Kelp Forest Fishes Lecture-2015.ppt · 10/5/2015 3 Western North American Coastal Fish Time in...

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10/5/2015 1 © Jared Figurski What have ecological studies of fishes in kelp forests contributed to our broader ecological understanding? How has application of broader ecological understanding contributed to our understanding of the ecology of kelp forest fishes? Theme numero uno: Life History Traits Population Attributes Community Attributes distribution structure (size, age, genetic, spatial) dynamics (species-wide, genetic, reproductive success) reproductive modes longevity, fecundity life cycle biogeography structure (composition, abundance) dynamics diversity Theme numero dos:

Transcript of Kelp Forest Fishes Lecture-2015.ppt · 10/5/2015 3 Western North American Coastal Fish Time in...

Page 1: Kelp Forest Fishes Lecture-2015.ppt · 10/5/2015 3 Western North American Coastal Fish Time in Larval Stage midpoint (range) Shanks et al. 2003 AVERAGE = 94 days Time in the larval

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© Jared Figurski

What have ecological studies of fishes in kelp forests

contributed to our broader ecological understanding?

How has application of broader ecological

understanding contributed to our understanding of the

ecology of kelp forest fishes?

Theme numero uno:

Life History Traits

Population Attributes

Community Attributes

distribution

structure (size, age, genetic, spatial)

dynamics

(species-wide, genetic, reproductive success)

reproductive modes

longevity, fecundity

life cycle

biogeography

structure (composition, abundance)

dynamics

diversity

Theme numero dos:

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“Bipartite” life cycle of marine organismwith pelagic larvae

Benthic Environment

Adult

Larvae

Juvenile

Pelagic Environment

survive, grow, mature

survive, grow, disperse, develop

settlementreproduce

“Bipartite” life history of marine speciesand “open” populations

Larval recruitment replenishes local populations!!

“OPEN” POPULATIONS“CLOSED” POPULATIONS

SupplyProduction

Little or no exchange among

populations

Significant exchange among

populations

SupplyProduction

Supply ProductionSupplyProduction

Conclusion: 76% of these species moved less than 0.5 km

Home ranges of 25 west coast rocky habitat fish species

Median max. distance (km)

nu

mb

er

of s

pe

cie

s

0

4

8

12

Freiwald, J. 2012 Can. Jor. Fish. Aquat. Sci.

Reef Fish Adult Movement Ranges

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Western North American Coastal FishTime in Larval Stage

midpoint (range)

Shanks et al. 2003AVERAGE = 94 days

Time in the larval stage (fish)

The larval stage of the majority of (reef) fish is 1-3 months.

Time in the larval stage (fish)

Photo - G. Jones

<1 day

1 month

1-3 months

>3 months

Data from Carr and Syms 2006

Fraction of fish species

Time as larvae (hours)

Dis

per

sal

Dis

tance

(k

ilom

eter

s)

Shanks et al. 2003 Ecological Applications

Dispersal of invertebrate larvae: <1-100 km

0.0001

0.001

0.01

0.1

1

10

100

1000

10000

0.01 0.1 1 10 100 1000 10000

invertebrates

passive dispersal

r2= 0.61, P= 0.001

fishes

2 mo = 1440 hr

Genetic difference estimate dispersal distance

“ Isolation by Distance”

Gen

etic

di

ffer

ence

Geographic distance (kilometers)

Slope measures average distance of dispersal

short

low

long

high

populations nearby one another

populations further apart

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Slopes estimate dispersal distances

8000 200 400 600

Geographic distance (kilometers)

Copper rockfish

CA snailsRosethorn rockfish

CA corals

Gen

etic

di

ffer

ence

low

high

Fish: 20-200 kilometers

Palumbi 2003Kinlan and Gaines 2003

Larval dispersalBased on geneticdifference

Inverts: <1-100 kilometers

Num

ber

of s

peci

es

Temperate reef fish assemblages comprised of BOTH

“open” and “closed” populationsEcological consequences of larval dispersal:

(1) decouples local recruitment (replenishment) from local production

(2) larval recruitment critical to replenishment of local populations

(3) recruitment and post-recruitment mortality is important source ofpopulation regulation (i.e density dependence)

(4) “open” spatial structure of local and regional populations

But remember that “openness” is a function of:

(1) spatial scale: openness decreases as scale of population increases

(2) adult movement: openness decreases as movement increases

(3) “retention”: openness decreases as likelihood that larvae return to adult population increases

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Sources of spatial and temporal variation in recruitment

Larval production

Larval dispersal

Settlement

Post-settlement

Sources of spatial and temporal variation in recruitment

Larval production:

- regional adult abundance- adult fecundity (eggs per female)

size/age structure / sex ratioadult condition

- reproductive mode

Reproductive modes of kelp forest fishes:

(1) internal vs. external fertilization

(2) internal vs. external eggs

(3) external eggs: benthic or “broadcast”

(i) internal fertilization, internal eggs: viviparitye.g., rays, sharks, surfperch, rockfish

(ii) internal fertilization, external eggs: ovoviviparitye.g., skates, sharks (swell, horn), sculpins

(iii) external fertilization (oviparity), broadcast eggse.g., kelp bass, wrasses (senorita, sheephead)

(iv) external fertilization (oviparity), benthic eggse.g., greenlings, gobies, damselfishes, kelpfishes

Consequences of reproductive modes:

(2) behavior and social structure

e.g., benthic eggs -- nest guarding, territorialitybroadcast eggs -- spawning aggregations

(3) Defines resources that influence populationdistribution and abundance

e.g., competition for nest sites

Also, some species are hermaphroditic

e.g., kelp bass, wrasses (sequential, protogynous)gobies (sequential, protandrous)

(1) “openness” of a population

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Sources of spatial and temporal variation in recruitment

Larval production:

- adult abundance- adult fecundity (eggs per female)

Size/age structure / sex ratioadult condition

- reproductive mode

Bigger fish produce far more larvae

Approx. 11-fold increase

Approx. 7-fold increase

Older mothers produce better larvae

GR

OW

TH

(

WT

)G

RO

WT

H (

LE

NG

TH

)L

AR

VA

L

SU

RV

IVA

L

Maternal age (yr)

black rockfishSebastes melanops

Larvae produced by older femalesgrow faster and survive better

Berkeley et al. 2004 Ecology; 2004 Fisheries

Sources of spatial and temporal variation in recruitment

Larval production:

- adult abundance- adult fecundity (eggs per female)

size/age structure / sex ratioadult condition – e.g., Pacific Decadal Oscillation

- reproductive mode

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Climatic variability effect larval production?

- Bight-wide patterns of juvenile impingement

- declines in recruitment for many spp. (1980 - 1991)

- attributed to reduced larval production (but maybe larval survival)

- reflecting large-scale decline in productivity

Power plant impingement of fish larvae:Ocean climate change

1) Love et al. 1998 Fishery Bulletinincluded commercial species

2) Brooks et al. 2002 Mar. Freshwater Res.no commercial spp.

Offspring production: climatic variability

Perch recruitment

Population responses:4 surfperch

species

Benthic productivity

Surfperch production

Holbrook et al. 1997 Ecological Applications

Ocean climate change

Sources of spatial and temporal variation in recruitment

Larval dispersal (direction, distance, delivery):

- larval behavior- larval duration

- oceanographic features- interaction among these

Larval production:

- location of reproduction- timing of reproduction

Sources of spatial and temporal variation in recruitment

Larval dispersal (direction, distance, delivery):

- larval behavior- larval duration

- oceanographic features- interaction among these

Larval production:

- location of reproduction- timing of reproduction

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e.g., Norris 1963, Ecological Monographs

Physical processes and larval behavior

(1) Larval cues: (light, pressure, temperature, structure)

- Opal eye (Girella nigricans)

- recruitment related to tide pool temp.

- lab experiments: thermal preference

- coast-wide patterns of recruitment

- hypothesized mechanisms of larval delivery:- internal waves

- thermal / structural cues

- upwelling

Shanks 1983Mar. Ecol. Prg. Ser.ONSHORE TRANSPORT

Large-scale (biogeographic) processes

currents — e.g., California current - El Nino

Cowen 1985 Jour. Mar Research

Large scale patterns of temporal (episodic) variability

Normal year (La Nada)

El Nino

Hypothesis: Change in current patterns influences spatial patterns of sheephead recruitment

Specifically, northward El Nino currents would increase recruitment in northern portion of sheephead range.

Hypothesis: Recruitment of sheephead will be greater in northern portion of range during 1983 El Nino

Test: Use annual otolith increments and settlement mark to back-calculate what year individuals settled…

Use this to construct strength of year-class recruitment

San Nicolas Is.

Is. Guadalupe

Cabo Thurloe

0 0 0

0ND

ND ND

0ND

10

20

10

20

20

20

10

10

30

40

Is. San Benito

75 77 79 81 83

Year

“Structure - schooling”Long larval duration(3 - 4 months)

“Benthic - solitary”Short larval duration(1-2 months)

Black-&-yellow rockfish

Gopher rockfish

Kelp rockfish

Black rockfish

Yellowtail rockfish

Olive rockfish

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(1998) (1999) (2000)El Nino La Nina La Nada

Mid-water complexLong larval duration(3 - 4 months)

Benthic complexShort larval duration(1-2 months)

Kelp, Black-&-yellow, and Gopher rockfish

Olive, Yellowtail and Black rockfish

1007550250

255075

100

Re

lati

ve A

bu

nd

an

ce

1986 1992

1.0

0.5

0.5

1.0

0

Pro

po

rtio

n

Lenarz et al. 1995 CalCOFI

El Nino

Mid-water complexLong larval duration(3 - 4 months)

Upwelling

10

30

50

70

(1998) (1999) (2000)

El NiñoLa Niña

Normal

Fis

h p

er 2

40 m

3

Olive, Yellowtail and Black rockfish

Black rockfish

Olive rockfish

Yellowtail rockfish

Benthic complexShort larval duration(1-2 months)

Relaxation

(1998) (1999) (2000)

El NiñoLa Niña

Normal

Fis

h p

er 2

40 m

3

0

4

8

12

16

20 Kelp, Black-&-yellow, and Gopher rockfish

Black-&-yellow rockfish

Gopher rockfish

Kelp rockfish

biologicaldynamics

physical processes

&

Sampling Strategy

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May June July August

Nu

mb

er

of

fis

hp

er s

amp

ling

un

it Benthic complexn = 363

0.5

0.3

0.4

0.2

0.1

0.0

Mid-water complexn = 227

Nu

mb

er

of

fis

hp

er s

amp

ling

un

it

0.5

0.3

0.4

0.2

0.1

0.0

Tem

per

atu

re (

°C)

May June July August

Year 2000

9

10

11

12

13

14

(3) Smaller-scale, more frequent events(Ammann unpublished)

e.g., Larson et al. 1994, Lenarz et al. 1995, CalCOFI Rpt.s

shifts in vertical distribution with ontogeny -- upwelling

- vertical distribution of early and late larval rockfishes

0 0.2 0.4 0.6

13

37

87-117

proportion

depth (m)

“structure - schooling” spp.

“benthic - solitary” spp.

Physical processes and larval distribution

offshore

onshore

depthearly

larvae

latelarvae

pelagicjuveniles

kelp bed

Sources of spatial and temporal variation in recruitment

Settlement:

- habitat structure- priority effects

conspecific cues

predation

- larval cues

competition

e.g., Carr 1991, JEMBE

Settlement (post-settlement): habitat structure

(1) Macrocystis (rockfishes in central California)

- manipulated presence of giant kelp- some species recruit to kelp, others to rocky reef

(2) Macrocystis vs. understory (southern California)

e.g., Carr 1989, JEMBE

- manipulated presence of giant kelp and monitored recruitment

- recruitment of some species higher to kelp plots

- recruitment of some species higher to understory

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e.g., Carr 1994, Ecology

Settlement (post-settlement): habitat structure

(3) Macrocystis (kelp bass in southern California)

- manipulated kelp density- positive correlation between recruitment and kelp biomass

(4) Macrocystis (kelp surfperch in southern California)

e.g., Anderson 1994, MEPS

- manipulated presence of giant kelp canopy and monitored recruitment

(5) Sea urchins (blue-banded goby in southern California)

- manipulated presence of urchins and monitored recruitment

e.g., Hartney and Grorud 2002, Oecologia 0

10

20

30

Macrocystis

Absent Present

P < 0.0001

Den

sity

of

kel

p b

ass

recr

uit

s

(No.

per

60 m

3)

Greater density of kelp bass settlers in areas of a reef with giant kelp compared to areas without

Relationship within reefs…

Variation in giant kelp (Macrocystis) influences variation in settlement of kelp bass (Paralabrax clathratus)

10

20

30

0 100 200 300 4001

2

3

5

Macrocystis density (Stipes per 30 m2)

kelp

ba

ss

recr

uit

den

sity

(Num

ber

per

60 m

)3

Spatial and temporal variation among reefs and years…

Density of kelp bass settlers increases with increasing density of giant kelp… but it is not linear!

kelp bass recruit density:

blade biomass(gm per 5 m3 )

0 500 1,000 1,500

0

2

4

6

(Num

ber

per

10 m

2)

(Nu

mb

er /

10

m

)2

0 40 80 120 1600

1

2

3

4

5

A

BB

Macrocystis density (stipes / 30 m2 )

0

A

BB

400

800

1,200

(gra

ms

/ 1

0 m

)

2

0 40 80 120

blade biomass per reef area:

kelp bass recruit density:

Local density of giant kelp DETERMINESlocal density of kelp bass settlers

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Conclusions:

i) Local and “regional” patterns of kelp bass recruitment are influenced by dynamics of giant kelp abundance

ii) The relationship is not based strictly on plant density, but on biomass (shelter!). Because kelp biomass changes with plant density, recruitment relationship is asymptotic.

iii) Giant kelp facilitates recruitment of kelp bass by providing habitat that they encounter as they pass over reefs

Sources of spatial and temporal variation in recruitment

Settlement:

- habitat structure- priority effects

conspecific cues

predation

- larval cues

competition

Very little information available!

Sources of spatial and temporal variation in recruitment

Early post-settlement:

- growth- movement

competition

predation

- survival

0 20 40 60 80 100

kelp rockfish

0.0

0.2

0.4

0.6

0.8

0 5 10 15

black eyed goby

Initial density

Early post-settlement: predation

per-capitamortality

Anderson 2002 Ecology

kelp perch

Steele 1997 Oecologia

Johnson unpublished

predators present

predators absent

1.0

1.01.0

0 20 40 60

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15m

15m

(P+) Predator exposed

(P-) Predator excluded

Johnson 2006a,b Ecology

r2 = 0.039, P = 0.67

+ Predators

-- Predators

r2 = 0.949, P < 0.001

Does local density-dependent predation scale up ?

Post-settlement mortalityis density-dependent

Predation isthe source

Local scale densitydependence manifestedwithin and across reefs

Johnson 2006a,b Ecology

e.g., Steele 1997a, Ecology

Conspecific and interspecific resident effects

- black-eyed and blue-banded gobies in So. California

- manipulated presence of adults of both

- settlement of black-eyed decreased in presence of adult conspecifics

- settlement of black-eyed not influenced by presence of adult blue-banned

- settlement of blue-banded (+) influenced in presence of adult conspecifics

- settlement of blue-banded not influenced in presence of adult black-eyed

Early post-settlement: competition Sources of spatial and temporal variation in recruitment

Late post-settlement:

- growth- movement

competitionpredation

- survival

adult and juvenile interactions

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(1) Hixon 1980, Schmitt and Holbrook 1990, etc.

Late post-settlement: interspecific competition

- striped and black surfperch in So. California

- two species exhibit depth stratified distributions- manipulated presence of either species

- monitored change in depth distribution

shallow

deep

stripe

black

Late post-settlement: interspecific competition

Striped (+)

Black (+)

Striped (+)

Black (+)

Striped (+)

Black (+)

reef: 1 32time:

pre-

Striped (+)

Black (+)

Striped (--)

Black (+)

Striped (+)

Black (--)

Striped (+)

Black (+)

Striped (+)

nobody home

manipulation

post-Black (+)

Black (+)

Conclusion: striped perch competitively dominant:excludes (interference) black perch from shallow.

Late post-settlement: interspecific competition

(2) Larson 1980, Ecological Monographs

- same as above for sibling surfperches

- black-and-yellow and gopher rockfish in So. Calif.

shallow

deep

black and yellow

gopher

Territory size limits local density and pop. size

Late post-settlement: intraspecific competition

(1) Garibaldi in So. California -- Clarke 1970

- map territory sizes and distribution

- monitored change in territory sizes and density

(2) striped and black surfperch in So. California

- same as above

- Larson 1980 a, b Marine Biology

- Schmitt & Holbrook

(3) black-and-yellow and gopher rockfish in So. Calif.

- remove individual

- same as above

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Effects of habitat on fish assemblages

e.g., Larson and DeMartini 1984, U.S. Fishery Bull.

(1) Macrocystis (southern California)

- cobblestone bottom off San Onofre

(2) Macrocystis vs. Nereocystis (central California)

e.g., Bodkin 1986, U.S. Fishery Bull.

- difference in relative abundance of species

- compared fish assemblage in areas with and with giant kelp

- difference in relative abundance of species

- compared fish assemblages on either side ofPiedras Blancas (Nereo. north, Macro. south)

e.g., Ambrose and Swarbrick 1989, Bull. Mar. Sci.

(3) Macrocystis (southern California)

- included artificial reefs

- little difference in relative abundance of species

- compared fish assemblage on reefs with and with giant kelp

e.g., Holbrook et al. 1990,1994, Austr. J. Ecol., Am. Zool.

(4) Macrocystis (southern California)

- same as (3) above, no difference in species richness

- planktivores and macro-invert eaters, reduced with kelp

Effects of habitat on fish assemblages

1999200020012002200320042005

Sites by Year Sampling Began

Monterey Bay

Pt. Conception

Large-scale biogeographic patterns 2 m

2 m

Fishdensitysizes

Densitykelps

Coveralgaeinverts

macro inverts

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Coastline

Fish transect distribution

5 m

10 m

15 m

20 m

12 m

5 m

20 m

Algae / invertebrate transect distribution

Approach: within-site sampling designGeographic Variation in Kelp Forest Fish Assemblages

Monterey Bay

Pt. Conception

Sedimentary

Granite

Basalt

Monterey Bay

Pt. Conception

Sedimentary

Granite

Basalt

SIMPROF (P= 0.01)

Regions North of Point Conception

PC4: Low Relief, Sand

-2 -1 0 1 2 3 4-3

-2

-1

0

1

2

3

4

5

-1 0 1 2 3-2

-1

0

1

2

3

4

5

-2 -1 0 1 2 3 4-2

-1

0

1

2

3

4

-2 -1 0 1 2 3-2

-1

0

1

2

3

4

5

High relief rocky reefs protected from high swell exposure

SIMPROF (P= 0.01)

P< 0.0001R2= 0.31

P< 0.0001R2= 0.28

P= 0.0007R2= 0.09

P< 0.015R2= 0.05

PC3: High Relief

PC1: NW Swell

PC2: South Swell

“cold water” assemblage

PC – cold water

e.g., Cowen 1983, Oecologia

(1) “Top-down”: keystone predators

- manipulated local presence of sheephead and observed red sea urchin behavior

- urchins more exposed and mobile in absence of sheephead

- sheephead (Semicossyphus pulcher) in So. Calif.

Role of fishes in kelp forest communities

sheephead

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Cascading Effects of Predator Removal

sea otterssheephead

sea urchins

barrenskelp forest

rockfishes

Southern California Central California

lobstere.g., Bray et al. 1991, Science

(2) “Bottom-up”: enhanced nutrient availability & productivity

- monitored nutrient availability and macroalgal production in crevices with and without blacksmith

Role of fishes in kelp forest communities

- planktivorous blacksmith (Chromis punctipinnis) hole up in crevices at night

- greater nutrient availability and macroalgal production in crevices with blacksmith

- example of planktivorous fishes directing planktonic production to benthos

e.g., Gaines and Roughgarden 1987, Science

(3) Planktivorous fishes reducing larval supply

- could be hydrodynamic influence of kelp or predation by planktivorous juvenile rockfishes

Role of fishes in kelp forest communities

- reduced recruitment of intertidal barnacles in years with thick Macrocystis forest at Hopkins

- used barnacle molts to decouple potential causes

- barnacle molts not reduced as they passed through forest, concluded reduction due to planktivory

- high recruitment of planktivorous juvenile rockfishes in years with thick Macrocystis forest

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