4

0001 Z

0003

N bull tbea 1111111coJa No ft

12 11 01 0170

13 2 0117 0004

1 0002

Hea1podua boreall No ft

1 0011

Paudopolydora ku No ft

n 11 0012 0021

11 5 0027 003

10 0301

0 0230

Po1ydora 119111 No ft

2 1 000 0005

2 1 0010 0006

1 0011

1 0004

PygoapJo elg No ft

2 7 + 0003

3 001

Heteraatua f111foraia No ft

1 2 0003 0045

1 2 0012 0003

3 0004

Ho~onla flor1da No ft

10 10 0041 0032

3 OOU 0005

3 0005

2 0002

cJlU8TACampA He11eucon p No

ft II

+ 0005 32

0010 5

0002

Bohauator1ua eatuar1a No ft

1 0004

1 0003

2 0001

Bogru conferv1colubullbull0 ft

1 0002

Coropb1u aalaOll1 No ft

1 0002

3 0007

BIVALVIA Ifytllu Hul1a No

ft 1

0002 1

0001 2

0001

_ 1M1tb1ca No ft

n 155

71 6213

59 3026

13 525

15 2715

11 5121

Ifya arenar1a No ft

21 0113

21 0136

22 0186 +

3 0011

0024

48

Appendix Table--Continued

atation 18_1) 21A) IB) IC) 31A) IB) IC) 41A) IB) Ie) 51A) IB) IC) Date April Ill 10 10 10 10

Taxon TIlllllELLAJlIA No 3 5 3 12

lit 0001 0003 + + + 0002 + 0006 +

JlBllEATEA No 1 1 1 lit 000 0007 0004

POLYCIlAllTA Btone diltbullbull No 10 2 14 2 5 3 3 3 5 5

lit 0021 + 0002 0043 0027 000$ 0010 0004 0003 0006 0005 0004

Mbullbullnth 11n1col No 3 12 31 54 51 4amp 52 40 11 lit 0077 0154 0102 1254 0713 05 0614 0543 0410 1amp32 OUO

bullbulludopolydor kellp1 No 1 1 lit 0003 0004

Nopl0 1glI No I 1 20 II 2 60 1 5 2 3 5 lit 0002 + 0004 0024 0020 0014 + 0001 bull 0001 0001

Robaon1 florid No 14 2 30 11 45 50 1 2 1 3 6 1 lit 0145 0001 02amp1 011t OOtl 0160 0004 0007 0004 001 0042 0004

CRU8TACEA Rndlucon 8p No 1

lit bull 0001 bull bull bull BGbutorlubullbullbulltur1 No 16 3 25 31 44 22 34 55

lit 0112 0009 0131 01 0160 00amp1 0107 0232

Bogru oclairi No 1 lit 0001

EDg_ru confrv1colu No 1 1 2 5 1 lit 0001 0001 000 0026 bull

Coroph1ua bullbull18OnI8 No Ii 56 124 31 I 3 1 Nt 0002 bull 0123 0242 0076 0015 0001 0003

Coroph1ua plnlcorn No 2 lit bull

_ri No 1 lit 0001

IN8ECTA Dolichopodi No 3 3 3 2

lit 0017 0011 0014 0001

Chirona1 No 349 112 30 7 7 1 lit 0293 0153 0017 0003 0004 bull

BIVALVIA lflcoae bdtllic No 3 16 31 45 40 63 40 41 30

lit 0042 0473 0 1371 bullbull 350 3410 7245 2010 53 1333

bull

~

bull

47

Appendix Table--Continued

ltaloft C_~Da ch 11 lOCAl

21 CBI lei lllAI

2 IBI cel

Taxon POLyellAlTA Bton tUlata No

ft I

+ 0014 4

0001 Z

0003

N bull tbea 1111111coJa No ft

12 11 01 0170

13 2 0117 0004

1 0002

Hea1podua boreall No ft

1 0011

Paudopolydora ku No ft

n 11 0012 0021

11 5 0027 003

10 0301

0 0230

Po1ydora 119111 No ft

2 1 000 0005

2 1 0010 0006

1 0011

1 0004

PygoapJo elg No ft

2 7 + 0003

3 001

Heteraatua f111foraia No ft

1 2 0003 0045

1 2 0012 0003

3 0004

Ho~onla flor1da No ft

10 10 0041 0032

3 OOU 0005

3 0005

2 0002

cJlU8TACampA He11eucon p No

ft II

+ 0005 32

0010 5

0002

Bohauator1ua eatuar1a No ft

1 0004

1 0003

2 0001

Bogru conferv1colubullbull0 ft

1 0002

Coropb1u aalaOll1 No ft

1 0002

3 0007

BIVALVIA Ifytllu Hul1a No

ft 1

0002 1

0001 2

0001

_ 1M1tb1ca No ft

n 155

71 6213

59 3026

13 525

15 2715

11 5121

Ifya arenar1a No ft

21 0113

21 0136

22 0186 +

3 0011

0024

48

Appendix Table--Continued

atation 18_1) 21A) IB) IC) 31A) IB) IC) 41A) IB) Ie) 51A) IB) IC) Date April Ill 10 10 10 10

Taxon TIlllllELLAJlIA No 3 5 3 12

lit 0001 0003 + + + 0002 + 0006 +

JlBllEATEA No 1 1 1 lit 000 0007 0004

POLYCIlAllTA Btone diltbullbull No 10 2 14 2 5 3 3 3 5 5

lit 0021 + 0002 0043 0027 000$ 0010 0004 0003 0006 0005 0004

Mbullbullnth 11n1col No 3 12 31 54 51 4amp 52 40 11 lit 0077 0154 0102 1254 0713 05 0614 0543 0410 1amp32 OUO

bullbulludopolydor kellp1 No 1 1 lit 0003 0004

Nopl0 1glI No I 1 20 II 2 60 1 5 2 3 5 lit 0002 + 0004 0024 0020 0014 + 0001 bull 0001 0001

Robaon1 florid No 14 2 30 11 45 50 1 2 1 3 6 1 lit 0145 0001 02amp1 011t OOtl 0160 0004 0007 0004 001 0042 0004

CRU8TACEA Rndlucon 8p No 1

lit bull 0001 bull bull bull BGbutorlubullbullbulltur1 No 16 3 25 31 44 22 34 55

lit 0112 0009 0131 01 0160 00amp1 0107 0232

Bogru oclairi No 1 lit 0001

EDg_ru confrv1colu No 1 1 2 5 1 lit 0001 0001 000 0026 bull

Coroph1ua bullbull18OnI8 No Ii 56 124 31 I 3 1 Nt 0002 bull 0123 0242 0076 0015 0001 0003

Coroph1ua plnlcorn No 2 lit bull

_ri No 1 lit 0001

IN8ECTA Dolichopodi No 3 3 3 2

lit 0017 0011 0014 0001

Chirona1 No 349 112 30 7 7 1 lit 0293 0153 0017 0003 0004 bull

BIVALVIA lflcoae bdtllic No 3 16 31 45 40 63 40 41 30

lit 0042 0473 0 1371 bullbull 350 3410 7245 2010 53 1333

bull

~

bull

48

Appendix Table--Continued

atation 18_1) 21A) IB) IC) 31A) IB) IC) 41A) IB) Ie) 51A) IB) IC) Date April Ill 10 10 10 10

Taxon TIlllllELLAJlIA No 3 5 3 12

lit 0001 0003 + + + 0002 + 0006 +

JlBllEATEA No 1 1 1 lit 000 0007 0004

POLYCIlAllTA Btone diltbullbull No 10 2 14 2 5 3 3 3 5 5

lit 0021 + 0002 0043 0027 000$ 0010 0004 0003 0006 0005 0004

Mbullbullnth 11n1col No 3 12 31 54 51 4amp 52 40 11 lit 0077 0154 0102 1254 0713 05 0614 0543 0410 1amp32 OUO

bullbulludopolydor kellp1 No 1 1 lit 0003 0004

Nopl0 1glI No I 1 20 II 2 60 1 5 2 3 5 lit 0002 + 0004 0024 0020 0014 + 0001 bull 0001 0001

Robaon1 florid No 14 2 30 11 45 50 1 2 1 3 6 1 lit 0145 0001 02amp1 011t OOtl 0160 0004 0007 0004 001 0042 0004

CRU8TACEA Rndlucon 8p No 1

lit bull 0001 bull bull bull BGbutorlubullbullbulltur1 No 16 3 25 31 44 22 34 55

lit 0112 0009 0131 01 0160 00amp1 0107 0232

Bogru oclairi No 1 lit 0001

EDg_ru confrv1colu No 1 1 2 5 1 lit 0001 0001 000 0026 bull

Coroph1ua bullbull18OnI8 No Ii 56 124 31 I 3 1 Nt 0002 bull 0123 0242 0076 0015 0001 0003

Coroph1ua plnlcorn No 2 lit bull

_ri No 1 lit 0001

IN8ECTA Dolichopodi No 3 3 3 2

lit 0017 0011 0014 0001

Chirona1 No 349 112 30 7 7 1 lit 0293 0153 0017 0003 0004 bull

BIVALVIA lflcoae bdtllic No 3 16 31 45 40 63 40 41 30

lit 0042 0473 0 1371 bullbull 350 3410 7245 2010 53 1333

bull

~

bull

49

Appendix Table--Continued

nation (a_le) Oat_ April 1t11

6U~) 10

(B) (e) 7(1) 10

(B) (e) (1) 23

(B) (e) 111) 10

(B) (e)

Taxon ~LLIItIA 0

ft 2

+ 0001 5

0003 3 1

+

IIIIIIIIUA 0 ft

2 0041

2 0015

2 0033

POLYCIIAIIA Bt ultbullbull

Nanth lanlcola

0 ft

0 ft

I 2 0012 0004

21 35 0545 07

3 0005

33 0712

54 1310

1 0002

14 57

1317

+

35 0

U 0501

2

37 0621

11 3000

1 0002

3t 0715

bull 40

0115

bullbullbulludopolydora ku 0 ft

1 0003

1 0002

5 0005

2 0013

3 OOot

3 0007

11 005

7 0020

bull olydora l1gnl 0 ft

2 0010

1 0014

ygopio elgan 0 ft

3 0001 +

1 +

4 0001

5 0001

4 0001

5 0001

2 3 0001 +

Hteraaetue tlllto~ 0 Nt

1 0034

1 0010

Hobaon1a flor1da No ft

2 0001

2 0005

2 0005

7 0022

11 0014

0005

13 0020

4 0021

I 0020

6 0001

CIIVaTACEA HH1lucon ap

Gnorlopbaraa lutbullbull

ito lit

0 ft

1 0011

bull 1 +

Bohauetorlubullbullbulltuar1e No lit

41 0174

5 02

53 0212

4 OOU

4 0014

5 0024

5 0023

3 001

6 0011

2 0004

3 001

Boga_rue confrv1colue No ft

2 0004

I 0032

2 0004

2 0003

Coropb1u ealon1 0 ft

2 0003

2 0004

1 0002

2 0007

6 000

1 0002

5 0001

3 0005

3 0005

Crangon tranalcor 0 lit

1 0010

4 0073

1 0007

Coropb1u ap (juvenile) No lit

1 0002

BIVALVIA balthlea 0

ft 35

2757 33

2116 31

31 62

247 31

2050 57

4515 1

7053 17

3ot 53

16 64

21U 101

2241 3622

1Qf bull bull ranaria 0 ft

1 0007

1 0112 +

1 0002

1 002

1 0001

2 0021

1 0027

50 bull

bull

bull

1

Appendix Table--Continued

Stat-lon C bull -pl) 10CA) (8) Ie) 11CA) (8) Ie) Dat PeU all 23 23

Taxon POLyeHUTA Bteone d1lte 0 I 1

ft 0001 0002

nthe l1an1col 0 I 12 13 3 1It 0066 0050 0040 0032

Hea1podu borel1 0 1 1 1It 0011 0035

Peuclopolydor kcent 0 a 23 15 61 79 41 1It OOU 0035 0021 0312 0314 0163

Polydor l1gn1 0 1 3 2 2 1 1It 0002 0012 0003 0007 0001

PyfJop1o elegn 0 2 11 5 ft bull 0004 0001

Heteroaatu f1l1forat 0 2 2 1 2 1 1It 0021 0016 0005 0005 0005

Hobaon1 flor1d 0 a 21 11 3 4 5 1It 0043 0056 oon 0005 0003 0005

CRUSTACBA Ha1leucon p 0 2 2 6 4 1

1It bull 0002 0001 0001

bullbulldud entOllOll 0 1It bull

Bobutor1u etur1 0 2 2 1It 00011 0003 0007

Bogru ocl1r1 0 3 0016

Bogru conferv1colubullbull0 3 1It 0005

Coropb1ua bullbulllan1 0 3 4 2 1 1It - 0007 OOOS 0001

Coropb1ua p1n1corne 0 1 2 1It 0004 OOOS

Crngon fruc1corua So 1 ft OOOS

Hyt1lu edul1 So 1 1It 0001

BIVALVIA COIN bod th1c 0 13 67 U 76 79 52

ft 2010 42111 2071 1463 OIIS 2360

Ify rend So I 26 15 2 bullft 0237 0417 005 0033 O12S

50 bull

bull

bull

1

Appendix Table--Continued

Stat-lon C bull -pl) 10CA) (8) Ie) 11CA) (8) Ie) Dat PeU all 23 23

Taxon POLyeHUTA Bteone d1lte 0 I 1

ft 0001 0002

nthe l1an1col 0 I 12 13 3 1It 0066 0050 0040 0032

Hea1podu borel1 0 1 1 1It 0011 0035

Peuclopolydor kcent 0 a 23 15 61 79 41 1It OOU 0035 0021 0312 0314 0163

Polydor l1gn1 0 1 3 2 2 1 1It 0002 0012 0003 0007 0001

PyfJop1o elegn 0 2 11 5 ft bull 0004 0001

Heteroaatu f1l1forat 0 2 2 1 2 1 1It 0021 0016 0005 0005 0005

Hobaon1 flor1d 0 a 21 11 3 4 5 1It 0043 0056 oon 0005 0003 0005

CRUSTACBA Ha1leucon p 0 2 2 6 4 1

1It bull 0002 0001 0001

bullbulldud entOllOll 0 1It bull

Bobutor1u etur1 0 2 2 1It 00011 0003 0007

Bogru ocl1r1 0 3 0016

Bogru conferv1colubullbull0 3 1It 0005

Coropb1ua bullbulllan1 0 3 4 2 1 1It - 0007 OOOS 0001

Coropb1ua p1n1corne 0 1 2 1It 0004 OOOS

Crngon fruc1corua So 1 ft OOOS

Hyt1lu edul1 So 1 1It 0001

BIVALVIA COIN bod th1c 0 13 67 U 76 79 52

ft 2010 42111 2071 1463 OIIS 2360

Ify rend So I 26 15 2 bullft 0237 0417 005 0033 O12S

51

Appendix Table--Continued

~a~lon C1 Da~ Jlay un

2CAI 21

CBI cel lCAI 21

CBI cel 4CAI 21

CBI cel 5CAI 21

CBI cel

Taxon TUJI8IILLAIUA 0

Itt l

0002 4

0003 + 3

0002 1

0015 2

0001 - it 0001

5

_TIIA 0 Itt

1 1- 0004 1

0001

POLYCIIAampTA BtOII dJlata 0

ft 10

0021 I

0031 12

0014 5

0006 1

0004 3

0002

0006

I - 0011 3

0005

nthbullbull ltUcola 10 Itt

5 Ol1lt

2 0111

2 005 bullbull115

M 10

55 1045

32 51

40 OSM

40 0510 -

72 0215

42 0511

Pygoplo lgan 10 Itt

1 0001

230 001

11 0014

47 0005

2 +

2 4 + - 1

0001

trtu fJ1Jfora1 10 Itt

2 0013

Hobaonla florlda 10 Itt

12 0014

12 0014

1 0001

51 OOU

32 0054

16 0031

CJlUTACBAHOIdlucon ap 0

Itt + +

Pancolu callforn1nl 10 Itt +

Bobautorlubullbullbulltuarl 10 Itt

2 0003

221 0315

102 020

131 0401

62- 0145 SO

0154

Boga_ru confrvlcolu 10 Itt

2 0001

2 - 0001

Coropbl_ daonl 10 Itt bull +

21 0014

51 0076

U 0044

1 0002

2 0004

2 - 0003 +

Crangon fnnclcorua 10 Itt - 1

0055

I CTA Dol1cbopodl 10

Itt I

0011 6

0001 1

0013 1

0005

Ch1ronoa1dbullbull 10 ft

22 0013

22 11- 0010

BIVALVIA - baltll1ea 0

Itt 6

0162 3

11 1

0112 U 35 10431 1232 15515

U 5601

31 5214

U 2

20- 14 31

31

52

bull bull

bull bull

Appendix Table--Continued

81 1atat1on ~(AI (81 (CI 7(11 (81 (CI 1111 (CI 1(11 (81 (CIDate llay 1111 21 Z1 20 20

laaon TllR8llLLlUUA No 3 7 11 4 3

lit 0002 0004 0001 0002 0001

NDlERftA No 2 2 1 lit 0022 0011 0001

POLYCHUrA Bteone dU te No ~ 5 1 4 3 5bulllit bull 0005 0013 0004 0001 OOOt 0004 0004

enthe 11anlaole No 13 U 33 51 40 21 10 U 32 11 lit bull 0U5 0U7 OU~ 0133 0411 1174 0134 0140 1lOt OUO 0215 0353

Peudopolydor kelp1 80 1 1 1 2 12 17 Z1 33 lit 0002 0001 0001 OOli OOU 0025 0053 0051 0101

Polydor 11gn1 80 1 2 1 lit 0002 000 0003

Pygopl0 elegn No 2 ~ 5 1 12 I 4 lit bull 0001 0001 + 0005 0004 0002

Heteroatu flllfora1 No 1 lit 0002

HobIJonl florid No 1 4 3 1 I 5 4 12 at 11 lit 0005 0001 0001 0003 0001 0010 0021 OOU 0011 0045

CRUSTACZA HeUeuaon bull p 80 bull

lit +

Iopocla No lit bull Bohutoriu eturi 80 III 54 50 23 4 3 1 2 1 lit 0123 0132 0137 0014 001 0011 0034 0017 0005 0006 0001 bull

Bogru aonfervlcolu Bo 2 3 4 13 lit 0002 0004 0001 0011

Coropblua bullbull18Ofti No 1 3 2 7 1 I 2 I 4 7 lit 0001 0005 0005 0012 0002 0013 bull 0002 0001 0003 0015

Coropbl bullp1n1aome 80 1 3 1 lit 0002 0002 0001

crlngon frnclcoru No 2 1 3 1 4 lit 0015 0006 0225 0002 0016

8IVALVIA 1fI_ bllthlc No U 22 2S U 45 4S 75 II 11 12 11

lit 4125 2723 30U 3120 3114 240 5192 LIDO 33 4111 U4 4267

Ny relllri BO 1 1 4 3 4 lit 0110 0027 OOU 01S1 0132

bull

~

52

bull bull

bull bull

Appendix Table--Continued

81 1atat1on ~(AI (81 (CI 7(11 (81 (CI 1111 (CI 1(11 (81 (CIDate llay 1111 21 Z1 20 20

laaon TllR8llLLlUUA No 3 7 11 4 3

lit 0002 0004 0001 0002 0001

NDlERftA No 2 2 1 lit 0022 0011 0001

POLYCHUrA Bteone dU te No ~ 5 1 4 3 5bulllit bull 0005 0013 0004 0001 OOOt 0004 0004

enthe 11anlaole No 13 U 33 51 40 21 10 U 32 11 lit bull 0U5 0U7 OU~ 0133 0411 1174 0134 0140 1lOt OUO 0215 0353

Peudopolydor kelp1 80 1 1 1 2 12 17 Z1 33 lit 0002 0001 0001 OOli OOU 0025 0053 0051 0101

Polydor 11gn1 80 1 2 1 lit 0002 000 0003

Pygopl0 elegn No 2 ~ 5 1 12 I 4 lit bull 0001 0001 + 0005 0004 0002

Heteroatu flllfora1 No 1 lit 0002

HobIJonl florid No 1 4 3 1 I 5 4 12 at 11 lit 0005 0001 0001 0003 0001 0010 0021 OOU 0011 0045

CRUSTACZA HeUeuaon bull p 80 bull

lit +

Iopocla No lit bull Bohutoriu eturi 80 III 54 50 23 4 3 1 2 1 lit 0123 0132 0137 0014 001 0011 0034 0017 0005 0006 0001 bull

Bogru aonfervlcolu Bo 2 3 4 13 lit 0002 0004 0001 0011

Coropblua bullbull18Ofti No 1 3 2 7 1 I 2 I 4 7 lit 0001 0005 0005 0012 0002 0013 bull 0002 0001 0003 0015

Coropbl bullp1n1aome 80 1 3 1 lit 0002 0002 0001

crlngon frnclcoru No 2 1 3 1 4 lit 0015 0006 0225 0002 0016

8IVALVIA 1fI_ bllthlc No U 22 2S U 45 4S 75 II 11 12 11

lit 4125 2723 30U 3120 3114 240 5192 LIDO 33 4111 U4 4267

Ny relllri BO 1 1 4 3 4 lit 0110 0027 OOU 01S1 0132

bull

~

53

Appendix Table--Continued

Statlon ce_lel Date My all

10 (l~1 20

CBI cel llCAI 20

CBI cel

Ifbullbullon IU1IIIampLLAltIA Mo

ft bull ~LyellAE1A atOIIe dll t bullbull Mo

ft bull 1

0002 1

0002 1

0002

bullbullbullnthbullbull 1111ftcol Mo ft

I 0215

5 0135

I 0107

0051

Hea1podu borbullbullll Mo ft

1 0002

1 0001

bullbulludopolydor ku Mo ft

27

bull 003 I

0006 51

0311 72

Ot21 72

ono Polydor 11gnj Mo

ft 4

0004 2 4

0006 0005 2

000 1

0004

PY9opJo 19811 Mo ft

2 bull

a 4 0004 bull

Htrtu tll1tonJ

HobaOllia tlorida

Mo ft

Mo ft

1 0001

32 0113

2 3 - 0015 51 - 0106

2 0005

3 0010

0007

3 0004

1 0001

CIIUS1ACIIA Hmluoon ep Mo

ft 3

0001 bull0003 22

0007 17

0006 14

OOOt

aoga_ru contrvlcolue 80 ft

1 - 0002

Coropblua bullbullJonl Mo ft

14 0033

13 0026

I 0010

Coropblua spJnlcorn 80 ft

1 0002

BIVALVIA ~ bdthlca Mo

ft 125

6410 161

6775 11 I

6460 l0 77

11176 0l72 104

2470

Ify rnd Mo ft

37 Olll

n 1710

U 07

1 0123

1 0036

bull

~

~ I

54

Appendix Table--Continued

Station 11IP1el Dat Jun lIll

21AI 22

IBI leI 31AI 22

IBI leI AI 22

IBI leI SIAl 22

IBI leI

Taxon TVRBampLLARIA 110

lit 2 +

4 0002 + bull0003 +

2 0001

IlUlllRTVt 110 lit

1 0005

POLyellAampTA Bteone dllatae

_nth l1an1coJa

yvopJo ele9an

110 lit

110 lit

110 lit

4 0001

1 0001

1 0002

4 000

4 0003

145 05

0002

112 1051 0002

000

113 0455

I 0003

5 0004

0405

3 0004

43 0211

1 0004

U 0212 0513

3 0003

11 041

3 0002

11 0351

H~onla rlorlde 110 lit

2 0004

U 0031

13 0012

13 0012 +

3 0003

3 0001

4 0002 +

3 000

CRUSTACEAHeml bull p

Babetorlbullbullbullterl

110 bull lit

110 lit

+

5 003 bull0041

150 01

11 0431

131 0312

41 0112

51 0141

104 0314

Bogearu rervlcol 110 lit

Bog_aru ap or pp 110 lyounVI lit

ODropbl el8onl 110 lit

1 0001

34 0011

1 0002

143 0333

11 002

4 0004

2 0003

+

0002

1 0002

5 0002

bull0013

3 0002

3 0002

caa-arldbullbull 110 lit +

Crangon rrenclacor 110 lit

1 oon

1 0063

III8IIClA Dol1chopod1dbullbull

Ch1rOllaa1de

110 lit

110 lit

I 0001

21 0004

000

3 0001

11 0021

25 0003

1 0004

BIVALVIA Ha_ balthlee 110

lit bull 1

0041 1 30

000 12241 2 51 42

204 13 12111 35 53

1345 1552 22D 32

233 24

04

55

Appendix Table--Continued

Station Ca1) Dat J 1t11

CAl 22

C8) CC) 7CA) 22

C8) CC) ICA) 2t

C8) CC) CAl at

C8) CC)

Tbullbullon TURllliLLAltlA 80

lit 1 2

0001 0001 3

0002

DlmRftA 80 lit

1 0003

POLYCIIMlA It cUlata

atha 11JlnJcola

80 ft

80 lit

1 1 + 0002

1 57 0401 0334

3 0003

14 0342

+

7t 031

+

2 0310

100 0143

0342

135 00

It o41a

1 2 0002 + 0004

10 3 1115 04n Oa45

Psudopolydora k-p1 80 lit

2 1 1 - 0003 0001

Pyvospjo ls 80 lit

Htroastus f111for1s 80 lit

1 0013

HaNon1a florida 80 lit bull0002

2 + 0001

9 0003

2 0002

10 0005

0004

n OOU

27 0016

U 00

51 0027

47 0027

CRUSlACEA Eohaustorius stuar1s 80

lit 11

0225 91

0311 lOt

0305 bull0011 20

00$5

0027 1

0004 3

000 1

0005 1

0002 1

0003

Bogs_rus oonfrv1colu 80 lit

3 000

1 0002

Bogru ap or app CyoV)

80 lit +

2 + + +

Coroph1u bullbull1an1 80 lit

0009

4 0005

5 0016

12 0011

20 0045

16 0023

t 0024

7 OOU

15 00

22 0053

22 0054

20 0064

CrngGn frno1corua 80 lit

1 0022

2 0236

2 0057

BIVALVIA _ belth1cs 80

lit 27

1201 20

1010 11

0613 21

2lt 3t

2004 27

3113 17

5121 14

2532 23

2004 27

2001 35

32 11

1n

56

Appendix Table--Continued

Station la_leI 10111 IBI leI 11111 IBI leI Date June 1111 292

Taxon TURBStLARIA Mo 1

ft 0001

_1tTU Mo 1 ft 0003

POlYCIlUTA Nbullbullnth lianlcol Mo 14 11 13 4 5

ft 00 0014 002 000 0014 0011

udopolyrlor keu Mo 2 4 2 11 22 ft bull 0002 0004 0002 0071 00

Htratu rJIJrora1 Mo 1 1 1 1 2 1 ft 0001 0012 0001 0006 0005 0001

HDbllonJ rlorJd Mo 51 III 10 21 11 111 ft bull 0011 0112 00 00111 0003 0015

CRUSTACampA HJl_ ap Mo bull 3 1

ft 0002 0001 0002

eoropbJwa elon1 Mo 12 31 4 1 ft OOU 0015 0141- 0001

BIVAlVIA coae bIolth1c Mo 77 102 111 1 13 11

ft 575 032 521 046 2351 4420

Ifye ernr1 Mo 3 1 II ft 0n4 0432 0490

bull

~

~ I

54

Appendix Table--Continued

Station 11IP1el Dat Jun lIll

21AI 22

IBI leI 31AI 22

IBI leI AI 22

IBI leI SIAl 22

IBI leI

Taxon TVRBampLLARIA 110

lit 2 +

4 0002 + bull0003 +

2 0001

IlUlllRTVt 110 lit

1 0005

POLyellAampTA Bteone dllatae

_nth l1an1coJa

yvopJo ele9an

110 lit

110 lit

110 lit

4 0001

1 0001

1 0002

4 000

4 0003

145 05

0002

112 1051 0002

000

113 0455

I 0003

5 0004

0405

3 0004

43 0211

1 0004

U 0212 0513

3 0003

11 041

3 0002

11 0351

H~onla rlorlde 110 lit

2 0004

U 0031

13 0012

13 0012 +

3 0003

3 0001

4 0002 +

3 000

CRUSTACEAHeml bull p

Babetorlbullbullbullterl

110 bull lit

110 lit

+

5 003 bull0041

150 01

11 0431

131 0312

41 0112

51 0141

104 0314

Bogearu rervlcol 110 lit

Bog_aru ap or pp 110 lyounVI lit

ODropbl el8onl 110 lit

1 0001

34 0011

1 0002

143 0333

11 002

4 0004

2 0003

+

0002

1 0002

5 0002

bull0013

3 0002

3 0002

caa-arldbullbull 110 lit +

Crangon rrenclacor 110 lit

1 oon

1 0063

III8IIClA Dol1chopod1dbullbull

Ch1rOllaa1de

110 lit

110 lit

I 0001

21 0004

000

3 0001

11 0021

25 0003

1 0004

BIVALVIA Ha_ balthlee 110

lit bull 1

0041 1 30

000 12241 2 51 42

204 13 12111 35 53

1345 1552 22D 32

233 24

04

55

Appendix Table--Continued

Station Ca1) Dat J 1t11

CAl 22

C8) CC) 7CA) 22

C8) CC) ICA) 2t

C8) CC) CAl at

C8) CC)

Tbullbullon TURllliLLAltlA 80

lit 1 2

0001 0001 3

0002

DlmRftA 80 lit

1 0003

POLYCIIMlA It cUlata

atha 11JlnJcola

80 ft

80 lit

1 1 + 0002

1 57 0401 0334

3 0003

14 0342

+

7t 031

+

2 0310

100 0143

0342

135 00

It o41a

1 2 0002 + 0004

10 3 1115 04n Oa45

Psudopolydora k-p1 80 lit

2 1 1 - 0003 0001

Pyvospjo ls 80 lit

Htroastus f111for1s 80 lit

1 0013

HaNon1a florida 80 lit bull0002

2 + 0001

9 0003

2 0002

10 0005

0004

n OOU

27 0016

U 00

51 0027

47 0027

CRUSlACEA Eohaustorius stuar1s 80

lit 11

0225 91

0311 lOt

0305 bull0011 20

00$5

0027 1

0004 3

000 1

0005 1

0002 1

0003

Bogs_rus oonfrv1colu 80 lit

3 000

1 0002

Bogru ap or app CyoV)

80 lit +

2 + + +

Coroph1u bullbull1an1 80 lit

0009

4 0005

5 0016

12 0011

20 0045

16 0023

t 0024

7 OOU

15 00

22 0053

22 0054

20 0064

CrngGn frno1corua 80 lit

1 0022

2 0236

2 0057

BIVALVIA _ belth1cs 80

lit 27

1201 20

1010 11

0613 21

2lt 3t

2004 27

3113 17

5121 14

2532 23

2004 27

2001 35

32 11

1n

56

Appendix Table--Continued

Station la_leI 10111 IBI leI 11111 IBI leI Date June 1111 292

Taxon TURBStLARIA Mo 1

ft 0001

_1tTU Mo 1 ft 0003

POlYCIlUTA Nbullbullnth lianlcol Mo 14 11 13 4 5

ft 00 0014 002 000 0014 0011

udopolyrlor keu Mo 2 4 2 11 22 ft bull 0002 0004 0002 0071 00

Htratu rJIJrora1 Mo 1 1 1 1 2 1 ft 0001 0012 0001 0006 0005 0001

HDbllonJ rlorJd Mo 51 III 10 21 11 111 ft bull 0011 0112 00 00111 0003 0015

CRUSTACampA HJl_ ap Mo bull 3 1

ft 0002 0001 0002

eoropbJwa elon1 Mo 12 31 4 1 ft OOU 0015 0141- 0001

BIVAlVIA coae bIolth1c Mo 77 102 111 1 13 11

ft 575 032 521 046 2351 4420

Ifye ernr1 Mo 3 1 II ft 0n4 0432 0490

55

Appendix Table--Continued

Station Ca1) Dat J 1t11

CAl 22

C8) CC) 7CA) 22

C8) CC) ICA) 2t

C8) CC) CAl at

C8) CC)

Tbullbullon TURllliLLAltlA 80

lit 1 2

0001 0001 3

0002

DlmRftA 80 lit

1 0003

POLYCIIMlA It cUlata

atha 11JlnJcola

80 ft

80 lit

1 1 + 0002

1 57 0401 0334

3 0003

14 0342

+

7t 031

+

2 0310

100 0143

0342

135 00

It o41a

1 2 0002 + 0004

10 3 1115 04n Oa45

Psudopolydora k-p1 80 lit

2 1 1 - 0003 0001

Pyvospjo ls 80 lit

Htroastus f111for1s 80 lit

1 0013

HaNon1a florida 80 lit bull0002

2 + 0001

9 0003

2 0002

10 0005

0004

n OOU

27 0016

U 00

51 0027

47 0027

CRUSlACEA Eohaustorius stuar1s 80

lit 11

0225 91

0311 lOt

0305 bull0011 20

00$5

0027 1

0004 3

000 1

0005 1

0002 1

0003

Bogs_rus oonfrv1colu 80 lit

3 000

1 0002

Bogru ap or app CyoV)

80 lit +

2 + + +

Coroph1u bullbull1an1 80 lit

0009

4 0005

5 0016

12 0011

20 0045

16 0023

t 0024

7 OOU

15 00

22 0053

22 0054

20 0064

CrngGn frno1corua 80 lit

1 0022

2 0236

2 0057

BIVALVIA _ belth1cs 80

lit 27

1201 20

1010 11

0613 21

2lt 3t

2004 27

3113 17

5121 14

2532 23

2004 27

2001 35

32 11

1n

56

Appendix Table--Continued

Station la_leI 10111 IBI leI 11111 IBI leI Date June 1111 292

Taxon TURBStLARIA Mo 1

ft 0001

_1tTU Mo 1 ft 0003

POlYCIlUTA Nbullbullnth lianlcol Mo 14 11 13 4 5

ft 00 0014 002 000 0014 0011

udopolyrlor keu Mo 2 4 2 11 22 ft bull 0002 0004 0002 0071 00

Htratu rJIJrora1 Mo 1 1 1 1 2 1 ft 0001 0012 0001 0006 0005 0001

HDbllonJ rlorJd Mo 51 III 10 21 11 111 ft bull 0011 0112 00 00111 0003 0015

CRUSTACampA HJl_ ap Mo bull 3 1

ft 0002 0001 0002

eoropbJwa elon1 Mo 12 31 4 1 ft OOU 0015 0141- 0001

BIVAlVIA coae bIolth1c Mo 77 102 111 1 13 11

ft 575 032 521 046 2351 4420

Ifye ernr1 Mo 3 1 II ft 0n4 0432 0490

56

Appendix Table--Continued

Station la_leI 10111 IBI leI 11111 IBI leI Date June 1111 292

Taxon TURBStLARIA Mo 1

ft 0001

_1tTU Mo 1 ft 0003

POlYCIlUTA Nbullbullnth lianlcol Mo 14 11 13 4 5

ft 00 0014 002 000 0014 0011

udopolyrlor keu Mo 2 4 2 11 22 ft bull 0002 0004 0002 0071 00

Htratu rJIJrora1 Mo 1 1 1 1 2 1 ft 0001 0012 0001 0006 0005 0001

HDbllonJ rlorJd Mo 51 III 10 21 11 111 ft bull 0011 0112 00 00111 0003 0015

CRUSTACampA HJl_ ap Mo bull 3 1

ft 0002 0001 0002

eoropbJwa elon1 Mo 12 31 4 1 ft OOU 0015 0141- 0001

BIVAlVIA coae bIolth1c Mo 77 102 111 1 13 11

ft 575 032 521 046 2351 4420

Ifye ernr1 Mo 3 1 II ft 0n4 0432 0490

57

Appendix Table--Continued

a~~10n Cl) Da~ July Ill

lCA) 11

CB) ce) 3CA) U

CB) ce) 4CA) U

CB) ce) 5CA) U

CB) ce)

Taxon TlRIIampLLAJUA No

ft 1

0001 5

0002 + 4

o au 11

0001 16

0011 17

0004 5

0001 4 +

Ii 0001

oou +

POLYellU1A ton dutbullbull No

ft 4

0002 4

0002 1

0003 4

0005 2

0002 2

0011 1

0001 2

0002 1

0002

_nth llanjcol No ft

U 0021

0026

1 0002

114 010

213 1134

332 2141

50 0365

65 0U1

140 1113 Ost

103 0152

121 1631

PytJouo lagn

Hobaon1 florid

Bo ft

No ft

1 1 + 0001

53 0057

0011

20 0003

243 0230

I 0004

1 0002

30 0016

5 0001

12 0001

11 0001

CRVa1ACV Gftorlopbbullbullroa lutbullbull NO

ft 5

0005 2

0004

ampohutorlubullbullbullturI No ft

5 0046

155 0420

232 0134

65 0230

10 021

55 0120

20 0053

bull Ofru confrvlcolu NO ft

53 0123

2 0005

21 0045

Eogru ocllrl

Coropl1_ 11_1 NO ft

No ft

1 0003

12 0021

11 0034

1 1003

53 0065

4 0004

5 0002

0004

1 0002

1 0004

Coropbl_ unicorn No ft

26 0061

1 0001

2 0002

2 0001

INallC1A Dollahopodidbullbull Bo

ft 26

0093 11

001 20

0061 5

0005 1

0002 1

0004

ehironoaide No ft

443 011

531 0125

I 0301 +

BIVALVIA baltMe No

ft 2

0043 22

052 30 44 t

6519 16251 19202 26 lit

1U2 11404 22

2120 21

4501 17

6151

58

Appendix Table--Continued

Stat10n (8aple) 6(10) (8) (C) 7(10) (8) (C) 1(10) (8) (C) (A) (8) (e) Date July ltll 22 22 27 27

Taxon TlIIIBampLLARIA No 2 4 1 4 3

lit bull 0002 0002 0001 bull bull 0002 0001

IIDIERTEA No 1 lit 0026

POLYCIIAETA Eton cUltbullbull No 1 2 2 1

lit 0001 0002 bull 0001 0002

bullbullbullnthbullbull l1l1111aol No 64 53 11 7 132 150 14 5 51 72 57 52 lit 0317 0U4 1563 OIt 1221 1306 0726 0513 0554 0453 0412 027

Pbullbulludopolydor k~ No 1 2 1 3 lit 0003 0004 0003 0014

Htroaatu fl11forai No 1 1 lit 0010 0024

Hobonl florJd No 7 7 10 23 Z2 26 44 57 4 257 315 255 lit 0005 0010 0040 0021 OOU 0045 0056 0103 0267 0307 0322bull

CRUSTACEA GnorJlIOphbullbullr lutbullbull No 2

lit bull EohutoriubullbullbulltvrI No 71 14 3 25 15 10 1 1 2

lit 0144 025 0016 002 0037 0022 0007 0007 0002

Bogru ocllri 0 lit

Bogru aonfrvlaolu No 2 5 26 1 3 lit 000 0016 0054 0001 0005

Corophlua bullbulllaonl 0 2 2 5 4 5 It 34 13 11 21 lit bull 0004 0012 0007 0010 0052 0001 oon 003amp 0037 oon

Corophlua p1nIaorn No 3 1 13 2 lit 0003 0001 000 0001 0013

Crangon franclaaorua No 1 2 1 1 lit 007 012 0012 011

BIVALVIA balthlc No 24 14 20 24 23 21 26 21 30 53 52 5

lit 4amp3t 4 bull 0 3004 11lt 371 4703 1 3lt4 3311 5nO 5106 4303

Ify rnrJ No 3 lit 0029

bull

58

Appendix Table--Continued

Stat10n (8aple) 6(10) (8) (C) 7(10) (8) (C) 1(10) (8) (C) (A) (8) (e) Date July ltll 22 22 27 27

Taxon TlIIIBampLLARIA No 2 4 1 4 3

lit bull 0002 0002 0001 bull bull 0002 0001

IIDIERTEA No 1 lit 0026

POLYCIIAETA Eton cUltbullbull No 1 2 2 1

lit 0001 0002 bull 0001 0002

bullbullbullnthbullbull l1l1111aol No 64 53 11 7 132 150 14 5 51 72 57 52 lit 0317 0U4 1563 OIt 1221 1306 0726 0513 0554 0453 0412 027

Pbullbulludopolydor k~ No 1 2 1 3 lit 0003 0004 0003 0014

Htroaatu fl11forai No 1 1 lit 0010 0024

Hobonl florJd No 7 7 10 23 Z2 26 44 57 4 257 315 255 lit 0005 0010 0040 0021 OOU 0045 0056 0103 0267 0307 0322bull

CRUSTACEA GnorJlIOphbullbullr lutbullbull No 2

lit bull EohutoriubullbullbulltvrI No 71 14 3 25 15 10 1 1 2

lit 0144 025 0016 002 0037 0022 0007 0007 0002

Bogru ocllri 0 lit

Bogru aonfrvlaolu No 2 5 26 1 3 lit 000 0016 0054 0001 0005

Corophlua bullbulllaonl 0 2 2 5 4 5 It 34 13 11 21 lit bull 0004 0012 0007 0010 0052 0001 oon 003amp 0037 oon

Corophlua p1nIaorn No 3 1 13 2 lit 0003 0001 000 0001 0013

Crangon franclaaorua No 1 2 1 1 lit 007 012 0012 011

BIVALVIA balthlc No 24 14 20 24 23 21 26 21 30 53 52 5

lit 4amp3t 4 bull 0 3004 11lt 371 4703 1 3lt4 3311 5nO 5106 4303

Ify rnrJ No 3 lit 0029

bull

59

Appendix Table--Continued

ftt~on (a_l Date July Ill

bullbullon lVIIBBLJARIA

POLYCJLUfA Bton dllata

utlla l~lcola

VopI0 lgan

stroatu ~ll1~~

HabeDnla ~lorida

CRUafACQIfaJI1leucon bull p

Bohauatorlua bullbulltuari

Coropblua alani

Corophlua p1n1corne

BIVALVIA _ hIIlthloa

Mya arenaria

0 ft

0 ft

Xo ft

0 ft

Xo ft

0 ft

Xo bull ft

Xo ft

Xo ft

Xo ft

0 ft

Xo ft

10ilU 27

2 0006

I 0101

+

111 0110

2 0002

I 0004

7456 1

0002

(B

+

1 0001

3 0001

2

212 0154

+

4 0001

22 0054

1 0002

10 5406

4 0070

(C

4 0001

I 0005

245 0213

2 0005

I 0030

2 0002

10 5UI

10 0U5

ll(A (B (C 27

1 2 1 0002 0011 0001

7 15 3 0004 0011 0003

4 13 3 0001 0004 0001

13 71 4114 6010 6341

60

Appendix Table--Continued

Station lIampl) Date Auquot 1911

1IA) 21

IB) Ie) 21A) 21

IB) Ie) ]IA) IB) 21

Ie) 41A) 21

IB) Ie)

Taxon lURBELLAIUA No

ft ]

O 001 13 21

0001 0012 ]2

0015 3

0002 1

0003

IIKNItItTKA No ft

1 0021

POLyeHAETA Beon dllaeu Jlo

ft 5 5

0005 0001 5

0005 4

0005 ]

0004

bullbullbullntbbullbull l111111cola No ft

1 0021

11 0005

2 0011

13 104 0121 0620

11 0115

14 0523

3 0]]1

54 0347

PYfJOSpjo legan Jlo Nt

] 2] + 0004

20 000] +

HoUon1a flodda No Nt

351 LUI

347 0115

]15 0145

II 0121

14 OOll

14 0016

eRVSTACampA Bobautodubull bullbulltud No

ft ]

0021 I 62

0266

0311

121 0431

Bogru ocl1r1 No ft

1 0015

B09~ru conferv1colu No ft

]

0004 11

0061 2

0002 1

000]

Coroph1 alonl Jlo ft

lS]

0465 115

0321 I]

02ll 4

0007 4

0004 I

0016

eorophlW1 plnlcorne No Nt

1 0002

6 0004

INSECTA Dol1chopocl1c1bullbull Jlo

ft 4

0006 30 47

0090 44

0010 2

000]

Ch1ronoa1c1bullbull No ft

6 5 0002

1122 040]

49] 0195

110 032] +

2 +

GASTROPODA aC0910bullbullbull 110

ft 2

0001 ]

0001 1

0002 1

000]

BIVALVIA - bsltb1c Jlo

ft 24

1631 36

13120 21

10116 36

6104 31

140ll 21

9612

~

61

Appendix Table--Continued

atat10n 11el Oat Auquat Ull

SIAl 21

IBI leI AI 21

IB) Ie) 7(10) 21

IBI leI 1(10) 25

IB) leI

axon lVllllampLUlltIA 110

ft 5~

0014 5

0011 22

0006 3

0001 2

0002 1

0001

POLYCIIMIA Bteane cUlatae 110

ft 1

0001 bull 1

0001 2

0002 1

0002

bullbullantha l1an1cola 110 ft

34 0420

101 1241

53 005

5 2015

24 0447

31 0652

51 10

I~ 1152

66 061

40 0305

32 0410

43 0217

P790ap10 legana 110 lit bull

Hetraaatua f1l1ro~ 110 lit

1 0001

1 0002

1 0003

2 0005

1 0003

H~on1a flor1da 110 lit

7 0001

163 0561

3 00

15 0025

0015

4 0005

0007

22 0042

16 0014

50 003

61 0107

2t 0023

CRVampIACU Gftor1aoapbaraa luta 110

ft bull 1

0002

Bohauator1ua atvar1a 110 lit

52 0124

30 003

73 0111

14 0033

144 0312

121 0341

11 0011

11 0063

12 0034

I 0027

16 0040

13 0035

BD9a_rua ocldr1 110 lit

1 0005

BD9a_rua confrv1colua 110 lit

16 0024

3 0013

Coropbju al8On1a 110

lit 4

0003 43

0064 7

0002 2

0006

0007 2

0005 10

0011 I

000 2

0004 11

0024 11

0024 13

0013

Coropbjwa p1n1corn

BIVALVIA coea haltb1

110 lit

110 lit

35 0050

11 2t 42U 14205

22 4UO

3 0004

21 7412

20 2154

22 4133

21 4541

5 OOOl

25 5154

23 4221

21 400

1 0002

2 5525

11 4120

62

Appendix Table--Continued

atat10n Ca_le) Date Au9Uat 1111

IIA) 26

(8) ce) 10CA) 25

(8) ce) llCA) 26

(8) ce)

Taxon TURBELLARlA 110

lit 2 3

0002 bull IIBIIKRftA 110

lit 1

0006 1

0004 2

POLyeHAZTA BteOll dilata 110

lit 2

0002 2

0002 2

0001 1

0001 2

0001

allth 111cola 110 lit bull

2 115

54 1016

51 051

50 0511

4 0651

21 OUO

10 004

1 0003

Peaudopolydora tapl 110 lit

3 0010

3 0014

3 0011

14 000

20 0015

17 0015

Pygoap10 alegalla 110 lit bull

2 bull

Hataroaatua fll1fonda 110 lit

1 0035

1 0005

1 0017

3 0074

3 0011

2 0021

Hobsonla florlda 110 lit

55 0073

5 0075

31 0040

162 0271

210 0511

200 0355

7 0001

000

eRIIBTAeRA lIa81laucon ap 110

lit 2 bull

Eohauetorlua aetuarla 110 lit

1 0004

5 0010

1 0006

Eoga_rue confrv1colue 110 lit

1 0315

3 0004

Coropl1U1O aaton1e 110 lit

2 1 0002

5 1 0002

1 0002

CorophlU1O ap1111corn 110 lit

7 0004

4 0004

I 0004

4 0002

CrangOll frallc1acorUlO 110 lit

1 03115

BIVALVIA Ifa_ balthlca 110

lit 21

7223 25

7111 11

3125 60

7112

11246 129

103 10557 61 111

7417 15612

Ifya arallada 110 lit bull

bull

$

~

63

AppencUx Tab~e--Continued

fttlon (~l) Dat lept_~ 11111

2(A) 15

(al (e) 3(A) 15

(a) (e) 4(AI 15

(a) (el 5(A) 15

(al (e)

Taxon TUlUlampLLAIIIA ao

lit 2

0002 I

0005 U

0020 U

0014 5

0001 2

0001 15

0004 4

+ 0002 2

0001

_DA ao lit

1 0010

IOLYellAlllA Iton diltbullbull ao

lit 7

0001 111

OOU 5

bull 1

0001 bull lIt1l lllln1col ao

lit 4

0030 115

2015 21

0213 0704 123

0 51

0417 57

0290 51

0327 32

0505 U

011 21

021

udopolydor t-pI

yvopjo 1glI ao ft

ao ft bull

sbull

1 0001

H0b8onl florId a ft

3 ooos

13 14 0001

172 0273

471 31 - oon 114

035 0157 11

0013 13 7 - 0005

CIIUIIACU Gnor180pbbullbullra lut aD

ft 1

0001

BohuatorJua bullbulltur1 ao ft

3 0031

4 02

74 0343

71 0223

121 0379

53 OUI

Iogru oclairi ao ft

1 0005

Iogru confrvicolu ao ft +

111 5

Coropb1ua bullbulll8Gn1 ao ft

2 0004

3 0002 bull0001

131 0213

382 0110

9 0002

4 0004

l0022

4 000

37 0071

3 0004

Coroplliua pjll1corn ao ft

1 0002 bull0001

2 0002

12

IalampCIA Dollahopocl1 a

ft 54

0251 3

0007 10

0040 22

00amp5 2

0005

Chl~_oa1 aD lit

III 057

4 0037

1151 107

I 0003

2bull

ampphytl~lt1bullbull

au_ middot00910bullbullbull

ao ft

ao ft

73 0201

12 0051

170 01

1 0010

22 0050

3 0004

aIVALVIA Ifa_ 1M1tll1oa ao

ft 5

1351 21 3

7017 1711 25 27 45 33

952 10311 14012 1121 11 3

4012 12353 U

451

64

Appendix Table--Continued

na1JOIl 1__101 amplAI IBI ICI llAI 181 ICI IIAI IBI ICI IIAI IBI ICI Dat ep1_r Ill 15 15 25 25

Taxon TUlIBEIIAIUA 110 2 2 3 2 2 2 2

ft + + 0001 0001 0001 0001

JlKllZRTBA 110 1 1 1 ft 0004 0002 0004

POIYCIIAETA Bteone dil te 110 1 1 1 2 3 2

ft 0001 0001 0001 0001 0002 0001

Neatbo lllcola 110 64 61 101 11 57 36 42 16 11 53 25 65 ft 114 0400 0314 0665 0431 0130 032 0719 00 05 0110 0774

nudopolydora ku 110 5 6 1 1 2 ft - 0003 - 0001 0002

Heteraatu flllfor1 110 1 1 1 1 ft 0015 0030 003 0023

Hoboonla florlda 110 5 4 10 3 40 46 66 ft - 0016 0011 0012 - 0113 0091 0100 0165 020 0141

CIIUSTACampA GJlodaoplaeraa lutea liD 1

ft 0001

Bohautodua tuad liD 106 113 154 7 21 15 12 10 1 1 ft - 0312 0461 002 - 0066 0052 0044 0032 0002 0003

Bogru oclalr1 110 1 2 ft 0004 0007

Bogru confervlcolu 110 2 2 3 3 3 ft 0005 0001 0011 0007 0005

Coropl1u bullbulllaonl 110 5 11 14 15 6 1 ft 0014 - 0023 - 0010 0020 0027 - 0014 - 0003

Coropl1u ap11come 110 10 3 3 12 ft + 0011 0005 0003 000amp

BIVALVIA 1fI_ baltlJ1ca liD 17 21 22 22 I 16 24 11 20 21 15

ft 3315 3635 5300 5021 7245 1124 361 7026 3521 6240 1151 3767l

I

1~

61

Appendix Table--Continued

atat10n 11el Oat Auquat Ull

SIAl 21

IBI leI AI 21

IB) Ie) 7(10) 21

IBI leI 1(10) 25

IB) leI

axon lVllllampLUlltIA 110

ft 5~

0014 5

0011 22

0006 3

0001 2

0002 1

0001

POLYCIIMIA Bteane cUlatae 110

ft 1

0001 bull 1

0001 2

0002 1

0002

bullbullantha l1an1cola 110 ft

34 0420

101 1241

53 005

5 2015

24 0447

31 0652

51 10

I~ 1152

66 061

40 0305

32 0410

43 0217

P790ap10 legana 110 lit bull

Hetraaatua f1l1ro~ 110 lit

1 0001

1 0002

1 0003

2 0005

1 0003

H~on1a flor1da 110 lit

7 0001

163 0561

3 00

15 0025

0015

4 0005

0007

22 0042

16 0014

50 003

61 0107

2t 0023

CRVampIACU Gftor1aoapbaraa luta 110

ft bull 1

0002

Bohauator1ua atvar1a 110 lit

52 0124

30 003

73 0111

14 0033

144 0312

121 0341

11 0011

11 0063

12 0034

I 0027

16 0040

13 0035

BD9a_rua ocldr1 110 lit

1 0005

BD9a_rua confrv1colua 110 lit

16 0024

3 0013

Coropbju al8On1a 110

lit 4

0003 43

0064 7

0002 2

0006

0007 2

0005 10

0011 I

000 2

0004 11

0024 11

0024 13

0013

Coropbjwa p1n1corn

BIVALVIA coea haltb1

110 lit

110 lit

35 0050

11 2t 42U 14205

22 4UO

3 0004

21 7412

20 2154

22 4133

21 4541

5 OOOl

25 5154

23 4221

21 400

1 0002

2 5525

11 4120

62

Appendix Table--Continued

atat10n Ca_le) Date Au9Uat 1111

IIA) 26

(8) ce) 10CA) 25

(8) ce) llCA) 26

(8) ce)

Taxon TURBELLARlA 110

lit 2 3

0002 bull IIBIIKRftA 110

lit 1

0006 1

0004 2

POLyeHAZTA BteOll dilata 110

lit 2

0002 2

0002 2

0001 1

0001 2

0001

allth 111cola 110 lit bull

2 115

54 1016

51 051

50 0511

4 0651

21 OUO

10 004

1 0003

Peaudopolydora tapl 110 lit

3 0010

3 0014

3 0011

14 000

20 0015

17 0015

Pygoap10 alegalla 110 lit bull

2 bull

Hataroaatua fll1fonda 110 lit

1 0035

1 0005

1 0017

3 0074

3 0011

2 0021

Hobsonla florlda 110 lit

55 0073

5 0075

31 0040

162 0271

210 0511

200 0355

7 0001

000

eRIIBTAeRA lIa81laucon ap 110

lit 2 bull

Eohauetorlua aetuarla 110 lit

1 0004

5 0010

1 0006

Eoga_rue confrv1colue 110 lit

1 0315

3 0004

Coropl1U1O aaton1e 110 lit

2 1 0002

5 1 0002

1 0002

CorophlU1O ap1111corn 110 lit

7 0004

4 0004

I 0004

4 0002

CrangOll frallc1acorUlO 110 lit

1 03115

BIVALVIA Ifa_ balthlca 110

lit 21

7223 25

7111 11

3125 60

7112

11246 129

103 10557 61 111

7417 15612

Ifya arallada 110 lit bull

bull

$

~

63

AppencUx Tab~e--Continued

fttlon (~l) Dat lept_~ 11111

2(A) 15

(al (e) 3(A) 15

(a) (e) 4(AI 15

(a) (el 5(A) 15

(al (e)

Taxon TUlUlampLLAIIIA ao

lit 2

0002 I

0005 U

0020 U

0014 5

0001 2

0001 15

0004 4

+ 0002 2

0001

_DA ao lit

1 0010

IOLYellAlllA Iton diltbullbull ao

lit 7

0001 111

OOU 5

bull 1

0001 bull lIt1l lllln1col ao

lit 4

0030 115

2015 21

0213 0704 123

0 51

0417 57

0290 51

0327 32

0505 U

011 21

021

udopolydor t-pI

yvopjo 1glI ao ft

ao ft bull

sbull

1 0001

H0b8onl florId a ft

3 ooos

13 14 0001

172 0273

471 31 - oon 114

035 0157 11

0013 13 7 - 0005

CIIUIIACU Gnor180pbbullbullra lut aD

ft 1

0001

BohuatorJua bullbulltur1 ao ft

3 0031

4 02

74 0343

71 0223

121 0379

53 OUI

Iogru oclairi ao ft

1 0005

Iogru confrvicolu ao ft +

111 5

Coropb1ua bullbulll8Gn1 ao ft

2 0004

3 0002 bull0001

131 0213

382 0110

9 0002

4 0004

l0022

4 000

37 0071

3 0004

Coroplliua pjll1corn ao ft

1 0002 bull0001

2 0002

12

IalampCIA Dollahopocl1 a

ft 54

0251 3

0007 10

0040 22

00amp5 2

0005

Chl~_oa1 aD lit

III 057

4 0037

1151 107

I 0003

2bull

ampphytl~lt1bullbull

au_ middot00910bullbullbull

ao ft

ao ft

73 0201

12 0051

170 01

1 0010

22 0050

3 0004

aIVALVIA Ifa_ 1M1tll1oa ao

ft 5

1351 21 3

7017 1711 25 27 45 33

952 10311 14012 1121 11 3

4012 12353 U

451

64

Appendix Table--Continued

na1JOIl 1__101 amplAI IBI ICI llAI 181 ICI IIAI IBI ICI IIAI IBI ICI Dat ep1_r Ill 15 15 25 25

Taxon TUlIBEIIAIUA 110 2 2 3 2 2 2 2

ft + + 0001 0001 0001 0001

JlKllZRTBA 110 1 1 1 ft 0004 0002 0004

POIYCIIAETA Bteone dil te 110 1 1 1 2 3 2

ft 0001 0001 0001 0001 0002 0001

Neatbo lllcola 110 64 61 101 11 57 36 42 16 11 53 25 65 ft 114 0400 0314 0665 0431 0130 032 0719 00 05 0110 0774

nudopolydora ku 110 5 6 1 1 2 ft - 0003 - 0001 0002

Heteraatu flllfor1 110 1 1 1 1 ft 0015 0030 003 0023

Hoboonla florlda 110 5 4 10 3 40 46 66 ft - 0016 0011 0012 - 0113 0091 0100 0165 020 0141

CIIUSTACampA GJlodaoplaeraa lutea liD 1

ft 0001

Bohautodua tuad liD 106 113 154 7 21 15 12 10 1 1 ft - 0312 0461 002 - 0066 0052 0044 0032 0002 0003

Bogru oclalr1 110 1 2 ft 0004 0007

Bogru confervlcolu 110 2 2 3 3 3 ft 0005 0001 0011 0007 0005

Coropl1u bullbulllaonl 110 5 11 14 15 6 1 ft 0014 - 0023 - 0010 0020 0027 - 0014 - 0003

Coropl1u ap11come 110 10 3 3 12 ft + 0011 0005 0003 000amp

BIVALVIA 1fI_ baltlJ1ca liD 17 21 22 22 I 16 24 11 20 21 15

ft 3315 3635 5300 5021 7245 1124 361 7026 3521 6240 1151 3767l

I

1~

62

Appendix Table--Continued

atat10n Ca_le) Date Au9Uat 1111

IIA) 26

(8) ce) 10CA) 25

(8) ce) llCA) 26

(8) ce)

Taxon TURBELLARlA 110

lit 2 3

0002 bull IIBIIKRftA 110

lit 1

0006 1

0004 2

POLyeHAZTA BteOll dilata 110

lit 2

0002 2

0002 2

0001 1

0001 2

0001

allth 111cola 110 lit bull

2 115

54 1016

51 051

50 0511

4 0651

21 OUO

10 004

1 0003

Peaudopolydora tapl 110 lit

3 0010

3 0014

3 0011

14 000

20 0015

17 0015

Pygoap10 alegalla 110 lit bull

2 bull

Hataroaatua fll1fonda 110 lit

1 0035

1 0005

1 0017

3 0074

3 0011

2 0021

Hobsonla florlda 110 lit

55 0073

5 0075

31 0040

162 0271

210 0511

200 0355

7 0001

000

eRIIBTAeRA lIa81laucon ap 110

lit 2 bull

Eohauetorlua aetuarla 110 lit

1 0004

5 0010

1 0006

Eoga_rue confrv1colue 110 lit

1 0315

3 0004

Coropl1U1O aaton1e 110 lit

2 1 0002

5 1 0002

1 0002

CorophlU1O ap1111corn 110 lit

7 0004

4 0004

I 0004

4 0002

CrangOll frallc1acorUlO 110 lit

1 03115

BIVALVIA Ifa_ balthlca 110

lit 21

7223 25

7111 11

3125 60

7112

11246 129

103 10557 61 111

7417 15612

Ifya arallada 110 lit bull

bull

$

~

63

AppencUx Tab~e--Continued

fttlon (~l) Dat lept_~ 11111

2(A) 15

(al (e) 3(A) 15

(a) (e) 4(AI 15

(a) (el 5(A) 15

(al (e)

Taxon TUlUlampLLAIIIA ao

lit 2

0002 I

0005 U

0020 U

0014 5

0001 2

0001 15

0004 4

+ 0002 2

0001

_DA ao lit

1 0010

IOLYellAlllA Iton diltbullbull ao

lit 7

0001 111

OOU 5

bull 1

0001 bull lIt1l lllln1col ao

lit 4

0030 115

2015 21

0213 0704 123

0 51

0417 57

0290 51

0327 32

0505 U

011 21

021

udopolydor t-pI

yvopjo 1glI ao ft

ao ft bull

sbull

1 0001

H0b8onl florId a ft

3 ooos

13 14 0001

172 0273

471 31 - oon 114

035 0157 11

0013 13 7 - 0005

CIIUIIACU Gnor180pbbullbullra lut aD

ft 1

0001

BohuatorJua bullbulltur1 ao ft

3 0031

4 02

74 0343

71 0223

121 0379

53 OUI

Iogru oclairi ao ft

1 0005

Iogru confrvicolu ao ft +

111 5

Coropb1ua bullbulll8Gn1 ao ft

2 0004

3 0002 bull0001

131 0213

382 0110

9 0002

4 0004

l0022

4 000

37 0071

3 0004

Coroplliua pjll1corn ao ft

1 0002 bull0001

2 0002

12

IalampCIA Dollahopocl1 a

ft 54

0251 3

0007 10

0040 22

00amp5 2

0005

Chl~_oa1 aD lit

III 057

4 0037

1151 107

I 0003

2bull

ampphytl~lt1bullbull

au_ middot00910bullbullbull

ao ft

ao ft

73 0201

12 0051

170 01

1 0010

22 0050

3 0004

aIVALVIA Ifa_ 1M1tll1oa ao

ft 5

1351 21 3

7017 1711 25 27 45 33

952 10311 14012 1121 11 3

4012 12353 U

451

64

Appendix Table--Continued

na1JOIl 1__101 amplAI IBI ICI llAI 181 ICI IIAI IBI ICI IIAI IBI ICI Dat ep1_r Ill 15 15 25 25

Taxon TUlIBEIIAIUA 110 2 2 3 2 2 2 2

ft + + 0001 0001 0001 0001

JlKllZRTBA 110 1 1 1 ft 0004 0002 0004

POIYCIIAETA Bteone dil te 110 1 1 1 2 3 2

ft 0001 0001 0001 0001 0002 0001

Neatbo lllcola 110 64 61 101 11 57 36 42 16 11 53 25 65 ft 114 0400 0314 0665 0431 0130 032 0719 00 05 0110 0774

nudopolydora ku 110 5 6 1 1 2 ft - 0003 - 0001 0002

Heteraatu flllfor1 110 1 1 1 1 ft 0015 0030 003 0023

Hoboonla florlda 110 5 4 10 3 40 46 66 ft - 0016 0011 0012 - 0113 0091 0100 0165 020 0141

CIIUSTACampA GJlodaoplaeraa lutea liD 1

ft 0001

Bohautodua tuad liD 106 113 154 7 21 15 12 10 1 1 ft - 0312 0461 002 - 0066 0052 0044 0032 0002 0003

Bogru oclalr1 110 1 2 ft 0004 0007

Bogru confervlcolu 110 2 2 3 3 3 ft 0005 0001 0011 0007 0005

Coropl1u bullbulllaonl 110 5 11 14 15 6 1 ft 0014 - 0023 - 0010 0020 0027 - 0014 - 0003

Coropl1u ap11come 110 10 3 3 12 ft + 0011 0005 0003 000amp

BIVALVIA 1fI_ baltlJ1ca liD 17 21 22 22 I 16 24 11 20 21 15

ft 3315 3635 5300 5021 7245 1124 361 7026 3521 6240 1151 3767l

I

1~

63

AppencUx Tab~e--Continued

fttlon (~l) Dat lept_~ 11111

2(A) 15

(al (e) 3(A) 15

(a) (e) 4(AI 15

(a) (el 5(A) 15

(al (e)

Taxon TUlUlampLLAIIIA ao

lit 2

0002 I

0005 U

0020 U

0014 5

0001 2

0001 15

0004 4

+ 0002 2

0001

_DA ao lit

1 0010

IOLYellAlllA Iton diltbullbull ao

lit 7

0001 111

OOU 5

bull 1

0001 bull lIt1l lllln1col ao

lit 4

0030 115

2015 21

0213 0704 123

0 51

0417 57

0290 51

0327 32

0505 U

011 21

021

udopolydor t-pI

yvopjo 1glI ao ft

ao ft bull

sbull

1 0001

H0b8onl florId a ft

3 ooos

13 14 0001

172 0273

471 31 - oon 114

035 0157 11

0013 13 7 - 0005

CIIUIIACU Gnor180pbbullbullra lut aD

ft 1

0001

BohuatorJua bullbulltur1 ao ft

3 0031

4 02

74 0343

71 0223

121 0379

53 OUI

Iogru oclairi ao ft

1 0005

Iogru confrvicolu ao ft +

111 5

Coropb1ua bullbulll8Gn1 ao ft

2 0004

3 0002 bull0001

131 0213

382 0110

9 0002

4 0004

l0022

4 000

37 0071

3 0004

Coroplliua pjll1corn ao ft

1 0002 bull0001

2 0002

12

IalampCIA Dollahopocl1 a

ft 54

0251 3

0007 10

0040 22

00amp5 2

0005

Chl~_oa1 aD lit

III 057

4 0037

1151 107

I 0003

2bull

ampphytl~lt1bullbull

au_ middot00910bullbullbull

ao ft

ao ft

73 0201

12 0051

170 01

1 0010

22 0050

3 0004

aIVALVIA Ifa_ 1M1tll1oa ao

ft 5

1351 21 3

7017 1711 25 27 45 33

952 10311 14012 1121 11 3

4012 12353 U

451

64

Appendix Table--Continued

na1JOIl 1__101 amplAI IBI ICI llAI 181 ICI IIAI IBI ICI IIAI IBI ICI Dat ep1_r Ill 15 15 25 25

Taxon TUlIBEIIAIUA 110 2 2 3 2 2 2 2

ft + + 0001 0001 0001 0001

JlKllZRTBA 110 1 1 1 ft 0004 0002 0004

POIYCIIAETA Bteone dil te 110 1 1 1 2 3 2

ft 0001 0001 0001 0001 0002 0001

Neatbo lllcola 110 64 61 101 11 57 36 42 16 11 53 25 65 ft 114 0400 0314 0665 0431 0130 032 0719 00 05 0110 0774

nudopolydora ku 110 5 6 1 1 2 ft - 0003 - 0001 0002

Heteraatu flllfor1 110 1 1 1 1 ft 0015 0030 003 0023

Hoboonla florlda 110 5 4 10 3 40 46 66 ft - 0016 0011 0012 - 0113 0091 0100 0165 020 0141

CIIUSTACampA GJlodaoplaeraa lutea liD 1

ft 0001

Bohautodua tuad liD 106 113 154 7 21 15 12 10 1 1 ft - 0312 0461 002 - 0066 0052 0044 0032 0002 0003

Bogru oclalr1 110 1 2 ft 0004 0007

Bogru confervlcolu 110 2 2 3 3 3 ft 0005 0001 0011 0007 0005

Coropl1u bullbulllaonl 110 5 11 14 15 6 1 ft 0014 - 0023 - 0010 0020 0027 - 0014 - 0003

Coropl1u ap11come 110 10 3 3 12 ft + 0011 0005 0003 000amp

BIVALVIA 1fI_ baltlJ1ca liD 17 21 22 22 I 16 24 11 20 21 15

ft 3315 3635 5300 5021 7245 1124 361 7026 3521 6240 1151 3767l

I

1~

64

Appendix Table--Continued

na1JOIl 1__101 amplAI IBI ICI llAI 181 ICI IIAI IBI ICI IIAI IBI ICI Dat ep1_r Ill 15 15 25 25

Taxon TUlIBEIIAIUA 110 2 2 3 2 2 2 2

ft + + 0001 0001 0001 0001

JlKllZRTBA 110 1 1 1 ft 0004 0002 0004

POIYCIIAETA Bteone dil te 110 1 1 1 2 3 2

ft 0001 0001 0001 0001 0002 0001

Neatbo lllcola 110 64 61 101 11 57 36 42 16 11 53 25 65 ft 114 0400 0314 0665 0431 0130 032 0719 00 05 0110 0774

nudopolydora ku 110 5 6 1 1 2 ft - 0003 - 0001 0002

Heteraatu flllfor1 110 1 1 1 1 ft 0015 0030 003 0023

Hoboonla florlda 110 5 4 10 3 40 46 66 ft - 0016 0011 0012 - 0113 0091 0100 0165 020 0141

CIIUSTACampA GJlodaoplaeraa lutea liD 1

ft 0001

Bohautodua tuad liD 106 113 154 7 21 15 12 10 1 1 ft - 0312 0461 002 - 0066 0052 0044 0032 0002 0003

Bogru oclalr1 110 1 2 ft 0004 0007

Bogru confervlcolu 110 2 2 3 3 3 ft 0005 0001 0011 0007 0005

Coropl1u bullbulllaonl 110 5 11 14 15 6 1 ft 0014 - 0023 - 0010 0020 0027 - 0014 - 0003

Coropl1u ap11come 110 10 3 3 12 ft + 0011 0005 0003 000amp

BIVALVIA 1fI_ baltlJ1ca liD 17 21 22 22 I 16 24 11 20 21 15

ft 3315 3635 5300 5021 7245 1124 361 7026 3521 6240 1151 3767l

I

1~

65

Appendix Table--Continuedbull

lOCAl 25

2 0002

23 0311

3 0005

bull2

1 0001

111 OUl

1 0025

3 0004

13M3

3 5020

cal

1 000

11 01 000

3 +

1 0002

241 0141

bull000

as 0042

118 13102

eC1 11 CAl cal CCI 25

2 0005

+

1 2 2 1 0265 0024 0012 0011

1 11 51 0001 0155 0101 0041

1 4 2 0041 001 0042 0011

51 4 4 0152 0001 0002 +

3 0004

2 0001

5 0011

2 0002

23 0017

2 07

37 nl 148 152 5115 18345 11872 20

bull taUOft c_l Dat aept_~ 1111

Tn TVRULLAIlIA

_TEA

POLYCIlAlliTA Bt_ dUtbullbull

enthbullbull JjjGOl

PeudOpoJydor t~

pygopjo eJo

Heteroatu f1l1fo~

HoIraquoon1 rlodd

aVTAcLadnubullbullp

~_a

Bog_ru ocldd

Bog_ru canrerv1GO1u ao ft

Coropll1 d8Oll1 ao ft

COropl1 p1n1come 0 ft

_~1c1a ao ft

Crogan rrno1coru 0 ft

alVAloVlA boIltlllca ao

ft

~ renr1 ao ft

0 ft

0 ft

0 ft

0 ft

0 ft

0 ft

ao ft

ao ft

ao ft

ao ft

ao ft

66

Appendix Table--Continuedbull

bull ttlon Cpl 2CAI CBI CCI 3CAI CBI CCI 4CAI CBI CCI 5 CAl CBI CCI Dat 00t01oe 1111 21 21 21 21

fbullbullOft ~LLARIA Ko 12 5 47 41 4 21 5 11 3 n 10 13

ft - 0001 0027 0002 0017 0002 0004 0001 0010 0003 0003

_DA Ko 2 ft 0037

POLYCHUTA Bteon dJltbullbull Ko 24 I 11 1 2

lit 010 0020 0051 0002

Wbullbullnth l1n1col Ko 1 4 121 0 155 57 71 53 41 7 42 lit 0015 0211 1bullbull3 0155 1173 0502 0475 0410 0551 1011 0525

bullbulludopolydor tu Ko 2 1 lit 0004 + 0001

YfJOp1o ln Ko bulllit 0001 +

Htraatu r1l1rora1 Ko 1 1 ft 0004 0002

Hobaon1 rlor1d Ko 225 10 140 21 31 51 11 151 20 lit 0516 0142 0270 0057 0010 0175 0026 0125 oon

CIIUTACKA Gnor1bullbullpbbullbullr_ lutbullbull Ko 1

lit 0001 Bohutor1u tur1 Ko 3 1 135 20 53 17 41 lit 0011 0004 0513 001amp - 0334 - 0222

ru ocJdd Ko 4 1 ft 0005 0002

Bovru conrrv1colu Ko 3 4 13 ft - 0004 - 0035

ru ap 0 app Ko bullCy ft

Coropb1_ aJlIOft1 Ko n 111 317 15 32 55 4 51 10 lit 0145 0112 0422 0011 - 0012 0002 0121 0005

Coropb1_ p1n1corne BO 21 2 11 2 22 3 lit + 0050 0002 0021 0001 0015 0001

IKZCTA Dol101aopodl Ko 22 2 27 2

ft - 0041 0070 0004

Ch1onOll1 Ko 1515 3411 1454 11 1 lit 1355 1452 1200 0007 0001

ZpbyCd Bo 12 15 ft 0130

GAII_ bullbull_loa Ko 0 55 100 2

lit - 0151 0004-BIVALVIA Ifa_ balth1ca KO 22 22 31 11 41 31 15 51 17

ft 1515 5 21157 5733 14UI 15552 5051 17025 41

bull

~

~

~

At

1

67

Appendix Table--Continued

ta~~on Cal 6CAI C81 cel 1CAI (8) cel ICAI CBI cel teAl C81 cel Dah OOtClber 1111 21 21 U 25

Tbullbullon TllllBampLUaIA 80 2 6 3 1 2 1 11 I 11 15 13 13

ft 0001 0003 0002 + 0002 0001 0004 0003 0003 0001 0001 0001 _BA 80 1 2 1 1 ft 0024 0031 0005 0056

POLyellUTA Bt d11ata 80 1 4 1 2 2 2 2

ft + 0003 0002 0002 0003 0001 0002

thbullbull 111oola 80 II 40 3D 58 12 U 32 4 40 H 10 Sl ft 0U1 1035 30S lon OS 01 0U3 02S1 0255 2240 0115 1231

Paudopolydora tellp1 80 2 1 I 5 4 1ft + 0002 OOOS + 0019 0001 0022 - 0014

Polydora 119111 80 1 1 5 ft + 0002 0001

Pyvop1o elgan 80 1 ft 0001

troaatu E111Eor81 80 1 ft 0001 +

Hobaon1a Elor1da 80 S 21 11 45 120 N 113 311 US 152 121 150 ft 0010 0055 OOot 0052 0113 011 0lS0 0424 0314 0211 0211 0U4

CIIVTACampA HUeuoon ap Bo 3

ft 0001 +

Bahautor1ua aturia 80 121 5 105 22 10 22 13 31 20 1 1 ft 0410 0242 0311 001 0021 0074 0017 OUI 0011 0002 0004

Bogru conEerv1oolu Bo 1 21 3 15 5 2 ft 0002 0012 0001 0010 0015 0010

Coropb1ua aalan1a 80 2 11 5 2 12 20 23 4 2 ft 0001 0015 0001 0001 0031 0024 0021 0041 0004 0005

Coropb1 ap1n1oorne Bo 32 10 1 3 S 3 1 ft + 0011 0003 0001 0001 + 0005 0002 0001

IBSCTA Ch1rcmoa1cla Bo 1

ft 0002

BIVALVIA Ifa_ JNlth1ca 80 12 24 11 21 21 22 40 32 U 32 11

ft 3SI3 12 3215 4217 S01 4U4 12737 005 sns 5S3I 22 5100

lIya arenar1a 80 1 ft 0004

i

~

~

~

~

68

Appendix Table--Continued

S~t1on Cbullbullbullbull lOCAl CBI CCI 11 CAl CBI CCI Date OCtober 1911 26 25

Taxon TlIUIILLAIUA Bo 1 1 12

lit 000l 0001 0004

IIDIERTEA Bo 1 2 lit bull 0005 0005

aLYCHAITA Bteone dUt Bo 1

lit 0001

Mbullbullnthe l~lcol Bo 21 25 2a 1 1 2 B~ 051 1402 031 0001 0014 oon

eudopolydoz Jrnpi Bo 23 11 27 7 I 11 lit bull 00 0033 oon 000 0011 0033

olydor l1nl Bo 2 7 7 1 1 lit 0001 oon 0001 0001 0003

yvop1o elevn Bo 3 2 n lit 0001 bull 0004

bull Heter_tu lillonU Bo 1 2 2 $ 7 II~ 0037 0100 0110 0022 0032 0146

HobsonJ t 1 orid 110 ua U4 22 3 lit 0397 0471 ono 0003 000

CltUSTACEA Hell11eucon p No 2 3

lit bull 0001

Eoru oclJrJ Bo 2 lit bull OOOll

Eoru contervlcolu Bo 1 111 0001

Coropblu bullbulllonl Bbullbull 2 1 II~ 0001 0001

Cozopbiu p1nlcorne Bo 2a ZI lit 0019 0014

alVAJVIA _ baltMc Bo It n 7

II~ 12069 12U5 11361 130 12163 2 My aranada Bo 2 1 1

lit bull DOO 0004 0002

bull 19~ lt 0001 9 - Indlc~bullbull vol~~ no~ ~kn

i

~

~

~

~

68

Appendix Table--Continued

S~t1on Cbullbullbullbull lOCAl CBI CCI 11 CAl CBI CCI Date OCtober 1911 26 25

Taxon TlIUIILLAIUA Bo 1 1 12

lit 000l 0001 0004

IIDIERTEA Bo 1 2 lit bull 0005 0005

aLYCHAITA Bteone dUt Bo 1

lit 0001

Mbullbullnthe l~lcol Bo 21 25 2a 1 1 2 B~ 051 1402 031 0001 0014 oon

eudopolydoz Jrnpi Bo 23 11 27 7 I 11 lit bull 00 0033 oon 000 0011 0033

olydor l1nl Bo 2 7 7 1 1 lit 0001 oon 0001 0001 0003

yvop1o elevn Bo 3 2 n lit 0001 bull 0004

bull Heter_tu lillonU Bo 1 2 2 $ 7 II~ 0037 0100 0110 0022 0032 0146

HobsonJ t 1 orid 110 ua U4 22 3 lit 0397 0471 ono 0003 000

CltUSTACEA Hell11eucon p No 2 3

lit bull 0001

Eoru oclJrJ Bo 2 lit bull OOOll

Eoru contervlcolu Bo 1 111 0001

Coropblu bullbulllonl Bbullbull 2 1 II~ 0001 0001

Cozopbiu p1nlcorne Bo 2a ZI lit 0019 0014

alVAJVIA _ baltMc Bo It n 7

II~ 12069 12U5 11361 130 12163 2 My aranada Bo 2 1 1

lit bull DOO 0004 0002

bull 19~ lt 0001 9 - Indlc~bullbull vol~~ no~ ~kn