i4ARIElE RESOLIRCE SLIRVEYS OiJ THE CONTIldEIITAL SHELF AND UPPER SLOPE OFF WASHIliGTON, 1975-76 COMPLETI014 REPORT J u l y 1, 1975 t o September 30, 1977 W i l l iam H. Barss Robert 1. Demory N e i l Ten Eyck Oregon Department o f F i sh and W i 1d l if e National Marine F i s h e r i e s Servi ce National Oceanic and Atmospheric Administration U.S. Department of Commerce Commercial F i s h e r i e s Research and Development Act P r o j e c t Nos. 1-108-R-1, 1-108-R-2 Con t r a c t Nos. 14 04-6-208-41003, 14 04-6-208-40037 September 1977 CONTENTS Page No ............................... HETHODS AND MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . Survey Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vessel and Gear C h a r a c t e r i s t i c s . . . . . . . . . . . . . . . . . . . Catch Processing . . . . . . . . . . . . . . . . . . . . . . . . . . Estimates o f Biomass. Usable Biomass and P o t e n t i a l Y i e l d . . . . . . Year Class Strength . . . . . . . . . . . . . . . . . . . . . . . . . Instantaneous T o t a l M o r t a l i t y Rate . . . . . . . . . . . . . . . . . E x p l o i t a t i o n Rate and F i s h i n g Rate . . . . . . . . . . . . . . . . . RESULTSANDDISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . Estimates o f Biomass . . . . . . . . . . . . . . . . . . . . . . . . Estimates o f Usable Biomass . . . . . . . . . . . . . . . . . . . . . Total InstantaneousMortalityRate . . . . . . . . . . . . . . . . . E x p l o i t a t i o n Rate and F i s h i n g Rate . . . . . . . . . . . . . . . . . Potential Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . Year Class S t r e n g t h . . . . . . . . . . . . . . . . . . . . . . . . . Survey Eva 1ua ti on . . . . . . . . . . . . . . . . . . . . . . . . . . Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recomrnendati ons . . . . . . . . . . . . . . . . . . . . . . . . . . . ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LITERATURECITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTION 1 2 2 2 4 4 4 5 5 5 5 7 7 7 8 9 25 29 29 31 31 32 32 33 . TABLES Table ido. 1 Page No. Estimates o f biomass (n.t.) o f p r i n c i p l e species between Cape F l a t t e r y and the Columbia River, 1975-76-/. Confidence l i m i t s , 95%, are expressed as +% ............................. Estimated usable biomass, p o t e n t i a l y i e l d and commercial landings (m. t.) o f p r i n c i p a l species o f f l a t f i s h f o r the Washington coast, 1975-76. . . . - 2 3 4 5 6 7 (s) Estimates o f e x p l o i t a t i o n r a t e ( v ) , annual m o r t a l i t y r a t e and instantaneous n i o r t a l i ty r a t e ( z ) o f p r i n c i p a l species o f f l a t f i s h f o r the Washington coast i n 1975 and 1976 .................. Nean weight (kg) o f selected species by depth s t r a t a as determined from groundfish survey o f f LJashington, 1975-76 . . . . . . . . . . . . . . . . Mean l e n g t h (cm) and m a n age ( y r ) by depth s t r a t a (fm) f o r Dover sole from groundfish survey o f f Washington, 197611 . . . . . . . . . . . . . . 8 25 25 FIGURES Figure No. 1 Location of t r a w l s t a t i o n s of groundfish surveys o f f Washington, 1975-76. Heavy broken l i n e defines survey l i m i t s . Sediment types from Cross e t a1 (1967), Roberts (1974) and Vendatarathnam (1973) ............ 2 3 4 D i s t r i b u t i o n and re1 a t i ve abundance (weight) o f Dover sole i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken 1 ine defines survey 1im i t s ................. 10 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f English sole i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey 1i m i t s ................. 11 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f p e t r a l e sole i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s 12 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f r e x s o l e i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s 13 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f P a c i f i c sanddabs i n September 1975 and 1976 o f f lldashington as determined by groundfish surveys. The heavy broken 1i n e defines survey l i m i t s 14 D i s t r i b u t i o n and re1a t i ve abundance (weight) o f arrowtooth flounder i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey 1i m i t s 15 D i s t r i b u t i o n and re1a t i v e abundance (weight) o f rockfish i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken 1ine defines survey 1i m i t s 16 ................. 5 ................. 6 .......... 7 .......... 8 3 ................. Figure No. 9 Page No. D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f l i n g c o d i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s 17 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f s a b l e f i s h i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. 'The heavy broken 1ine def ines survey 1im i t s 18 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f spiny dogfish i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey 1i m i t s 19 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f skates ( a l l species) i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s 20 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f r a t f i s h i n September 1975 and 1976 off Washington as determined by groundfish surveys. 'The heavybrokenlinedefinessurveylimits.. 21 D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f P a c i f i c hake i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s 22 D i s t r i b u t i o n o f selected species by depth as determined from groundfish m.t. surveys o f f Washington, 1975-76. T = ~ 5 0 23 ................. 10 ................. 11 .......... 12 .......... 13 ............... 14 .......... 15 16 17 ............. R e l a t i v e year class strength, as i n d i c a t e d by percent frequency from groundfi sh surveys o f f northern Oregon (1971, 1973) and Mas h i ngton (1975-76). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Total number by age o f selected species compared t o the commercially u t i l i z a b l e p o r t i o n (dark p a r t o f t h e bar graphs) o f f Washington (1976). . 30 MARINE RESOURCE SURVEYS ON THE CONTINENTAL SHELF AiID UPPER SLOPE OFF WASHINGTON, 1975-76 ABSTRACT Groundfish surveys o f f the Washington coast were conducted i n September of 1975 and 1976 between Cape F l a t t e r y and the Columbia River. The primary purposes of the surveys were t o o b t a i n estimates o f biomass and f u r t h e r our knowledge on population parameters o f important groundfish species, especial l y f l a t f i s h , occupying the continental she1 f and upper continental slope. Survey design was based on a 5x6 14. m i g r i d w i t h a random s t a r t i n g point. Samples were obtained f o r age, s i z e and sex composition from important f l a t f i s h species. Heights were obtained from a1 1 species o f fish. Estimates o f biomass, a l l species, were 143,447 and 147,303 m e t r i c tons i n 1975 and 1976, respectively. P a c i f i c hake and English sole were the most abundant species. Estimates of biomass and p o t e n t i a l y i e l d were determined f o r s i x species of f l a t f i s h . Data i n d i c a t e t h a t most f l a t f i s h species are n o t f u l l y exploited, b u t several species may be nearing f u l l u t i l i z a t i o n . Increased y i e l d could be obtained w i t h o u t increased f i s h i n g e f f o r t i f market demand would increase on c e r t a i n under-util ized species. Several population parameters were o b t a i ned. Age, length-wei ght constants, t o t a l annual and f i s h i n g m o r t a l i t y r a t e s and e x p l o i t a t i o n r a t e were estimated f o r s i x species of f l a t f i s h . D i s t r i b u t i o n and abundance was depicted f o r major species by catch mapsD i s t r i b u t i o n o f some species was c l o s e l y c o r r e l a t e d w i t h depth and sediment typeIncrease i n mean weight was associated w i t h increasing depth f o r many species, Strong year classes were i n d i c a t e d f o r several species. Data suggests t h a t t h e A s t o r i a Canyon may separate Dover s o l e and a l s o arrowtooth flounder stocks. IMTRODUCTION This r e p o r t summarizes study a c t i v i t i e s from J u l y 1, 1975 through September 30, 1977. The p r o j e c t was a comprehensive marine resource survey o f the continental shelf and upper continental slope o f f bilashington between Caps F l a t t e r y and t h e Columbia River. Objectives were: t o o b t a i n estimates o f biomass f o r demersal f i s h e s w i t h P a r t i c u l a r emphasis on f l a t f i s h ; t o determine estimates f o r the population parameters o f age composition, growth and m o r t a l i t y ; t o index year class strength of f l a t f i s h e s important t o the commercial t r a w l f i s h e r y p r i o r t o t h e i r recruitment t o the fishery; and t o estimate p o t e n t i a l y i e l d o f selected species. Emphasis was placed on f l a t f i s h due t o t h e i r h i s t o r i c a l importance t o the Oregon t r a w l f i s h e r y . The survey was a cooperative e f f o r t between the Ore on Department o f Fish and M i l d l i f e (ODFW), the Washington Department o f Fisheries qWDF), and U.S. National Narine Fisheries Service (NMFS, 1975). WDF supplied one man-month o f support per year plus commercial catch records and market sample data. Data c o l l e c t e d on P a c i f i c hake i n 1975 were supplied t o the iiHFS as p a r t o f t h e i r 1975 synoptic hake survey. ODFW i n i t i a t e d the survey o f f Mashington because o f the t r a d i t i o n a l importance o f the area t o the A s t o r i a t r a w l f l e e t . The survey o f f Washington was a n a t u r a l extension o f surveys conducted o f f Oregon (1971-74) since some f i s h stocks transcend the p o l i t i c a l boundary. The A s t o r i a Canyon and the Juan de Fuca Canyon appear t o be n a t u r a l b a r r i e r s a t l e a s t t o some stocks as w e l l as convenient geographical boundaries f o r t h i s type o f a stu&r Surveys based on a systematic sampling program were considered necessary t o p r o v i de unbiased estimates o f stock conditions. Commerci a1 gear r e s t r i c t i o n s , market conditions antd economic needs do n o t bias survey data. Marine resource surveys have been used as a management and research t o o l o f f the Washington coast sjnce 1951 '(Alverson 1951). The two surveys (1975, 1975) under t h i s study, however, were the f i r s t speci f i cal l y planned t o obtain re1iable biomass estimates. METHCIDS AND i4ATERIALS Survey Design The survey was conducted o f f the Washington coast (Figure 1) between Cape F l a t t e r y ( l a t . 48" 23'N) and the Columbia River ( l a t . 46" 16'N) i n 10 t o 300 fathoms (18-549 m). The survey p e r i o d was l a t e August t o l a t e September, u s u a l l y a good weather i n t e r v a l and p r i o r t o most f i s h spawning migrations. The study area was 2,733 N. m i 2 (9,374 krn2) i n area ( t r a w l a b l e area). Trawling l o c a t i o n s were systematically determined by use o f a 5x6 N. m i (9.3x11.1 km) g r i d w i t h a random s t a r t i n g point. Stations were l o c a t e d 5 miles apart along t r a c k l ines- l o c a t e d a t 6-mile i n t e r v a l s . There were 99 s t a t i o n s located i n 1975, o f which 74 were occupied. I n 1976 there were 97 s t a t i o n s l o c a t e d o f which 79 were occupied. Stations were l o c a t e d by l o r a n A, depth and s h i p ' s radar. Tow l e n g t h was one n a u t i c a l m i l e except f o r 21, 30-minute duration c a l i b r a t i o n tows made i n 1975 i n cooperation w i t h the NMFS. Catch rates o f these tows were subsequently adjusted t o one mile. A1 1 tows were made during day1 i g h t hours a t speeds o f 2 t o 3 knots. There were minor survey changes during the study concerning depth l i m i t s and number o f tows. I n 1976, depths surveyed were l i m i t e d t o 10 t o 260 fathoms (18-476 m) due t o vessel l i m i t a t i o n s . Also i n the i n t e r e s t o f time, we omitted the northern-most and southern-most t r a c k l ines i n 1976 (one s t a t i o n each). We attempted t o make expendable bathythermograph (XBT) casts on both cruises, b u t the equipment f a i l e d t o perform adequately a t sea. Vessel and Gear C h a r a c t e r i s t i c s Two vessels were chartered. The 67-foot (20 m.) western seiner-type t r a w l e r R/V Commando was chartered i n 1975, and t h e 7 5 - f t (23 m.) schooner-type t r a w l e r M/V TordenskjoZd was chartered i n 1976. R/V Cornando was powered by a 358 hp engine. Doors ( o t t e r boards) were "V" type, s t e e l , 5x7-ft (1.5x2.1 m. ) and weighed 1,050 pounds (476 kg) each. M/V TordenskjoZd's "V" type, s t e e l o t t e r boards were 5x7-ft and weighed about 1,350 pounds (612 kg) each. The vessel was powered by a 365 hp engine. The t r a w l used was a $00-mesh eastern type constructed e n t i r e l y of 3.5-in (89 mm) mesh, stretched measure. Footrope-headrope lengths were 77 and 6 0 - f t (23.5; 18.3 m) respectively. The t r a w l had a rubber disc, chain footrope, made up o f 4.5-in (114 mrn) diameter rubber discs. Thirteen, 8-in (203 mm) p l a s t i c f l o a t s were e q u a l l y spaced on the headrope. A 71-ft (21.6 m), 3/8-in (9.5 mm) t i c k l e r chain was attached t o each end of the footrope. Figure 1. Location o f t r a w l s t a t i o n s o f groundfish surveys o f f Washington, 1975-76. Heavy broken l i n e defines survey l i m i t s . Sediment types from Cross e t a1 (1967), Roberts (1974) and Vendatarathnam (1973). Short sweep 1ines [lo-fm b r i d l e s (18.3 m) , 5-fm dandy 1ines (9.1. m)] were used t o reduce herdf ng o f f i s h Snto the trawl. ODFlJ and i4P'iFS s c i e n t i s t - d i v e r s measured the h o r i z o n t a l and v e r t i c a l openings and appraised the workabi 1ity o f the trawl i n Puget Sound, Washington a t towing speed i n 8-12 fm (14.6-21.9 m) o f water. Horizontal and v e r t i c a l openings were about 3 0 - f t and 5 - f t (9.1; 1.5 m), respectively, Average swept area (length of tow x h o r i z o n t a l opening) was estimated t o be 0.00494 N. m i 2 (1.694 ha). Catch Processing Catches were dumped i n t o a 6 - f t 2 by 1-ft deep s o r t i n g table. Catch was sorted by species, and weight determined f o r each species by using a 60-lb (27 kg) capacity s p r i n g scale. An average weight and estimated t o t a l weight was obtained f o r a l l f i s h species. Catch of Dungeness crab (cancer magister) was recorded by number. Occurrence of o t h e r invertebrates was noted. Ten f l a t f i s h species i n 1975 and s i x i n 1976 were sampled f o r age, l e n g t h and sex composition. Length was measured from the snout t o the center o f the t a i l and recorded to. the nearest cm. Sampling r a t e o r the p r o p o r t i o n o f the catch sampled ranged from 5% t o 100% b u t was most o f t e n 20% t o 50%. Length by sex was recorded on p l a s t i c measuring s t r i p s and transcribed t o a permanent record. Heads were removed t o o b t a i n o t o l iths o r i n t e r o p e r c l e s f o r aging. Dover sole ( ~ c r o s t o m u spacificus) heads were n o t removed, b u t r a t h e r a f i l l e t w i t h s k i n attached was taken from the eyed s i d e f o r scales. Heads and f i l l e t s by sex and tow were placed i n p l a s t i c bags, 1abeled and frozen f o r processing ashore. Once ashore, aging s t r u c t u r e s were prepared f o r aging and stored by sex and tow. Scales were mounted between glass s l i d e s ; i n t e r o p e r c l e s were s t o r e d dry i n coin envelopes; and o t o l i ths were s t o r e d i n a 50% glycerine-water s o l u t i o n w i t h a few thymol c r y s t a l s added t o r e t a r d mold formation. Age s t r u c t u r e s were examined and assigned an age i n years using accepted techniques. Estimates o f Bionass, Usable Biomass and P o t e n t i a l Y i e l d 'The continental she1 f area was s t r a t i f i e d i n t o 10-fm (18 m) s t r a t a between 10 and 99-frn (18-182 m). Slope s t r a t a were 100-199 fm (183-364 m) and 200-299 fm (365-547 m). The area o f each stratum was c a l c u l a t e d from measurilrnents made w i t h a compensating p o l a r p l a n i m t e r on CGS n a u t i c a l charts 18450 and 18500. Estimates o f biomass and usable biomass were determined by the method described by -0emory, e t a1 , (1976). Estimates o f usable biomass were determined f o r c u r r e n t l y and p o t e n t i a l l y important f l a t f i s h spscies: t h a t i s , Dover sole (~Ecrostomuspacificus), English sole ( ~ a r o p h r y sv e t u l u s ) , p e t r a l e s o l e ( ~ o p s e t t aj o r d a n i ) , r c x scjle (~Zyptocephaluszachirus ) , Paci f ic sanddab ( ~ i t h a r i c h t h g ssordidus ) and arrowtoo t h f.lounder ( ~ t h e r e s t h e sstomias ) Length-wci gh t cons tan t s are g i ven i n Appcndi x 2. . P o t e n t i a l y i e l d , under e q u i l i b r i u m conditions, was dctermincd by mu1t i p l y i n g usable biomass by estimates o f the instantaneous f i s h i n g r a t e (F). Year Class Strength R e l a t i v e year class strength, expressed i n percent frequency, was d c t e r m i w d f o r selected species, f o r each annual cruise. Age composition was compared by survey year, and outstanding brood years were noted. Instantaneous Total i l o r t a l ity Rate Estimates o f t o t a l instantaneous mortal ity r a t e (Z) were determined from catch curves using the method of Robson and Chapman (1961). To construct t h e catch curves, age samples were weighted t o t h e i r respective catches by using the sampling rate. E x p l o i t a t i o n Rate and Fishing Rate E x p l o i t a t i o n r a t e ( l ~ )was determined by d i v i d i n g the commercial landings by usable biomass. The instantaneous f i s h i n g r a t e (F) was determined by the formula, where l~ i s the e x p l o i t a t i o n r a t e , Z i s the instantaneous t o t a l m o r t a l i t y r a t e o f females and d i s the annual t o t a l m o r t a l i t y r a t e of females. Females were used because they dominate the f i s h e r y i n terms o f weight. Using females, which are normally longer l i v e d than males, produces lower estimates of Z than estimates using males, hence the estimated f i s h i n g r a t e would be l e s s conducive t o over-exploi t a t i o n . HESLILTS AND DISCUSSION Estimates o f Biomass The t o t a l biomass estimate (a1 1 species) f o r the survey i n 1976 was 147,303 m.t., an increase o f 3% over the 1975 estimate of 143,447 m. t. (Table 1). P a c i f i c hake was the most abundant species i n 1976 comprising 24% o f the biomass, a three f o l d increase over 1975 when hake ranked s i x t h i n biomass. The f l a t f i s h complex comprised about 50% o f the estimated biomass. There were 70,617 m.t. of f l a t f i s h i n 1976, down 17% from the 1975 estimate o f 84,656 m.t. All major f l a t f i s h species showed a decrease i n estimated biomass ranging from -12% f o r English s o l e t o -51% f o r b u t t e r sole. Dover s o l e biomass was down by 23%. I n 1976, the r o c k f i s h group (scorpaenidae) showed a 46% decrease t o 6,442 m. t. compared t o the 1975 estimate o f 11,911 n. t. The commonly occurring species, ye1 lowt a i 1 r o c k f i s h ( ~ e b a s t e sfZavidus ), canary r o c k f i s h (sebastes pinniger) and spl it-nose r o c k f i s h (sebastes dipzoproa) were down more than 50%. Biomass estimates o f semi p e l a g i c species such as r o c k f i s h are under-estimated because the trawl was n o t e f f i c i e n t a t catching off-bottom species; the survey t r a w l was designed f o r f l a t f i s h . A1 verson and Pereyra (1969) discussed t h i s subject. - Since the 95% confidence l i m i t s overlap, most changes i n biomass estimates between survey years were o f a magnitude t h a t l i e w i t h i n expected v a r i a t i o n . Therefore, while our biomass estimates i n d i c a t e changes between surveys, vie can n o t r e a d i l y demonstrate t h a t a s t a t i s t i c a l l y s i g n i f i c a n t change a c t u a l l y occurred. Changes i n biomass might be expected f o r species whose d i s t r i b u t i o n extends i n t o areas outside the survey 1ini ts. Food avai 7 a b i l it y , currents o r o t h e r environmental changes between years might i n f l u e n c e f i s h a v a i l a b i l i t y ; thus our estimates o f biomass. By n o t occupying s t a t i o n s j u s t n o r t h o f the Columbia River, a high production area, we may have underestimated the biomass o f species such as English sole, Dover s o l e and Paci f ic sanddab. Table 1. Estimates o f biornass (m. t. ) o f p r i n c i p l e species between Cape F l a t t e r y and t h e Columbia River, 1975-76l/. Confidence 1i m i ts, 95%, are expressed as +%. Biomass m.t. % change 1975 +% 1976 +% from 1975-76 - Species2/ S i n y dogfish rates Ratfish American shad Paci f ic cod P a c i f i c hake bJal leye pol lock Rockfish Shortspi ne thorneyhead Paci f i c ocean perch Ye1 l o w t a i 1 r o c k f i s h Canary r o c k f i s h Spl itnose r o c k f i s h Greenstripe r o c k f i s h Darkbl otcked r o c k f i s h Redbanded r o c k f i s h Yelloweye r o c k f i s h Rosethorn rockfish Boccaci o Rougheye r o c k f i s h Black rockfish Sharpchin rockfish S t r i p e t a i1 rockfish Redstri pe rockfish S i 1vergray r o c k f i s h Uui 11back rockfish Aurora r o c k f i s h Widow r o c k f i s h Sabl e f i sh Lingcod Flatfish English sole Arrowtooth flounder Dover s o l e Hex s o l e Paci f i c sanddab Butter sole Slender s o l e Petrale sole S t a r r y flounder Flathead s o l e Sand s o l e Paci f i c ha1ib u t Rock s o l e Curl f i n s o l e Total Flatfish Rockfish 1/ -2/ - - - 62 7,791 12,991 1,780 709 1,977 11,400 44 55 504 112 2,724 2,616 1,976 1,309 553 549 374 2 79 107 93 G6 50 48 19 16 12 10 4 2 5,515 4,717 68 - 18,443 15,070 14,501 13,511 8,442 8,02 1 2,345 1,650 1,011 1,018 4 35 84 78 47 143,447 84,656 11,911 - 44 81 79 .. 127 91 186 51 54 87 104 43 140 75 142 114 166 200 166 290 200 200 54 37 60 42 31 31 69 105 47 33 144 108 85 147 78 146 11,225 13,343 1,534 5 34 1,491 35,662 29 329 2,421 611 825 798 503 181 79 169 108 31 36 75 183 5 19 18 - 1 3,982 2,498 16,141 10,558 11,218 13,938 8,276 3,962 2,09 1 1,043 1,359 1,067 930 - 8 26 147,303 70,617 6,442 Survey l i m i t : 48" 23' 14 Lat. 46" 16' iJ Lat., 10-300 fm. Common and s c i e n t i f i c names are shown i n Appendix 1. Estimates of Usable Biomass Estimates of usable biomass f o r s i x common species of f l a t f i s h ranged from 14,452 m.t. i n 1975 f o r arrowtooth flounder t o 655 m.t. f o r p e t r a l e s o l e i n 1976 (Table 2). Estimates were l e s s i n 1976 f o r Dover s o l e (255), English s o l e (4%), p e t r a l e sole (49%) and arrowtooth flounder (30%) w h i l e estimates were greater f o r r e x sole and P a c i f i c sanddab (4 and 20% r e s p e c t i v e l y ) . Table 2. Species Estimated usable biomass, p o t e n t i a l y i e l d and commercial landings (m. t. ) o f p r i n c i p a l species o f f l a t f i s h f o r t h e Ljashington coast, 1975-76. Poten ti a1 Comerci a1 Usable biomass, m. t. F yield,m.t. landing,m.t. 1975 1976 1975 1976 1975 1976 1975 1976 Dover s o l e 8,630 6,495 .08 .16 690 1,039 579 English s o l e 6,940 6,645 .13 .27 902 1,794 695 Petrale sole 1,279 .75 1.15 959 753 854 569 Rex s o l e 5,918 6,178 .07 .08 414 494 316 384 Paci f i c sanddab;/ 2,623 3,151 .O1 .02 26 63 22 38 Arrowtooth flounder1/ 14,452 10,126 .002 .O1 29 101 32 83 - -1/ 655 865 1,353 Species normally discarded a t sea o r avoided Total I n s tan taneous Mortal ity Rate Estimates of instantaneous t o t a l mortal it y r a t e (Z) varied widely between species and sex w i t h i n species (Table 3). For exac~ple, Z f o r p e t r a l e s o l e was estimated a t 0.24 i n 1975 and 0.44 i n 1976. Small catches o f p e t r a l e sole precluded confidence i n our estimates of Z f o r t h a t species. ivlortality r a t e estimates f o r arrowtooth flounder were complicated by the great d i f f i c u l t y i n aging the samples. E x p l o i t a t i o n Rate and Fishing Rate E x p l o i t a t i o n r a t e (p) ranged from 0 f o r arrowtooth flounder t o 0.87 f o r p e t r a l e sole (Table 3). E x p l o i t a t i o n rates f o r major commercial species o f f l a t f i s h i n 1976 were: Dover sole, 0.13; English sole, 0.20; p e t r a l e sole, 0.87; and r e x sole, 0.06. The e x p l o i t a t i o n rates i n 1976 were higher than those o f 1975 and generally r e f l e c t e d the improved markets i n 1976. Estimates o f e x p l o i t a t i o n r a t e might be underestimated when market 1im i t s have the e f f e c t o f surpressing expl o i t a t i o n . Discard o f 1argely unsalable f i s h such as arrowtooth flounder a l s o has the effect o f surpressing t h e expl o i t a t i o n rate. We f e e l t h a t an e x p l o i t a t i o n r a t e over .10 probably i n d i cates t a r g e t species w i t h market demand. The instantaneous f i s h i n g m o r t a l i t y r a t e F, ranged from near 0 f o r arrowtooth flounder t o 1.15 f o r p e t r a l e s o l e (Table 2). I n 1976, F was 0.16 f o r Dover sole, 0.27 f o r English sole, 1.15 f o r p e t r a l e s o l e and 0.08 f o r r e x sole. The higher F i n 1976 when compared t o 1975 r e f l e c t e d improved markets. I t appears t h a t the f i s h i n g r a t e could be increased on most species w i t h the possible exception o f p e t r a l e sole. Since the c a l c u l a t e d F f o r p e t r a l e s o l e exceeds Z, i t i s possible t h a t p e t r a l e sole may require protection; however, i f the biomass o f p e t r a l e s o l e were underestimated then F i s overestimated. Since catches of p e t r a l e sole were small during the two surveys, the estimates were most 1ik e l y underestimated because o f f i s h u n a v a i l a b i l ity. Table 3. S ~ e ces i Estimates o f e x p l o i t a t i o n r a t e (p), annual m o r t a l i t y r a t e (i) and instantaneous mortal it y r a t e ( Z ) o f p r i n c i p a l species o f f l a t f i s h f o r the Washington coast i n 1975 and 1976. IqaPtal it y r a t e s ,Femal es . bla1e s z L/ Year u a a z 2.l Dover sole 1975 1976 .067 -133 .39 .44 .50(6-15) -58 (6-17) .30 .31 .35(5-17) .37 (6-23) English sole 1975 1976 .I00 .204 .35 .32 .43 (3-12) .38 (3-15) .39 .45 .49 (3-13) .60 (4-13) 1975 1976 .668 .%9 .48 .5l .65 (6-11) .71(6-10) .24 .44 .27 (5-17) .58(6-12) P a c i f i c sanddab 1975 1976 .008 .012 .57 .56 .84(6-10) .82 (7-10) .55 .53 .79(7-11) .77 (7-11) Arrowtooth flounder 1975 1976 .002 .008 .30 .34 .35 (6-17) .42 (9-17) .34 .15 .42 (7-17) .16 (4-23) Petrale sole Rex sole -1/ Age range i n parenthesis P e t r a l e sole are u s u a l l y caught i n a mu1t i - s p e c i e s t r a w l fishery. The summer fishery i s often on grounds occupied by more abundant species such as English sole, rex sole, 1 ingcod and others. An overharvest o f p e t r a l e sole may be unavoidable, i n order t o optimize y i e l d from more abundant species (Pedersen, 1975). F i s h i n g r e s t r i c t i o n s might be more j u s t i f i a b l e d u r i n g the spawning p e r i o d when p e t r a l e are o f t e n concentrated i n known areas and are mainly i s o l a t e d from o t h e r species. Pedersen (1975) a l s o concluded t h a t a spawning ground f i s h e r y has a profound effect on the summer inshore f i s h e r y . F i s h i n g may be overemphasized as an adverse f a c t o r t o p e t r a l e s o l e stock size. Ketchen and Forres t e r (1966) and Pedersen (1975) concl uded t h a t envi ronmental effects on l a r v a l - j u v e n i l e s u r v i v a l were more important than f i s h i n g i n reducing stock size. Potential Yield Estimates o f p o t e n t i a l annual y i e l d ranged from 26 m.t. f o r P a c i f i c sanddabs t o 1,794 m. t. f o r English s o l e (Table 2). I n 1976, p o t e n t i a l y i e l d 'was c a l c u l a t e d . a t 1,039 m. t. f o r Dover sole; 1,794 m. t. f o r English sole;- 753m.t. f o r petr?ale:e:e:.$qj$. and 494 m. t. f o r rex s o l e Our e s t i m ~ t e sof y i e l d are 1i m i t e d by , ~ p e ~ , a l : ~ . ~ + ~. d ~ : .. , . - . , :... .., , .. . . . . , . 3.. .,? ... >"%*.,~.!,~.."&?,. . . Y i e l d i s o n l y i n d i c a t e d f o r f i s h occupying the survey area, over trawlable bottom i n September t h a t were avai 1able t o our survey trawl. Furthermore, p o t e n t i a l y i e l d f o r under-uti 1ized species i s probably underestimated, because we have n o t been able t o q u a l i f y the e f f e c t s o f market 1i m i t s , gear and discard m o r t a l i t y on p and F. Distribution Catch maps (Figures 2-14) show d i s t r i b u t i o n o f most major species. U i s t r i b u t i o n by depth and abundance by area was often h i g h l y v a r i a b l e w i t h i n survey periods and somewhat v a r i a b l e between survey years. The same areas o f h i g h abundance occurred f o r many species during both surveys. i ~ l o s ts t a t i o n s between N i l l a p a Bay and t h e Columbia River were n o t occupied i n 1975; therefore, w h i l e Figures 2-14 i n d i c a t e low abundance i n 1975 f o r t h a t area, abundance was n o t a c t u a l l y determined. F l a t f i s h were most abundant i n an area west t o southwest o f Destruction I s l a n d i n 20-50 fm (37-91 in). Here the l a r g e s t catches f o r a 1 14' m i tow were 1,454 1b (660 kg) of English sole, 1,230 l b (558 kg) of P a c i f i c sanddab, 1,000 1b (454 kg) o f b u t t e r sole, 465 l b (211 kg) o f r e x s o l e and 314 1b (142 kg) o f Dover sole. A second area t h a t produced l a r g e catches was the f l a t j u s t south o f Grays Canyon i n 100-300 fm. Here, highest catches were 694 (315 kg) of r o c k f i s h , 314 l b (142 kg) of s a b l e f i s h and 195 l b (88 kg) of Dover sole. Tows were generally good j u s t n o r t h o f the A s t o r i a Canyon, and they produced up t o 377 1b (171 kg) o f r e x s o l e and 244 1b (111 kg) o f Dover sole. The l a r g e s t s i n g l e catch o f Dover sole, 526 l b (239 kg), was made i n deep water off Cape F l a t t e r y . While catches were generally b e s t i n t h e above areas, several species were associated w i t h c e r t a i n depths o r bottom types (Figure 15). Figure 1 grossly shows sediment type d i s t r i b u t i o n l / . B u t t e r sole were caught p r i m a r i l y shallower than 30 f m (55 m) over sand. ~ n g l i s h - s o l e and P a c i f i c sanddab were generally taken i n s i d e of 60 fm (110 m) over sand. Arrowtooth flounder and s a b l e f i s h were u s u a l l y found outside of 50 f m ( 9 1 m) over s i l t bottom. Dover sole, rex s o l e and l i n g c o d were caught throughout most survey depths, b u t Dover s o l e tended t o show a preference f o r s i l t bottom. Flathead sole were caught p r i m a r i l y over s i l t . Bottom type preference was n o t apparent f o r r e x sole and p e t r a l e sole, a1 though p e t r a l e s o l e were n o t caught i n shallow water over sand. Sediment was almost e n t i r e l y sand i n s i d e o f 50 fm, although gravel areas were found o f f Cape Elizabeth and Grays Harbor. Sediments outside o f 50 fm were mostly coarse s i l t . Many species showed an increase i n m a n weight w i t h 'increasing depth. This was e s p e c i a l l y apparent f o r English sole, p e t r a l e s o l e and sablefish and t o a l e s s e r degree, f o r Dover sole, r e x sole, b u t t e r s o l e and s t a r r y flounder. Slender s o l e were r a t h e r uniform i n mean weight regardless of depth s t r a t a (Table 4). A bimodal depth d i s t r i b u t i o n was observed f o r Dover sole (Figure 15). Females dominated the catch i n s i d e o f 70 fm (128 m) w h i l e males were more p l e n t i f u l i n deeper water. The mean weight was generally greater f o r deep water Dover sole. The 1976 data showed t h a t mean length f o r Dover sole females generally increased w i t h depth o u t t o 70 f m where i t then l e v e l e d off (Table 5). With minor exceptions, mean length -1/ This f i g u r e was prepared by surnmarizing several marine sediment studies (Roberts 1974, Vandatarathnam and HcManus 1973 and Gross e t a1 , 1967). 0 Troc. 0 @ 440 lbs l(orr (23 ks) 50-100 1bs1101 (23-46 b) w r r l t o w (45-81 kg) zoo lbsltor* (861 kg) Figure 2. D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f Dover s o l e i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken f i n e defines survey 1 i m i ts. so-roo Ibsltou (23-45 kg) 100-200 lbsltow (*5-91 Figure 3. ks) D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f English sole i n September 1975 and 1976 off Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s . Figure 4. Distribution and relative abundance {weight) of petrale sole i n September 1975 and 1976 o f f rrlashington as determined by groundfish surveys. The heavy broken l i n e defines survey 'lirni t s . Figure 5. D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f rex s o l e i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s , 60.~0Ibs/to* (23-45 kg) 100-200 l b r l t w (46-81 Figure 6. kg) D i s t r f b u t i o n and r e l a t i v e abundance (weight) s f P a c i f i c sanddabs i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s . F i g u r e 7. Distribution and re1 a t 1 ve abundance (weight) of arrowtooth flounder in September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken line defines survey limits. Figure 8. D i s t r i b u t i o n and r e l a t i v e abundance (weight) o f r o c k f i s h i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken I ine defines survey 1 i m i ts, Figure 9. Distribution and relative abundance (weight) of lingcod i n September 1975 and 1976 off Washington as determined by groundfish surveys. The heavy broken 1ine defines survey 7 i m i t s . 100-ZOO Ihr/tow (4.9-91 kg) *ZOO Ibr / tew +91 Figure 10, kg) Distribution and r e l a t i v e abundance (weight) of sablefish i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey limits, 50-100 ibs / l o w (23-45 kg; @ 100-200 Ibr/tov 145-93 kg) -t F i g u r e 11. D i s t r i b u t i c n and r e l a t i v e abundance ( w e i g h t } o f s p i n y d o g f i s h i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy brsken l i n e defines survey limits. Figure 12. Distribution and re1 a t i ve abundance (weight) of skates (a11 species) in September 1975 and I976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey 1 imi ts. Figure 13. D i s t r i b u t i o n and re1 a t i v e abundance (weight) o f r a t f i s h i n September 1975 and 1936 o f f Washington as determined by groundfish surveys, The heavy broken l i n e defines survey l i m i t s , Figure 14. D i s t r i b u t i o n and r e l a t i v e abundance (weight) of P a c i f i c hake i n September 1975 and 1976 o f f Washington as determined by groundfish surveys. The heavy broken l i n e defines survey l i m i t s . Dover sole, 1975 I 1 Dover sole, 1976 English sole, 1976 Petrale sole, 1975 -I Petrale sole, 1976 r- Rex sole, 1975 . - Rex sole, 1976 - - 7 7 I 1 0 r( I 0 ' + 0 m 0 u l l 0 - DEPTH (fm) Figure 15. 0 1 cno 1 0 0 d . 1 0 m I 0 m . 1 cn ' rn 07 P In 0 l- I 0 I 0 0 d C\1 0 \ 0 0 cncnm I d N O I I 0 7 0 0 0 0 ; ; I rU DEPTH (fin) Distribution of selected species by depth as determined from groundfish surveys off Washington, 1975-76, T = 4 0 m.t. P a c i f i c sanddab, 1976 4 1 Arrowtooth Lingcod, 1976 Lingcod, 1975 P a c i f i c hake ake, 1975 l e f i sh, 1975 I DEPTH ( f m ) Fi gure 15. Contl nued. 4 hl f o r males increased w i t h depth. Mean age generally increased w i t h depth f o r Dover sole b u t dropped s l i g h t l y f o r females outside o f 90 f m (165 rn) and dropped sharply f o r males caught outside of 100 fm (183 m) (Table 5). Table 4. Mean weight (kg) of selected species by depth s t r a t a as determined from groundfish survey o f f Washington, 1975-76. Depth S t r a t a 10- 20- 30- 40- 50- 60- 70- 80- 90- 100- 20019 29 39 49 59 69 79 89 99 199 299 Species Dover s o l e English s o l e Petrale s o l e Rex sole c sanddab Paci fi Arrowtooth flounder Slender s o l e Butter sole F l a thead s o l e Sablefish Lingcod P a c i f i c hake S t a r r y flounder Table 5. Depth s t r a t a -1/ Elean l e n g t h (cm) and mean age ( y r ) by depth s t r a t a (fm) f o r Dover s o l e from groundfish survey o f f Washington, 197Q1/. - Mean l e n g t h Ma1e Female Mean age I>lale Female Weighted t o sampling r a t e Year Class Strength Age composition was analyzed f o r s i x f l a t f i s h species by comparing age frequencies and by f o l lowing brood years (Figure 16). The 1970 year class was s t r o n g f o r Dover sole, r e x sole, p e t r a l e sole, English sole and P a c i f i c sanddabs o f f Washington. The 1972 English s o l e brood year dominated the survey catch i n 1975 and remained r e l a t i v e l y s t r o n g i n 1976. The 1972 year class 30 1 I 70 Dover sole 197 1 English sole 1971 n = 2,019 Dover sole 1973 English sole 1973 Dover sole 1975 n = 672 English sole Dover sole 1976 n = 1,553 English sole 1976 n = 1,428 20 - 10 0 30 .. 70 AGE (yr) Figure 16. AGE (yr) Re1 ative year class strength, as indicated by percent frequency from groundfish surveys off northern Oregon (1971, 1973) and Wa.shington (1975-76). 66 r 30 Petraie sole 1971 Rex sole n = 875 n 1971 = 2,822 20 10 I 0 Petrale sole 66 1973 n = 750 iI jI Petrale sole 30 r, Rex sole 1973 n = 1,612 Rex sole 1975 1975 n = 130 n = 1,100 Petrale sole Rex sole 1976 1976 AGE {yr) Figure 16. Continued, 30 40 1 Paci f i c sanddab 1971 n = 1,549 65 Paci f ic sanddab 30 1 Arrowtooth flounder 1971 Arrowtooth flounder 1973 20 10 0 30 P a c i f i c sanddab 69. Arrowtooth flounder 1975 19 75 n = 824 20 Paci fi c sanddab Arrowtooth flounder 1976 n = 799 5 10 15 AGE (yr) Figure 16. Continued. 20 AGE (yr] showed promise f o r p e t r a l e sole, arrowtooth f l o u n d e r and E n g l i s h sole. Apparent stock d i f f e r e n c e s were found by comparing age frequencies from Oregon t o those o f f Washington. The Dover s o l e p o p u l a t i o n appeared t o be much younger o f f Washington than t h e p o p u l a t i o n south o f t h e A s t o r i a Canyon. 'This conclusion i s supported b y a Dover s o l e t a g g i n g study (Hestrheim and Ezlorgan 1963) and suggests t h a t t h e A s t o r i a Canyon i s a n a t u r a l b a r r i e r t o Dover sole. The same might apply t o arrowt o o t h f l o u n d e r i n t h a t the stocks n o r t h o f t h e A s t o r i a Canyon are o l d e r than stocks t o t h e south. Figure frequencies t o show the what may be 17 shows how age frequencies of o u r survey samples r e l a t e t o the age expected i n t h e usable biomass. I t i s apparent t h a t survey data helped c o n t r i b u t i o n o f young f i s h t o t h e population. Such data should help show a v a i l a b l e t o t h e commercial catch a t a l a t e r date. Survey Eval u a t i o n The ldashington surveys enabled us t o meet our proposed o b j e c t i v e s . Ide obtained, under p a r t i a l l y c o n t r o l l e d conditions, reasonably unbiased i n d i c a t i o n s o f the s t a t u s o f i m p o r t a n t f l a t f i s h species. bJe were able t o o b t a i n a new i n s i g h t on f i s h d i s t r i b u t i o n and r e l a t i v e abundance. bJe f e e l t h a t o u r 3.5-inch mesh t r a w l n e t captured s u f f i c i e n t numbers o f younger f i s h t o enable us t o monitor year c l a s s s t r e n g t h p r i o r t o commercial exploitation. The surveys d i d n o t enable us t o determine e x a c t biomass n o r could we d e t e c t small annual changes i n biomass. Biomass over untrawlable grounds was n o t estimated. Also a p i c t u r e o f seasonal d i s t r i b u t i o n was n o t obtained. We should note t h a t reference t o t o t a l biomass o f f the Washington coast includes biomass beyond t h e d e ~ t hl i m i t a t i o n s o f o u r survey. Several species such as Dover s o l e and s t a r r y flounder have d i s t r i b u t i o n s which commonly extend i n t o depths o u t s i d e of o u r study area. Such species t h e r e f o r e have biomass o f f Washington n o t detected by o u r survey. Movement o f such species i n t o o r o u t o f o u r survey area might affect biomass c a l c u l a t e d f o r t h e survey area. The resource survey complerllen t s t r a d i t i o n a l s t u d i e s o f the commerci a1 f i s h e r y , i.e. , f i s h e r y catch and CPUE. The survey i s p r e s e n t l y one o f o u r b e s t t o o l s f o r research and management. Biolnass estimates from surveys are val uable as i n d i cators o f p o p u l a t i o n trends and estimates o f s t o c k s i z e w i t h i n r e l a t i v e l y wide confidence l i m i t s . Costs Costs of t h e program by f i s c a l y e a r (FY) are shown below: Budget Category Persona7 Services Contractual Services Equipment & Supplies Overhead .-.s c e l 1aneous 1'111 Total $ 58,919 27,641 6,689 14,045 4,905 $112,119 - -1/ FY 1976 - 15 month c o n t r a c t FY 1 9 7 7 y $108,261 54 $610 9,266 24,000 7,973 $204,110 Dover 14 - r?"? I 12 - 5 P a c i f i c sanddab Rex 10 15 5 10 15 AGE (yr) Figure 17. T o t a l number by age o f s e l e c t e d species compared t o t h e commercially u t i litable p o r t i o n (dark p a r t o f t h e b a r graphs) o f f Washington (1976). SUMMARY A comprehensive marine resource survey baras conducted on t h e c o n t i n e n t a l s h e l f and upper c o n t i n e n t a l slope o f f 'blashington i n 1975 and 1976. Objectives were: t o estimate biomass o f demersal f i s h e s by an on bottom t r a w l , w i t h emphasis on f l a t f i s h ; t o estimate popul a t i o n parameters of age composition, growth and mortal ity; and t o index year c l a s s s t r e n g t h of commercial l y ir:lyortant f l a t f i s h . The survey was a systematic design based on a 5x6 iJ m i g r i d w i t h a random s t a r t i n g p o i n t . Catches of fla t f i s h were sampled s y s t e m a t i c a l l y . Estimates o f usable biomass were determined by a p p l y i n g age-specific u t i l i z a t i o n r a t e : and age-specific mean weights t o estimated biomass. Estimates of y i e l d were deteriilined by i i i u l t i p l y i n g usable biomass by t h e estimated instantaneous f i s h i n g mortal ity r a t e , F. Total biomass ( a l l species) was estimated a t 143,447 m.t. i n 1975 and 147,303 m.t. i n 1976. F l a t f i s h cor~iprisedabout 50% o f t h e t o t a l biomass. English s o l e was the major species i n 1975 w h i l e P a c i f i c hake was t h e most p l e n t i f u l species i n 1976. Usable biomass f o r p r i n c i p a l species o f f l a t f i s h ranged from 14,452 m. t. f o r arrowtooth flounder t o 655 m.t. f o r p e t r a l e sole. Estimates o f p o t e n t i a l y i e l d ranged from 1,794 m. t. f o r E n g l i s h s o l e t o 26 m.t. f o r P a c i f i c sanddab. Species o f f e r i n g the g r e a t e s t p o t e n t i a1 f o r increased harvest were arrowtooth f l o u n d e r and P a c i f i c sanddab. Improved market demand i s r e q u i r e d f o r increased u t i 1iz a t i o n o f these species. Species d i s t r i b u t i o n i n d i c a t e d preferences f o r depth and/or sediment type. E n g l i s h sole, P a c i f i c sanddab and b u t t e r s o l e occurred mostly i n shallow water over sand sediments. Arrowtooth f l o u n d e r and s a b l e f i s h were u s u a l l y found i n deeper water over s i l t bottom. Dover s o l e and f l a t h e a d s o l e were most abundant over s i l t bottom. tiany species showed an increase i n mean w e i g h t w i t h i n c r e a s i n g depth. A bimodal depth d i s t r i b u t i o n occurred f o r Dover sole. A g r e a t e r p r o p o r t i o n of females were found i n stla1 low water, w h i l e more males were found i n deep water. Strong y e a r classes were i n d i c a t e d f o r many species. and 1972 were s t r o n g f o r several species. The y e a r classes o f 1970 Our data suggests t h a t the Dover s o l e and arrowtooth f l o u n d e r stocks found n o r t h o f t h e A s t o r i a Canyon are separate stocks frotn l i k e species found south o f t h e canyon. For s i x s p e c i e s A o f f l a t f i s h age, length-wei g h t constants, t o t a l annual and f i s h i n g m o r t a l i t y r a t e s (Z, a, F), and e x p l o i t a t i o n r a t e were estimated. Recommendations 1. Survey refinement i s d e s i r a b l e t o i n c l u d e assessment by season, untrawlable bottom, mid-water and depths p r e s e n t l y n o t surveyed. This would g i v e a more complete p i c t u r e o f t h e d i s t r i b u t i o n , abundance, composition and h e a l t h o f t h e marine f i s h community . 2. l.Je recommend t h a t a survey o f t h e type described i n t h i s r e p o r t be repeated b i e n n i a l l y w i t h a reduced sampl i n g i n t e n s i ty. lie g i v e s p e c i a l thanks t o t h e captains and crews o f the H/V Cornando and W/V We g r a t e f u l l y acknowledge t h e assistance of personnel from Oregon Department o f F i s h and W i l d l i f e , ldashington Department o f Fisheries, and Oregon S t a t e U n i v e r s i t y , f o r t h e i r p a r t i c i p a t i o n a t sea. Val uable assistance was provided by Louis Fredd w i t h s t a t i s t i c s and by o u r C l ackamas c l e r i c a l s t a f f i n p r e p a r i n g t h e d i s t r i b u t i o n and abundance maps. Funding was granted through P.L. 88-309, t h e C o t m r c i a l F i s h e r i e s Research and Development Act o f 1964, under annual c o n t r a c t s : 1975, 14 04-6-206-41&y~ and 1976, f j 04-6-208-40037. Tordenskjold f o r p r o v i d i n g o u t s t a n d i ny support. LITERATURE CITED Alverson, D.L. 1951. Deepwater t r a w l i n g survey o f f the coast of 'lashington. Fish. Review. Vol. 13, NO. 11, pp 1-16. Comm. A1 verson , D. L. and Gd.T. Pereyra. 1969. Demersal f i s h e x p l o r a t i o n s i n t h e northeastern an e v a l u a t i o n o f e x p l o r a t o r y f i s h i n g methods and a n a l y t i c a l P a c i f i c ocean approaches t o stock s i z e and y i e l d forecasts. J. Fish. Res. Bd. Canada. 26(8): 1985-2001. - Demory, R. L. 1971. Depth d i s t r i b u t i o n o f some small f l a t f i s h e s o f f n o r t h e r n Oregonsouthern ldashington coast. F i s h Con~m. Oreg. Res. Rept. 3:44-48. Demory, R.L., iv1.J. Hosie, Id. Ten Eyck and B.O. Forsberg. 1976. Resource survey on t h e Oregon coast. Comm. Fish. Res. and Dev. Acts Completion Report. Oregon Dept. o f F i s h and k j i l d l i f e . Proc. Rept., 49p. Gross, H.G. , D.A. F~lcE.lanusand H. Ling. 1967. Continental shel f sediment, Ijorthwestern U n i t e d States. Jour. Sedimentary Petrology. Vol. 37, No. 3, pp. 790-795. and C.R. Forrester. 1966. Population dynamics of t h e p e t r a l e sole, Eopsetta jordani, i n waters o f f western Canada. Fish. Res. Bd. Canada. Ketchen, K.S. B u l l . 153. Pedersen , iY1.G. Columbia. 195p. 1975. Recent i n v e s t i g a t i o n o f p e t r a l e s o l e o f f :Jashington and B r i t i s h Wash. Dept. o f Fisheries. Tech. Rept. No. 17, 71p. Pruter, A.T. and G.Y. Harry, Jr. 1952. Results o f p r e l i m i n a r y shrimp e x p l o r a t i o n s o f f the Oregon coast. Fish. Comrn. Ore., Res. Briefs. Roberts, R.H. 1974. Sedimentological d a t a o f t h e Washington c o n t i n e n t a l shel f. Univ. o f lilashington, Dept. o f Oceanography, Special Report 140. 57, Reference M 74-75, 129p. Robson, D.S. and D.G. Chapman. 1961. Fish. Soc. 90(2): 181-189. Catch curves and m o r t a l i t y rates. Trans. Amer. Vendatarathnam, G.K. and D.A. MclYanus. 1973. O r i g i n and D i s t r i b u t i o n of sands and gravels on t h e n o r t h e r n c o n t i n e n t a l shel f o f f 1Jashington. Jour. Sedimentary 3, pp. 799-811. Petrology. Vol. 43, 1310. Mestrheim, S. J. and A. K. Morgan. 1963. Dover sole, Microstomus pacificus. Results from t a g g i n g a spawning s t o c k o f Pac. Nar. F i s h e r i e s Comm. B u l l . 6, pp. 14-21. Appendix 1. Cormnon and s c i e n t i f i c narnes of species on groundfish surveys o f f Washington, 1975 and 1976. Co~nnion iJarne Spiny dogfish Skates R a t f i sh American shad P a c i f i c cod P a c i f i c hake Wal leye p o l lock Shortspine thornyhead Rougheye r o c k f i s h P a c i f i c ocean perch Aurora r o c k f i s h Redbanded r o c k f ish S i lvergray rockfish Darkbl otched r o c k f is h Spl itnose r o c k f is h Greenstri ped r o c k f is h Widow r o c k f i s h Yellowtail rockfish Rosethorn r o c k f is h Qui1lback r o c k f i s h Black r o c k f i s h Bocacci o Canary r o c k f i s h Redstri pe r o c k f i s h Ye1 loweye r o c k f i s h Stripetai 1 rockfish Sharpchin rockfish Sablefish Lingcod Paci f i c sanddab Arrowtooth flounder Petrale s o l e Rex sole Flathead s o l e Paci f i c ha1ib u t B u t t e r sole Rock s o l e Slender s o l e Dover sole English sole S t a r r y flounder C u r l f i n sole Sand s o l e S c i e n t i f i c Name SquaZus acanthias Rajidae Hydrazagus coZZiei AZosa sapidissima Gadus macrocephuZus MerZuccius productus Therogra chaZcogranm~ Sebasto Zobus aZascanus Sebastes aZeutianus Sebastes aZutus Sebaste s aurora Sebastes babcocki Sebastes brevispinis Sebastes crameri Sebastes dip Zoproa Sebastes eZongatus Sebastes entomeZas Sebastes f Zavidus Sebastes heZvomacuZatus Sebastes maZiger Sebastes meZanops Sebastes paucipinis Sebastes pinniger Sebastes proriger Sebastes ruberrirnus Sebastes saxicoZa Sebastes zacentrus A m p Zoroma fimbria Ophiodon e Zongatus Citharichthys sordidus Atheresthes stomias Eopsetta jordani GZyptocephuZus zachirus Hippog Zossoides e Zassodon HippogZossus stenolepis Isopsetta isoZepis Lepidopsetta bizineata Lyopsetta e x i t i s Microstomus pacificus Parophrys ve *uzus PZatichthys steltatus BZeuronichthys decwlrens Psettichthys mezanosticus Appendix 2. Length-weight constants obtained through 1inear r e g r e s s i o n o f mean weight by length1/. ivla le s Species a b Dover s o l e English sole Petra 1e so 1e2/ Rex s o l e P a c i f i c sanddab Arrowtooth flounder Slender s o l e Flathead s o l e Butter sol e 1975 survey data. -2/ Constants from Pedersen, 1975 f o r female p e t r a l e sole. a Fema 1 es b