FtEFERENCIE COPY Do Not Remove from the Llbrery -

U. S. Fish and Wi!d!ife % d C 4

Biological Report 82(11.84) N~tkNhOl W@tlaws K~~~ 700 Cajun ~ o m e 800kvard

TR EL-82-4 September 1988

-, Loukiom 7-

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and lnverte brates (Pacific Southwest)

CALIFORNIA SEA M U S S E L AND BAY M U S S E L

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 Repor t 82(11.84) TR EL-82-4 September 1988

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 o f Coastal F ishes and I n v e r t e b r a t e s ( P a c i f i c Southwest)

CALIFORNIA SEA MUSSEL AND BAY MUSSEL

W i l l i a m N. Shaw Fred Te lon i che r Mar ine Labo ra to r y

Humboldt S t a t e U n i v e r s i t y T r i n i dad , CA 95570

Thomas J. Hass ler U.S. F i s h and W i l d l i f e Se rv i ce

C a l i f o r n i a Coopera t i ve F i s h e r y Research U n i t Humboldt S t a t e U n i v e r s i t y

Arcata, CA 95521 and

David P. 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 Wetl ands Research Center 1010 Gause Boulevard

S l i d e l I , LA 70458

P r o j e c t O f f i c e r C a r r o l l Cordes

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

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

Performed f o r

Coasta l Ecology Group Waterways Experiment S t a t i o n U.S. Army Corps of Engineers

Vicksburg, MS 39180

and

U.S. Department of 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

Na t i ona l Wetl ands Research Center Washington, DC 20240

This series may be referenced as follows:

U.S. Fish and Wildlife Service. 1983-19- . Species profiles: life histories and environmental requirements of coastal fishes and invertebrates. U.S. Fish Wildl. Serv. Biol. Rep. 82(11). U.S. Army Corps of Engineers, TR EL-82-4.

This profile may be cited as follows:

Shaw, W.N., T.J. Hassler, and D.P. Moran. 1988. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest)--California sea mussel and bay mussel. U.S. Fish Wildl. Serv. Biol. Rep. 82(11.84). U.S. Army Corps of Engineers, TR EL-82-4. 16 pp.

PREFACE

This species p r o f i l e i s one o f a se r i es on coas ta 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 coas ta 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 h e 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 coas ta 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 app l 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 the j l a re 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 t he f o l 1 owing addresses.

I n fo rma t i on Trans fer S p e c i a l i s t Nat iona l Wetlands Research Center U.S. F i sh 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 ten t i on : WESER-C Post O f f i c e Box 631 Vicksburg, MS 39180

CONVERSION T A B L E

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

m i l l i m e t e r s (mm) c e n t i m e t e r s (cm) meters (m) meters (m) k i l o m e t e r s (km) k i 1 ometers (km)

5 To O b t a i n

0.03937 inches 0.3937 i nches 3 .281 f e e t 0.5468 fathoms 0.6214 s t a t u t e m i l e s 0.5396 n a u t i c a l m i l e s

square meters (m2) 10.76 square f e e t square k i 1 ometers (km2) 0 .3861 square m i l e s hec ta res (ha) 2 .471 ac res

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

m i l l i g r a m s (mg) grams ( g ) k i 1 ograms (kg ) m e t r i c t ons ( t ) m e t r i c t ons ( t )

k i l o c a l o r i e s ( k c a l ) C e l s i u s degrees (OC)

0 .2642 g a l l o n s 3 5 . 3 1 c u b i c f e e t

0.0008110 a c r e - f e e t

0.00003527 ounces 0.03527 ounces 2.205 pounds

2205.0 pounds 1.102 s h o r t t o n s

3.968 B r i t i s h the rma l u n i t s 1 . 8 ( 0 ~ ) + 32 F a h r e n h e i t degrees

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

inches 25.40 m i l l i m e t e r s inches 2 .54 c e n t i m e t e r s f e e t ( f t ) 0.3048 me te rs fathoms 1.829 meters s t a t u t e m i l e s (m i ) 1.609 k i 1 ometers n a u t i c a l m i l e s (nmi) 1.852 k i 1 ometers

square f e e t ( f t 2 ) square m i l e s (m i2 ) ac res

g a l 1 ons ( g a l ) c u b i c f e e t ( f t3) a c r e - f e e t

ounces ( o z ) ounces (02) pounds ( l b ) pounds ( l b ) s h o r t t ons ( t o n )

0.0929 square me te rs 2.590 square k i 1 ometers 0.4047 hec ta res

3.785 1 i t e r s 0 .02831 c u b i c meters

1233.0 c u b i c meters

28350.0 m i l l i g r a m s 28.35 grams

0.4536 k i lograms 0.00045 m e t r i c t o n s 0.9072 m e t r i c t ons

B r i t i s h the rma l u n i t s (B tu ) 0.2520 k i l o c a l o r i e s F a h r e n h e i t degrees (OF) 0.5556 (OF - 32) C e l s i u s degrees

CONTENTS

................................................................ PREFACE CONVERSION FACTORS ..................................................... ACKNOWLEDGMENTS ........................................................ NOMENCLATURE/TAXONOMY .................................................. MORPHOLOGY/IDENTIFICATION AIDS ......................................... ................................................ Cal i f o r n i a Sea Mussel

Bay Mussel ........................................................... REASON FOR INCLUSION IN SERIES ......................................... LIFE HISTORY ........................................................... ............................................................. Spawning

L a r v a l Stage ......................................................... Pos t l a r vae and Recru i tment ........................................... ............................................................. M a t u r i t y ....................................................... Age and Growth

COMMERCIAL AND SPORT FISHERIES AND AQUACULTURE ......................... ECOLOGICAL ROLE ........................................................ .............................................................. Feeding .......................................................... Compet i tors

Preda to rs ............................................................ Commensals. Paras i tes . and Enc rus t i ng Epi fauna ....................... ............................................. ENVIRONMENTAL REQUIREMENTS Temperature and S a l i n i t y ............................................. .............................................................. H a b i t a t Phys ica l D is tu rbance ................................................. Other Environmental Fac to r s ..........................................

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

PacJg

iii i v v i

1 1 1 3 3 3 3 4 4 6 6 7 8 8 8 9

10 10

ACKNOWLEDGMENTS

We acknowledge t h e r e v i e w s b y James Peterson, Los Angeles County N a t u r a l H i s t o r y Museum, and M ichae l M a r t i n , C a l i f o r ' n i a Department o f F i s h and Game.

F igu re 1. She l l s o f t h e C a l i f o r n i a sea mussel (A), and bay mussel (B) .

CALIFORNIA SEA MUSSEL AND BAY MUSSEL

S c i e n t i f i c name . . . . . . . M y t i l u s c a l i f o r n i anus Conrad P re fe r r ed common name . . C a l i f o r n i a sea mussel ( F i g u r e 1A) Other common names . . . Rock mussel, b i g mussel, C a l i f o r n i a mussel, sea mussel - - - -

S c i e n t i f i c name . . . M y t i l u s e d u l i s Linnaeus Pre fe r red common name. . . Bay mussel ( F i g u r e 1B) Other common names . . .Ed ib le mussel, b l ack mussel, b l u e mussel, p i l e mussel

Geographic range: The Cal i f o r n i a sea mussel ranges f rom t h e A l e u t i a n

I s l ands t o Socorro I s l and , Mexico ( C a l i f o r n i a d i s t r i b u t i o n i s shown i n F i gu re 2 ) and t h e bay mussel f rom t h e A r c t i c Ocean t o Cape San Lucas, Baja C a l i f o r n i a ( F i t c h 1953).

MORPHOLOGY/IDENTIFICATION AIDS

Cal i f o r n i a Sea Mussel

Umbo a t extreme a n t e r i o r end o f s h e l l . S h e l l covered w i t h a heavy, b l ack per iost racum. Older specimens, f rom which t h i s cove r i ng i s worn o f f , are b l u e and have an eroded appearance. E x t e r i o r o f she1 1 w i t h r a d i a t i n g r i d g e s and concen t r i c growth

NEVADA

SAN FRANCISCO BA

PACIFIC OCEAN

ANTA BARBARA

Mytllus edulls

M y t l l ~ ~ callfornlanus and # LOS ANGELES Mytllus edulls

MILES

0 50 1W

KILOMETERS

CALIFORNIA

Figure 2. Coastal d i s t r i b u t i o n o f t he C a l i f o r n i a sea mussel and bay mussel i n C a l i f o r n i a .

2

l i n e s . I n t e r i o r of s h e l l b l u i s h - b l a c k i r i descence shows i n r e f l e c t e d l i g h t . Length t o 25 cm. D i f f e r s from t h e bay mussel i n hav ing up t o a dozen broad r a d i a l r i b s ( F i t c h 1953).

Bay Mussel

She l l wedge-shaped, w i t h umbos a t extreme a n t e r i o r t i p . Per ios t racum u s u a l l y heavy, smooth, s a t i n y b l ack . I n t e r i o r of s h e l l smooth, b l ue -b l ack around margin, and showing some i r i descence i n r e f l e c t e d l i g h t . F lesh a d u l l brownish-orange. Length t o 10 cm. D i f f e r s from t h e C a l i f o r n i a sea mussel p a r t l y i n hav ing a smooth exte- r i o r unmarked by r a d i a t i n g r i d g e s and grooves ( F i t c h 1953).

REASONS FOR INCLUSION IN SERIES

The C a l i f o r n i a sea and bay mussels are r e 1 a t i v e l y common a1 ong t h e r o c k y c o a s t l i n e and i n bays and es tua r i es . They suppor t a smal l commerci a1 b a i t f i s h e r y and a re c u l t u r e d f o r food on a smal l s ca l e i n Tomales Bay and j u s t n o r t h of San Diego.

The areas of g r e a t e s t p o t e n t i a l f o r t h e commercial ha r ves t of M. e d u l i s i n C a l i f o r n i a f o r food, i n G E E i i d i n g o rder o f importance, a re Humboldt Bay, Tomales Bay, Drakes Estero, San Franc isco Bay, E lkhorn Slough, Morro Bay, San Diego Bay, and T i j uana Bay (Cha l f an t e t a l . 1980).

Mussels a re an impo r t an t food i t e m th roughou t t h e wor ld . There i s a p o t e n t i a l f o r c u l t u r i n g bo th o f these spec ies f o r food more e x t e n s i v e l y i n Cal i f o r n i a . Problems assoc ia ted w i t h such c u l t u r i n g a re seasonal c l osu res caused b y p o l l u t i o n and p a r a l y t i c s h e l l f i s h po i son ing (PSP), f i n d i n g a p p r o p r i a t e c u l t u r e s i t e s , and o b t a i n i n g pub1 i c acceptance t o use these s i t e s .

Man's man ipu l a t i on of t h e coas ta l zone cou ld p r o v i d e a d d i t i o n a l h a b i t a t s

f o r mussels. P ie rs , f l o a t i n g marinas, j e t t i e s , and p i l i n g s f o r o i l r i g s a re examples of surfaces i d e a l f o r s e t t l i n g mussels. I n f a c t , i n Humboldt Bay, C a l i f o r n i a , t h e o n l y s u b s t a n t i a l popu la t i on of M. e d u l i s occurs on t h e under surfaces-of floats i n a newly cons t r uc ted marina.

LIFE HISTORY

Spawn i n g

The C a l i f o r n i a sea mussel c o n t i n u a l l y spawns th roughou t t h e year a t a v e r y low l e v e l (Suchanek 19811, w i t h b reed ing peaks i n J u l y and December (Mo r r i s e t a l . 1980). I n n o r t h e r n Cal i f o r n i a, Edwards (1984 found no d e f i n i t e spawning cyc l e . Ripe mussels were seen from February t o May and from December t o February. Spawning was observed i n January, February, May, and December.

The bay mussel has a s i n g l e massive spawning ou tpu t each year (Suchanek 1981) which can occur i n l a t e f a l l and/or w i n t e r a long t h e c e n t r a l C a l i f o r n i a coas t (Mo r r i s e t a l . 1980). I n n o r t h e r n C a l i f o r n i a spawning was f i r s t observed i n May and again f rom J u l y th rough November (Edwards 1984 1.

I n t h e l a b o r a t o r y , spawning has been s t i m u l a t e d b y r a i s i n g and l owe r i ng t h e water temperature, adding s i n g l e c e l l algae, us i ng water t r e a t e d w i t h u l t r a v i o l e t 1 i g h t , adding mussel sperm, and us i ng water c o n t a i n i n g hydrogen perox ide. Breese e t a l . (1963) found 4% K r a f t m i l l e f f l u e n t t o be a h i g h l y e f f e c t i v e s t imu lus i n t r i g g e r i n g mussel spawning. I n t h e n a t u r a l environment, temperature does n o t seem t o p rov i de a major s t imu lus f o r spawning. Mechanical s t i m u l i , such as p u l l i n g on t h e byssal threads, may i n i t i a t e t h e r e l ease of gametes. Also, spawning o f one animal may s t i m u l a t e o the r s t o spawn (Mo r r i s e t a1 . 1980).

Dur ing spawning t h e eggs and sperm are d ischarged through t h e excur ren t chamber. The eggs, which appear as orange r ibbons, a re f e r t i l i z e d i n t h e open water.

La rva l Stage

The embryos develop i n t o t rochophore l a r vae (60-80 micrometers) about 24 h a f t e r f e r t i l i z a t i o n . The v e l i g e r ( s t r a i g h t - h i n g e s tage) devel - ops 24 h l a t e r (F i gu re 3A). A c i l i a t e d velum forms and he lps t h e l a r v a swim and ma in ta i n i t s e l f i n t h e water c o l umn . Larvae feed on phytoplankton and a re about 0.17 mn long a f t e r 1 week. The v e l i g e r , which develops an umbo, may reach a l eng th o f 0.20 t o 0.24 mm i n 2 weeks. Loosanoff and Davis (1963) found t h a t t h e s i z e o f mussel l a r vae (M. e d u l i s ) a t metamorphosis va r i ed by almost 0.09 mm; leng ths ranged f rom 0.21 mm t o almost 0.30 mm i n l eng th (F i gu re 3K). Jus t before metamorphosis, t h e l a r v a develops an eyespot and f o o t .

The l a r vae o f M. c a l i f o r n i a n u s have been reared i n t h e l a b o r a t o r y t o metamorphosis i n 17-24 days a f t e r f e r t i l i z a t i o n . Eyespots were observed when t h e l a r vae were 0.23 t o 0.24 mn long (Skidmore and Chew 1985).

Breeding success o r f a i l u r e i s f r e q u e n t l y determined du r i ng t h e c r i t i c a l l a r v a l stage. The l a r v a e a re a t t h e mercy o f c u r r e n t s and may be c a r r i e d away f rom s e t t i n g areas and d i e .

Post1 arvae and Recru i tment

M y t i l u s e d u l i s se ts on t h e byssal threads o f adu l ts , on a v a r i e t y o f algae, and on newly exposed hard surfaces; M. c a l i f o r n i anus se ts on barnacles, o l d mussel she1 1, and newly exposed hard sur f aces ( P e t r a i t e s 1978). I n C a l i f o r n i a , M. e d u l i s s e t t l e d immediate ly on s c r a p e d , b a r e subs t ra te ( i .e. no successi on occurred) i n w i n t e r and spr ing ; i t d i d no t s e t t l e i n summer and f a l l (Reish

1964). Dens i t y o f newly s e t t l e d M. c a l i f o r n i a n u s was h i ghes t on f i la- mentous a1 gae (Peterson 1984). The au thor observed i n t h e l a b o r a t o r y t h a t M. e d u l i s l a r vae avoided a d u l t M. - c a l i f o r n i a n u s . I n v e s t i g a t o r s d isagree about s e t t l i n a behavior . For example, . . t h e presence " o f a d u l t M. e d u l i s may i n h i b i t l a r v a l se t t lement . S e e d m u s - s e l s appear t o s e t elsewhere, and t hen m ig ra te t o a d u l t beds, where t hey a t t a c h t o byssal th reads o f t h e a d u l t s wherever t h e r e i s space (Jamieson e t a1 . 1975). M. c a l i f o r n i a n u s p r e f e r r e d t o s e t on b5ssal th reads from a d u l t s (Trevelyan and Chang 1983).

I n southern C a l i f o r n i a - - M. e d u l i s s e t t l e s i n massive numbers i n some years, b u t sparse ly i n o the rs (Mo r r i s e t a l . 1980). I n areas where b o t h species have s e t t l e d , M. e d u l i s was t h e more mob i le and was g e n e r a l l y found on t h e o u t e r p a r t o f t h e c o l - on ies. It was a l s o more suscep t i b l e t o wave a c t i o n . M y t i 1 us c a l i f o r n i a n u s ho lds i t s ~ o s i t i o n more s t r o n g l y t han - - does M. edul i s (Harger 1970a). - -

Cha l f an t e t a l . (1980) s t a t e d t h a t se t t lement o f M. e d u l i s was general l y gregar ious; i n Maine, f o r example, mussel spa t d e n s i t i e s exceeding 300,000/m2 have been found i n shal low, s u b t i d a l areas.

The c l ean ing o f su r face areas ( "b rush ing t h e f l a t s " ) has increased rec ru i tmen t . A1 so, t h e placement of p i l i n g s , stakes, o r po les i s a common commerci a1 method o f c o l 1 e c t i ng seed mussels. I n t h e Santa Barbara Channel, n a t u r a l se ts o f M. c a l i f o r n i a n u s are c o l l e c t e d f rom t h e l egs o f o i l d r i l l i n g p la t fo rms. S e t t i n g areas are prepared by c l ean ing unwanted growth o r wrapping areas w i t h speci a1 m a t e r i a l s t h a t a t t r a c t w i l d spat .

It probab ly takes many years fo r M y t i l u s t o become es tab l i shed i n t h e h i g h i n t e r t i d a l zone a t approx imate ly +1.8 t o +2.4 m above mean lower low

Figure 3. Larval development of the bay mussel, size (height and length) in micrometers.

water (Dayton 1971). Es tab l i shment i s s e r i o u s l y decreased growth, b u t a1 so f a s t e r a t lower l e v e l s (Dayton 1971). caused mo r t a l i t i e s o f 89%-100%.

Matur i t y

Sex r a t i o s a re g e n e r a l l y equal and t h e r e i s no i n d i c a t i o n o f sex change w i t h age. Some s e x u a l l y mature mussels were o n l y 4 months o l d o r 25 mm long. V i ab l e sperm was observed i n mussels 30 mm long. Spawning occurred near t h e end o f t h e f i r s t year o r when t h e mussels were 70 mm l ong (Coe and Fox 1942).

Age and Growth

The age o f mo l lusks i s determined by t h r e e methods: (1) s ize - f requency s t ud i es ; ( 2 ) t h e i n t e r p r e t a t i o n o f growth i n t e r r u p t i o n l i n e s on t h e she1 1 ; and (3 ) exper imenta l methods i n v o l v i n g t h e r e l e a s e and recovery o f marked i n d i v i d u a l s (Haskin 1954). Jamieson e t a l . (1975) r e p o r t e d t h a t growth r a t e s o f mussels i n any g iven p o p u l a t i o n were so v a r i a b l e t h a t year c lasses cou ld n o t be determined f rom s ize . Most workers have at tempted t o age mussels th rough i n t e r p r e t a t i o n o f growth i n t e r r u p t i o n l i n e s , a l though some have s t u d i e d marked i n d i v i d u a l s . L u t z (1976) aged mussels by us i ng ace ta te on p o l i s h e d l o n g i t u d i n a l s h e l l sec t ions .

Fac to rs i n f l u e n c i n g growth o f M. e d u l i s were d i v i d e d i n t o two ca tego r i es by Jamieson e t a l . (1975): b i o l o g i c a l (age, s i ze , and genotype), and phys i ca l (1 i g h t , temperature, depth, food, s a l i n i t y , and c u r r e n t ) . O f these, water temperature was t h e o n l y f a c t o r which i n f 1 uenced growth th roughou t t h e musse l ' s geographic range. I n some areas (e.g., Maine), growth was seasonal, whereas i n Cal i f o r n i a , where t h e annual temperature range was r e 1 a t i v e l y narrow, t h e r e was no obv ious seasonal v a r i a t i o n i n s h e l l growth r a t e (Cha l f an t e t a l . 1980). L u t z and P o r t e r (1977) r e p o r t e d t h a t water temperature above 25 OC n o t o n l y

I n ex tens i ve growth s t u d i e s conducted i n Puget Sound, Washington, by Skidmore and Chew (19851, s e t s of M. e d u l i s i n f o u r o f f i v e experiments - - a t t a i n e d market s i z e (50 mm) w i t h i n 12 t o 13 months. The growth r a t e s o f M. e d u l i s and M. c a l i f o r n i a n u s were a l s o compared at-two s i t e s i n Puget Sound. M y t i l u s e d u l i s grew t h e f a s t e s t f o r t h e f i r s t r e e months, b u t s i z e d i f f e r e n c e s between t h e two spec ies were smal l by t h e end of 9 months.

I n southern C a l i f o r n i a (Scr ipps I n s t i t u t i o n o f Oceanoqraphy dock, San . -

Diego) M. c a l i f o r n i a n u s sometimes wows asmuch as 7 mm per month. Th is i p e c i e s may reach a l e n g t h o f 80-86 mm w i t h i n a year o f se t t l ement , 120 mm a f t e r 2 years, and 140-150 mm a f t e r 3 years (Coe and Fox 1942). Maximum s i z e i s 200-250 mm (Harger 1972). Growth i s f a s t e s t d u r i n g t h e c o l d e r months and s lowes t (soqet imes n i l i n mid-summer o r above 20 C.

M y t i l u s e d u l i s does n o t grow as l a r g e as M. c a l i f o r n i a n u s (F i gu re 4 ) . I n sou thern C a l i f o r n i a , t h e bay mussel grew t o a l e n g t h o f 66 t o 76 mm a f t e r 1 year and 90-99 mm a f t e r 2 years (Coe 1945). Therea f te r , growth was v e r y slow (Table 1). Maximum s i z e ranges f rom 120-150 mm (Harger 1972).

Mussels ea t a v a r i e t y of organisms, such as d i no f 1 agel 1 ates, o rgan i c p a r t i c l e s , smal l diatoms, zoospores, m inu te ova and spermatozoa, f l a g e l l a t e s and o t h e r protozoans, va r i ous u n i c e l l u l a r algae, and d e t r i t u s ( c o n s i s t i n g o f p a r t i c l e s from t h e c y t o l y s i s o f c e l l s o f a l a r g e v a r i e t y o f p l a n t s and an imals) . Growth r a t e s a re r e l a t e d t o t h e abundance o f d i nof 1 agel 1 a tes (Coe and Fox 1942). My t i 1 us c a l i f o r n i anus from southern C a l i f o r n i a grew 100% f a s t e r i n h e i g h t and 50% f a s t e r i n w i d t h a t +0.1 m ( t h e p l u s s i g n i n t h i s r e p o r t i n d i c a t e s v e r t i c a l h e i g h t above mean

COMMERCIAL AND SPORT FISHERIES AND AQUACULTURE

2 3 4 5 6 7 8

Projected Tlme (years)

F igu re 4. P ro j ec ted growth curves f o r M y t i l u s e d u l i s (open symbols) and My t i l u s c m n i a n u s ( c l osed symbols) based on da ta ob ta ined f rom und is tu rbed popu la t i ons o f mussels a t Santa Barbara Harbor, C a l i f o r n i a (Harger 1970b).

l ower low water) t han a t +O. 3 m where feed ing t ime was s h o r t e r (Dehnel 1956). Males grow f a s t e r than females t h e f i r s t 1.5 years (Coe and Fox 1942 1.

Food p a r t i c l e s , drawn through an i n h a l e n t ape r t u re by c i l i a r y ac t ion , a re caught on sheets o f mucus and c a r r i e d a long t h e s i des o f pa lps t o t h e mouth. Some p a r t i c l e s a re inges ted b u t o thers , i f excessive, are d ischarged from t h e mant le c a v i t y as pseudofeces. The most common food i s t h e d i n o f 1 aael 1 a t e Prorocentrum micans a t a syze o f 57 x 30 pm (Fox -3

and Coe 1943).

Table 1. Growth of M t i l u s e d u l i s i n r e l a t i o n t o s i z e (Coe -!+- 945)

Average inc rease S i ze (rim) per month (mm)

Both spec ies of mussels were once commerc ia l ly impo r t an t i n Cal i f o r n i a . Over 69,000 pounds were landed i n 1917 (Table 21, b u t i n 1927, and t he rea f t e r , most areas were c losed t o f i s h i n g by t h e C a l i f o r n i a S t a t e Board o f Heal th , due t o mussel po isoniqg. No mussels can now be s o l d f o r human consumption f rom May 1 t o October 31 because o f t h e presence o f p a r a l y t i c s h e l l f i s h po ison ing . The consumption o f mussels t h a t have concen t ra ted l a r g e amounts of t h e po ison-producing mic roscop ic d i n o f l a g e l l a t e Gonyaulax c a t e n e l l a sometimes causes se r i ous i d l n e s s ( N i s h i t a n i and Chew 1983). I n 1980, f o r example, po i son ing was recorded i n 98 r e s i d e n t s o f Mar in and Sonoma coun t ies , C a l i f o r n i a , o f whom two d i ed (Estes and VanBlaricom 1985).

A l i m i t e d s p o r t f i s h e r y , where mussels a re u s u a l l y removed f rom p i l i n g o r rocks by hand, now e x i s t s d u r i n g t h e open season. A d a i l y ha r ves t o f 25 pounds i s a l lowed.

Four companies have shown i n t e r e s t i n fa rm ing mussels f o r human consumption i n Tomales Bay, C a l i - f o rn i a , because t h e demand f o r a year - round supp ly o f qua1 i t y mussels has outgrown t h e supp ly f rom n a t i v e beds. They hang ropes from long1 i nes supported by f l o a t s t o c o l l e c t a n a t u r a l se t . The seed i s then p laced i n p l a s t i c n e t t i n g , which i s then hung f rom t h e l o n g l i n e s .

One company c u l t u r e s mussels f rom t h e l egs o f o i l d r i l l i n g p l a t f o rms i n t h e Santa Barbara channels. Seed, p laced i n p l a s t i c n e t t i n g , i s wrapped around t h e legs. When t h e mussels reach m a t u r i t y d i v e r s scrape them o f f t h e legs. The mussels a re conveyed t o t h e su r f ace th rough s u c t i o n hoses and a re cleaned, packaged, and shipped f r e s h t o market.

The r a t i o o f meat t o t o t a l we igh t i s h i gh i n mussels. The compos i t i on

Table 2. Y e a r l y l a n d i n g s o f mussels i n C a l i f o r n i a .

c rude f a t , 2.6%-3.5%; ash, 2.0%-2.7%; and carbohydrate , 1.2%-5.8%.

Landings Year (1b)

1922 43;872 1923 60,026 1924 49,223 1925 25,942 1926 14,614 1927 29,631 1928 1,610 1929 1,028 1930 325 1931 1,800 1932 230 1933 465 1935 10 1936 750 1937 1,490 1938 150 1939 1,800 1940 100 1942 5 0 1946b 639 1947 5 30 1972: 111,799g 1974 81, 642g 1975; 53,691: 1976 47,336

a ~ e a r s 1916-1947 (Bureau o f Mar ine F i s h e r i e s 1949).

b ~ o commerci a1 1 andi ngs between 1948- 1971.

'p inkas 1974. d ~ c ~ l 1 i s t e r 1976. e ~ i n k a s 1977. f ~ l i p h a n t 1979. g ~ a i t. h2,357 pounds f o r human consumption;

r e s t f o r b a i t .

of c u l t u r e d M. e d u l i s , ana lyzed by S l a b y j e t a l T (1478), i s mo is tu re , 71 .I%-75.7%; p r o t e i n , 14.1%-21.0%;

ECOLOGICAL ROLE

Feeding

Mussels a re suspension feeders, a r e cons ide red t o be scavengers, and c o l l e c t a n y t h i n g i n t h e p l a n k t o n t h a t i s sma l l enough t o i n g e s t . D i g e s t i o n i s i n t r a c e l l u l a r (Coe and Fox 1944).

Compet i to rs

When a r e s o u r c e i s p o t e n t i a l l y l i m i t i n g (as i n t h e case of l i v i n g space f o r s e s s i l e organisms i n t h e r o c k y i n t e r t i d a l zone) one spec ies of c o m p e t i t o r may p o t e n t i a1 l y dominate t h e o t h e r s i n p r o c u r i n g o r h o l d i n g t h e resource . P r e d a t i o n o r p h y s i c a l d i s t u r b a n c e may cause m o r t a l i t y o f t h e dominant c o m p e t i t o r s u f f i c i e n t t o p r e v e n t t h e e x c l u s i o n o f t h e o t h e r compet i to rs , a1 l o w i n g s e v e r a l spec ies t o c o e x i s t . Such phenomena occur i n t h e r o c k y i n t e r t i d a l zone of t h e P a c i f i c coas t o f t h e U n i t e d S ta tes , where s i g n i f i c a n t i n s i g h t s i n t o such processes o f community f u n c t i o n have been ob ta ined e s p e c i a l l y from s t u d i e s done on t h e coas t o f Washington. As shown i n t h e f o l l o w i n g d iscuss ion , t h e d i s t r i b u t i o n o f M. c a l i f o r n i a n u s i s c o n t r o l l e d by ~ r d a t i o n and p h y s i c a l d i s tu rbance , w h i l e t h e d i s t r i b u t i o n of M. e d u l i s i s c o n t r o l l e d by these two - - f a c t o r s and c o m p e t i t i o n as w e l l .

On Washington's exposed o u t e r coast , M. c a l i f o r n i a n u s i s t h e dominant c o m p e t i t o r f o r ava i 1 a b l e space and w i 11 f o r m dense monospeci f i c s tands un less d e t e r r e d (Paine 1966). M y t i l u s c a l i f o r n i a n u s i s one o f t h e most c o n s i s t e n t occupants of space i n t h e i n t e r t i d a l barnacle-mussel a s s o c i a t i o n the re . a lonq w i t h t h e barnac les g l a n d u l a , anemone

~ h t h a m a l u s d a f l i , Bal anus and B. ca r iosa , and t h e sea An th5p leu ra e l e g a n t i s s i m a

,971). The name " C a l i f o r n i a . < -

sea mussel" was g i v e n t o M.

8

c a l i f o r n i anus because o f i t s r e s t r i c t i o n mos t l v t o t he ou te r coast . M y t i l u s c a l i f o r n i a n u s w i 11 s e t t l e among Balanus and comple te ly cover the barnacles (Dayton 19711, eventual l y exc lud ing them (Paine 1966). M y t i l u s c a l i f o r n i a n u s denies space t o M. e d u l i s on t h e open coast, b u t i t seems t o o f f e r p r o t e c t i o n from wave a c t i o n t o those M. e d u l i s t h a t do become at tached m a r g e r 9 7 0 c 1. Myt i 1 us e d u l i s i s c a l l e d t he "bay mussel" because i t has long been thought t o be common most ly i n q u i e t waters, b u t i t i s now known t o be common on t he ou te r coast as we l l (Suchanek 1978). M y t i l u s e d u l i s on t h e exposed ou te r coast o f Washington u s u a l l y occupies a band 0.3 m i n v e r t i c a l he igh t ( a t about +2.9 t o +3.2 m) above t he M. c a l i f o r n i a n u s zone, which i s a t about +0.5 t o +2.9 m (Suchanek 1978). The lower l i m i t o f M. e d u l i s zone i s p robab ly se t by c o m p e t i t i v e exc lus ion by M. ca l i f o rn - i anus and by p reda t i on (Suf ianek 1978).

Predators

A number o f p redators p rey on mussels i n C a l i f o r n i a . Harger (1972a) repo r ted t h a t M. e d u l i s was p r e f e r r e d over M. c a i i f o r n i a n u s by n ine i n v e r t e F r a t e p redators : two sea s ta rs , P i sas te r i anteus and P. ochraceus, f i v e s p e c b m u r i c i d gastropods, Thais emarginata, Acanthina sp i ra ta , Ocenebra pou lson i , Ceratostoma n u t t a l l i , and Jaton f es t i vus , and two species o f crabs, Cancer antennar i us - and Pachygrapus crass1 pes. A t h i r d crab, Puge t t i a producta, a te mussels b u t showed no pre fe rence f o r a p a r t i c u l a r species. Harger and Landenberger (1971) observed g rea te r losses f rom p reda t i on i n shal low water compared t o deep water.

Myt i 1 us c a l i f o r n i anus occupies on l y about 4% of t he space (between about +3 m and a depth o f about -27 m) t h a t i t would occupy under phys i ca l l y m i l d and p reda to r - f r ee cond i t i ons (Paine 1976b). The sea s t a r P. ochraceus may c l e a r patches of E.

c a l i f o r n i a n u s (Dayton 19711, one of i t s p r e f e r r e d p rey (Paine 1966). I n an experiment i n Washington, P. ochraceus was removed and t he area eventual l y became a monospecif i c s tand o f M. c a l i f o r n i a n u s (Paine 1966). P isac te r ochraceus c o n t r o l s t h e -- abundance o f t h e dominant mussel and thus a l lows o the r soecies t o c o e x i s t

( ~ h a j s .- spp. by a t t a i n i n g a ' v a r i a b l e minimum s i z e o f i n v u l n e r a b i l i t y (Dayton 1971 1. Thi s mussel escapes p reda t i on by P. ochraceus by growing t o a minimum s i z e t h a t increases as t h e s i z e o f t h e sea s t a r increases (Paine 1976b). Mean d e n s i t y o f P. ochraceus may va ry l o c a l l y by a t l e a s t two orders o f magnitude, a f f e c t i n g l o c a l abundance o f M. c a l i f o r n i a n u s (Paine 1976b). I n Washington, areas o f low M. c a l i f o r n i a n u s abundance and h igh P. ochraceus d e n s i t y occur s ide- by-s iTe w i t h dense stands o f l a r g e M. c a l i f o r n i a n u s t h a t have low 7. ochraceus dens i ty ; t h e mussels hzd p robab ly escaped p reda t i on by a t t a i n i n g an i n v u l n e r a b l e s i z e (Paine 1976b).

P i sas te r ochraceus may i n d i r e c t l y enhance rec ru i tmen t o f M. c a l i f o r n i a n u s by t h e f o l l o w i n g s e r i e s of events: 1 ) P. ochraceus consumes l impets ( l e s s p r e f e r r e d p rey ) and may reduce t h e i r abundance; 2) as shown exper imenta l ly , a r e d u c t i o n i n 1 impet d e n s i t y would consequent ly enhance t h e abundance o f one o f t he 1 impet ' s major foods, t h e red a lga Endocladia; and 3) mussel r ec ru i tmen t mau be enhanced because Endocladia i s the major s e t t l i n a subs t ra te f o r M. - c a l i f o r n i anus 1 arvae (Dayton 1971).

On the ou te r coast o f Washington, M. e d u l i s w i l l become es tab l i shed i n a - - patch c l ea red by phys i ca l d is tu rbance or p reda t i on i n t h e - M. c a l i f o r n i a n u s zone (which i s a t about +0.5 t o +2.9 m) o n l y i f the patch diameter i s g rea te r than about 40 cm (Suchanek 1978 1. Small e r patches expose s e t t l i n g M. e d u l i s (and the

f i l amentous algae used as s e t t l i n g mussel and swallow i t whole. The subs t ra te ) t o removal by grazers o the r mussels i n t he clump s ink t o t he (1 impets, c h i tons, and t he bottom (Skidmore and Chew 1985). op is thobranch gastropod Onch ide l la b o r e a l i s ) t h a t move i n f rom the edge o f t h e pa tch (Suchanek 1978). Those Commensals, Paras i tes, and Enc rus t i ng M. e d u l i s t h a t do invade the M. - Epi f auna c a l i f o r n i a n u s zone grow q u i c k l y b i i t a re p re fe r red over M. c a l i f o r n i a n u s by The commensal crab, Pinnotheres whelk predators, ~ h j i s spp. (Suchanek sp., has been found i n M. edu l i s . The 1978). On the ou te r coast, t he lower crabs ea t t h e food mussels have l i m i t o f M. e d u l i s band (about +2.9 m) i s p r o b & l y x e r m i n e d p a r t l y by p redat ion by gastropods, b i r ds , and sea s t a r s (Suchanek 1978). P i sas te r ochraceus has more t ime t o feed and thus can e a t more mussels a t lower i n t e r t i d a l l e v e l s . The abrupt lower 1 i m i t o f M. c a l i f o r n i a n u s banb (about +0.5 m) i y almost c e r t a i n l y t h e most conspicuous f e a t u r e of t he rocky i n t e r t i d a l community (Paine 1976) and i s probably s e t by p reda t i on by - P. ochraceus (Paine 1966, 1974).

The sea o t t e r (Enhydra l u t r i s ) i s known t o ea t both M. c a l i f o r n i a n u s and M. e d u l i s ( ~ s t e ? and VanBlaricom T985), mussels form on l y a smal l p o r t i o n o f i t s d i e t i n C a l i f o r n i a . Consumption o f mussels by sea o t t e r s appears t o be s u f f i c i e n t l y sca t te red i n t ime and space t o prec lude t he reg iona l dep le t i on o f harves tab le s tocks. The exposure o f much o f t he c e n t r a l C a l i f o r n i a coast t o heavy s u r f p robab ly p rov ides an impor tan t r e fuge f o r mussels from f o r a g i n g sea o t t e r s . Predat ion by the b lack oystercatcher , Haematopus bachmani , and dislodgement by storm waves are p robab ly a t l e a s t as impor tan t as sea o t t e r p redat ion i n 1 i m i t i ng t he avai 1 ab i 1 i t y o f mussels f o r human consumption i n C a l i f o r n i a .

D i v i n g ducks, e s p e c i a l l y scoters, are mussel predators. Three species of ducks are respons ib l e f o r most o f t he losses-- the s u r f scoter , M e l a n i t t a de l gandi , whi te-winged scoter , M. p e r s p i c i l l a t a , and b lack scoter , Oidemi a amereicana. I n feeding, t h e ducks d i v e underwater, remove a clump of mussels, r e t u r n t o t he surface, shake the clump, and d is lodge one

f i 1 t e r e d ou t and decrease t h e pumping r a t e s o f mussels. Mature female crabs can reduce t h e meat y i e l d by as much as 26% (Pregenzer 1981).

I n C a l i f o r n i a t he p a r a s i t i c copepod Myt i 1 i c o l a o r i en ta les was found i n 13 o f 20 M. c a l i f o r n i a n u s and i n 24 M. e d u l i s T ~ h e w e t a l . 1964) ~ r a d 1 e ~ - a n d e b e r t (1978) found ~ ~ t i l i c o l a i n M. e d u l i s from San Francisco Bay ( inc idence range, 36.8%- 48.5%); t hey be l i eved t he p a r a s i t e was imported w i t h t he Japanese oys te r (Crassostrea g i g a s ) . The gonads of o ~ f o r n i a n u s , f rom Humboldt Bay, were heavi l y p a r a s i t i z e d w i t h trematode c e r c a r i ae o f t he fami l y Bucephal idae (Edwards 19841, and trematode sporocysts were found i n t h e d i g e s t i v e g land and gonadal t i s s u e of M. edul i s (Brousseau 1983). - -

Subt ida l M. c a l i f o r n i a n u s may be overgrown by- sponges, barnacles, anemones, and o the r epi fauna (Paine 1976a). Heav i l y encrusted mussels weighed l e s s ( i n t i s s u e we igh t ) than those l e s s encrusted (Paine 1976a).

ENVIRONMENTAL REQUIREMENTS

Temperature and Sal i n i t y

Temperature p l ays an impor tan t r o l e i n growth. Coe and Fox (1944) found t h a t t h e growth of M. g a l i f o r n i a n u s was most r a p i d a t 17;TO

C and decreased sha rp l y above 20 C. Growth j iont inued (bu t a t a lower r a t e ) a t 14 C o r lower bu t l e s s r a p i d l y . Feeding con t inued a t 7-8 O C and 27-28 OC. F i l t r a t i o n r a t e and oxygen

consumption were h i g h e s t a t 20 OC (Coe and Fox 1942).

I n C a l i f o r n i a t h e optimum temper- a t u r e range f o r growth was 10-20 O C

(Mo r r i s e t a l . 1980). Feldmeth and A l p e r t (1977) found t h a t t h e mean wet we igh t o f mussels f rom t h e c o o l e r waters of A lami tos Bay, C a l i f o r n i a (14.8-15.8 OC) was f o u r t imes g rea te r than thoseo from San Gab r i e l R i ve r (22.7-25.0 C).

I n nature, M. c a l i f o r n i a n u s i s r a r e l y found i n cays and es tua r i es - - perhaps because eggs, sperm, and l a r v a e cannot w i t hs tand d i 1 u t i o n s below 75% sea water (Robertson 1964). I n c o n t r a s t , M. e d u l i s can accommodate a wide s a l i n i T y -(Bayne 1965)--an i n t e r s p e c i e s d i f f e r e n c e t h a t e x p l a i n s i t s wider d i s t r i b u t i o n bo th i n t h e open coas ta l waters and i n p r o t e c t i v e bays.

H a b i t a t

M y t i l u s e d u l i s i s s e n s i t i v e t o t h e e f f e c t s o-es (Harger 1970a). I t appears t h a t M. c a l i f o r n i a n u s ho l ds i t s p o s i t i o n more s t r o n g l y than does M. e d u l i s . - -

M y t i l u s e d u l i s i s b e h a v i o r a l l y adapted t o q u i e t waters b e t t e r than M. c a l i f o r n i a n u s . Mussels may fo rm c l u m ~ s UD t o 25 cm t h i c k : . i u ven i l e M. e d u l i s c'rawl t o t h e o u t i i i e o f s u ~ h clumps which may i n c l u d e M. c a l i f o r n i a n u s , b u t t h e l a t t e r mussel does no t (Harger 1968). Th i s c r a w l i n g behav io r p r o t e c t s M. e d u l i s f rom harmfu l s i l t t h a t a c c u m u l a t e s i n s i d e t h e clumps i n q u i e t waters. Th i s s i l t may tend t o exc lude M. c a l i f o r n i a n u s t h e r e (Harger 1968).

The growth o f M. e d u l i s was s e r i o u s l y a f f e c t e d by T i d a l s u r e . L i t t l e o r no growth took p l ace a t 80% exposure and t h e mussels d i e d w i t h i n 3 months; growth was s i g n i f i c a n t l y l e s s a t 40% and 60% exposure than a t 0% and 20% exposure (Ch r i s tensen 1984). M o r r i s e t a l . (1980) s t a t e d t h a t - M.

e d u l i s needs t o be submerged a t l e a s t h a l f t h e t ime t o show s i g n i f i c a n t growth.

Phys ica l D is tu rbance

Wave a c t i o n o r wave-borne l o g s i n exposed areas may remove whole mats o f mussels i n t h e i n t e r t i d a l zone (Dayton 1971). A t t h e edge o f a c l ea red patch, s u b s t a n t i a l numbers o f a d d i t i o n a l mussels may be removed by wave a c t i o n (Dayton 1971 1. Mussels h i g h i n t h e i n t e r t i d a l zone away f rom s t a r f i s h p r e d a t i o n may s u r v i v e f o r a g rea t many years, u n t i l some a re k i 1 l e d by wave-borne logs, unusual co ld , o r o t h e r phys i ca l s t r esses (Dayton 1971). The upper l i m i t t o t h e M. e d u l i s zone i n t h e h i g h i n t e r t i d a l - - area a t Tatoosh I s 1 and, Washington, was c o n t r o l 1 ed by extreme summer hea t t h a t k i l l e d mussels, o r made t h e i r s h e l l s gape and made them easy p rey f o r g u l l s (Suchanek 1978).

Other Environmental Fac to r s

Because m u s s e l s - - p a r t i c u l a r l y M. edul i s - - a r e d i s t r i b u t e d a long t k e coast, and i n bays and es tua r i es , t h e y a re o f t e n sub jec ted t o sewage and o the r k i nds o f p o l l u t i o n (Rober ts 1976). The mussels may be unsafe t o ea t and must be depurated be fo re market ing. I n a d d i t i o n , bo th spec ies o f mussels i n g e s t c e r t a i n d i n o f l a - g e l l a t e s t h a t make them t o x i c t o humans, caus ing p a r a l y t i c s h e l l f i s h po ison ing .

Mussels concen t ra te hydrocarbons i n t h e i r t i s s u e s . The hydrocarbons are r a p i d l y taken up by t h e g i l l t i s s u e s and eventual l y a re depos i ted i n h i g h concen t ra t i ons i n t h e a1 imenta ry canal (Rober ts 1976). A l though o i l i s o n l y s l i g h t l y t o x i c t o mussels, i t may a f f e c t t h e marke t ing o f t h e animals by t a i n t i n g them. C la r k and F i n l e y (1975) r e p o r t e d t h a t t h e uptake and l o s s o f pe t ro leum hydrocarbons was r e l a t e d t o t h e

magn i tude o f exposure. When musse ls were p l a c e d i n c l e a n water , most hyd roca rbons were l o s t b u t s i g n i f i c a n t q u a n t i t i e s o f No. 2 f u e l o i l remained f o r as l o n g as 35 days. Fue l o i 1 and ou tboa rd mo to r o i l may i n h i b i t b y s s a l t h r e a d f o r m a t i o n b u t a t Long Beach Harbor , C a l i f o r n i a , motor b o a t a c t i v i t y posed 1 i t t l e t h r e a t ( C a r r and Re ish 1978).

A number o f t r a c e m e t a l s a r e found i n t h e s o f t t i s s u e s o f mussels, i n c l u d i n g Ag, Cu, C r , Mn, Pb, Cd, and Zn. L e v e l s i n M. e d u l i s f r o m Cal i f o r n i a ( T a b l e 3 ) Z g r e e d h t h o s e of t h e same spec ies i n New Zea land (Graham 1972 1.

S i n c e 1977 t h e C a l i f o r n i a Department o f F i s h and Game has been moni t o r i n g t h e amount o f t r a c e m e t a l s i n mussels ( S t a t e Mussel Watch) a l o n g t h e c o a s t (Stephenson e t a l . 1980a, 1980b). Of t h e s i t e s i n v e s t i g a t e d , Royal Palms, Corona d e l Mar, and La J o l l a were " h o t s p o t s " f o r s i l v e r , copper, l ead , and z i n c . S i l v e r was e s p e c i a l l y h i g h i n musse ls i n South San F r a n c i s c o Bay. Los Angeles Harbor and Santa C a t a l i n a I s l a n d had t h e h i g h e s t c o n c e n t r a t i o n o f s i l v e r and l e a d w h i l e mussels i n San Diego had t h e h i g h e s t c o n c e n t r a t i o n o f z i n c . The amount o f t r a c e m e t a l s i n mussels, depending on s i t e , were i n many i n s t a n c e s much h i g h e r t h a n t h o s e found by Graham (1972) .

Tab'le 3. D r y w e i g h t (ppm) of t r a c e m e t a l s i n s o f t p a r t s o f who le bod ies o f Myti 1 us e d u l i s . v a l u e s a r e app rox ima te means ( ranges i n pa ren theses ) (Graham 1972).-

L o c a t i o n N A 9 Cu C r M n Pb C d Zn

C a l i f o r n i a 2 4 1 7 4 16 5 5 284 1 - 1 . (5-11) (<2-8) (6-28) (2 -8 ) (3 -7 ) (204-3411

New Zeal and 6 1 9 16 27 12 10 9 1

(0.1-1.3) (8-11) (9-24) (12-38) (3-25) (10 ) (50-180)

LITERATURE CITED

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Bradley, W., and A.E. Siebert, Jr. 1978. Infection of Ostrea lurida and Mytilus edulis bytheparasite copepod Mytilicola orientalis in San Francisco Bay, California. Vel iger 21(1): 131-134.

Breese, W. P., R. E. Mi 1 lemann, and R.E. Dimick. 1963. Stimulation of spawning in the mussel Mytilus edul is Linnaeus and Myti lus californianus. Biol. Bull. (Woods Hole) 125(2):197-205.

Brousseau, D.J. 1983. Aspects of reproduction of the blue mussel, Myt i 1 us edul is (Pelecypoda: Mytilidae) in Long Island Sound. U.S. Natl. Mar. Fish Serv. Bull. 81 (4) : 733-739.

California Bureau of Marine Fisheries. 1949. The commercial fish catch of California for the year 1947 with an historical review 1916-1947. Cal if. Dep. Fish Game Fish. Bull. 74. 267 PP.

Carr, R.S., and D.J. Reish. 1978. Studies on the Mytilus edulis community in Alamitos Bay, Calif- ornia: VII. The influence of water- soluble petroleum hydrocarbons on byssal thread formation. Vel iger 21(2) :283-287.

Chalfant, J.S., Jr., T. Archambault, and A.E. West, J.G. Riley, and N. Smith. 1980. Natural stocks of mussels: growth, recruitment and harvest potential. Pages 36-68 - in

R.A. Lutz, ed. Mussel culture and harvest: A North Amer i can perspective. Elsevier Scientific Publishing Company, Amsterdam.

Chew, K.K., A.K. Sparks, and S.C. Katkansky. 1964. First record of Mytilicola orientalis Mori in the California mussel Myti 1us edulis Conrad. J. Fish. Res. Board Can.

Christensen, F.W. 1984. Intertidal growth response of Mytilus edulis (Linnaeus) in Humboldt Bay, Cali- fornia. M.S. Thesis. Humboldt State University, Arcata. 35 pp.

Clark, R.C. Jr., and J.S. Finley. 1975. Uptake and loss of petroleum hydrocarbons by mussels, Mytilus edulis, in laboratory experiments. U.S. Natl. Mar. Fish. Serv. Fish Bull. 73(3):508-515.

Coe, W.R. 1945. Nutrition and growth of the Cal iforni a bay-mussel (Mytilus edulis diegensis) J. Exp. Zool . 99 ( 1):1-14.

Coe, W.R., and D.L. Fox. 1942. Bioloqy of the Cal ifornia sea-mussel ti ius californianus). I. Inf 1 uence of temperature. food supply, sex and age' in the -rate of growth. J. Exp. Zool. 90(1):1-30.

Coe, W.R., and D.L. Fox. 1944. Bioloav of the California sea-mussel (~ytiiis cal ifornianus). 111. Environmental conditions and rate of growth. Biol. Bull. (Woods Hole) 87(1):59-72.

Dayton, P.K. 1971. Competition, disturbance, and community organ-

i z a t i o n : t h e p r o v i s i o n and sub- b i o l o g y o f sea mussels. Vel i g e r sequent u t i l i z a t i o n o f m a c e i n a 12 ( 4 ) :401-414. r o c k y i n t e r t i d a l communi t'y. Ecol . Monogr. 41(4):351-389. Harger, J.R.E. 1970b. Comparison

amona arowth c h a r a c t e r i s t i c s o f two - - Dehnel, P.A. 1956. Growth r a t e s i n spec ies o f sea mussel s , Myt i 1 us

l a t i t u d i n a l l y and v e r t i c a l l y e d u l i s and M y t i l u s c a l i f o r n i a n u s . separated popu la t i ons of Mytil us Veliger 13(1):44-56. c a l i f o r n i a n u s . B i o l . B u l l . 110:43- 53. Harger, J.R.E. 1970c. The e f f e c t of

spec ies compos i t i on on t h e s u r v i v a l Edwards, R. L. 1984. The r e p r o d u c t i v e

and percentage s o l i d s c y c l e s o f M y t i l u s e h l i s and - M y t i l u s c a l i f o r n i a n u s i n Humboldt County, C a l i f o r n i a . M.S. Thes is . Humboldt S t a t e U n i v e r s i t y , Arcata. 57 pp.

Estes, J.A., and G.R. VanBlaricom. 1985. Sea-o t te rs and she1 1 - f i s h e r i e s . Pages 187-235 i n J.R. Beddington, R.J.H. B e v e r t o x and D.M. Lavigne, eds. Marine Mammals and F i she r i es . George A l l e n and Unwi n, London.

Feldmeth, C.R., and M. A l p e r t . 1977. The e f f ec t of temperature on t h e d i s t r i b u t i o n and biomass o f M y t i l u s e d u l i s i n t h e A lami tos Bay area. V e l i g e r 20(1):39-42.

F i t c h , J.E. 1953. Common mar ine b i v a l v e s o f C a l i f o r n i a . C a l i f . Dep. F i s h Game Fish. B u l l . 90. 102 pp.

Fox, D.L., and W.R. Coe. 1943. B i o l o q y of t h e C a l i f o r n i a sea-mussel ti i u s c a l i f o r n i a n u s ) 11. N u t r i t i o n . metabolism. arowth and ca l c i um depos i t i on . j. hp. zoo1 ., 93:205-249.

Graham, D.L. 1972. Trace meta l l e v e l s i n i n t e r t i d a l mo l lusks o f C a l i f o r n i a . V e l i g e r 14(4):365-372.

Harger, J.R.E. 1968. The r o l e o f behav io ra l t r a i t s i n i n f l u e n c i n g t h e d i s t r i b u t i o n o f two s ~ e c i e s o f sea - -

mussel, ~ y t i l u s edu ' l is and M. c a l i f o r n i a n u s . Vel i g e r 11 (1 ) :45-49.

Harger, J.R.E. 1970a. The e f f e c t of wave impact on some aspects o f t h e

o f mixed ~ o ~ u l a t i o n s o f t h e sea mussels, ~ y t i l u s c a l i f o r n i a n u s and M y t i l u s e d u l i s . V e l i g e r 13(2):147- 152.

Harger, J.R.E. 1972. Compet i t i ve coex is tence : maintenance o f i n t e r a c t i n g assoc i a t i ons of t h e sea mussels M y t i l u s e d u l i s and M y t i l u s c a l i f o r n i a n u s . Vel i g e r 14(4):387- 410.

Harger, J.R.E., and D.E. Landenberger. 1971. The e f f ec t o f storms as a d e n s i t y dependent m o r t a l i t y f a c t o r on popu la t i ons of sea mussels. V e l i g e r 14(2):195-201.

Haskin, H.H. 1954. Age de te rm ina t i on i n mo l lusks . Trans. N.Y. Acad. Sc i . 16:300-304.

Jamieson, G.S., I . C . Neish, and C.S.L. C la rk . 1975. Perspec t i ve and deve l - opment p rospec ts of mussel c u l t i v a - t i o n i n t h e Mar i t ime Prov inces o f Canada. Mar. Ecol . Lab. Nova Sco t ia . Ref. AMRL74-11. 75 pp.

Loosanoff, V.L., and H.C. Davis. 1963. Rear ing of b i v a l v e m o l l usks . Advances i n Mar ine B i o l o g y 1: l -136.

Lutz , R.A. 1976. Annual growth p a t t e r n s i n t h e i n n e r s h e l l l a v e r o f M t i l u s e d u l i s L. J. Mar. B i o l . k K .56:723-731.

Lu tz , R.A., and B. Por te r . 1977. Exper imenta l c u l t u r e o f b l u e mussels M y t i l u s e d u l i s i n heated e f f l u e n t waters o f a nuc l ea r power p l a n t . Proc. World M a r i c u l t . Soc. 8:427- 445.

McAll i s t e r , R. 1976. C a l i f o r n i a marine f i s h landings f o r 1974. C a l i f . F i sh Game F i sh B u l l . 166. 53 PP.

Morr is , R.H., D.P. Abbot, and E.C. Haderl i e . 1980. I n t e r t i d a l i n v e r - t eb ra tes o f Cal i f o r n i a . Stanford Un i ve rs i t y , Stanford, C a l i f o r n i a . 690 pp.

N i s h i t a n i , L., and K.K. Chew. 1983. Gathering sa fe s h e l l f i s h i n Washington. Wash. Sea Grant Program Advis. Rep. WSG-RF82-3: 6 pp.

Ol iphant , M.S. 1979. C a l i f o r n i a marine f i s h landings fo r 1976. C a l i f . F i sh Game F i sh B u l l . 170. 56 PP.

Paine, R.T. 1966. Food web complex- i t y and species d i v e r s i t y . Am. Nat. 100: 65-75.

Paine, R.T. 1974. I n t e r t i d a l commu- n i t y s t ruc tu re . Experimental stud- i e s on the r e l a t i o n s h i p between a dominant compet i tor and i t s p r i n c i - pa l predator . Oecologia 15:93-120.

Pinkas, L. 1974. C a l i f o r n i a marine f i s h landings f o r 1972. C a l i f . F i sh Game Fish. B u l l . 161. 53 pp.

Pinkas. L. 1977. C a l i f o r n i a marine f i s h landings f o r 1975. Ca l i f . F i s h Game F i s h B u l l . 168. 55 pp.

Preaenzer. C.L. 1981. The e f f e c t of pinnotheres hickmani on the meat y i e l d ( cond i t i on ) of M y t i l u s e d u l i s measured several ways. Vel i ger

Reish, D.J. 1964. Studies on t h e M y t i l u s e d u l i s community i n A t l a n i t o s Bay, C a l i f o r n i a : I. Development and des t ruc t i on o f t he community. Vel i g e r 6(3) : 124-131.

Roberts, D. 1976. Mussels and p o l l u - t i o n . Pages 67-80 i n B.L. Bayne, ed. Marine mussels, t T e i r ecology and physio logy. Cambridge U n i v e r s i t y Press, Cambridge.

Robertson, J.D. 1964. Osmotic and i o n i c regu la t i on . Pages 283-311 in Kar l M. Wilbur and C.M. Yonge. Physiology o f mollusca, Volume 1. Academic Press, New York.

Paine, R.T. 1976a. B i o l o g i c a l Skidmore, D., and K.K. Chew. 1985. observat ions on a sub t i da l Myt i l u s Mussel aquacul ture i n Puget Sound. c a l i f o r n i a n u s bed. Vel i g e r 19(2): Wash. Sea Grant Program, WSG 85-4. 125-130. 57 PP-

Paine, R.T. 1976b. Size-1 i m i t ed predat ion : an observat ional and experimental approach w i t h t he My t i l us -P i sas te r i n t e r a c t i o n . Ecol- ogy 57 : 858-873.

Petersen, J.H. 1984. Larva l s e t t l e - ment behavior i n competing species: M t i l u s c a l i f o r n i a n u s and M. edu l i s .

Rar. B i o l . t c o l . 8 E 147TV.

P e t r a i t i s , P.S. 1978. D i s t r i b u t i o n pa t te rns o f j u v e n i l e Myt i l u s e d u l i s and M y t i l u s c a l i f o r n i a n u s . Ve l i ge r 21(2):288-291.

S l abyj, B.M., D.L. Creamer, and R.H. True. 1978. Seasonal e f f e c t s on y i e l d , proximate composi t ion and qua1 i t y o f b l ue mussels (Myt i 1 us e d u l i s ) meats obta ined from c u l t i v a t e d and na tu ra l stocks. Mar. F i sh Rev. 40(8):18-23.

Stephenson, M.D., M. Mart in , and J.H. Mart in . 1980a. Trace metal concen- t r a t i o n s i n mussels from bays i n C a l i f o r n i a . S ta te mussel watch - Vol ume I V . Cal i f o r n i a Water Qua1 i t y Rep. No. 79-22. 56 pp.

Stephenson, M.D., S.L. Coale, M. Mart in , and J.H. Mart in . 1980b.

C a l i f o r n i a mussel watch 1979-1980. Trace me ta l c o n c e n t r a t i o n s i n t h e C a l i f o r n i a mussel , Myti l u s c a l i f o r n i a n u s , and bay mussel, M. e d u l i s , a l o n g t h e C a l i f o r n i a c o a s t and s e l e c t e d h a r b o r s and bays. P a r t I. C a l i f o r n i a Water Q u a l i t y M o n i t o r i n g Rep. 80-8. 95 pp.

Suchanek, T.J. 1978. The e c o l o g y o f M y t i l u s e d u l i s L. i n exposed r o c k y i n t e r t i d a l communi t ies . J. Exp. Mar. B i o l . Eco l . 31: 105-120.

Suchanek, T.H. 1981. The r o l e o f d i s t u r b a n c e i n t h e e v o l u t i o n o f l i f e h i s t o r y s t r a t e g i e s i n t h e i n t e r t i d a l musse ls M y t i l u s e d u l i s and M t i l u s c a l i f o r n i a n u s . Oeco log ia (h 50: 143-152.

T reve lyan , G.A., and E.S. Chang. 1983. Exper imen ts on 1 a r v a l r e a r i n g o f t h e C a l i f o r n i a mussel ( M y t i l u s c a l i f o r n i a n u s ) . J. Wor ld M a r i c u l t . SOC. 14:137-148.

. I & Abstnct ( U r n i t 2OQ words)

Species p r o f i l e s are l i t e r a t u r e sumuaries o f t h e taxonomy, morphology, d i s t r i b u t i o n , 1 i f e h i s to ry , and environmental requirements o f coasta l a q u a t i c species. They a r e prepared t o a s s i s t i n environmental impact assessment. The Cal i f o r n i a sea mussel , Myt i 1 us c a l i f o r n i a n u s , and t h e bay mussel, M. e d u l i s , a r e comnonly c o l l e c t e d f o r b a i t . Some c o m e r c i a l l a n d i n g and aquacu l ture occurs a t a ve ry low l e v e l o f p roduct ion . Both species a r e d i s t r i b u t e d along t h e C a l i f o r n i a coas t ; t h e sea mussel i s more comnonly found on i n t e r t i d a l coas ta l rocks and t h e bay mussel on p i l i n g s and o t h e r hard subs t ra tes i n bays and es tua r ies . The eggs o f bo th s ~ e c i e s develop i n t o a t rochophore stage i n 12-24 hours a f t e r f e r t i l i z a t i o n , and t h e p l a n k t o n i c l a r v a l s tage l a s t s 3-4 weeks. Sexual m a t u r i t y can occur i n one year. Spawning o f t he sea mussel occurs s p o r a d i c a l l y through- o u t t h e year; t h e bay mussel spawns i n c e n t r a l C a l i f o r n i a i n l a t e f a l l and w i n t e r . Maximum l e n g t h i s 120-150 mm f o r t h e bay mussel and 200-250 nun f o r t h e sea mussel. Both species a re regarded as unsafe t o e a t f rom May 1 t o October 31 due t o t h e p o s s i b l e presence o f p a r a l y t i c s h e l l f i s h poisoning.

REPORT OOCUMEHTATION PACE

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DEPARTMENT OF THE INTERIOR U.S. ASH AND WILDLIFE 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 resources, protecting our fish and wildlife, preserving thsenvironmentai and cultural values of our national parks and hlstorical 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 people who live in island territories under U.S. administration.