REFERENCECOPY Do N o t Remove from the Library

U. S. Fish and Wi ld l i fe Service Biological Report 82 (11.69) I U ~ P I O ~ ~ I vverlanas Kesearch L e n W TR EL-82-4 August 1986 700 Ca j ~ : n Dome Boulevard

I-afaqette, Lou i~ iana 70506

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

AMPHIPODS

WASHINGTON

Fish and Wildlife Service Coastal Ecology Group

Waterways Ex~er iment Station

U.S. Department of the Interior U.S. Army Corps of Engineers

B i o l o g i c a l Report 82(11.69) TR EL-82-4 August 1986

Species P ro f i 1 es: L i f e H i s t o r i e s and Environmental Requirements o f Coastal Fishes and Inve r teb ra tes ( P a c i f i c Northwest)

AMPHI PODS

Danie l J. Grosse and G i l b e r t B. Pauley Washington Cooperat ive F i she ry Research U n i t

U n i v e r s i t y o f Washington S e a t t l e , WA 98195

and David Moran

Nat iona l Wetlands Research Center

P r o j e c t O f f i c e r John Parsons

Nat iona l Wetlands Research Center U.S. F i s h and W i l d l i f e Serv ice

1010 Gause Boulevard S l i d e l l , LA 70458

Performed f o r Coastal Ecology Group

Waterways Experiment S t a t i o n U.S. Army Corps o f Engineers

Vicksburg, MS 39180

and

Nat iona l Wet1 ands Research Center Research and Development F i s h and W i l d l i f e Serv ice

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

This se r i es may be referenced as fo l l ows :

U. S. F i s h and W i l d l i f e Service. 1983-19-. Species p r o f i l e s : 1 i f e h i s t o r i e s and environmental requirements o f coas ta l f i s h e s and i nve r teb ra tes . U. S. F i s h W i l d l . Serv. B i o l . Rep. 82(11). U.S. A r m y Corps o f Engineers, TR EL- 82-4.

This p r o f i l e may be c i t e d as fo l l ows :

Grosse, D. J., G.B. Pauley, and D. Moran. 1986. Species p r o f i l e s : l i f e h i s t o r i e s and environmental requ i rements o f coas ta l f i shes and i nve r teb ra tes ( P a c i f i c Northwest)--amphipods. U.S. F i s h W i l d l . Serv. B i o l . Rep. 82(11.69). U. S. A r m y Corps o f Engineers, TR EL-82-4. 15 pp.

PREFACE

Th is species p r o f i l e i s one o f a s e r i e s on coasta l aquat ic organisms, p r i n c i p a l l y f i s h , o f spo r t , commercial, o r eco log i ca l importance. The p r o f i l e s are designed t o p rov 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 sketch o f t h e b i o l o g i c a l c h a r a c t e r i s t i c s and environmental requirements o f t he species and t o descr ibe how popu la t ions o f t h e species may be expected t o r e a c t t o environmental changes caused by coasta l development. Each p r o f i l e has sec t ions on taxonomy, 1 i f e h i s t o r y , eco log i ca l r o l e , environmental requirements, and economic importance, i f appl i cab le . A t h r e e - r i n g b inde r i s used f o r t h i s se r i es so t h a t new p r o f i l e s can be added as they are prepared. Th is p r o j e c t i s j o i n t l y planned and f inanced by t h e U. S. Army Corps o f Engineers and t h e U.S. F i s h and W i l d l i f e Service.

Suggestions o r quest ions regard ing t h i s r e p o r t should be d i r e c t e d t o one of the f o l l o w i n g addresses.

I n fo rma t ion Trans fer S p e c i a l i s t Nat iona l Wetlands Research Center U.S. F i s h and W i l d l i f e Serv ice NASA-Slidel l Computer Complex 1010 Gause Boulevard S l i d e l l , LA 70458

U. S. Army Engineer Waterways Experiment S t a t i o n A t t e n t i o n : WESER-C Post O f f i c e Box 631 Vicksburg, MS 39180

CONVERSION TABLE

H e t r i c t o U.S. Custanary

Elul t i p l y !ti To O b t a i n

m i l 1 i .ne te rs (nun) cer i t imeters ( cm) meters (m) k i 1 ometers ( km)

2 square a e t e r s (m ) 10.76 square k i l o n e t e r s ( km2) 0.3861 hec ta res (ha) 2.471

l i t e r s ( 1 ) cuh ic ;neters ( m 3 ) cub ic meters

m i l l igrams (mg) g r a m ( g ) k i l ogralns ( k g ) m e t r i c tons ( t ) m e t r i c tons k i 1 ocal o r i e s ( kca l )

i nches inches f e e t m i l es

square f e e t square . n i l es acres

gal l ons c u b i c f e e t a c r e - f e e t

ounces ounces pounds pounds s h o r t tons B r i t i s h thennal u n i t s

Cel s i u s degrees 1.8(Oc) + 32 Fahrenhe i t degrees

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

inches 25.40 inches 2.54 f e e t ( f t ) 0.3048 f a thorns 1.829 m i l e s ( m i ) 1.609 n a u t i c a l m i l e s ( m i ) 1.852

square f e e t ( f t 2 ) acres 2 square m i l e s (mi 1

ga l 1 ons ( gal ) cub ic f e e t ( f t 3 ) a c r e - f e e t

ounces (02) 28.35 pounds ( l b ) 0.4536 s h o r t t o n s ( t o n ) 0.9072 B r i t i s h thermal u n i t s ( B t u ) 0.2520

m i l 1 imete rs cen t imete rs meters meters k i l o m e t e r s k i 1 one te rs

square meters hec ta res square k i l o m e t e r s

1 i t e r s c u h i c meters cub ic meters

grams k i l o g r a m s m e t r i c tons k i 1 ocal o r i e s

Fahrenhe i t degrees 0.5556("F - 32) Cel s i u s degrees

CONTENTS

Page

PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii C O N V E R S I O N T A B L E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i v ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v i

NOMENCLATURE/TAXONOMY/RANGE . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . . . . . . . MORPHOLOGY/IDENTIFICATION A I D S 4 . . . . . . . . . . . . . . . . . . . . . . REASON FOR I N C L U S I O N I N S E R I E S 4

L I F E H ISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 GROWTH CHARACTERIST ICS . . . . . . . . . . . . . . . . . . . . . . . . . . 5

. . . . . . . . . . . . . . . POPULATION DYNAMICS AND IMPORTANCE TO F I S H E R Y 5 E C O L O G I C A L R O L E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 and D r e d g i n g . . . . . . . . . . . . . . . . . . . . . . . . . 10

L I T E R A T U R E C I T E D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

ACKNOWLEDGMENTS

We g r a t e f u l l y acknowledge t h e reviews by R i c k A1 b r i g h t , School o f F i s h e r i e s , U n i v e r s i t y o f Washington, S e a t t l e , and C r a i g P. Staude, F r i d a y Harbor L a b o r a t o r i e s , U n i v e r s i t y o f Washington, S e a t t l e .

Per eon

Gland Cone

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

AMPHI PODS

S c i e n t i f i c name . . . . . . Amphipoda (F igure 1)

Pre fe r red common name . . . Amphipods Class . . . . . . . . . . . Crustacea Subclass . . . . . . . . Ma1 acostraca Order . . . . . . . . . . . Amphipoda Suborders . . Gammaridea, Hyper i idea,

Capre11 idea, I n g o l f i e l l i dea (F igure 2)

Geographic range: Th is r e p o r t w i 11 focus l a r g e l y on the suborders Gammari dea, Capre l l idea, and Hyperi i dea because o f t h e i r impor- tance i n coasta l areas o f t h e

no r theas t P a c i f i c Ocean (F igure 3). Gammaridea a r e t h e most abundant and d i ve rse o f t h e amphipods. A1 though p r i m a r i l y marine, they are a l so found i n f reshwater and c e r t a i n mo is t t e r r e s t r i a1 h a b i t a t s (Rei sh and Barnard 1979). Marine Gammari dea a r e u b i q u i t o u s l y d i s t r i b u t e d . They a r e found i n a l l reg ions , i n a l l h a b i t a t s , and a t most depths. About 40% o f t h e 80 gammaridean f a m i l i e s a r e cosmopol i tan i n d i s t r i b u t i o n ; t h e remaining 60% are l oose l y assoc ia ted w i t h s p e c i f i c reg ions o r zones (Barnard 1969; Bousef i e l d 1978). Gammaridean d i s t r i b u t i o n s remain p o o r l y known, b u t more recent s tud ies (e. g. , Barnard 1971) a re

Figure 2. A, Elasmopus and B, Eohaustorius, both gammarid amphipods. C, Caprel la fe r rea, a c a p r e l l i d amphipod. D, Neocyamus physeter is (female), a c a p r e l l i d amphipod from sperm whale. E, Phronima sedentaria, a h y p e r i i d amphipod t h a t l i v e s ins ide the t u n i c o f urochordates. (A and B from Barnard 1975; C and D from McCain 1975; E from Barnes 1974. A-D r e p r i n t e d w i t h permission from the U n i v e r s i t y o f C a l i f o r n i a Press; E r e p r i n t e d w i t h permission from Saunders College Publ ishing.)

f i n d i n g more widespread d i s t r i b u - t i o n s than were p rev ious ly assumed. O f f t he Oregon Coast, 97 species o f gammarids have been found from the surface t o a depth o f 2900 m (Barnard 1971), and 20 species d i v ided among 11 fami 1 i e s were i n the upper 200 m (Pearcy 1972).

About 200 gammarid species have been found i n Washington waters (Staude e t a l . 1977). Some gamrnarid species dwel l i n sub t ida l o r i n t e r t i d a l environments (Rei sh and Barnard 1979). The suborder Hyper i idea i s e n t i r e l y marine and pe lag ic ; most members o f t h e taxon 1 i v e i n the

W A S H I N G T O N

KILOMETERS r@$i Concentrated estuarlne ... .. areas

CALIFORNIA

Figure 3. Distribution of the ubiquitous amphi pod suborders Gammaridea and Hyperiidea in the coastal areas of the northeast Pacific Ocean.

3

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

MORPHOLOGY/IDENTIFICATION AIDS

Animals o f t h e o rde r Amphipoda are d i s t i n g u i s h e d by sess i l e , compound eyes, though some species a re b l i n d . A carapace i s n o t p resen t and the f i r s t , and sometimes t h e second, t h o r a c i c segments are fused w i t h t he head. A "shrimp1 i ke" appearance r e s u l t s f rom l a t e r a l body compression. Gammarids and h y p e r i i d s have th ree p a i r s o f pleopods (swimmerets); two o r t h ree p a i r s o f uropods on the p leon (abdomen); a t l e a s t e i g h t p a i r s o f thoracopods, coun t i ng the m a x i l l i p e d ; u s u a l l y seven major l e g p a i r s , c a l l e d pereopods; and f i v e o r more p a i r s o f g i 11s. Males and females o f t e n can be d i s t i n g u i s h e d morphological ly. The head has f i v e fused segments, two p a i r s each o f antennae and maxi 1 l ae , a h e a v i l y c h i t i n i z e d mandible, and a 1 imbl i ke maxi 11 iped. There are seven f r e e l y a r t i c u l a t e d somites on the thorax (pereon). Coxal p l ate1 i ke l a t e r a l extensions o f t h e t h o r a c i c pereon are developed from t h e f i r s t segment o f each leg . Branchiae ( g i l l s ) a re f l e s h y and p l a t e l i k e and are a t tached medial t o t h e coxae, 2-6 on each side. The abdominal r e g i o n cons i s t s o f t h r e e a r t i c u l a t i n g segments on bo th a n t e r i o r p leon and p o s t e r i o r urosome; the urosome has a te rm ina l t e l son.

The f o l l o w i n g key (adapted from Barnes 1974; Koz lo f f 1974) i s pre- sented as an a i d t o separate the sub- orders o f amphipods:

l a . Pereon w i t h seven apparent segments, a l l having wel l -developed appendages. Abdomen n o t v e s t i g i a l . Body n e i t h e r s lender no r resembl i ng t h a t o f a p r a y i n g mantis. . . . . 2

l b . Pereon w i t h s i x apparent segments, some may have v e s t i g i a l appendages ; abdomen ves ti g i a1 ; head

fused w i t h second t h o r a c i c segment. Body s lender and resembl ing t h a t o f a p r a y i n g mant is (except f o r whale 1 i ce ) . Marine. Inc ludes ske le ton shrimp . . . Suborder Capre l l idea.

2a. Eyes g e n e r a l l y l a r g e , occu- p y i n g most o f head; coxae o f pereopods smal l , o f t e n fused w i t h t h e body, m a x i l l i p e d s w i t h o u t pa lp ; l a s t two abdominal segments fused; body more o r 1 ess t ransparent . Marine, and usual l y p l a n k t o n i c o r assoc ia ted w i t h j e l l y - f i s h o r i n t u n i c s o f dead salps . . . . . Suborder Hyperi idea.

2b. Eyes u s u a l l y p resent and conspicuous, b u t n o t l a r g e enough t o cover most o f t h e head; coxae o f pereopods w e l l developed, u s u a l l y expanded. Marine, f reshwater , and t e r r e s t r i a l . . . Suborder Gammaridea.

2c. Body e longate; coxae small ; abdominal segments d i s t i n c t ; a1 1 b u t f o u r t h and f i f t h p a i r s o f abdominal appendages v e s t i g i a l . Marine, i n t e r - s t i t i a l . Rare. . . . Suborder I n g o l f i e 1 1 idea.

There c u r r e n t l y e x i s t s no concise guide t o amphipod species i n t he nor thwest P a c i f i c . Pub1 i c a t i o n s o f t he Na t i ona l Museum o f Canada, such as t h a t by Conlan and B o u s f i e l d (1982), w i l l e v e n t u a l l y cu lminate i n a compre- hensive reg iona l handbook on marine gammari deans. Con t r i bu t i ons by Barnard (1975) and Staude e t a l . (1977) may be use fu l f o r i d e n t i f y i n g Gammaridea i n r e s t r i c t e d i n t e r t i d a l reg ions ; t h e work o f B o u s f i e l d (1978) descr ibed f reshwater Gammaridea. K o z l o f f (1974) prov ided keys t o t h e Capre l l idea. Hyper i i d s can be i d e n t i - f i e d t o genus by u s i n g the descr ip - t i o n s pub l i shed by Bowman and Gruner (1973).

REASON FOR INCLUSION I N SERIES

H y p e r i i d amphipods a re the t h i r d most abundant group o f coas ta l marine crustacean zooplankton, f o l l o w i n g

Copepoda and Euphausidea (Bowman and Gruner 1973). The ben th i c amphipods, especi a1 l y Gammaridea, a re an i nval u- ab le food source f o r many economical ly impor tan t f i s h and i n v e r t e b r a t e species. T h e i r 1 i m i t e d mobi 1 i t y suggests t h a t t h e i r d i s t r i b u t i o n and abundance can be used as an i n d i c a t o r o f environmental qua1 i ty ( A l b r i g h t 1982). Omnivorous, o p p o r t u n i s t i c feeders such as l ys ianass ids (a gammaridean fam i l y ) r e c y c l e d e t r i t u s and may he lp a v e r t p o l l u t i o n by scav- enging carcasses o f 1 a rge r animals f o l l ow ing mass m o r t a l i t i e s (Reish and Barnard 1979).

LIFE HISTORY

Female Amphipoda spawn v i a an amplexus (mating embrace) w i t h males which l a s t s f o r hours o r days. I n swimming species t h e female swims w i t h t he male on top, o r bo th swim on t h e i r s ides. Fo l l ow ing ecdysis (mol t ing) and mating, eggs a re l a i d through two v e n t r a l pores i n t h e female 's s i x t h t h o r a c i c s t e r n i t e . Eggs can number from 1 t o 200 o r more. Thin, tube-dwel 1 i ng gammari ds have t h e fewest eggs, which tend t o be l a r g e o r con ta in l a r g e amounts o f y o l k . Because o f t h e l a r g e s i z e o f t h e eggs, o n l y one can be c a r r i e d by some young females, w h i l e f u l l y mature females c a r r y t h ree o r f ou r . Eggs hatch d i r e c t l y i n t o j u v e n i l e s resembl ing adu l t s . I n gammarids , one-quarter t o one-ha1 f o f t h e eggs may d i e be fo re hatching. Juveni 1 es a re general l y h e l d i n t h e brood pouch f o r a few hours t o a few days a f t e r ha tch ing before they a re re leased (Barnard 1969; Rei sh and Barnard 1979).

Chang and Parsons (1975) found t h a t t h e common inshore qammarid - Ani sogammarus puge t tens i s breeds vear round i n t h e P a c i f i c Northwest. .. i n c o n t r a s t t o beach and some i n t e r - t i d a l amphipods o f t h e c o o l e r Nor th A t l a n t i c . Those species e i t h e r have one brood p e r year o r cease t h e i r rep roduc t i ve a c t i v i t y d u r i n g the

c o l d e s t w i n t e r months. Females 1 ay eggs d u r i n g each o f t h e l a s t f i v e o r s i x m o l t i n g stages, o r a t every o the r stage (Barnard 1969).

GROWTH CHARACTERISTICS

Growth i s i n i t i a l l y r a p i d i n Gammaridea; m o l t i n g i n i t i a t e s w i t h i n several days o f ha tch ing and cont inues a f t e r m a t u r i t y , s lowing t o every 20 t o 30 days i n t h e l a t e r stages o f development. The average i n s t a r (s tage o f devel opment between successive mol ts ) l a s t s 15 days. Gammarids go through a t l e a s t 12 i n s t a r s ; thus, t h e maximum 1 i fespan est imates are a l i t t l e more than 6 months, a1 though some p o l a r species are known t o 1 i v e 5 o r 6 years (Reish and Barnard 1979).

Amphipod growth ra tes .and lengths vary cons iderab ly . Adu l t amphipods range i n s i z e from less than 1 cm t o about 28 cm, t h e l a r g e s t be ing an undescribed l y s i a n a s s i d t h a t was photographed i n t h e abyssal P a c i f i c Ocean (Schmidt 1968). Maximum growth r a t e s o f A. puge t tens i s , mentioned above, were 4.1% p e r week a t 10 OC, i n c r e a s i n g more than t h r e e f o l d t o 14.3% pe r week a t 20 OC (F igure 4), w i t h h igher e f f i c i e n c y a t 20 OC. Growth r e l a t i v e t o food i n t a k e i n l a r g e (10 mg) i n d i v i d u a l s o f t h i s species was 47% t o 72% when f e d Enteromorpha (Chang and Parsons 1975).

POPULATION DYNAMICS AND IMPORTANCE TO FISHERIES

Amphipods a re t h e main food i t em o f many f i s h species, as w e l l as o the r aquat ic animals (F igure 5). Some p e l a g i c species sometimes comprise t h e b u l k o f t h e d i e t o f he r r i ng , mackerel, and Biscayan tunny (Schmit t 1968). Gammarids, on t h e bas i s o f t h e Index o f R e l a t i v e Importance ( I R I ) , were t h e most impor tan t food species f o r nearshore f i s h e s i n t h e S t r a i t o f Juan de Fuca (compr is ing more than h a l f o f

chum salmon (Oncorhynchus m) and coho salmon (Oncorhynchus k i su tch ) may be a t t r i b u t a b l e i n p a r t t o t h e abun- dance o f food organisms i n r i v e r s and es tuar ies . Abundant popu la t ions o f gammarids i n t h e upper es tuary o f Hyman Creek, B r i t i s h Columbia, con- s t i t u t e d t h e main d i e t o f t h e f ry o f these two salmon species. They a l so c o n s t i t u t e d t h e m a j o r i t y o f t h e d i e t o f chum f ry a t s i x nearby es tua r ies a t low t i d e i n t h e spr ing .

.O1 2 4 6 8 10 12 14

W e e k s

Figure 4. Growtn o t Anisogammarus puget tens is f e d Enteromorpha i n t e s - t i n a l i s a t 10 and 20 OC. ( R e ~ r i n t e d w i t h permission from the ~ o u i n a l of the F i she r ies Research Board o f - Canada, from Chang and Parsons 1 9 7 5 K

t h e t o t a l I R I spectrum f o r 38% o f t h e 55 f i s h species s tud ied) and were t h e most impor tant food i t em t o t i depoo l f i shes (Cross e t a l . 1978). For t h e most p a r t , t he gammarids were epiben- t h i c r a t h e r than in fauna l o r pe lag ic . Cross e t a l . (1978) suggested t h a t s ince hyper i i d popu la t ions on which n e r i t i c f i s h e s feed a re n a t u r a l l y patchy, small 1 ocal i z e d pe r tu rba t i ons are l i k e l y t o c reate more patchiness. I f adjacent areas remain unaf fected, t he n e r i t i c f i s h popu la t ions may n o t be adversely a f fec ted . However, sub1 i t t o r a l f i shes , especia l l y juve- n i l e f i shes , a re more dependent on ep ibenth ic prey, and thus more l i k e l y t o be a f f e c t e d by pe r tu rba t i on , a l though the amphipod supply i s o f t e n replenished by t i d a l ac t i on . Because o f t h e i r r e l a t i v e i s o l a t i o n , t i depoo l f i s h e s a re most h e a v i l y a f f e c t e d by p e r t u r b a t i o n (Cross e t a l . 1978).

Mason (1974) hypothesized t h a t delayed seaward migra t ions o f j u v e n i l e

Corophi um salmoni s, a tube- d w e l l i n g aammarid. i s an abundant and p r e f e r r e d p r e y organism o f chum salmon i n t h e Skag i t R iver s a l t marsh i n Washington S ta te (Congleton and Smith 1976). Though l i t t l e i s known o f t he seasonal abundances o f 5. salmonis, A1 b r i g h t (1982) found peak d e n s i t i e s o f t h e 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 t h e i nne r h a l f o f t he bay they were t h e dominant organism on mud and sandy mud bottoms. Dens i t i es as h igh as 57,00O/m2 have been observed ( A l b r i g h t and Rammer 1976). From A p r i l through September product ion was 3.6-10.7 g/m2, and turnover (production/mean biomass) was 7.2 t o 8.6 n/m2. I n Grays Harbor, C. salmonis i s an i m ~ o r t ~ n t ore" i t e m for - - - - . - . . . . ,~ - - - r - -4 - - ~ dun1 i n (Cal i d r i s a lp ina) , Engl i s h so le (Parophyrys v e t u l us), and s t a r r y f lounder (P la t i ch thys s t e l l a t u s ) accordina t o Smith and Mudd (1976) and f o r o the r f i s h species, a; w e l l as shrimp (Crangon spp. ) and Dungeness crab (Cancer magi s t e r ) (A1 b r i g h t 1982). Smith (1980) repor ted s i m i l a r l y h igh - C. salmonis d e n s i t i e s and p reda t ion on t h i s amphipod by var ious species i n o the r northwest es tuar ies .

Numerical ly , amphi pods are the major component o f t h e fauna o f harbor p i 1 ings i n C a l i f o r n i a . Most a re in t roduced species t h a t have had 1 i t t l e e f f e c t on indigenous amphipods i n nearby areas (Barnard 1961; Reish 1964). N e g l i g i b l e economic 1 oss due t o f o u l i n g has r e s u l t e d (Reish and Barnard 1979). I n h e a v i l y p o l 1 uted

rogamm,- . - - Western Sandpiper 1 Dunlin

Sh iner Perch

Starry

S n a k e Prickleback

D u n g e n e s s Crab / \ Shrimp Longf in S m e l t Nemertean Worms

Figure 5. F i s h and i n v e r t e b r a t e predators o f t he amphipod Corophium salmonis (from A l b r i g h t 1982).

sec t ions o f harbors, amphipods are repo r ted l y absent bo th i n the benthos and on p i l i n g s (Reish 1959).

O f the pe lag i c organisms i n the upper 200 m o f f the Oregon coast, hyper i i ds comprise more than 10% o f organisms by number; t h e i r abundance i s known t o vary seasonal ly (Van Arsdale 1967, c i t e d by Pearcy 1972).

Two garnmarid species have been examined f o r t h e i r p o t e n t i a l as food i n f i s h cu l tu re . Mass c u l t u r e o f Anisogammarus puget tens is was proposed by Chang and Parsons (1975) as an a1 t e r n a t i v e t o b r i n e shrimp c u l t u r e f o r young salmon; A. puget tens is can t o l e r a t e wide ranges o f temperatures and s a l i n i t i e s and t h r i v e s on a v a r i e t y o f p l a n t and animal ma te r ia l .

I t a lso scavenges dead f i shes and uneaten f i s h food i n ponds. However, i t s qrowth i s slower than t h a t o f b r i ne - shrimp. Gammarus l a c u s t r i s , found i n shal low p r a i r i e lakes o f the Hudson Bay drainage, meets d i e t a r y requirements f o r rainbow t r o u t ( ~ a l m o g a i r d n e r i ) 5 cm o r greater , i s e a s i l y captured. and can be harvested a t a F a t e ' o f 1,000 kg pe r ha pe r year. For most food ing red ien ts i t i s comparable t o o r b e t t e r than commer- c i a l feeds, and i t improves body c o l o r a t i o n and hence marketabi 1 i ty o f t r o u t (Mathias e t a l . 1982).

ECOLOGICAL ROLE

Amphipods a re considered the most e f f i c i e n t scavengers o f sea bottoms

and shores, p robab ly c l e a r i n g up and recyc l i ng more organ ic shore deb r i s than any o the r animal (Schmit t 1968). G r i f f i t h s and Stenton-Dozey (1981) descr ibed t h e importance o f t h e gammarid ~ a l o r c h e s - t i a capensi s i n consuming beached ke lp i n South - A f r i c a . This species and d i p t e r a n l a rvae consume some 60% t o 80% o f beached k e l p w i t h i n 2 weeks, and the gammarid i s thought t o make a s i g n i f i - can t c o n t r i b u t i o n ( through feces) t o o rgan ic enrichment o f t he inshore marine system.

Caine (1980), i n an eco log i ca l comparison o f two 1 i t t o r a l species o f c a p r e l l i d amphi pods i n Washington Sta te , i n d i c a t e d t h a t each species has a d i f f e r e n t e f f e c t on i t s communitv. Deutel l a c a l i f o r n i c a i s a predator , b u t i t s removal d i d n o t a l t e r com- muni ty s t r u c t u r e , even though i t d i sp lays a pre ference f o r t he e p i b i o t i c community o f Obel i a dichotoma. I n con t ras t , Capre l l a l aev iuscu la i s a pe r i phy ton scraper t h a t has an enormous impact on t h e per iphy ton on Zostera mari'na, and thus increases a v a i l a b l e l i g h t f o r t h e seagrass, and permi ts i t s growth i n areas where i t would have o therwise been excluded. Observations on i n t e r s p e c i f i c aggressive behav ior - - i n d i c a t e t h a t C. l aev iuscu la i s dominant over oTher c a ~ r e l 1 i d s i n p ro tec ted hab i ta t s . Predatory c a p r e l l i d s d i d n o t appear t o occur together where they would compete d i r e c t l y f o r food, w h i l e f i 1 t e r - feed ing c a p r e l l i d s do compete t o some ex ten t f o r food (Caine 1977).

Reish and Barnard (1979) catego- r i z e d gammarids and h y p e r i i d s by hab i ta t . Nest1 e rs i n c l u d e beach- hoppers o f t he gammarid f a m i l y T a l i t r i d a e , commonly found on sandy i n t e r t i d a l areas. High numbers occur under moi s tu re-main ta i n i ng a1 ga l wrack, as discussed above. These species must be t r a n s i t o r y , t he authors speculated, because o f f re- quent changes i n t i d e and wrack accumulations. Species o f s i x o r

seven gammarid f a m i l i e s (e.g. , - - - ~ m p e l i s c a - sp. and Pho t i s sp. ) con- s t r u c t tubes o r c rad les on s o f t o r hard subs t ra ta , accord ing t o Barnard (1969). Corophium sp. , common i n es tua r ies where s i 1 ti ng i s heavy, forms masses o f heavy tubes and c reates cu r ren ts w i t h i t s abdominal appendages. The cu r ren ts a re s t r a i n e d by f r i nges o f f i n e h a i r s on the appendages fo rward o f t h e abdomen; then whatever i s c o l l e c t e d i s scraped i n t o the mouth ( K o z l o f f 1973). Other species i n h a b i t dwe l l i ngs o f o the r organisms. Many species are burrow- e rs , e s p e c i a l l y i n t h e gammarid fami 1 i e s Haustor i idae, Oedicerot idae, and Phoxcephalidae. E l ongated setae on t h e d i s t a l a r t i c l e s o f t h e p o s t e r i o r pereopods a re an adapta t ion f o r burrowing (Reish and Barnard 1979).

A number o f Gammaridea l i v e on sedentary i nve r teb ra tes such as c o r a l s , sponges, t u n i cates , anemones, and polychaetes. T h e i r r e l a t i o n s h i p s w i t h t h e hosts a re n o t w e l l understood (Reish and Barnard 1979).

Hyper i idea a r e p r i m a r i l y nek- t o n i c . They have we1 1 -developed swimming devices o r buoyancy c o n t r o l , o r a re found i n assoc ia t i on w i t h medusae o r sa lps (Reish and Barnard 1979). Phronima sp., sometimes c o l l e c t e d i n p lank ton tows o r a long docks i n t he San Juan I s lands , i s found i n empty sa lp t e s t s ( K o z l o f f 1974). Hyper i i ds may feed on the ve ry organisms t h a t hos t them, b u t may a l so use them as a base from which t o forage, o r t hey may feed on food captured by the hos t (Bowman e t a l . 1963). T h e i r feed ing h a b i t s a re p o o r l y understood. I n one 1 abora tory study of Les t r igonus sp. and Boug is ia sp., food was shared w i t h t h e hos t , Leptomedusa sp. , when food supplv was adequate. b u t when i t was . . - no t , t h e amphipods f e d on hos t t i s s u e (Bowman and Gruner 1972). Para- themis to sp. , a f ree-1 i v i n g h y p e r i i d , p reys on o the r p l a n k t e r s (Bowman 1960).

A few nektonic gammarids are found i n n e r i t i c waters. These are e i t h e r predators o r a re mat ing o r d ispersa l phases o f benth ic gammarids (Reish and Barnard 1979).

Chel u ra terebrans, a wood-borer found i n C a l i f o r n i a . i s the bes t known amphipod pest . It enlarges holes i n wood made by the isopod Limnor ia sp. (Reish and Barnard 1979).

The swimming c a p a b i l i t y o f ep i - benth ic gammarids may reduce t h e i r sussept i b i 1 i t y t o predat ion. Fel l e r and Kaczynski (1975) suggest t h a t ha rpac t i co i d copepods were p r e f e r r e d over amphipods by j u v e n i l e chum salmon i n Puget Sound du r ing the s p r i n g because they are r e l a t i v e l y easy t o capture. Simenstad (1976) noted the same predatory h a b i t s f o r j u v e n i l e p i n k and chum salmon i n Hood Canal, Washington, and found t h a t j u v e n i l e salmon, i n a d d i t i o n t o p r e f e r r i n g the l ess numerous and small e r harpactacoid copepods, a l s o consumed gammarid eggs.

Anisogammarus con fe rv i cu lus i s be1 ieved t o defend o r " b u f f e r " i t s popu la t ions aga ins t p reda t ion by m i - g r a t i n g f i shes , such as j u v e n i l e chum salmon, by eco log ica l adaptat ions. These adaptat ions decrease t h e fo rag ing e f f i c i e n c y o f t he predator and i nc l ude assoc ia t i on w i t h refuges i n vegetat ion, clumping i n refuges, assoc ia t i on w i t h s t r u c t u r a l l y complex h a b i t a t s and d i s t r i b u t i o n s re1 a ted t o r i v e r f l o w and t i d e s (Levings and Levy 1976). I n Grays Harbor, Washington, however, mature male C. salmonis are sub jec t t o heavy p reda t ion beginning i n Apr i 1 , when they wander over t i d e - f l a t s i n search o f females ( A l b r i g h t 1982).

Hyperi i d swimming v a r i e s from feeb le movement o f appendages i n Cystisoma sp. t o r a p i d swimming i n Paraprone sp. which has s t rong p l eonal musculature (Bowman and Gruner 1973). Capre l l i d s , a t t a c h i n g w i t h p o s t e r i o r legs , feed by grasping food w i t h t h e i r f r e e a n t e r i o r legs and antennae.

Locomotion i s accomplished w i t h a l o o p - l i k e movement i n which the f r o n t legs a t t a c h w h i l e the r e a r ones re1 ease and rea t tach (Kozl o f f 1973).

I n a d d i t i o n t o be ing prey f o r many f i s h and inve r teb ra te species, some p e l a g i c amphipods comprise p a r t o f t he crustacean d i e t o f whales. Most o f t he grey whale d i e t on the west coast cons is t s o f s i x species o f ben th i c amphi pods (Matthews 1978). B r i t i s h g u l l s are a l so known t o consume ben th i c amphipods (Schmitt 1968).

Locomotion i n gammarids i s la rge- l y by swimming; they are p o o r l y balanced f o r wal k ing. Even burrowers are s t rong swimmers. Small coup1 i n g hooks j o i n pleopods, f a c i l i t a t i n g coordinated paddl i ng motions. Some sof tbo t tom gammarids have elongated pereopods spread o u t 1 i ke a s p i d e r ' s legs t o prevent s i n k i n g i n t o the mud. The body hangs upside down, lower ing the center o f g r a v i t y . Sediment burrowers possess s t rong and densely packed spines on t h e i r pereopods (Barnard 1969).

Capre l l i ds , t he suborder which inc ludes ske le ton shrimp, are l a r g e l y i n t e r t i d a l and shal low sub t ida l . T h e i r preference o f subst ra te i n the P a c i f i c Northwest i s no t s p e c i f i c , b u t they do need t o c l i n g t o something. Thus, they a re found on algae, sea- grasses, sponges, hydroids, and bryozoans, b u t n o t on bare sand o r mud bottoms. Capre l l i d s feed on diatoms, small i nve r teb ra tes , and p o s s i b l y d e t r i t u s , and a re p rey f o r many f i shes ( i n c l u d i n g cod, b lenn ies , and skates) and a l so f o r shrimp (McCain 1975). Whale pa ras i tes o f the genus Cyamus a r e a l s o i n the c a p r e l l i d suborder. Th i s group inc ludes about 18 host- s p e c i f i c species. They l a c k a f ree- swimming stage; they leave the pa ren ta l brood pouch and d i g i n t o the host w i t h hooked d a c t y l s (Schmit t 1968).

ENVIRONMENTAL REQUIREMENTS S a l i n i t y

Dissolved Oxygen

Pelagic gammari d and hyper i i d amphi pods have been c o l 1 ec ted from a s c a t t e r i n g l a y e r i n deep, p o o r l y oxygenated waters o f f southeastern Vancouver I s land , B r i t i s h Columbia (Waldichuck and B o u s f i e l d 1962). ~n i so~ammarus sp. and A1 lo rchestes sp. , both common inshore gammarid amphipod genera, were found i n low d isso lved oxygen environments (as 1 ow as 0.04 ppm a t 12 O C ) near s u l f i t e - r i c h paper pu lp e f f l u e n t . The former species was found i n h igh numbers on the bottom (15 t o 22 m) and the l a t t e r species, normal ly found i n shal lower waters, was observed near the surface, perhaps seeking more oxygenated water (Waldichuk and Bous f ie ld 1962). Low oxygen to le rance i n e i t h e r species remains t o be determined, b u t Chang and Parsons (1975) observed t h a t Anisogammarus puget tens i s surv ived f o r several hours a t 20% satura- t i o n l eve ls . They a l so determined a

o f 1.6, lower than those o f o the r f o r which i t i s around

Adu l t gammarids found i n es- t u a r i e s are f a i r l y t o l e r a n t t o a wide sa l i n i ty range whi 1 e many juven i 1 es and embryos are not. Adu l t es tua r ine Corophi um vo l u t a t o r surv ived i n sa l i n - i t i e s o f 2 t o 59 p p t (McClusky 1967), b u t p r e f e r r e d a range o f 10 t o 30 p p t (McClusky 1970). Adu l t C. t r iaenonyx surv ived i n a s i m i l a r l y wide range o f sa l i n i t i e s (Shyamasundari 1973), though juven i l es cou ld 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 l a r g e numbers o f i n d i v i d u a l s t o sur- v i v e and develop, 20 t o 32.5 p p t were requ i red (Shyamasundari 1976). ~nisogammarus - puget tens i s, found n a t u r a l l y i n 20 t o 28 D D ~ s a l i n i t i e s . cannot i u r v i v e i n fres'hwater b u t can su rv i ve a t 11 p p t f o r a t l e a s t 1 week (Chang and Parsons 1975). Some species, such as Phoxocephalid spp. o r Ampel i scad spp. , may have very narrow sa l i n i ty to lerances. Other amphipods (e. g. , g am mar us spp. , ~ ~ a l e l i a spp. and Crangonyx spp.) a re found i n f reshwater .

i s the f a c t o r by which the pollution and Dred in f e t a t ~ 9 i c r a t e increases a f t e r a 100 increase i n temperature). They sug- gest t h a t t h i s i s an adapta t ion f o r coping w i t h r a p i d l y changing i n t e r - t i d a l temperatures. Capre l l i d s a re known t o leave eelgrass beds " i n droves" a t n i g h t when d isso lved oxygen l e v e l s i n the beds drop below 2 PPm.

To1 erances t o 1 ow d i sso lved oxygen l e v e l s vary g r e a t l y among species; many a re very s e n s i t i v e t o low l e v e l s , e s p e c i a l l y species r e s t r i c t e d t o areas where d i sso l ved oxygen does no t h i s t o r i c a l l y vary g rea t l y . Groups such as phoxo- cephal i d s (used as i n d i c a t o r s o f p o l - l u t a n t l e v e l s i n sediment bioassays) appear much l e s s t o l e r a n t t o s t ress- f u l cond i t i ons than many o f t he

Reish and Barnard (1979) observed t h a t some amphipod species a re more t o l e r a n t than o thers t o organic po l - l u t i o n , b u t do n o t know what environ- mental f a c t o r s cause the d i f f e rences . I t i s known t h a t some amphipods are s e n s i t i v e t o p o l 1 u t i o n i n harbors. Cap i te l l a sp. , a marine polychaete which i s commonly used as a p o l l u t i o n i n d i c a t o r and which has a d i s t r i b u t i o n t h a t i s o f t e n mu tua l l y exc lus i ve t o t h a t o f amphipods, i s found i n h e a v i l y p o l l u t e d harbors. Cap i te l l a sp. i s a l s o found i n unpo l l u ted areas, such as deep sea bottoms o f f t h e coast o f C a l i f o r n i a , which a re sub jec t t o f reshwater i n f 1 ow -- places where amphipods a re notab ly absent (Reish and Barnard 1979).

species discussed above (R.- A1 b r i g h t , U n i v e r s i t y o f Washington; pers. The d i s t r i b u t i o n o f Corophium comm. ). salmonis i s i n f l uenced by sediment

t ype and depth ( it p r e f e r s shal low, muddy sand subst ra tes) more than by s a l i n i t y . Other species o f Corophi urn e x h i b i t g rea te r produc- t i o n near sewer o u t f a l l s -- an i n - crease which i s presumably a t t r i b u - t a b l e t o organ ic enrichment ( B i r k l und 1977).

Behaviora l changes i n amphipods exposed t o sub le tha l q u a n t i t i e s o f o i l have been noted and suggest a s e n s i t i v i t y t o f r e s h o i l . Beach- hoppers a re most l i k e l y t o be a f f e c t e d by o i l due t o t h e i r occur- rence i n t h e h i g h - t i d e wrack zone (Baker 1971), whi 1 e species o f

Ampelisca show s e n s i t i v i t y i n sub- t i d a l areas.

Dredging i s l i k e l y t o e l i m i n a t e ben th i c amphipods, which l i v e on o r c l ose t o t h e subs t ra te (Reish and Barnard 1979). However, McCaul 1 ey e t a l . (1977) suggest t h a t i n t h e event o f dredging, a d u l t s a re l i k e l y t o move t o nearby unaf fec ted areas o r juve- n i l e s may r a p i d l y s e t t l e and repopu- l a t e t h e dredged areas (McCaulley e t a l . 1977). Crustaceans are general l y very s e n s i t i v e t o p o l 1 u- ti on and, t he re fo re , species depend- e n t on them as food are i n d i r e c t l y a f f e c t e d by p o l l u t i o n .

LITERATURE CITED

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A l b r i g h t , R., and A.D. Rammer. 1976. Maintenance dredging and t h e envi ronment o f Grays Harbor, Wash- ington. Appendix E: The e f f e c t o f i n t e r t i d a l dredged mate r ia l disposal on benthic inver tebra tes . U. S. Army Corps o f Engineers, Sea t t l e D i s t r i c t . 244 pp.

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Caine, E.A. 1977. Feeding mecha- nisms and poss ib le resource p a r t i - t i o n i ng o f t h e Caprel l idae (Crustacea: Amphipoda) from Puget Sound, U.S.A. Mar. B i o l . 42: 331-336.

Caine, E.A. 1980. Ecology o f two 1 i t t o r a l species o f c a p r e l l i d amphi pods (Crustacea) from Washington, U.S.A. Mar. B i o l . 56: 327-335.

Chang, B.D., and T.R. Parsons. 1975. Metabol ic s tud ies on t h e amphipod . . Ani sogammarus puget tens i s i n r e l a t i o n t o i t s t r o ~ h i c p o s i t i o n i n the food web o f salmonids. J. Fish. Res. Board Can. 32(2): 243-247.

Congleton, J.C. , and J. E. Smith. 1976. I n t e r a c t i o n s between j u v e n i l e salmon and benth ic inver tebra tes i n t h e Skagi t s a l t marsh. Pages 31-35 i n C.A. Simenstad and S.J. Lipovsky, - eds. F ish food hab i t s workshop, 1 s t Pac. N.W. Tech. Workshop, As to r ia , Oreg. Oct. 13-15.

Conlan, K.E., and E.L. Bousf ie ld. 1982. Studies on amphipod crus- taceans o f the northeastern P a c i f i c reg ion 2. Family Amphipodae. Nat l . Mus. Can. Publ. B i o l . Oceanog. No. 10: 41-75.

Cross, J.N., K.L. Fresh, B.S. M i l l e r , C. A. Simenstad, S. N. S t e i n t o r t , and J.C. Fegley. 1978. Nearshore f i s h and macroi nvertebrate assemblages along t h e S t r a i t o f Juan de Fuca i n c l u d i n g food hab i t s o f common nearshore f i s h . NOAA Tech. Memo. ERL MESA-32. 188 pp.

F e l l e r , R. J., and V.W. Kaczynski. 1975. Size s e l e c t i o n predat ion o f j u v e n i l e chum salmon (~ncorhynchus keta) on ep ibenth ic prey i n Puget Sound. J. Fish. Res. Board Can.

G r i f f i t h s , C.L., and J. Stenton- Dozey. 1981. The fauna and r a t e o f degradation o f standard kelp.

Estuar ine Coastal She1 f Sci. (1981) 12: 645-653.

Koz lo f f , E. N. 1973. Seashore 1 i f e o f Puget Sound, t h e S t r a i t o f Georgia, and t h e San Juan Archipelago. U n i v e r s i t y o f Washington Press, Seat t le . 282 pp.

Koz lo f f , E.N. 1974. Keys t o t h e marine inve r teb ra tes o f Puget Sound, t h e San Juan Archipelago, and adja- cent regions. U n i v e r s i t y o f Washington Press, Seat t le . 226 pp.

Levings, C. D. , and D. Levy. 1976. A "bugs-eye" view o f f i s h predat ion. Pages 147-152 i n C. A. Simenstad and S. J. ~ i p o v s k y 7 eds. F i sh food h a b i t s workshop, 1 s t Pac. N.W. Tech. Workshop, As to r ia , Oreg. Oct. 13-15.

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

Mathias, J.A., J. Mar t i n , M. Yorkow- s k i , J.G. I. Lark, M. Papst, and J. L. Tabache k. 1982. Harvest and n u t r i t i o n a l qua1 i t y o f Gammarus l a c u s t r i s f o r t r o u t cu l tu re . Trans. Am. Fish. Soc. lll(1): 83-89.

Matthews, L.H. 1978. The na tu ra l h i s t o r y o f t h e whale. Weidenfeld and Nicohson, London. 219 pp.

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7, Author(.) a a Daniel J. Grosse, G i l b e r t B. Pauley, and David Moran

b

j. h r f o r m l r y Oqanlzatlon Name and Address

a Washington Cooperative F ishery b ~ a t i o n a l Wet1 ands Research Center Research U n i t NASA-Slidell Computer Complex

~ n i ve r s i ty o f Washington 1010 Gause Boulevard Seattl__e, WA 98195- S l i d e l l , LA 70458

12. Sponsoriry Oqanlzatlon Name and Address

Nat ional Wetlands Research Center U. S. Army Corps o f Engineers F ish and W i l d l i f e Service Waterways Experiment S ta t i on U. S. Department of t he I n t e r i o r P.O. Box 631 Washington, DC 20240 Vicksburg, MS 39180

SO272 -101 3. Rec~pienl's Accession No.

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2 REPORT DOCUMENTATION PAGE

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1. R'*m No.

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1s. supp~ementary Notas I *U. S. Army Corps o f Engineers Report No. TR EL-82-4

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Species p r o f i l e s are 1 i t e r a t u r e summaries of t he taxonomy, morphology, range, 1 i fe h i s t o r y , and environmental requirements o f coasta l aquat ic species. They a re prepared t o ass i s t i n environmental impact assessment. Amphipods are ub iqu i tous i n d i s t r i b u t i o n . Hyperi idea are t he t h i r d most abundant coasta l marine crustacean zooplankton, f o l l ow ing copepods and euphausids. Benth ic Gammaridea are an inva luab le food source f o r many economically impor tant f i s h and i nve r t eb ra te species. L i f e s t y l e s o f the major amphipod groups are var ied. On t he bas is o f t he Index o f Re la t i ve Importance ( I R I ) , they comprise more than h a l f o f t he t o t a l I R I spectrum f o r 38 o f 55 f i s h species i n t he S t r a i t o f Juan de Fuca. They are repor ted t o be i n d i c a t o r s o f heav i l y p o l l u t e d areas.

F isher ies Estuar ies S a l i n i t y

Food chains Oxygen L i f e cyc les Growth Water po l 1 u t i o n Feeding Habi ts

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DEPARTMENT OF THE IWTERIOR U.S. FISH AND Wl lDL lA SERVICE

As the Nation's principal conservation agency. the Department of the Interior has respon- sibility for most of our .nationally owned public lands and natural resources. This includes fostering the wisest use of our land and water resourcm, protecting our fish and wildlife, preserving thsenvironmental and cultural values of our national parks and historical places, and providing for the enjoyment of life through outdoor recreation. The Department as- sesses 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 American Indian reservation communities and for paople who live in island territories under U.S. administration.