1955. The life history of the tematode Meta-bronema salvelini (Fujita, 1920) parasitic in thespeckled trout, Salvelinus fontinalis (Mitchill), inQuebec. Can. J. Res. (D) 33: 14.

Coao, B. W. 1972. On the ecology and meristicvariation of the Gasterosteidae of the MatamekRiver System, Quebec. M.Sc. Thesis, Univ. Water-loo, Waterloo, Ont. 117 p.

FaNurru, H. 8., A. PoRTER, AND L. R. RrcHARDsoN.1939. Some Myxosporidia found, in certain fresh-water fishes in Quebec Province, Canada. Parasi-tology. 31: l-77.

1940. Somo more Myxosporidia observed inCanadian fishes. Parasitology 32: 333-353.

Hrcrs, F. J., lNn W. Tnnsrrarr,. 1973. Metazoanparasites of salmonids and coregonids from coastalLabrador. J. Fish Biol. 5:399-415.

Husns, C. L. aNo K. F. Lacr,rn. 1964. Fishes ofthe Great Lakes region. 3rd ed. University ofMichigan Press, Ann Arbor, Mich.

tt39

Mor,N.rn, K. nNo G. HaNpr. 1974. Further newEime'ria spp. (Coccidia Protozoa) from freshwaterfishes of Canada. J. Protozool. (In press)

O'CoNson, J. F. 1971. Ecology of brook trout,American smelt and American eel in two lakes ofthe N4atamek River System, Quebec. M.Sc. Thesis.Unil'. Waterloo, Waterloo, Ont. 84 p.

SauNoERs, C. H. 1969. Ecology of brook trout,American smelt and Arctic char of the Matameklake, Quebec. Ph.D. Thesis. Univ. Waterloo,Waterloo, Ont. 130 p.

ScnrsrER., K. 1969. Ecology of Atlantic salmon,Salmo salar L. in the Matamek River System.M.Sr:. Thesis. Univ. Waterloo, Waterloo, Ont.63 p .

SrrNrnn, M. S. 1931. Three new parasitic Nematodeworrns. Proc. U.S. Natl Museum.29: 1-9.

Vrr, R. 1964. Notes on the life history of Philonemaagubernaculum Simon & Simon, 1936 (Nematoda).Can. J. Zoo1.42: 511-512.

Adjustment of Buoyancy and Excess Internal Pressure ofSwimbladder Gases in Some North American

Freshwater Fishes

JouN H. Gnr, K.a.zrlrrenz MAcHNTAK, AND SANDRA M. CHALANcHUK

Department of Zoology, University of Manitoba, W'innipeg, Man.

Grr, J. H., K. M.rcnNrAK, AND S. M. Cna;,.r.Ncsur. 1974. Adjustment of buoyancyand excess internal pressure of swimbladder gases in some North Americanfreshwater fishes. J. Fish. Res. Board Can. 31:.1.139-1141.

A11 12 species of physostomes and 8 species of physoclists altered their buoyancy inresponse to a change in water velocity. All species showed excess internal pressure ofswimbladder gases.

Gnt, J. H., K. MacuNrAK, AND S. M. CHal,eNcnur. 1974. Adjustment of buoyancyand excess internal pressure of swimbladdler gases in some North Americanfreshwater fishes. J. Fish. Res. Board Carr. 31: 1139-1141.

Douze espdces de physostomes et huit espdces de physoclistes ajustent toutes leurflottabilitE en r6ponse d un changement de vitesse de I'eau. Toutes les espdces d6montrentun excds de pression interne des gaz de la vessie gazeuse.

Received October 1, 1973 Accepted January lO, 1974

Tnts study seeks to determine if adjustment of lowererd in increased current and raised when stillbuoyancy by altering swimbladder volume in water is encountered. Excess internal pressure isresponse to a change in water velocity and if excess common amongst Cypriniformes (Alexander 1959a,internal pressure of swimbladder gases are common 1961 ; Gee 1970; Machniak 1973) but has beenamong freshwater flshes. In Atlantic salmon parr, recorded for only one species of non Cypriniformesbrook trout (Saunders 1965), longnose and black- (McCutcheon 1958, 1962).nose dace (Gee 1968, 1970), tadpole madtom,and black bullhead (Machniak 1973) buoyancy is Materials arul methods - All fishes were coilected

from lt4anitoba waters except for Stizostedion vitreumPrinted in Canada (J3180) (Crean Lake hatchery, Saskatchewan) and Salmo

J. F

ish.

Res

. Bd.

Can

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Dep

osito

ry S

ervi

ces

Prog

ram

on

09/1

8/13

For

pers

onal

use

onl

y.

I 140

gairdneri (Rockwood hatchery, Manitoba). They wereheld in the laboratory under a 12-h photoperiod at15.5 + 1 C for up to 6 wk in st i l1 water prior to exami-nation. Extent of adjustment of buoyancy was deter-mined by holding some fish of each species in stillwater and others in current for 7 days. Current (40cm/s) was created in aquaria using the design of Geeand Bartnik (1969). Depth of water in current aquariawas 4-7 cm and in still rvater aquaria, 37 cm. Deviationsfrom the above procedure are noted in Table 1. Asimilar sizo range of fish was examined in still waterand current because buoyancy attained and internalpressure are often dependent on size (Gee 1972;Machniak 1973). Those species examined showingsuch a relationship were divided into size-groups.

On examination fish were removed individuallyfrom aquaria, anesthetized (tricane methanesulfonate),

JOURNAL TISHERIES RESEARCH BOARD OF CANADA, VOL. 31, NO. 6, 1974

and buoyancy and internal pressure were determinedusing the procedure of Gee (1970). Flotation pressure(Saunders 1965) was used as a measure of buoyancyin which the volume of the swimbladder (f 0.001 ml)was divided by the weight of the gas-free-fish (i0.001 g) in water (< 1.0 mllg : negative buoyancy;1.0 ml/g : neutral buoyancy; > 1.0 ml/g : posit ivebuoyancy). The volume of the swimbladder (milliliters)equals the difference in weight (grams) between theintact fish in water and the gas-free-flsh in water.Internal pressure of swimbladder gases was determinedby dividing the volume of gas released from the swim-bladder at atmospheric pressure by the volume of theswimbladder. It was impractical to correct for depthof capture, particularly between still water and currentaquaria. Such differences would have an almost negligi-ble effect on measures of buoyancy and internal pressure .

Tasrr 1. Mean flotation pressure and internal pressure of fishes held in still (A) and in current (B).

No. examinedMean flotationpressure (z/g)

Mean internalpressure (alm)

Fork length(mm) BABABA

Order Salmoniformes'Esox luciusSalmo gairdneri

Order Cypriniformes"Cato sto mus commersoni"Mo xosto ma macrolepidot umaSemo tilus at romac ulatus'Notropis cornutusc

Notropis blennius'

Notropis volucellusPimephales promelascHybognathus hankinsoni'Ictalurus punctatusNoturus flavus

Order GasierosteiformesbCulaea inconstansPungitius pungitius ,

Order PercopsiformesoP ercopsis omis comaycus

Order PerciformesbPercina maculcttusAmbloplites rupestrisAplodinotus grunniensPerca flavescensStizostedion vitreum

45- l l663-79

42-12548-1 I 334-4034-647't-177z J + 1

50-6648-7451-6055-74

287-382112-205

26-6150-61

35-101

46 6326 46

1 55-2083 1-68

106-126

1 6o

1 61 0

1 61 91 l78

l 3886

1 5

1 81 61 4l 798988

5',1 1 ' ,

1 6t 0

l 61 0

lzd1 0

1 6

l l1 4nt10

1

.947

.927

. 8 4 8

.925

.969

.972

.794. 9 3 6.964

1 . 0 2 0.939. 8 8 7. 8 5 1.487

I .009. 8 5 4

t . 0 2 4

. 7 3 91 . 0 4 91 . 1 0 0

. 9 7 7.966

r . 2 8 2. 3 8 6

.490

. 5 7 1

. 6 3 7

.690

. 4 5 8.609. 7 5 3. 8 1 6. 5 7 2. 7 1 4. 7 5 3.243

.441

. 1 9 8

. 8 3 6

.044

. 8 6 9

. 9 1 0

. 5 0 0

| . 1251 . 1 1 7

1 ,192r . 1 5 91 . 1 7 21 . 0 5 8| . t r 61 . 5 9 21 . 1 1 51 .1251 . 0 9 61 .1 ,02

1 . 1 3 8

1 . 0 8 11 .109

1 .087

I . 1041 . 1 1 71 .026I .0901 . 0 7 1

1.o491 . 1 7 5

1 .1 ,461 .2221.11,21 . 1 2 21 . t 6 41 . 1 6 11 . 1 0 8| . t l z1 . 0 9 11 . 1 3 9

1.209

1 . 0 3 4| .26 ' .1

1 .097

1 . 5 1 5I . 0981 .0671 . 1 1 11 . 0 8 5

1 8

1 08

1 5l 57

"Physostomes.bPhysoclists.

jHeld at 2r C (L1)."He1d in current 3-5 days.

fHetd in curent 11 days.'Held in water 37 cm deep.J.

Fis

h. R

es. B

d. C

an. D

ownl

oade

d fr

om w

ww

.nrc

rese

arch

pres

s.co

m b

y D

epos

itory

Ser

vice

s Pr

ogra

m o

n 09

/18/

13Fo

r pe

rson

al u

se o

nly.

tt4r

Results and discussion - All but one of the speciesexamined became significantly less buoyant (P< 0.001) in current than in still water (Table 1).A low negative buoyancy assists in holding positionin fast-flowing and turbulent waters of rivers andwave-washed beaches of lakes, whereas a nearneutral buoyancy allows for ease of movement instill water. Esox lucius became significantly (P< 0.001) more buoyant in current. These fish wereyoung-of-the-year and were taken from inlet streamsof large lakes. Possibly the shift from near neutralto positive buoyancy as current is encountered, isa mechanism for displacing these fish downstreamto lakes. Saunders (1965) concluded that the greaterbuoyancy of Atlantic salmon smolts comparedto parr increased their downstream movement.Noturus flavus and Percina maculatus were morenegatively buoyant in still water and current thanthe remaining species (Table 1). These fishes aretypical of fast waters of streams and rivers. SmallNotropis cornutus made a greater adjustment ofbuoyancy than did larger individuals. The reverseoccurred with Notropis blennius. Gee (1,968, 7972)and Machniak (1973) have also shown that extentof adjustment of buoyancy varies with size of fish.Hence fishes outside the sizes examined here maymake a greater, lesser, or no adjustment ofbuoyancy.

In still water all species exceptpossibly Aplodinotusgrunniens showed excess internal pressure and allspecies possessed excess internal pressure in current(Table 1). Alexander (1959a; 1961) examined anumber of species of Cypriniformes and foundexcess internal pressure in all. On examination of17 species of non-Cypriniformes he could find noevidence of excess internal pressure (Alexander1959b). The number of individuals of each speciesexamined was low (1-3 in all but one), his tech-nique used on Cypriniformes differed from that usedon non-Cypriniformes and may have lacked thenecessary precision. Excess internal pressure hasbeen recorded for Lagodon rhomboides (Perciformes)by McCutcheon (1958, 1962).

Excess internal pressure is signiflcant becauseits presence a) results in a taunt swimbladder wallwhich may be necessary for the operation ofWeberian ossicles in Cypriniformes (Alexander1959a), b) combined with a swimbladder wall oflimited extensibility reduces the rate at whichswimbladder volume changes with depth andthereby minimizes the required alteration ofbuoyancy (Alexander 1959a), and c) provides fora precise control of buoyancy adjustment (Mc-Cutcheon 1962). McCutcheon (1958) has observedthat slight alterations of internal pressure, changingswimbladder volume by only 1To tn Lagodon

rhomboides, has a measurable effect on buoyancyand fin compensation. Much of the initial alterationof swimbladder volume in response to a change in

water velocity is brought about by changes in internalpressure (Gee 1970; Machniak 1973).

Adjustment of buoyancy in response to a changein water velocity and excess internal pressure arecommon among North American freshwater flshes.The former is an important adaptation in freshwater where changes in water velocity and tur-bulence occur frequently.

Acknowledgmenls - This research was supported bygrants in aid of research from the National ResearchCouncil of Canada and the Fisheries and MarineService. Dr P. A. Gee provided helpful commentson tho manuscript. H. Balesic, G' E. Newsome, R. W.Moshenko, and R. Weselowski assisted in collectingfishes. Dr J. G. Eales assisted by angling for severalof the species examined.

Ar.rxaNonn, R. M. 1959a. The physical propertiesof the swimbladder in intact Cypriniformes. J.Exp. B io l . 36 : 315-332.

1,959b. The physical properties of the swim-bladders of fish other than Cypriniformes. J'Exp. Biol. 36:347-355.

1961. The physical properties ofthe swimbladdersof some South American Cypriniformes. J. Exp'Biol. 38: 403--410.

Gnp, J. H. 1968. Adjustment of buoyancy by long-nose dace (Rhinichthys cataractae) in relation tovelocity of water. J. Fish. Res. Board Can. 25:1.485-1496.

197 O. Adjustment of buoyancy by blacknose dace'Rhinichthys atratulus. J. Fish. Res' Board Can.27: 1855-1859.

1972. Adaptive variation in swimbladder lengthand volume in dace, genus Rhinichthys. J. Fish.Res. Board Can. 29: 119-127.

Gns, J. H., aNn V. G. B.q.Rrxrr. 1969. Simple streamtank simulating a rapids environment. J. Fish.Res. Board Can. 26: 2227-2230.

M.r.cuNr.lr, K. 1973. Adjustment of buoyancy bycatfish (Ictaluridae) in response to a change in watervelocity. M.Sc. Thesis. Univ. Manitoba, Winni-peg, Man. 36 p.

McCurcunoN, F. H. 1958. Swimbladder volume,buoyancy, and behavior in the pinfish, Lagodonrhomboides 0-inn.). J. Cell. Comp. Physiol. 52:4s3-480.

1962. Swimbladder volume control in the pin-fish, Lagodon rhomboides (Linn.)' J. Cell' Comp.Physiol. 59: 203-214.

SruNonns, R. L. 1965. Adjustment of buoyancy inyoung Atlantic salmon and brook trout by changesin swimbladder volume. J. Fish. Res. Board Can.22: 335-352.

J. F

ish.

Res

. Bd.

Can

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Dep

osito

ry S

ervi

ces

Prog

ram

on

09/1

8/13

For

pers

onal

use

onl

y.

This article has been cited by:

1. Robert I Holbrook, Theresa Burt de Perera. 2011. Fish navigation in the vertical dimension: can fish use hydrostatic pressureto determine depth?. Fish and Fisheries 12:4, 370-379. [CrossRef]

2. Lauren L. Bergey, Roger A. Rulifson, Margie L. Gallagher, Anthony S. Overton. 2003. Variability of Atlantic Coast Striped BassEgg Characteristics. North American Journal of Fisheries Management 23:2, 558-572. [CrossRef]

3. Eleni Cavadias, John H Gee. 1987. Variables affecting buoyancy in three species of Percina (pisces). Comparative Biochemistry andPhysiology Part A: Physiology 87:2, 275-285. [CrossRef]

4. D.Bruce Stewart, John H Gee. 1981. Mechanisms of buoyancy adjustment and effects of water velocity and temperature on abilityto maintain buoyancy in fathead minnows, Pimephales promelas, rafinesque. Comparative Biochemistry and Physiology Part A:Physiology 68:3, 337-347. [CrossRef]

5. J.H.S. BLAXTER, P. TYTLERPhysiology and Function of the Swimbladder 7, 311-367. [CrossRef]6. John H. Gee. 1977. Effects of size of fish, water temperature and water velocity on buoyancy alteration by fathead minnows,

Pimephales promelas. Comparative Biochemistry and Physiology Part A: Physiology 56:4, 503-508. [CrossRef]

J. F

ish.

Res

. Bd.

Can

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Dep

osito

ry S

ervi

ces

Prog

ram

on

09/1

8/13

For

pers

onal

use

onl

y.