REFERENCE COW Do Not Remove from the Librorv

U. S. Fish and Wildlife Service NQtinnnI W M Research Center

Blologlcal Report 82(11.106) 700 Cajun Dome Boulevard TR EL-82.4 August 1989 Lofoyette, Louisiana 70506

Species Profiles: Life Histories and Environmental ~equirements of Coastal Fishes and Invertebrates (North Atlantic)

RAINBOW SMELT

Coastal Ecology Group Fish and Wildlife Service Waterways Experiment 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(11.106) TR EL-82-4 August 1989

Species P r o f i 1 es: L i f e Hi s t o r i e s and Environmental Requirements o f Coasta l F ishes and I n v e r t e b r a t e s (Nor th A t l a n t i c )

RAINBOW SMELT

Jack Buck ley Massachusetts Cooperat ive F i she ry Research U n i t Department o f F o r e s t r y and W i l d l i f e Management

U n i v e r s i t y o f Massachusetts Amherst, MA 01003

P r o j e c t O f f i c e r David Moran

U.S. F i s h and W i l d l i f e Se rv i ce Na t i ona l Wetlands Research Center

1010 Gause Bou levard S l i d e l 1 , LA 70458

Performed f o r

Coasta l Ecol ogy Group Waterways Experiment S t a t i o n U. S. Army Corps o f Engineers

Vicksburg, MS 39180

and

U.S. Department o f t h e I n t e r i o r F i s h and W i l d l i f e Se rv i ce Research and Development

N a t i o n a l Wet1 ands Research Center Washington, DC 20240

T h i s s e r i e s may be r e f e renced as f o l l o w s :

U. S. F i s h and W i l d l i f e Serv ice . 1983-19-. Species p r o f i l e s : 1 i f e h i s t o r i f and env i ronmenta l requi rements o f coas ta l f i s h e s and i n v e r t e b r a t e s . U. S. F i s W i l d l . Serv. B i o l . Rep. 82(11). U.S. Army Corps o f Engineers, TR EL-82-4

Th i s p r o f i l e may be c i t e d as f o l l o w s :

Buck ley, J. L. 1989. Species p r o f i l e s : 1 i f e h i s t o r i e s and environment; requi rements of coas ta l f i s h e s and i n v e r t e b r a t e s (Nor th At1 a n t i c ) - - r a i nbc smel t . U.S. F i s h W i l d l . Serv. B i o l . Rep. 82(11.106). U.S. Army Corps I

Engineers, TR EL-82-4. 11 pp.

PREFACE

Th is species p r o f i l e i s one o f a se r i es on coasta l aquat ic organisms, p r i n c i p a l l y f i s h , o f spor t , commercial, o r eco log ica l importance. The p r o f i l e s are designed t o 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 sketch o f t he 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 sect ions on taxonomy, 1 i f e h i s t o r y , eco log ica l r o l e , environmental requirements, and economic importance, i f app l icab le . A t h r e e - r i n g b inder 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 the U.S. F i sh and W i l d l i f e Service.

Suggestions o r questions 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 t he f o l l owing addresses.

I n fo rma t ion Trans fer S p e c i a l i s t Nat ional Wetlands Research Center U.S. F i sh and W i l d l i f e Serv ice NASA-Sl i d e l 1 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 ten t i on : WESER-C Post O f f i c e Box 631 Vicksburg, MS 39180

CONVERSION TABLE

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

M u l t i p l y

m i l l i m e t e r s (mm) cen t imete rs (cm) meters (m) meters (m) k i 1 ometers (km) k i l omete rs (km)

square meters (m2) square k i lometers (km2) hectares (ha)

l i t e r s (1) c u b i c meters (m3) c u b i c meters (m3)

m i 1 1 i grams (mg) grams (g) k i lograms (kg) m e t r i c tons (t) m e t r i c tons (t)

k i l o c a l o r i e s ( k c a l ) Ce ls ius degrees (OC)

inches inches f e e t ( f t ) fathoms s t a t u t e m i l e s (mi) n a u t i c a l m i l e s (nmi)

square f e e t ( f t2 ) square m i l e s ( m i 2 ) acres

g a l lons ( g a l ) cub ic f e e t ( f t3) acre- f e e t

ounces (oz) ounces (oz) pounds ( l b ) pounds ( l b ) s h o r t tons ( ton )

B r i t i s h thermal u n i t s (Btu) Fahrenhei t degrees (OF)

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

25.40 2.54 0.3048 1.829 1.609 1.852

To Obta in

inches inches f e e t fathoms s t a t u t e m i l e s n a u t i c a l m i l e s

square f e e t square m i les acres

g a l 1 ons c u b i c f e e t acre- f e e t

ounces ounces pounds pounds s h o r t tons

B r i t i s h thermal u n i t s Fahrenhe i t degrees

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

square meters square k i 1 ometers hectares

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

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

k i 1 ocal o r i e s Ce ls ius degrees

CONTENTS

PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CONVERSION TABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NOMENCLATURE/TAXONOMY/RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MORPHULOGY/IDENTIFICATION AIDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REASONS FOR INCLUSION I N SERIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LIFE HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Spawning and M i g r a t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Eggs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yo lk -sac Larvae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J u v e n i l e / A d u l t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GROWTH CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Growth Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Length-Weight R e l a t i o n s h i p s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

THE FISHERY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S p o r t and Commercial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P o p u l a t i o n Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ECOLOGICAL ROLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Food H a b i t s and Feed ing B e h a v i o r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P r e d a t o r s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ENVIRONMENTAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S a l i n i t y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D isease and P a r a s i t e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page

iii i v v i

1 1 3 3 3 4 4 5 5 5 5 5 5 6 6 6 6 7 7 7 7 7

LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ACKNOWLEDGMENTS

I am g r a t e f u l f o r t h e rev iews by S.A. Murawski, Na t i ona l Mar ine F i s h e r i e s Serv ice , Woods Hole, Massachusetts, and Rober t Lawton, Massachusetts D i v i s i o n of Mar ine F i s h e r i e s , Sandwich.

Figure 1. Rainbow smelt. (From Lee e t a l . 1980.)

RAINBOW SMELT

...... S c i e n t i f i c name.. Osmerus mordax ( M i t c h i l l ) 1815

Pre fer red common name .... Rainbow smelt (F igure 1)

Other common names ............... smelt, American smelt, 1 eef i shy freshwater smelt, f r o s t f i s h (Scot t and Crossman 1973)

Class ..................... Osteichthyes Order .................... Salmoniformes Fami 1 y. ...................... Osmeri dae

Geographic range:

Rainbow smelt a re d i s t r i b u t e d a1 ong the east coast o f North America from eastern Labrador and the Gu l f o f St. Lawrence south t o the Delaware R iver (Figure 2). Smelt occur n a t u r a l l y i n lakes and ponds i n New Hampshire, Maine, New Brunswick, Nova Scotia, and Newfound1 and (Bigel ow and Schroeder 1953). The range o f smel t was g r e a t l y extended when they were int roduced i n t o the Great Lakes i n the e a r l y 1900's (Van Oosten 1937; Dymond 1944).

The species i s now abundant i n a l l o f t h e Great Lakes (Scot t and Crossman 1973). Smelt were f i r s t repor ted i n the M iss i ss ipp i drainage by Bur r and Maydew (1980).

MORPHOLOGY/IDENTIFICATION AIDS

The f o l l o w i n g desc r ip t i on o f t he rainbow smelt i s compiled from Bigelow and Schroeder (1963) and Scot t and Crossman (1973).

The smel t ' s body i s slender and elongated w i t h a long, po in ted head, 1 arge mouth, p ro t rud ing 1 ower jaw, maxi 11 ary extending t o middle of eye, deeply forked t a i l , and a small b u t ev ident adipose f i n . Cyc lo id scales number 62-72 i n l a t e r a l ser ies ; the peritoneum i s s i l v e r w i t h dark speckles. Nup t ia l tuberc les develop on the head, body, and f i n s o f males. The c o l o r i s t ransparent o l i v e t o pa le green on t h e back; t he s ides a re s i m i l a r , each w i t h a broad long i - t u d i nal s i 1 very band. When smelt a re f r e s h l y caught, s ides may have a

0 Coastal distribution

M I L E S

K I L O M E T E R S

ATLANTIC OCEAN

F i g u r e 2. D i s t r i b u t i o n o f ra inbow s m e l t i n t h e N o r t h A l t a n t i c Region.

p u r p l e , b l u e , and p i n k i r i d e s c e n t r e f l e c t i o n ; t h e b e l l y i s s i l v e r .

The taxonomic r e l a t i o n s h i p s among members o f t h e genus Osmerus have been t h e s u b j e c t o f p e r s i s t e n t con t roversy . A l though t h e r e have been numerous e f f o r t s t o c 1 a r i . f ~ t h e taxonomy, i n c l u d i n g a sys temat i c r e v i s i o n by McAl l i s t e r (1963), t h e r e l a t i o n s h i p s remain obscure. A rev iew o f t h e con t r ove r sy and p resen t s t a t u s i s g i ven by S c o t t and Crossman (1973).

REASONS FOR INCLUSION I N SERIES

The ra inbow sme l t i s an abundant fo rage f i s h , preyed upon by many commerc ia l ly and r e c r e a t i o n a l l y va l uab le coas ta l marine spec ies , such as s t r i p e d bass, Morone s a ' x a t i l i s , and b l u e f i s h , Pomatomus sa l t a t r i x (Smi th and Wel l s 1977 ) . 1n t h e Great Lakes i t i s t h e p rey o f seve ra l spec ies o f salmon and t r o u t ( S c o t t and Crossman 1973; S tewar t e t a l . 1981). I n a d d i t i o n , t h e spec ies suppor ts an impo r t an t c o a s t a l and e s t u a r i n e s p o r t - f i s h e r y th roughou t most o f i t s range, p a r t i c u l a r l y i n t h e Great Lakes, New England, and eas te rn Canada.

LIFE HISTORY

Spawning and M i g r a t i o n

Rainbow sme l t a re anadromous, spawning i n f r eshwa te r and growing and ma tu r i ng i n e s t u a r i e s and coas ta l waters . Na tu ra l l y o c c u r r i n g o r i n t r o d u c e d f r eshwa te r popu la t i ons have s i m i l a r m i g r a t i o n s i n t o streams f o r spawning, a l t hough success fu l shore spawning has been documented (Rupp 1965).

I n coas ta l streams, most sme l t spawn above t h e head o f t h e t i d e . Spawners u s u a l l y beg in t o move i n t o spawning areas b e f o r e t h e i c e breakup (McKenzie 1964). Spawni ng usual l y peaks w i t h

b imonth ly s p r i n g t i d e s (C lay ton 1976). Depending on l o c a t i o n , peak spawning occurs i n l a t e March th rough l a t e May (C lay ton 1976). Along t h e e a s t coas t , sme l t spawn a t wa te r temperatures o f 4.0 t o 9 .0 O C (C lay ton 1976). An excep t i on t o t h i s i s i n t h e M i r am ich i Es tuary , New Brunswick, where McKenzie (,1964) r epo r t ed e a r l y and l a t e runs i n t o t h e spawning area. E a r l y spawning runs began when water temperature reached 10 O C and l a t e r spawning runs l a s t e d u n t i l wa te r temperature reached 15 OC. I n some f reshwate r popu la t i ons , spawning occurs a t h i g h e r temperatures; J i l e k e t a l . (1979) r e p o r t e d r e p r o d u c t i o n i n Lake Mich igan a t 10 and 18 O C .

T y p i c a l l y , t h e s u b s t r a t e i n t h e spawning a rea o f coas ta l streams i s g r a v e l , w i t h wa te r depths a t low t i d e o f 0 . 1 t o 1 .3 m (Murawski e t a l . 1980). Accord ing t o C lay ton (1976), spawning s i t e s e l e c t i o n i s i n f l u e n c e d l a r g e l y by wa te r v e l o c i t y r a t h e r t han depth o r subs t r a t e . S u t t e r (1980) found a s i g n i f i c a n t p o s i t i v e r e l a t i o n - s h i p between s u r v i v a l t o t h e e a r l y - eyed egg s tage and i n c r e a s i n g wate r v e l o c i t y (up t o 60-80 cm/s). Hu' lbert (1974) found t h e g r e a t e s t number o f eggs depos i ted i n areas o f h i ghes t v e l o c i t y .

The degree o f gene t i c homogeneity w i t h i n an es tua r y w i t h m u l t i p l e spawning streams appears t o be r e l a t e d t o d i s t ance between streams. A mark and r ecap tu re s tudy by Murawski e t a l . (1980) showed t h a t i n d i v i d u a l f i s h sometimes spawn i n severa l streams i n an es tua r y d u r i n g t h e spawning pe r i od . Rupp (1968) found s i m i 1 a r "wanderi ng" o f spawning f i s h between streams f o r a f r eshwa te r p o p u l a t i o n i n Maine. F reche t e t a l . (1983) used v a r i a t i o n s i n m e r i s t i c s , growth, and f e c u n d i t y t o assess t h e degree o f s p a t i a l i n t e g r i t y o f sme l t groups i n r i v e r s . They found t h a t homing t o spawning r i v e r s i s r a r e when d i s t ances between r i v e r s w i t h i n a geographic area such as an es tua r y a re sma l l . I n c o n t r a s t , s t ud i es i n t h e M i ram ich i R i v e r found o n l y occas iona l

movement o f spawning f i s h between streams (McKenzie 1964). D is tance be- tween streams used f o r spawning c o u l d be an impo r t an t f a c t o r i n assess ing t h e e f f e c t o f sho r t - t e rm env i ronmenta l d i s t u rbances on sme l t popu la t i ons .

I n coas ta l wa te rs , sme l t spawn a t n i g h t and most r e t u r n t o t h e es tua r y d u r i n g t h e day, a l though some males may remain i n t h e spawning a rea (McKenzie 1964; C lay ton 1976). U s u a l l y severa l males a t t e n d one female d u r i n g spawning (Langl o i s 1935; C lay ton 1976). Smelt i n t h e spawning runs a re p redominan t l y ma1 es, b u t sex r a t i o s va r y w i d e l y over t h e d u r a t i o n o f t h e spawning r u n (Kendal l 1927; Lang lo i s 1935; Warfe l e t a l . 1943; McKenzie 1964). The preponderance o f males can be a t t r i b u t e d t o t h e l onge r spawning p e r i o d f o r males (Murawski e t a l . 1980). Rupp (1968) r e p o r t e d t h a t i n d i v i d u a l males may spawn on as many as 8 n i g h t s consecu t i ve l y , whereas females may spawn o n l y 3 t o 4 n i g h t s .

The age o f new r e c r u i t s i n spawning runs shows c l i n a l v a r i a t i o n a long t h e e a s t coas t , i n c r e a s i n g w i t h l a t i t u d e . I n t h e Parker R i ve r , Massachusetts, age I f i s h made up 26% o f t h e spawning r u n (Murawski 1976), whereas age I spawners were scarce o r absent i n a more n o r t h e r l y p o p u l a t i o n i n Grea t Bay, New Hampshire (Warfe l e t a l . 1943). I n t h e M i ram ich i R i ve r , a l l spawners were ages I 1 (66%), I 1 1 (30%), o r I V (4%) (McKenzie 1964). An i n t r oduced p o p u l a t i o n i n Lake Supe r i o r was n o t f u l l y r e c r u i t e d i n t o t h e spawning p o p u l a t i o n u n t i l age I 1 1 ( B a i l e y 1964). The a t t a i nmen t o f m a t u r i t y i n sme l t appears r e l a t e d t o s i z e ; t hus , f i s h i n t h e more s o u t h e r l y p o p u l a t i o n s w i t h f a s t e r growth r a t e s mature a t an e a r l i e r age.

C lay ton (1976) r e p o r t e d fecund i t i e s o f 7,000 t o 44,000 eggs f o r f i s h f rom t h e Parker R i v e r , Massachusetts. For t h e M i ramich i es tua r y i n New Brunswick, McKenzie (1964) r e p o r t e d

f e c u n d i t i e s o f 8,500 eggs f o r a f i s h o f 12.7 cm TL and 69,600 eggs f o r a f i s h o f 20.9 cm TL. F e r t i l i z e d eggs a r e demersal , adhesive, and range i n s i z e f rom 1 .0 t o 1 . 2 mm ( C r e s t i n 1973; Cooper 1978).

Water v e l o c i t y , s u b s t r a t e t ype , and egg d e n s i t y appear t o be impo r t an t f a c t o r s i n egg s u r v i v a l . S u t t e r (1980) found a s i g n i f i c a n t p o s i t i v e r e l a t i o n s h i p between s u r v i v a l t o t h e ear l y -eyed s tage and r a t e o f f l o w f rom 60 t o 80 cm/s. T y p i c a l l y , eggs a re depos i t ed over g r a v e l ; mean s u r v i v a l r a t e s r e p o r t e d have been 0.8%-1.8% (McKenzie 1964), 1.06% (Rupp 1965), 0.55% (Ro thsch i l d 1961), and 1.0% ( S u t t e r 1980). I n c o n t r a s t , S u t t e r (1980) observed a s u r v i v a l r a t e o f 10% when eggs were depos i t ed on a q u a t i c vege ta t i on .

Ha tch ing success has been shown t o be r e l a t e d t o egg d e n s i t y ; McKenzie (1964) r e p o r t e d 3.6% h a t c h i n g success a t a d e n s i t y o f 487 eggs / f t 2 . I n Maine, maximum p r o d u c t i o n o f yo1 k-sac 1 arvae was a t 11,745 eggs / f t 2 (Rothschi 1 d 1961). Egg crowding r e - s u l t s f rom spawning f i s h encoun te r ing o b s t r u c t i o n s i n t h e i r upstream m i g r a t i o n .

I n c u b a t i o n t i m e f o r eggs was 29 days a t 6 t o 7 O C ; 25 days a t 7 t o 8 O C ; 19 days a t 9 t o 10 O C ; 11 days a t 12.0 O C , and 8 days a t 16.5 O C (McKenzie 1964; Cooper 1978).

Ma jo r p r e d a t o r s on sme l t eggs a r e t h e common mummichog, (Fundul us h e t e r o c l i t u s ) and f ou r sp i ne s t i c k l e - back (Ape1 t e s quadracus) ( S u t t e r 1980).

Yo1 k-sac Larvae

The l a r v a e a t t h e t i m e o f ha t ch i ng a r e 5 t o 6 mm l o n g (McKenzie 1964; C lay ton 1976; Cooper 1978). Yo1 k-sac l a r v a e have been r e p o r t e d t o be n e g a t i v e l y p h o t o t a c t i c (Rupp 1965). The y o l k sac i s absorbed when t h e l a r v a e a re about 7 mm long . A f t e r

hatch i ng, t h e l a rvae d r i f t downstream, where they a re concentrated near the sur face (McKenzie 1964; C res t i n 1973). As t h e la rvae grow, they tend t o con- gregate on the bottom i n deeper areas (Clayton 1976). Using p lankton nets, McKenzie (1964) took 90% o f t he l a rvae c o l l e c t e d w i t h i n 5 f t o f t h e bottom. A t n i g h t they moved near t h e surface, apparent ly t o feed (McKenzie 1964). It has been pos tu la ted t h a t la rvae are maintained i n an estuary by the two- way t r a n s p o r t system (Rogers 1939).

Juveni 1 e/Adul t

As t h e smelt grow, they move i n t o waters o f increased s a l i n i t y i n t h e lower estuary o r i n t o nearshore coasta l waters (C res t i n 1973). Smelt begin t o school when they a re about 19 mm long (Belyanina 1969), moving i n t o shal low water a t n i g h t and r e t u r n i n g t o deeper channels du r i ng t h e day. Young f i s h have a l so been observed i n eelgrass (Zostera marina) beds (C res t i n 1 9 7 3 m t h e f a l l , as water temperatures drop, juven i 1 es move i n t o the upper estuary, concent ra t ing i n channels, where they mix w i t h a d u l t smelt (McKenzie 1964; Clayton 1976).

A f t e r spawning, adu l t s r e t u r n t o sa l twa te r t o spend t h e summer i n t he estuary o r i n a narrow zone along t h e coast. Smelt have never been repor ted more than 2 km from shore o r i n water depths greater than 6 m (Bigelow and Schroeder 1953). I n t he fa1 1, adu l t s r e t u r n t o t h e es tuary where they over- w in te r be fore beginning t h e i r sp r i ng spawning run.

GROWTH CHARACTERISTICS

Growth Rate

Growth i n l eng th i s g rea tes t i n t he f i r s t year and decreases the rea f te r . A f t e r females reach m a t u r i t y ( a t age I, 11, o r 111, depending on l oca t i on ) , they grow f a s t e r than males (Warfel

e t a l . 1943; B a i l e y 1964; Murawski and Cole 1978). Smelt i n marine popu la t ions usua l l y grow f a s t e r than those i n f reshwater populat ions, and smelt i n nor thern marine popu la t ions grow slower than those i n more sou the r l y populat ions. I n t he Parker R iver i n Massachusetts, t h e mean t o t a l lengths (sexes combined) f o r smelt ages I through V were 141, 192, 213, 240, 245 mm, r espec t i ve l y (Muraws k i 1976). I n Great Bay, New Hampshire, t he mean t o t a l l eng th f o r age I was 86 mm; age 11, 145 mm; age 111, 171 mm; and age I V Y 245 mm (Warfel e t a l . 1943). I n the Miramichi River , New Brunswick, mean t o t a l lengths f o r ages 11-V were 139, 165, 187, and 206 mm, r espec t i ve l y .

For smelt i n the Parker River , Massachusetts, Murawski and Cole (1978) gave the von B e r t a l a n f f y growth equat ion f o r t h e f i r s t year as:

where TL = t o t a l l eng th i n mm and t = years.

Length-weight Re la t ionsh ips

Table 1 contains publ ished equations f o r length-weight r e l a t i o n s h i p s f o r a d u l t s and juven i les .

THE FISHERY

Sport and Commercial

Smelt support a hook-and-1 i n e s p o r t f i s h e r y i n coasta l waters and a d ipne t s p o r t f i s h e r y du r ing the spawning run (B ige l ow and Schroeder 1953). A small commercial f i s h e r y i n eastern Canada and the Gu l f o f Maine uses t rapne ts (McKenzie 1964). I n 1976, t h e t o t a l smelt harvest i n the coasta l waters o f New England was 105,000 1b (U.S. Department o f Commerce 1980). I n 1976, commerci a1 landings from U.S. waters o f t he Great Lakes t o t a l e d 23,580,000 l b (U.S. Department o f Commerce 1980).

Table 1. Equat ions f o r l eng th -we igh t r e l a t i o n s h i p s f o r a d u l t and j u v e n i l e ra inbow smelt .

Age group Loca t i on Equa t ion Source

A d u l t s Lake Super io r Log W = -2.57962+2.95233 l o g L B a i l e y 1964 G u l l Lake, M I Log W = -5.0952+2.9539 l o g L Bu rb i dge 1969 Parker R i ve r , MA Log W = -6.0315+3.3592 1 og L Murawski and

Cole 1978

Juven i l e s Weweantic R i ve r , MA Log W = -2.73+3.51 l o g L C r e s t i n 1973

Popu la t i on Dynamics

Age I1 sme l t a re f u l l y r e c r u i t e d i n t o t h e f i s h e r y a l ong t h e e n t i r e range o f t h e spec ies i n t h e No r t h A t l a n t i c (McKenzie 1964; Murawski and Cole 1978). From Massachusetts southward, age I smel t a r e r e c r u i t e d i n t o t h e spawning runs b u t none a re taken by t h e f i s h e r y . Murawski and Cole (1978) a t t r i b u t e d t h i s t o e i t h e r h a b i t a t seg rega t i on o f age groups o r gear s e l e c t i v i t y .

I n t h e Parker R i ve r , Massachusetts, t h e m o r t a l i t y o f a d u l t s i s about 72% and i s appa ren t l y g r e a t e r among males than females (Murawski and Cole 1978). Th i s i s p robab ly because males spend more t ime on t h e spawning ground.

H i s t o r i c a l l y , dec l i nes i n sme l t abundance i n Massachusetts have been l i n k e d t o i n d u s t r i a l p o l l u t i o n , b l ock - age o f spawning m i g r a t i o n by dams, and p o s s i b l y t h e l o s s o f e s t u a r i n e h a b i t a t s such as ee l g rass beds c r u c i a l t o s p e c i f i c l i f e s tages (B ige low and Schroeder 1953; C r e s t i n 1973).

ECOLOGICAL ROLE

Food Hab i t s and Feeding Behavior

Larva l and j u v e n i l e sme l t i n coas ta l wa te rs feed on copepods and o t h e r

p l a n k t o n i c crustaceans. Larger j u v e n i l e s and a d u l t s feed on euphaus i ids , amphipods, po lychae tes , and f i s h (F lagg 1972). Adu l t s were r e p o r t e d t o feed on smal l mummichogs, cunner, anchovies, s t i c k l e b a c k s , A t l a n t i c s i l v e r s i d e s , and a lew ives (B ige low and Schroeder 1953).

I n t h e Grea t Lakes, sme l t l a r v a e f e d ma in l y on d i p t e r a n l a r v a e , crustaceans, and f i s h (Gordon 1961; Burb idge 1969). I n Lake Mich igan, a d u l t s and j u v e n i l e sme l t f e d l a r g e l y on Mysis i n t h e w i n t e r and young-of - the -year and year1 i n g a lew ives i n s p r i n g and summer; they began f eed ing a c t i v e l y a t dusk and ceased by n i g h t - f a l l ( F o l t z and Norden 1977).

P reda to rs

Smelt a r e t h e food o f many p reda to rs . Larvae and j u v e n i l e s a r e p robab l y eaten by most e s t u a r i n e p i s c i vores. A d u l t sme l t a r e preyed upon by b l u e f i s h , s t r i p e d bass, harbor sea ls , and o t h e r l a r g e p reda to r s (C lay ton e t a1 . 1978).

S ince t hey were i n t r oduced i n t o t h e Grea t Lakes, sme l t have become a major fo rage f i s h (A rgy l e 1982) and t h e ~ r i m a r v food o f t h e l a k e t r o u t i ~ a l v e i i nus namaycush) (S tewar t e t a1 . 1981).

ENVIRONMENTAL REQUIREMENTS

Temperature

I n t e s t s t o assess t h e e f f e c t s o f acu te thermal shock, ra inbow smel t showed t h e lowes t t o l e r a n c e when t e s t e d i n seawater (Barker e t a l . 1981). A sharp i nc rease i n wa te r temperature and i ncreased s a l i n i t y m igh t a c t s y n e r g i s t i c a l l y t o induce s t r e s s and m o r t a l i t y i n l a r v a l sme l t .

Most o f t h e l o c a l m i g r a t i o n s o f sme l t i n e s t u a r i e s a re searches f o r optimum wate r temperature (B ige low and Schroeder 1953). Sudden decreases i n wa te r temperature can cause temporary c e s s a t i o n o f spawning, and p ro1 onged low temperatures can r e s u l t i n a p r o t r a c t e d spawning p e r i o d (Murawski e t a1 . 1980).

Sal i n i t y

The exposure o f sme l t eggs t o s a l t o r b r a c k i s h wa te r can adverse ly a f f e c t embryonic development and 1 ead t o h i g h egg m o r t a l i t y . I n i n c u b a t i o n t e s t s , s a l i n i t i e s o f 12 t o 14 p p t were f a t a l t o eggs. Path01 o g i c a l changes were a l s o observed i n t h e eggs o f a c l o s e l y r e1 a t e d spec ies , Osmerus e p e r l anus, a t s a l i n i t i e s g r e a t e r t han 13 p p t by Unanian and So in (1963). They found t h a t i n a d d i t i o n t o caus ing inc reased egg mo r t a l i t y , h i g h s a l i n i t y (>26 p p t ) can p reven t f e r t i l i z a t i o n .

Any a c t i v i t y t h a t i nc reases s a l i n i t y i n spawning areas c o u l d have severe1 y d e l e t e r i o u s e f f e c t s on r e p r o d u c t i v e success.

Contami nants

The e f f e c t s o f c h l o r i n a t i o n on sme l t were s t u d i e d by Seeger t and Brooks (1978). They r e p o r t e d t h a t a t 10 O C

t h e 30 min LCs0 was 1.27 mg o f c h l o r i n e pe r l i t e r . M o r t a l i t y was s l i g h t a t 0.72 mg/l and n e a r l y complete a t 2 .0 mg/l. E f f e c t s o f

o t h e r contaminants on sme l t have n o t been repo r t ed .

Disease and Pa ras i t es

Severa l d iseases a re common among smel t popu la t i ons . P i s c i n e e r y t h r o - c y t i c nec ros i s (PEN), a v i r a l d i sease , i n f e c t s sme l t popu la t i ons f rom t h e Canadian p r o v i nces t o Massachusetts, b u t occurs a t low l e v e l s i n i n d i v i d u a l f i s h (Sherburne and Bean 1979). Suppor t ing t h i s , Jimenez e t a l . (1982) i n a s tudy on t h e occurrence o f PEN i n sme l t f rom Massachusetts coas ta l r i v e r s found a h i g h i nc i dence o f i n f e c t i o n (61% t o 97%) w i t h i n popu- l a t i o n s , though l e s s t han 1% o f t h e e r y t h r o c y t e s o f i n d i v i d u a l f i s h were i n f e c t e d . D e l e t e r i o u s e f f e c t s o f PEN on sme l t have n o t been descr ibed , a1 though Evelyn and T r a x l e r (1978) found severe anemia i n two spec ies o f salmon i n f e c t e d w i t h t h e disease. Jimenez e t a l . (1982) specu la ted t h a t PEN a c t i n g s y n e r g i s t i c a l l y w i t h o t h e r f a c t o r s may be d e b i l i t a t i n g and u l t i m a t e l y cause mo r t a l i t y .

The m i c r o s p o r i d i a n G l ygea h e r t w i g i has been found i n mar ine and f r esh - wa te r popu la t i ons , and i s ano ther cause o f d e b i l i t a t i o n and m o r t a l i t y i n sme l t (Haley 1953; Nepszy and Dech t i a r 1972; Chen and Power 1972; Jimenez e t a l . 1982). Jimenez e t a l . (1982) r e p o r t e d a mean i n f e c t i o n r a t e o f 13.4% (range 0-18%) i n Massachusetts coas ta l r i v e r s ; Hal ey (1953), work ing i n Grea t Bay, New Hampshire, r e p o r t e d a 23.3% i n f e c t i o n r a t e . The d e b i l i - t a t i ng e f f e c t s o f t h i s p a r a s i t e have been documented i n severa l s t ud i es . Jimenez e t a l . (1982) found t h a t we igh t and t o t a l l e n g t h were s i g n i f i - c a n t l y d i f f e r e n t between i n f e c t e d and non in fec ted f i s h . Chen and Power (1972) exami ned sme l t popu la t i ons i n Lake O n t a r i o and Lake E r i e and found t h e i nc i dence o f m i c r o s p o r i d i a n i n f e c - t i o n was 5.2% and 62.7%, r e s p e c t i v e l y . Because t h e i n f e c t i o n causes o v a r i a n t i s s u e t o be r ep l aced w i t h p a r a s i t i c c y s t s , t h e Lake E r i e p o p u l a t i o n s u f f e r e d a decrease i n f e c u n d i t y .

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S u t t e r , F. C. 1980. Reproduct ive b i o l o g y o f anadromous ra inbow smel t , Osmerus mordax, i n t h e Ipsw ich Bay Area, Massachusetts. M. S. Thesis. U n i v e r s i t y o f Massachusetts, Amherst.

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4. Title and Subtitla I 5. Ram* Date

Species P r o f i l e s : L i f e H i s t o r i e s and Environmental Requirements 1 August 1989 o f Coastal F ishes and I n v e r t e b r a t e s (Nor th At lan t ic ) - -Ra inbow Smelt

REPORT DOCUMENTATION 1. REPORT NO. 2.

PAGE ~i O l o g i c a l s p o r t 82(11.106)*~ 3. Rec~p~ent'a Acceasaon NO.

I

-- 15. Supplementary Notas

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

7. Author(,)

Jack Buckley 9. Petforming Organization Name and Address

Massachusetts Coopera t ive F i she ry Research U n i t Department o f F o r e s t r y and W i l d l i f e Management U n i v e r s i t y o f Massachusetts Amherst, MA 01003

16. Abstract (Limit: 200 words)

8. Petfonning Organization Rept. NO.

10. PmiectlTaakIWork u n i t No.

11. Contract(C) or Grant(C) NO.

(c)

Species p r o f i l e s a r e l i t e r a t u r e summaries o f t h e taxonomy, l i f e h i s t o r y , and env i ron - mental requirements o f c o a s t a l f i shes and aqua t i c i n v e r t e b r a t e s . They a r e designed t o a s s i s t w i t h env i ronmental impact assessments. The ra inbow smel t i s an abundant fo rage f i s h f o r commerc ia l l y and r e c r e a t i o n a l l y va luab le f i s h e s such as s t r i p e d bass and b l u e f i s h on t h e e a s t coas t and seve ra l spec ies o f salmon and t r o u t i n t h e Great Lakes. The ra inbow smel t a l s o suppor ts an impor tan t s p o r t f i s h e r y th roughout most o f i t s range. I n 1976, t h e t o t a l smel t ha rves t i n t h e c o a s t a l waters o f New England was 105,000 l b . Coastal ra inbow smel t a re anadromous, spawning i n f r eshwa te r and ma tu r i ng i n s a l i n e water. Spawning peaks i n sp r i ng . S a l i n i t i e s above 12 p p t were f a t a l t o eggs. Reported f e c u n d i t i e s a re 7,000 t o 44,000 eggs p e r female. Smelt a re always found i n sha l l ow water (<6 m deep) and w i t h i n 2 km o f t h e shore. La rva l and j u v e n i l e smel t a long t h e coas t feed on p l a n k t o n i c crustaceans. Larger j u v e n i l e s and a d u l t s feed on euphausi i d s , amphi pods, po lychaetes , and f i s h . Smelt move l o c a l l y t o search f o r optimum water temperatures.

( 17. Document Analysis a. Oescripton

12. Swnsorlng Oraanlx8tlon Name and Address

U.S. Department o f t h e I n t e r i o r Coastal Ecology Group F i s h and W i l d l i f e Se rv i ce Waterways Experiment S t a t i o n Research and Development U. S. Army Corps o f Engineers Na t i ona l Wetlands Research cen te r P.O. Box 631 Washington, DC 20240 V icksburg , MS 39180

E s t u a r i e s Fishes S a l i n i t y F i s h e r i e s L i f e c y c l e s Contaminants Feeding h a b i t s Temperature

(G)

13. T Y P ~ of Rew* a Period Covered

14.

I b. Identltienl0pn-Ended Terms

Rainbow smel t Environmental requ i rements Osmerus mordax -- Ecolog ica l r o l e

c. COSATl FieldlGroup

21. No. of Pages

11 22. Price

18. Avadability Statement

U n l i m i t e d r e l e a s e

(See ANSI-239.18) OCTIONAL FORM 272 (4-77) (Formerly NTIS-35) Department of Commerce

19. Securgty Class (This Repor0

U n c l a s s i f i e d 20. Security Class (This Page)

U n c l a s s i f i e d

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