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