Biological Report 82 (11.69) TR EL.82.4 August 1986

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest)

AMPHIPODS

Coastal Ecology Group Fish and Wildlife Service Waterways Experiment Station U.S. Department of the Interior U.S. Army Corps of Engineers

Biological Report 82(11.69) TR EL-82-4 August 1986

Species Prof i les : L i fe His tor ies and Environmental Requirements o f Coastal Fishes and Invertebrates (Pacif ic Northwest)

AMPHIPODS

Daniel J. Grosse and Gi lber t B. Pauley Washington Cooperative Fishery Research Un i t

Universi ty o f Washington Seattle, WA 98195

and David Moran

National Wet1 ands Research Center

Pro ject Of f icer John Parsons

National Wetlands Research Center U.S. Fish and Wildl i fe Service

1010 Gause Boulevard S l ide l 1, LA 70458

Performed f o r Coastal Ecology Group

Waterways Experiment Station U.S. Army Corps o f Engineers

Vicksburg, MS 39180

and

National Wetlands Research Center Research and Develcpment Fish and Wildl i fe Service

U.S. Department o f I n t e r i o r Washington, DC 20240

PREFACE

This species p r o f i l e i s ,one o f a series on coastal aquatic organisms, p r i n c i p a l l y f i s h , o f s p o r t , commercial, or ecological , importance. The p r o f i l e s are designed to prov ide coasta l managers, engineers, and b i o l o g i s t s w i t h a b r i e f comprehensive ske tch o f the b io log ica l charac ter is t i cs and environmental requirements of the species and t o describe how populat ions of the species may be expected t o r e a c t t o environmental changes caused by coastal development. Each p r o f i l e has sections on taxonomy, l i fe h is tory , eco log ica l ro le , env i ronmenta l requirements, and economic importance, i'f applicable. A th ree- r ing b inder i s used f o r t h i s s e r i e s so t h a t new p r o f i l e s can be added as they are prepared. T h i s p r o j e c t i s j o i n t l y planned and financed by the U.S. Army Corps o f Engineers and the U.S. Fish and W i l d l i f e Service.

Suggestions or questions regarding thi:; report should be d i rected t o one o f the f o 11 owing addresses.

Informat ion Transfer Special ist National Wet1 ands Research Center U.S. Fish and Wi ld l i fe Serv ice NASA-S1 ide1 1 Computer Complex 1010 Gause BCUI evard S l i d e l 1, LA 70458

o r

U. S. Army Engineer Waterways Experiment S ta t i on Attent ion: WESER-C Post Off ice Box 631 Vicksburg, MS 39180

iii

CONVERSION TABLE

M e t r i c t o O.S. Customary

!!Y

0.03937 o. 3937 3.281 O. 6214

10.76 O. 3861 2.471

O. 2642

O. O0081 10

0.00003527 O. 03527 2.205

1.102 3.968

1.8('C) + 32

35.31

2205.0

Mu1 t iply

mill i oe te rs (mn) centimeters (an) meters (m) k i 1 me te rs ( km)

square ne ters (m ) square k i 1 m e t e r s ( km2) hectares (ha)

l i t e r s (l) cubic ineters (m') cubic meters

mill igrarns (mg) grams (g) kilograms (k ) metr ic tons 9 t ) metric tons k i 1 ocal ories ( kcal )

Ce1 sius degrees

2

inches i n ches f e e t ( f t ) fathoms m i les ( m i ) naut ical mi les (mi)

square f e e t (ft2) ac rec sqsare mi les ( m i )

gal 1 ons ( gal ) cubic feet (ft') acre- feet

2

U.S. Customary t o M e t r i c

25.40 2.54 O. 3048 1.829 1.609 1.852

0.0929 O. 4047 2.590

3.785 0.02831

1233.0

ounces (oz) pounds ( l b )

28.35 O, 4536

shor t tons ( ton) 0.9072 B r i t i s h thermal un i ts (B tu) 0.2520

Fahrenheit degrees 0.5556("F - 32)

To Obtain

inches inches f e e t m i 1 es

square feet square ;nil es acres

gal l ons cub ic fee t acre-feet

ounces ounces pounds pounds sho r t tons B r i t i s h thermal u n i t s

Fahrenheit degrees

mil 1 imeters centimeters meters meters k i l m e t e r s k i 1 m e t e r s

square meters hectares square k i l m e t e r s

1 i t e r s cubic meters cubic meters

g r a m k i 1 ograrns metr ic tons k i 1 ocal or ies

Ce1 s ius degrees

i v

CONTENTS

Page

PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii CONVERSIONTABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i v ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v i

NOMENCLATURE/TAXONOMY/RANGE . . . . . . . . . . . . . . . . . . . . . . . 1 MORPHOLOGY/IDENTIFICATION AIDS . . . . . . . . . . . . . . . . . . . . . . 4 REASON FOP . INCLUSION I N SERIES . . . . . . . . . . . . . . . . . . . . . . 4 L I F E HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 GROWTH CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . 5 POPULATION DYNAMICS AND IMPORTANCE TO FISHERY . . . . . . . . . . . . . . . 5 ECOLOGICAL ROLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 ENVIRONMENTAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . 10

D i s s o l v e d O x y g e n . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 S a l i n i t y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 P o l l u t i o n a n d D r e d g i n g . . . . . . . . . . . . . . . . . . . . . . . . . 10

LITERATURECITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

V

ACKNOWLEDGMENTS

We gratefully acknowledge the reviews by Rick Albright, School o f Fisheries, University o f Washington, Seattle, and Craig P. Staude, Friday Harbor Laboratories, University of Washington, Seattle.

v i

I Pereon

Pleon

Urosome

Figure 1. A gammaridean amphipod (from Staude e t a l . 1977).

AMPHIPODS

NOMENCLATURE/TAXONOMY/RANGE

Scien t i f i c name . . . . . . Amphipoda

Preferred common name . . . Amphipods C l ass . . . . . . . . . . . Crustacea Subcl ass . . . . . . . . Mal acostraca Order . . . . . . . . . . . Amphipoda Suborders . . Gammaridea, Hyperi idea,

Caprell idea, Ingolfiell idea (Figure

(Figure 1)

2).

Geographic range: This report will focus largely on the suborders Gammaridea, Caprell idea, and Hyperi idea because o f t he i r impor- tance i n coastal areas o f the

northeast Pacific Ocean (Figure 3). Gammaridea are the most abundant and diverse of the amphipods. Although pr imar i ly marine, they are also found i n freshwater and cer ta in mois t ter rest r ia l habi ta ts (Reish and Barnard 1979). Marine Gammaridea are ubiquitously distributed. They are found i n a l l regions, i n a l l habitats, and a t most depths. About 40% of the 80 gammaridean families are cosmopolitan i n d i s t r i bu t i on ; the remaining 60% are loosely associated with specific regions o r zones (Barnard 1969; Bousef i e l d 1978). Gammaridean d is t r ibut ions remain poorl;. known, Dut more recent studies (e.o. , Barnard 1971) are

1

B

C

D E Figure 2. A, Elasmopus and B, Eohaustorius, both gammarid amphipods. C, Caprella ferrea, a c a p r e l l i d amphipod. D, Neocyamus physeteris (female), a capre l l id amphipod from sperm whale. E, Phronima sedentaria, a hyper i id amphipod that l ives inside the tunic of urochordates. (A and B from Barnard 1975; C and D from McCain 1975; E f rom Barnes 1974. A-D repr inted with permission from the Univers i ty o f Cal i forn ia Press; E reprinted with permission from Saunders College Publishing.)

f ind ing more widespread d i s t r i bu- t ions than were previously assumed. O f f the Oregon Coast, 97 species o f gammarids have been found from the surface t o a depth o f 2900 m (Barnard 19711, and 20 species div ided among 11 famil ies were i n the umer 200 m (Pearcy 1972).

About 200 gammarid species have been found i n Washington waters (Staude e t a l . 1977). Some ganmnarid species dwell i n subt ida l or in ter t ida l environments (Rei sh and Barnard 1979). The suborder Hyperi idea i s en t i re l y marine and pelagic; most members o f t he taxon 1 i v e i n the

2

WASHINGTON

MILES

......... ...... ..... O 50 100 ........ :.:.:..y .,...: ..:j;.y.q$$-

KILOMETERS ,$$.jp d ......

*..3q$(y- ........... ............. ........ ............... ........... Coastal dlrtrlbutlon

concentrated ertuarlne arena

OREGON

- --.

Figure 3. Distribution Hyperiidea i n the coastal

o f the ubiquitous amphipod suborders areas of the northeast Pacific Ocean.

Gammari dea and

bathyal zone, and some 1 i v e i n coastal waters (Bowman and Gruner 1973 1.

MORPHOLOGY/IDENTIFICATION AIDS

Animals of the order Amphipoda are distinguished by sessile, compound eyes, though some species are blind. A carapace i s not present and the f i r s t , and sometimes the second, thoracic segments are fused with the head. A "shrimp1 i ke" appearance resul ts from la te ra l body compression. Gammarids and hyperiids have three pa i rs o f pleopods (swimmerets) ; two o r three pairs of uropods on the pleon (abdomen); a t least e ight pa i rs o f thoracopods, counting the maxi 11 iped; usually seven major leg pairs, cal led pereopods; and f i ve o r more pairs o f g51 1s. Males and females of ten can be distinguished morphologically. The head has f i v e fused segments, two pa i rs each o f antennae and maxi 1 lae, a heavi ly chi t in ized mandible, and a l imblike maxil l iped. There are seven f ree ly ar t icu la ted somites on the thorax (pereon). Coxal p l ate1 i ke la te ra l extensions of the thoracic pereon are developed from the f i r s t segment o f each leg. Branchiae (gi l ls) are f leshy and p la te l i ke and are attached medial t o the coxae, 2-6 on each side. The abdominal region consists o f three art iculat ing segments on both anterior pleon and poster ior urosome; the urosome has a termi na1 t e l son.

The following key (adapted from Barnes 1974; Kozloff 1974) i s pre- sented as an a i d t o separate the sub- orders o f amphipods:

la . Pereon w i th seven apparent segments, a l 1 having we1 1 -devel oped appendages. Abdomen not vest ig ia l . Body neither slender nor resembling t h a t o f a praying mantis. . . . . 2

lb . Pereon with s i x apparent segments, some may have vest ig ia l appendages; abdomen ves t ig ia l ; head

fused with second thoracic segment. Body slender and resembl i n g t h a t o f a praying mantis (except f o r whale lice). Marir.?. Includes skeleton shrimp . . . Suborder Caprellidea.

2a. Eyes generally large, OCCU- pying most o f head; coxae o f pereopods small, often fused with the body, maxil l ipeds without palp; last two abdominal segments fused; body more o r less transparent. Marine, and usually planktonic or associated with je1 ly- f i s h o r i n t u n i c s o f dead salps . . . . . Suborder Hyperi idea.

2b. Eyes usually present and conspicuous, but not large enough t o cover most o f the head; coxae o f pereopods we1 1 developed, usual l y expanded. Mari ne, freshwater, and te r res t r i a l . . . Suborder Gammaridea.

2c. Body elongate; coxae small ; abdominal segments d i s t i n c t ; a l 1 but four th and f i f t h pa i rs o f abdominal appendages vest ig ia l . Mari ne, i n te r - s t i t i a l . Rare. . . . Suborder Ingol f ie l l idea.

There current ly ex is ts no concise guide t o amphipod species i n the northwest Pacific. Publications of the National Museum o f Canada, such as tha t by Conlan and Bousfield (1982), w i 11 eventually culmi nate i n a compre- hensive regional handbook on marine gammari deans. Contri butions by Barnard (1975) and Staude e t a l . (1977) may be usefu l for ident i fy ing Gammaridea i n res t r i c ted i n te r t i da l regions; the work of Bousfield (1978) described freshwater Gammaridea. Kozloff (1974) provided keys t o t h e Caprellidea. Hyperiids can be ident i - f i e d t o genus by using the descrip- t ions pub1 ished by Bowman and Gruner (1973).

REASON FOR INCLUSION I N SERIES

Hyperiid amphipods are the t h i r d most abundant group of coastal marine crustacean zooplankton, fo l lowing

4

Ccpepoda and Euphausidea (Bowman and G m e r 1973). The benthic amphipods, especially Gammaridea, are an invalu- able food source for maQy economically important f ish and invertebrate species. Their l imi ted mobi l i ty suggests tha t t he i r d i s t r i bu t i on and abundance can be sseri a5 an ind icator o f environmental qua l i t v (AlRright 1982). Omnivomus, opportunistic feeders such as Sysianassids {iz gammaridean family) recycle d e t r i t s and may help avert pol lut ion by scav- enging carcasses o f large?& animals fo l lowing mass morta l i t ies (Reish and Barnard 1979).

LIFE HISTORY

Female Amphipoda spawn v ia an amplexus (mating embrace) wi th males which l as ts f o r hours o r days. I n swimming species the female swims with the male on top, or bdth swim on t h e i r sides. Following ecdysis (molting) and mating, eggs a re l a id through two ventral pores i n the female's s i x t h thoracic sternite. Eggs can number from 1 t o 200 o r more. Thin, tube-dwel 1 i ng gammari ds have the fewest eggs, which tend t o be l a rge o r contain large amounts o f yo1 k. Because o f the large size o f the eggs, only one can be carr ied by some young females, wh i l e f u l l y mature females carry three or four. Eggs hatch direct ly into juveni les resembling adults. I n gammarids, one-quarter t o one-half of the eggs may die before hatching. Juveniles are generally held i n the brood pouch f o r a few hours t o a few days after hatching before they are released (Barnard 1969; Reish and Barnard 1979).

O

Chang and Parsons (1975) found that the common inshore gammarid - Ani sogammarus pugettensi s breeds year round i n the Paci f ic Northwest. j n contrast to beach and some inter: t i d a l amphipods of the cooler North At lant ic . Those mecies e i ther have one brood per year or cease t h e i r reproductive act ivi ty during the

coldest winter months. Females lay eggs during each o f t h e l a s t f i v e o r s ix molt ing stages, o r a t every other stage (Barnard 1969).

GROWTH C!IARACTERISTICS

Growth i s i n i t i a l l y r a p i d i n Gammaridea; mol ti ng i n i t i a t e s w i t h i n several days o f hatching and continues after maturity, slowing to every 20 t o 30 days i n the la ter stages o f development. The average ins ta r (stage o f development between successive molts) las ts 15 days. Gammarids go through a t l e a s t 12 instars; thus, the maximum l i fespan estimates are a l i t t l e more than 6 months, a l though some polar species are known t o l i v e 5 or 6 years (Reish and Barnard 1979).

Amphipod growth rates. and lengths vary considerably. Adult amphipods range i n s ize from less than 1 cm t o about 28 cm, the largest being an undescribed lysianassid that was photographed i n the abyssal Paci f ic Ocean (Schmidt 1968). Maximum growth ra tes o f A. U ettensis, mentioned above, were 4. F per week a t 10 OC,

increasing more than threefold to 14.3% per week a t 20 OC (Figure 4), wi th h igher e f f ic iency a t 20 OC.

Growth r e l a t i v e t o food intake i n large (10 mg) ind iv idua ls o f th is species was 47% t o 72% when fed Enteromorpha (Chang and Parsons 1975).

POPULATION DYNAMICS AND IMPORTANCE TO FISHERIES

Amphipods are the main food i t em o f many f i s h species, as wel l as other aquatic animals (Figure 5). Some pelagic species sometimes comprise the bu1 k of the d ie t o f herr ing, mackerel, and Biscayan tunny (Schmitt 1968). Gammarids, on the basis of the Index of Relat ive Importance (IRI), were the most important food species f o r nearshore f i shes i n the S t ra i t o f Juan de Fuca (comprising more than half of

5

BEST W?Y AvhluILt

10.0 1

6 1.0 E!

3

1

.c,

e Q .l0

.O1 2 4 . 6 8 10 12 14

Weeks

the to ta l ' IR1 spectrum f o r 38% of the 55 f i s h species studied) and were the most important food jtem to t idepool fishes (Cross e t a l . ' 1978). For the most part, the gammarids were epiben- th ic ra ther than infaunal or pelagic. Cross e t a l . (1978) suggested tha t since hyperiid populations on which nerit ic f ishes feed are natural ly patchy, small 1 oca1 i zed perturbations are 1 i kely to create more patchiness. I f adjacent areas remain unaffected, the ner i t ic f ish populat ions may not be adversely affected. However, sublittoral f ishes, especially juve- ni le f ishes, are more dependent on epibenthic prey, and thus more l i k e l y t o be affected by perturbation, although the amphipod supply i s often repledished by t ida l act ion. Because o f ' the i r re la t i ve i so la t ion , tidepool fishes are most heavily af fected by perturbation (Cross e t a l . 1978).

Mason (1974) hypothesized tha t delayed seaward migrations of juveni le

chum salmon (Oncorhynchus e) and coho salmon (Oncorhynchus kisutch) may he p t t r ibu tab le i n pa r t t o t he abun- dance o f food organisms i n r i ve rs and estuaries. Abundant populations of gammarids i n the upper estuary of Hyman' Creek, B r i t i s h Columbia, con- s t i tu ted the main d ie t o f t he fry o f these two sal'mon species. They a l so const i tu ted the major i ty o f the d ie t o f chum fry a t s i x nearby estuaries a t low t i d e i n t h e spring.

Coropii um salmonis , a tube- dwell ing gammarid, i s an abundant and preferred prey organism o f chum salmon i n the Skagi t River : s a l t marsh i n Washington State (Congleton and Smith 1976). Though 1 i t t l e i s known o f the seasonal abundances o f C. salmonis, Albr ight (1982) found peak densities of the species i n t i d e f l a t s o f Grays Harbor, Washington, i n J u l y and Au- .gust. I n the inner ha l f o f the bay they were the domi nant organism on mud and sandy mud bottoms. Densities as high as 57,00O/m2 have been observed (Albright and Rammer 1976). From Apri 1 through September production was 3.6-10.7 g/m* , and turnover (production/qean biomass) was 7.2 t o 8.6 g/m2. I n Grays Harbor, C. salmonis i s an important prey item för dunlin (Calidris al ina), English sole (Parophyrys vet* . and s ta r ry f 1 ounder ( P l at ichthys stel 1 atus) according t o Smith and Mudd ( 1 9 7 6 ) d fo r o ther f i sh species, as wel.1 as shrimp (Crangon spp. ) and Dungeness crab (Cancer magister) (Ai'bright 1982). Smi t h (1980) reported simi lar ly h igh C. salmonis densities and predation on t h i s amphipod by various species i n other northwest estuaries.

Numerically, amphipods are the major component o f the fauna o f harbor p i l i ngs i n California. Most are introduced species that have had l i t t l e , e f f e c t oil indigenous amphipods i n nearby areas (Barnard 1961; Reish 1964). Negl ig ib le economic loss due to f ou l i ng has resul ted (Rei sh and Barnard 1979). I n heavi ly pol luted

6

Eogammarus Western Sandpiper Dunlin

Starry

Snake Prickleback

Saddleback

Dungeness Crab Shrimp

Longfin Smelt Nemertean Worms

Figure 5. Fish and invertebrate predators o f the amphipod Corophium salmonis (from Albright 1982).

sections o f harbors, amphipods are reportedly absent both i n the benthos and on pi1 ings (Reish 1959).

O f the pelagic organisms i n the upper 200 m o f f the Oregon coast, hyperiids comprise more than 10% o f organisms by number; t h e i r abundance i s known t o vary seasonally (Van Arsdale 1967, c i ted by Pearcy 1972).

Two gammarid species have been examined f o r the i r potent ia l as food i n f i s h culture. Mass culturc! o f

It al so scavenges dead fi shes and uneaten f i s h food i n ponds. However, i t s growth i s ;lower than that o f br ine shrimp. Gammarus 1 acustr i s, found i n shal low prair ie lakes of the Hudson Bay drainage, meets . dietary requirements ' f o r ra!nbow t rou t (Salmo gai rdneri) 5 cm o r greater, i s easily captured, and can be harvested a t a r a t e o f 1,000 kg per ha per year. For most food ingredients it i s comparable t o or better than commer- c i a l feeds, and it improves h d y colorat ion and hence marl:elah.i ' i t v s f

Anisogammarus pugettensis was proposed t rou t (Math1 as e t a l . 1982 j. by Chang and Parsons (1975) as an a l ternat ive t o br ine shrimp cu l ture f o r young salmon; A. pugettensis can ECOLOGICAL ROLE to1 erate wide rmg6c L f tcrn:,?ratares and sa l i n i t i es a!& thriv.:r, on a Amphipods a re considered the m s t var ie ty O P p:ant and anirlal z:Ffer!al. e f f ic ient scavengers o f sea bottoms

7

and shores, probably clearing up and recycl ing more organic shore debris than any other animal (Schmitt 1968). Griff i ths and Stenton-Dozey (1981) described the importance of the gammarid Talorchestia capensis i n consum-iny beached kelp i n South Africa. This species and dipteran larvae consume some 60% t o 80% o f beached kelp wi th in 2 weeks, and 'the gammarid i s thought t o make a s i g n i f i - cant contribution (through .Feces) t o organic enrichment of the inshore mari ne system.

Caine (1980), i n an ecologica7 comparison o f two 1 i t t o r a l species o f caprel l i d amphipods i n Washington State, indicated that each species has a d i f f e ren t e f fec t on i t s community. Deute1 l a ca l i f o rn i ca i s a predator, b u t i t s removal d id no t a l t e r com- munity structure, even though it displays a preference f o r the ep ib io t i c community o f Obel i a dichotoma. I n contrast, Caprella laeviuscula i s a periphyton scraper tha t has an enormous impact on the periphyton on Zostera marina, and thus increases available l i g h t f o r the seagrass, and permits i t s growth i n areas where it would have otherwise been excluded. Observations on interspecific anaressive behavior indicate that C. laeviuscula i s dominant over oTher camel l i d s i n

--

protected habitats. ' Pridätory caprel l ids d ia not appear t o occur together where they would compete d i rec t l y f o r food, w h i l e f i l t e r - feeding caprell ids do compete t o some extent f o r food (Caine 1977).

Reish and Barnard (1979) catego- r i zed gammarids and ' hyperi ids by habitat. Nestlers include beach- hoppers o f the gammarid family Tal i t r idae, commonly found on sandy i n t e r t i d a l areas. High numbers occur under moi sture-mai n t a i n i ng a l ga l wrack, as discussed above. These species must be transitory, the authors speculated, because o f f re - quent changes i n t i d e and wrack accumulations. Species o f s i x or

seven gammarid families (e. Q. , Ampeliscd sp. and Photis sp.). con: s t ruc t tubes or cradles on so f t o r hard substrata, according t o Barnard (1969). Corophium sp. , common i n estuaries where s i l t i n g i s heavy, forms masses o f heavy tubes and creates currents with i t s abdominal appendages. The currents are strained by f r inges o f f ine ha i rs on the appendages forward of the abdomen; then whatever i s c o l l e c t e d i s scraped into the mouth (Kozloff 1973). Other species inhabit dwell ings of other organisms. Many species are burrow- ers, especially i n the gammarid families Haustoriidae, Oedicerotidae, and Phoxcephal idae. Elongated setae on the d fs ta l ar t ic l9s o f the poster ior poreopods are an adaptation for burrowing (Reish and Barnard 1979).

A number o f Gammaridea 1 i ve on sedentary invertebrates such as coral s y sponges, tunicates y anemones, and polychaetes. Their relationships with the hosts are not well understood (Reish and Barnard 1979).

Hyperi idea are primarily nek- tonic. They have we1 1-developed swimming devices or buoyancy control, o r w e found i n association with medusae OP salps (Reish and Barnard 1979). Phronima sp., sometimes col lected i n plankton tows o r along docks i n the San Juan Islands, i s found i n empty salp tests (Kozloff 1974). Hyperiids may feed on the very organisms that host them, but may also use them as a base from which t o forage, or they may feed on food captured by the host (Bowman e t al. 1963). Their feeding habits are poorly understood. I n one laboratory study o f Lestrigonus sp. and Bougisia sp. , food was shared wi th the host, Leptomedusa sp., when food supply was adequate, but when it was not, the amphipods fed on host t issue (Bowman and Gruner 1972). Para- themisto sp., a f ree- l iv ing hyper i id, preys on other plankters (Bowman 1960).

8

A few nektonic gammarids are found i n n e r i t i c waters. These are either predators or are mating or dispersal phases of benthic gammarids (Rei sh and Barnard 1979).

Che1 ura terebrans , a wood-borer found i n CalSfornia, i s the best known amphipod pest. It enlarges holes i n wood made by the isopod Limnoria sp. (Reish and Barnard 1979).

The swimmipg capabi l i ty of epi- benthic gammarids may reduce t h e i r suscept ib i l i t y t o predation. Feller and Kaczynski (1975) suggest tha t harpacticoid copepods were preferred over amphipods by juveni le chum salmon i n Puget Sound during the spring because they are re la t i ve l y easy t o capture. Simenstad (1976) noted the same predatory habits for ' juvenile pink and chum salmon i n Hood Canal, Washington, and found that juveni le salmon, i n addi t ion to preferr ing the less numerous and smaller harpactacoid copepods, also consumed gammarid eggs.

Ani sogammarus confervi cul u5 i s bel ieved to defend or "buffer" i t s populations against predation by m i - grating f ishes, such as juveni le chum salmon, by ecological adaptations. These adaptations decrease the foraging eff iciency of the predator and include association with refuges i n vegetation, clumping i n refuges, associat ion wi th structural ly complex habi tats and d is t r i bu t ions re la ted to r i ver f low and t ides (Levings and Levy 1976). I n Grays Harbor, Washington, however, mature male C. salmonis are subject to heavy predation beginning i n Apri 1, when they wander over t ide- f l a t s i n search o f females (Albr ight 1982).

Hyperiid swimming varies from feeble movement o f appendages i n Cystisoma sp. t o rap id swimming i n Paraprone sp. which has strong pleonal musculature (Bowman and Gruner 1973). Caprel l ids, attaching with posterior 1 egs , feed by grasping food with the i r f ree anter ior legs and antennae.

Locomotion i s accompl ished with a 1 oop-l i ke movement i n which the front legs attach while the rear ones re1 ease and reattach (Kozloff 1973 1.

In addi t ion to be ing prey for many f i s h and invertebrate species, some pelagic amphipods comprise pa r t of the crustacean diet of whales. Most o f the grey whale d i e t on the west coast consists of six species of benthic amphipods (Matthews 1978). Br i t i sh gu l l s a re a lso known t o consume benthic amphipods (Schmitt 1968).

Locomotion i n gammarids i s large- l y by swimming; they are poorly balanced f o r Wal king. Even burrowers are strong swimmers. Small coupling hooks j o i n pleopods, f ac i 1 i t a t i ng coordi nated paddl i ng motions. Some softbottom gammarids have elongated pereopods spread out 1 i ke a spider' S legs t o prevent sinking into the mud. The body hangs upside down, lowering the center of gravity. Sediment burrowers possess strong and densely packed spines on the i r pereopods (Barnard 1969).

Caprell ids, the suborder which includes skeleton shrimp, are largely i n te r t i da l and shallow subtidal. Their preference of substrate i n the Paci f ic Northwest is not specif ic, but they do need t o c l i n g t o something. Thus, they are found on algae, 'sea- grasses, sponges, hydroids , and bryozoans, but not on bare sand or mud bottoms. Caprell ids feed on diatoms, small invertebrates and possibly detr i tus, and are prey for many fishes (includii lg cod, blennies, and skates) and a lso for shrimp (McCain 1975). Whale parasi tes of the genus Cyamus are also i n the caprel l i d suborder. This group includes about 18 host- specific species. They lack a free- swimming stage; they leave the parental brood pouch and d ig in to the host with hooked dactyl S (Schmitt 1968).

9

ENVIRONMENTAL REQUIREMENTS

D i ss01 ved Oxygen

Pel agi c gammari d and hyperi i d amphipods have been col lected from a scattering layer i n deep, poorly oxygenated waters o f f southeastern Vancouver Is land, Br i t ish Columbia (Wal dichuck and Bousf i e l d 1962). Ani sogammarus sp. and A l lorchestes sp., both common inshore gammarid amphipod genera, were found i n low dissolved oxygen environments (as low as O. 04 ppm a t 12 OC) near su1 f i te - r i c h paper pulp eff luent. The former species was found i n high numbers on the bottom (15 t o 22 m) and the la t te r species, normally found i n shallower waters, was observed near the surface, perhaps seeking more oxygenated water (Waldichuk and Bousfield 1962). Low oxygen tolerance i n e i ther species remains t o Ge determined, but Chang and Parsons (1975) observed tha t Anisogammarus pugettensis su:vived f o r several hours a t 20% satura-

~

t ion levels. They also determined a o f 1.6, lower than those of other

c staceans fo r which it i s around 2 (Q i s the factor by which the metabiqic rate increases after a 10' increase i n temperature). They sug- ges t t ha t t h i s i s an adaptation for coping wi th rap id ly chanSing in ter - t i d a l temperatures. Caprell ids are known t o leave eel grass beds " in droves" a t n igh t when dissolved oxygen 1 evel s i n the beds drop below 2 PPm-

Tolerances t o low dissolved oxygen levels vary greatly among species; many are very sensit ive to 1 ow 1 evel s , especial l y species r e s t r i c t e d t o areas where dissolved oxygen does not h is tor ica l ly vary greatly. Groups such as phoxo- cephalids (used as indicators of pol- l u t a n t l e v e l s i n sediment bioassays) appear much less tolerant to stress- ful condit ions than many o f the species discussed above (R. Albright, Universi ty of Washington; pers. comm. ).

10

Sal i n i ty

Adult gammarids found i n es- t ua r ies a re f a i r l y t o le ran t t o a wide s a l i n i t y range while many juveniles and embryos are not. Adult estuarine Corophi um vol utator survived i n sal in- i t i e s o f 2 t o 59 ppt (McClusky 1967), but preferred a range o f 10 t o 30 ppt (McClusky 1970). Adult g. triaenonvx survived i n a s im i la r l y wide range o f sa l i n i t i es (Shyamasundari 1973), though juveniles could develop on ly a t s a l i n i t i e s o f 7.5 t o 37.5 ppt. For large numbers of ind iv idua ls to sur- vive and develop, 20 t o 32.5 ppt were required (Shyamasundari 1976). Anisogammarus pugettensis , found natural ly i n 20 t o 28 ppt sa l in i t ies , cannot survive i n freshwater but can survive at 11 pp t f o r a t l eas t 1 week (Chang and Parsons 1975). Some species, such as Phoxocephalid spp. o r Ampel i scad spp. , may have very narrow sal inity tolerances. Other amphipods (e.g., Gammarus spp. , Hyalel la spp. and Crangonyx spp.) are found i n freshwater.

Pol 1 ut i03 and Dredging

Reist8 and Barnard (1979) observed tha t some amphipod species are more tolerant than others to organic pol- lu t ion, but do not know what environ- mental factors cause the differences. It i s known tha t some amphipods are sens i t i ve t o po l l u t i on i n harbors. Capi te l la sp., a marine polychaete which i s commonly used as a pol 1 ut ion indicator and which has a d i s t r i bu t i on that is o f ten mutual ly exc lus ive t o t h a t o f amphipods, i s found i n heavily polluted harbors. Capitella sp. i s also found i n unpoll uted areas, such as deep sea bottoms of f the coast of California, which are subject t o freshwater in f low -- places where amphipods are notably absent (Reish and Barnard 1979).

The d i s t r i bu t i on o f Corophi um salmonis i s influenced by sediment

type and depth (it prefers shal l ow, muddy sand substrates) more than by sal i n i ty. Other species o f Corophi um exhibi t greater produc- ' t i o n near sewer ou t fa l l s -- an in- crease which i s presumably a t t r ibu- tab le t o organic enrichment (Birklund 1977).

Behavioral changes i n amphipods exposed t o sublethal quantit ies of o i l have been noted and suggest a sens i t i v i t y t o f resh o i l . Beach- hoppers are most 1 i ke l y t o be affected by o i l due t o t h e i r occur- rence i n the high-tide wrack zone (Baker 1971), whi le species o f

Ampel isca show s e n s i t i v i t y i n sub- ti da1 areas.

Dredging i s l i k e l y t o e l i m i n a t e benthic amphipods, which l i v e on or close to the substrate (Reish and Barnard 1979). However, McCaul l e y e t al. (1977) suggest t h a t i n t h e event o f dredging, adults are 1 i k e l y t o move t o nearby unaffected areas o r juve- n i les may rap id ly se t t le and repopu- 1 ate the dredged areas (McCaul ley e t a l . 1977). Crustaceans are generally very sensitive t o pol lu- t i o n and, therefore, species depend- ent on them as food are i nd i rec t l y affected by pol lut ion.

11

LITERATURE CITED

Albright, R. 1982. Population dynam- i cs and production of the amphipod Corophium salmonis i n Grays Harbor, Washington. M.S. Thesis. Univer- s i t y o f Washington, Seattle. 76 pp.

Albright, R. , and A. D. Rammer. 1976. Maintenance dredging and the environment o f Grays Harbor, Wash- ington. Appendix E: The e f fec t o f i n t e r t i d a l dredged material disposal on benthic invertebrates. U. S. Army Corps o f Engineers, Seatt le Distr ict . 244 pp.

Baker, J.M. 1971. Growth simu- la t ion fo l lowing o i l po l lu t ion. Pages 72-77 in E. B. Cowell, ed. The ecolog iLa l e f fects o f o i l po l lu t ion on l i t t o r a l communities. I n s t i t u t e o f Petroleum, London.

Barnard, J.L. 1961. Relationship of Cal i forn ia amphipod fauna. i n New- po r t Bay and i n the open sea. Pac. Nat. 2: 166-168.

Barnard, J. L. 1969. The families and genera o f marine gammaridean amphipoda. U. S. Natl. Mus. Bul l . 271. 535 pp.

Barnard, J. L. 1971. Gammaridean amphipoda from a deep-sea transect o f f Oregon. Smi thson. Contrib. Zool. 61. 86 pp.

Barnard, J. L. 1975. Iden t i f i ca t ion o f gammaridean amphipods. Pages 314-366 in R.I. Smith and J.T. Carl ton, eds. Light ' S manual : inter t ida l inver tebrates o f f the central Cal i fo rn i a coast . University of Cal i forn ia Press, Berkeley.

13

Barnes, R. D. 1974. Invertebrate zoology, 3rd ed. W.B. Saunders, Philadelphia, Pa. 870 pp.

Bengston, C. , and J. Brown. 1976. Maintenance dredging and the envi- ronment o f Grays Harbor, Washington. Appendix G: Impact o f dredging on the f ishes of Grays Harbor. U.S. Army Corps o f Engineers, Seattle D is t r i c t . 125 pp.

Birklund, J. 1977. Biomass, growth and production of the amphipod CorophIum insidiosum (Crawford) and pre l lmmnary notes on Cor0 hium volutator (Pallas). Ophelia+ 187-203.

Bousefield, E.L. 1978. A revised c lass i f i ca t ion and phylogeny o f amphipod crustaceans. Trans. R. Soc. Can. Ser. 4(16): 343-390.

Bowman, T.E. 1960. The pelagic amphipod genus Parathemi sto (Hyperi i dea: Hyperi i dae) i n the North Pacif ic and adjacent Arctic Ocean. Proc. U.S. Natl. Mus. 112 (3439): 343-392.

Bowman, T.E. , and H. Gruner. 1973. The fami l ies and genera of Hyperiidea (Crustacea: Amphipoda). Smithson. Contrib. Zool. No. 146. 64 PP*

Bowman, T. E. , C.D. Meyers, and S.D. Hicks. 1953. Notes on the associa- t ions between hyper i id amphipods and medusae i n Chesapeake and Narragansett Bays and the Niantic River. Chesapeake $ci. 4(3): 141-146.

Caine, E.A. 1977. Feeding mecha- n i sms and possible resource parti- t ioning of the Caprel l idae (Crustacea: Amphipoda) from Puget Sound, U.S. R . Mar. Biol. 42: 331- 336.

Caine, E.A. 1980. Ecology o f two 1 i t t o r a l species o f capre l l i d amphipods (Crustacea) from Washington, U.S.A. Mar. Biol. 56: 327-335.

Chang, B.D., and T.R. Parsons. 1975. Metabolic studies on the amDhiDod . . Ani sogammarus ugettensi S i n re la t i on t o i t s t!ophic pos i t ion i n the food web o f young salmonids. J. Fish. Res. Board Can. 32(2):243-247.

~ ~ ~~

Congleton, J. C. , and J. E. Smith. 1976. Interactions between juveni le salmon and benthic invertebrates i n the Skagit salt marsh. Pages 31-35

eds. Fish food habits workshop, 1s t Pac. N.W. Tech. Workshop, Astoria, Oreg. Oct. 13-15.

- i n C.A. Simenstad and S.J. Lipovsky,

Con1 an, K. E. , and E. L. Bousfield. 1982. Studies on amphipod crus- taceans o f the northeastern Pacific region 2. Family Amphipodae. Natl. Mus. Can. Publ. B io l . Oceanog. No. 10: 41-75.

Cross, J.N., K.L. Fresh, B.S. M i l le r , C.A. Simenstad, S.N. Steintort , and J. C. Fegley. 1978. Nearshore f i r 3 and macroi nvertebrate assemblages along the Strai t o f Juan de Fuca including food habits of common nearshore f ish. NOAA Tech. Memo. ERL MESA-32. 188 pp.

Fe1 1 er, R. J. , and V. W. Kaczynski . 1975. Size selection predation of juveni le chum salmon (Oncorhynchus

Sound. J. Fish. Res. Board Can. 32 (8) : 1419- 1429.

- keta) on epibenthic prey i n Puget

Gr i f f i t hs , C.L., and J. Stenton- Dozey. 1981. The fauna and ra te o f degradation o f standard kelp.

Estuarine Coastal Shelf Sci . (1981) 12: 645-653.

Kozloff, E.N. 1973. Seashore l i f e o f Puget Sound, t h e S t r a i t o f Georgia, and the San Juan Archipelago. Universi ty of Washington Press, Seattle. 282 pp.

Kozloff, E.N. 1974. Keys t o t h e marine invertebrates of Puget Sound, the San Juan Archipelago, and adja- cent regions. University of Washington Press, Seattle. 226 pp.

Levings, C. D. , arrd D. Levy. 1976. A "bugs-eye" view o f f i s h predation. Pages 147-152 i n C.A. Simenstad and S.J. L i p o v s b T eds. Fish food habits workshop, 1 s t Pac. N.W. Tech. Workshop, Astoria, Oreg. Oct. 13-15.

Mason, J.C. 1974. Behavioral ecology o f chum salmon fry (Oncorhynchus keta) i n a small estuary. J. Fish. Res. Board Can. 31(1): 83-92.

Mathias, J. A. , J. Martin, M. Yorkow- ski, J.G. I. Lark, M. Papst, and J. L. Tabachek. 1982. Harvest and nu t r i t iona l aual i t y o f Gammarus

1 ture. Trans. 83-89.

l acus t r i s f o r t rou t Cu Am. Fish. Soc. lll(1):

Matthews, L. H. 1978. h is to ry o f the whale

The natural !. Wei denf e l d

and Nicohson, London. 219 pp.

McCai n, J. C. 1975. Phylum Arthro- poda: Crustacea, Amphipoda: Caprell idea. Pages 367-376 in R. I . Smith and J.T. Carlton, eds. Light 's manual: in ter t ida l inver- tebrates of the central Cal i fornia coast, 3rd ed. University of Cal i- forn ia Press, Berkeley.

McCaul ley, J. E. , R. A. Parr, and D. R. Hancock. 1977. Benthic infauna and maintenance o f dredging. Water Res. 11( 1) : 83-89.

14

McClusky, D.S. 1967. Some ef fects o f s a l i n i t y on the survival, moult- i ng and growth o f Corophium voluta- - t o r (Amphipoda). J. Mar. Biol . Assoc. U.K. 48(2): 607-617.

McCluskv. D.S. 1970. Sa l in i ty we-

o f j uven i l e salmonids i n Hood Canal, Washington. Pages 163-176

eds. Fish food habits workshop, 1st Pac. N.W. Tech. Workshop, Astoria, Oreg. Oct. 13-15.

- i n C.A. Simenstad and S.J. Lipovsky,

f i r e r k e i n Corophi um vol utatÖr.. J . Mar. Biol. Assoc. U . K m 747- 752.

Park, T.S. 1961. Tentative keys to t he gammarid amphipods o f the San Juan area. Unpubl . manuscript, University of Washington. Friday Harbor Laboratory, Friday Harbor.

Pearcy, W.G. 1972. Dis t r ibut ion and ecology o f oceanic animals o f f Ore- gon. Pages 351-377 @ A.T. Pruter and C. L. Alverson, eds. The Columbia River Estuary and adjacent ocean waters: bioenvironmental studies. University of Washington Press, Seattle. 868 pp.

Reish, D.J. 1959. An ecological study of pol 1 u t i o n i n Los Angeles- long Beach Harbors , Cal i fornia. Occas. Pap. Al lan Hancock Found. No. 22: 1-119.

Reish, D.J. 1964. Studies on the My1 i t u s edul i s community i n Alamitos Bay, California. I I . Population var iat ions and discussion of the associated organisms. Veliger 6: 202-207.

Reish, D. J. , and J. L. Barnard. 1979. Chapter 11. Amphipods (Arthropoda: Crustacea: Amphipoda). Pages 345-700 fi C.W. Hart, ed . Pollution ecology of estuarine invertebrates. Academic Press, New York.

Schmitt, W. C. 1968. Crustaceans. University of Michigan Press, Ann Arbor. 204 pp.

Simenstad, C.A. 1976. Prey orga- nisms and prey community composition

15

Shyamasundari, K. 1973. Studies on the tube-building amphipods (Corophium triaenonyx) (Stebbi ng) from Visaknapatnam Harbor: e f f e c t o f s a l i n i t y and temperature. B io l . Bult. (Woods Hole) "3): 503-510.

Shyamasundari, K. 1976. Ef fects o f s a l i n i t y and temperature on the development o f eggs or1 the tube-büilding amphipod Corophium

(Stebbing). Biol . Bull. 150( 2): 286-293.

Smith, J.E. 1980. Seasonality, spatial dispersion patterns and migration of benthi c invertebrates i n an i n t e r t i d a l marsh-sandflat system o f Puget Sound, Washington, and the i r re la t ion to water fowl , foraging and for feeding ecology of staghorìi sculpin, - Leptocöttus armatus. Ph.D. Dissertation. Universi ty of Washington, Seattle. 177 pp.

Smith, J. L. and D. R. Mudd. 1976. Maintenance dredging and the envi- ronment o f Grays Harbor, Washington. Appendix H: Impact o f dredging on the avian fauna i n Grays Harbor. U. S. Army Corps o f Engineers, Seat t le Dis t r ic t . 217 pp.

Staude, C. P. , J.W. Armstrong, R. M. Thom, and K.K. Chew. 1977. An i 11 ustrated key to the i r r te r t ida l gammaridean amphipods of central Puget Sound. Coll. Fish. Univ. Wash. Contrib. No. 466: 1-27.

Waldichuk, M. , and E.L. Bousfield. 1962. Amphipods i n low-oxygen marine waters adjacent t o a su l f i t e pulp mill. J. Fish. Res. Board Can. 19(6): 1163-1165.

l¶72 -101 lmRT ~ U Y E N T A f i O N 1- Rgmm m*

, M* and Summ S upn D* pecies Prof i les: L i fe Histor ies and Environmental August 1986 equirements of Coastal Fishes and Invertebrates L

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?AGE Biological Report 82(11.69)* - Päci f i c Northwest)--Amphipods

laniel J. Grosse," G i l be r t B. Pauley? and David Moran . 0vgnnlz.Hm Nom and Addmm 1 Washington Cooperative Fishery bNational Wetlands Research Center

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Research Un i t NASA-S1 ide1 1 Computer Complex Il. Eol*mtm c GmI*m) Na Univers i ty o f Washington 1010 Sau! Seattle. WA 98195 Sl ide l l , LA 71

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Pational Wetlands Research Center U. S. Army Corps o f Engineers :ish and Wildl i fe Service Waterways Experiment Stat ion J.S. Department o f t he I n te r i o r P.O. Box 631 lashi ngton, DC 20240 Vicksburg, MS 39180

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*U.S. Army Corps o f Engineers Report No. TR EL-82-4

Species p ro f i l es a re l i t e ra tu re summaries o f the taxonomy, morphology, range, l i f e history, and environmental requirements of coastal aquatic species. They are prepared t o assist i n environmental impact assessment. Amphipods are ubiquitous i n d i s t r i b u t i o n . Hyperiidea are the t h i r d most abundant coastal marine crustacean zooplankton, following copepods and euphausids. Benthic Gammaridea are an invaluable food source f o r many economically important f i s h and invertebrate species. L i fes ty les of the major amphipod groups are varied. On the basis of the Index o f Relative Importance (IRI), they comprise nore than ha l f o f the to ta l IR1 spectrum f o r 38 o f 55 f i s h species i n t h e S t r a i t o f Juan de Fuca. They are reported t o be ind icators o f heavi ly po l lu ted areas.

Fisheries Estuaries Sal i n i t y b. Idmtifion/O#n.End.d lema

Food chains Oxygen L i fe cyc les Growth Water pol 1 u t i on Feeding Habits

Dissolved oxygen requirements L i f e h i s t o r y Sal i n i ty requirements Hyperi idea Gammaridea Caprell idea

TAKE PRIDE ìn Amerìca

DEPARTMENT OP THE IMTERIOR U.S. FISH AND MlDLlFE SERVICE

Au the Nation’s principal conservation agency, the Department of the Interior has mpon- sibility for most of our.nationally owned public lands and natural resources. this includes fostering the wisest usa of our land and water resources, protecting our fish and wildlih, preserving theenvironmental and cultural values of our national parks and hlstorical plaC08, and providing for the enjoyment of life through 6ut-r reenation. the IWartment as- sesms our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also has a major responsibility for Amrrican Indian reservation communities and for plople who Ihm in island hrritoriw under US. admlnlstntion.