498 Bechtol Ei Yaen Flatfish Abundance in Kachemak Bay, Alaska
arrowtooth flounder, Dover sole, and flathead sole. Arrowtooth flounder were represented by ages0 through 4 and 6 but I and 3 year old fish predominated. Dover sole ranged from age 2 to 5 but age 3 and 4 fish predominated. Flathead sole ages ranged from 1 through 12 with inost specimens between ages2 and 6.
Introduction Many traditional Alaskan salmon and crab fisheries have recently been subjected to biological or economic declines in the northwestern Gulf of Alaska Bechtol 1994!. At the same time, market conditions for groundfish species have improved because of collapses in many North Atlantic groundfish resources and a desire by many Alaskan fish processors to diversify their businesses. Greater gear efficiency has increased the economic viability in targeting grouridfish, resulting in greater effort for many species that were previously limited to iiiciden- tal catches Blackburn et al. 1983; Bechtol and Morrison in press!. Little is known about the abundance and distribution of flatfishes in Kachemak Bay,Alaska. Although numerous Outer Continental Shelf OCS! projects were initiated during the 1970sto assessmarine resources off the coast of Alaska, most studies focused on salmon, shellfish, and the shallow subtidal resources. Although some OCS studies examined marine resources, little survey effort occurred in Kachernak Bay Blackburn 1978!, and few of the OCSsurveys conducted in Kachemak Bay were directed at groundfish Lees et al. 1980!, Lower Cook Inlet was also surveyed in 1990as part of the triennial bottom trawl surveys con- ducted in the western and central Gulf of Alaska by the National Marine Fisheries Service NMFS!, but Kachemak Bay was not included Payne and Stark 1991!. Resourceassessment studies following the 1989Exxon Valdezoil spill in Prince William Sound provided the first opportunity to collect basic information on a variety of resources along the northern Gulf of Alaska. A trawl survey conducted by the Alaska Department of Fish and Game ADF8iG! as part of those assessment studies provided a unique opportunity to estimate species composition and absolute abundance of commercially iinportant fish and shellfish species in Kachemak Bay A. Kimker, Alaska Departmeiit of Fish and Game, Horner, Alaska, personal communication!, This report summarizes the tlatfish species coinposition, biomass, and abundaiice estimates froin that Kachemak Bay trawl survey. Proceedings of the International Symposium an IVarth Pacific Flatfish 499
Figure I. Study area and sample stations for October l 989 tratol survey of Kachemak Bay, Alaska.
Methods Fish sampleswere collected from KachemakBay, an embayment centeredapproximately at 59 35'N, 151'52'W in the northern Gulf of Alaska Figure I!. The 20.1 m ADF%Gresearch vesselPandalus towed a 400-mesheastern trawl with 364 kg, 152 cm x 213.3 cm Nor'Eastern Astoria V trawl doors. The trawl mesh was 10.2 cm in the wings and body, 8.9 crn in the intermediate, and 3.2 cm in the cod end. With headropeand footropelengths of 71 m and 29.0 m, the estimated fishing height and width of the trawl were 2,7 m and 12.1 m, respec- tively. The surveyfollowed a stratifiedrandom designand divided areas of Kachemak Bay deeper than 18 m 0 fathotns! into 3 strata Figure 1!. The Inner Kachemak stratum had depths between 18 and 91 m 0 and 50 fathoms! and a surface area of 35.7 square nautical miles 500 Bech/oiII Yuen I'latfish Abundancein KachemakBay, Alaska
Table1. Samplesite and tow characteristicsfrom the 1989Kachemak Bay multispecies trawl survey.
Haul I 2 3 4 5 6 Outer Outer Outer Inner Inner Inner Area Shallow Deep Deep Bay Bay Bay
Station number 208 301 302 101 102 105 Date 10/03 10/03 10/04 /07 10/08 10/08 Longitude 151'41.2' 151'39.8' 151'30.3' 151'05.4' 15I'09.2' 151'14.4' Latitude 59'36.6' 59'31,4' 59 33.6' 59o437 59 41.3' 59'38.9' Heading deg.! 270 240 45 200 210 210 Avg. depth fm! 16 57 84 33 28 31 Duration min! 24 27 32 24 26 27 Distance nm! 1.0 1.0 l.0 1.0 !.0 1.0
Haul 7 8 9 10 Outer Outer Outer Outer Outer Shallow Shallow Shallow Sha!low Deep
Station number 202 2 1.8 215 220 303 Da e 10/09 10/09 10/10 ] 0/ 10/25 Longitude 151'50.8' 151'51.3' 151 36.8' 151'34.1' 151'28.2' Latitude 59'39.8' 59'30.5' 59'33.4' 59 30 9' 59 33,8' Heading deg.! 195 250 30 230 220 Avg. depth frn! 14 35 48 53 90 Duration min! 21 25 24 25 27 Distance nm! 0,6 1.0 1.0 I.O 1.0 Note: Seetext for specific descriptions of areas.
nm !. The Outer Kachemak Shallow stratum was also between 18 and 91 m deep and was the largest in area at 194.0nm . The Outer Kachemak Deep stratum had depths > 91 rn 0 fathoms! and was the smallest in area at 17.3 nm2. Table 1 lists the individuals tows within each stratum. Within each stratum, 6,25 nm2 .5 nm x 2,5 nm! were delineated within bottom contour constraints, Stations were selected randomly and tow paths were based on the vesselcaptain's determi- nation of irawlablesubstrate from NOAAnautical chartsand hydro- acoustic assessment of the bottom contour, as well as tide and weather constraints. A total of 11 tows were made between 3 October and 25 October 1989, with three tows each in the Inner Kachernak and Proceedingsof the lnternaiionai Symposiumon Ivorth Pacific Flatfish 501
Table 2. Flatfish speciescaptured during the October 1989 trawl surveyof KachemakBay, Alaska.
Common name Scientific name
Alaska plaice Pleuronectesquadri tuberculatus Arrowtooth flo under A theresthes stomias Butter sole fsopsettaisolepis Dover sole JHicrostomus pacificus English sole Parophrys vetulus Flathead sole Hi p poglossoides elassodon Halibut lfippog ossus stenolepis Rex sole Giyptocephaluszachirus Rock sole Lepidopsetta bilineata Sand. sole Psertichthysmelanostictus Starry flounder Plati chthys stella tus Yell owfin sole Limanda aspera
Outer KachemakDeep strataand five tows in the Outer Kachemak Shallowstratum, For any tow in which the trawl becametangled in the substrata to the extent that the trawl and the vessel were stopped, the tow was deemed unsuccessful, the catch was discarded, and the tow was repeated,Each station was sampled by a 1.0-nrntow, exceptfor station 2-2 which was sampled by a 0.6-nm tow because the bottom terrain reduced the likelihood of a successfullong tow. Each successful tow was broughtaboard, weighed, and all crabs and largefish were countedand weighedor measured.For tows totaling < 450 kg, the remaining catch was sorted by species,counted, and weighed or measured Hart 1973; Lee 1979; Kramer and O' Connell 1986!. For taws > 450 kg, the composition of the smaller species was extrapolatedfrom a 2-bushelsubsample which was sorted, counted, and weighedby species,All towswere expressedin catch per nautical mile and later converted to biomass and abundance estimates for each stratum, and for all of Kachemak Bay.The species of flatfish caughtduring the October 1989survey are listed in Table 2. Most halibut were measured for length, and weight was later estimated from a standardized length-weight key Quinn et al. 1983!. For each tow, length, sex, and sexual maturity were recorded for 20-50 indi- vidual arrowtooth flounder, Dover sole, flathead sole, and rex sole. Ages for these samples were later detertnined in the laboratory from 502 Bechiol& Yuen Flarfish Abundance in KachemakBay, Alaska otolithspreserved in a glycerinsolution Chiitonand Bearnish 1983!. Lengthfrequency data were also collected for halibut, rex sole, and rock sole. Schnute's 981! generalfour-parameter model was used to examinelength-at-age relationships for arrowtoothflounder, Dover sole,and flathead sole, and weight-at-agefor Dover sole:
wherey, = lengthor weightat aget, t, = youngestobserved age, t = oldestobserved age. The model parameters tobe estimated were: y, = sizeat t,, y2= sizeat t2,a, and b. Initial values were yi observed sizeat t,, yz observedsize at tz,a =0.2, b =1.0. Special cases of this generalmodel included the von Bertalanffycurve where a >0, b >0; the logisticcurve where a >0, b = 1;and the exponential curve where a<0, b= 1.
Catch by area Letc,, = catch,either number of individuals orweight per nautical mile,from the ith tow in areaa, and n, = number of towswithin area a. Mean catchby speciesper nautical mile by area,c , was
Z!
The associated standard error, which did not account for tow mea- surementerror when the total catchwas extrapolatedfrom a single Z-bushel subsample, was
n. 1/ !
Totalcatch within a stratum,T either in numbersof individualsor weightby species, was calculated from the mean catch by area, a, the surfacearea, A in squarenautical miles, and a factorof 151.9 to extrapolatefrom the areaswept by the trawl!as
T =15L9c A . !
The associated standard error was Proceedings of the International Symposium on lvorth Pacific Flatfish 503
sz i' 51.9A!'s, . Assumingnormally distributed measurementerrors, lower and upper 95% confidence limits, which did not account for measurement errors when total catch was extrapolatedfrom single2-bushel subsatnples, were:
T 1.96''a Ta Ta+ 1.96Sze. !
Catch for ail areas combined For the cotnbined areas of Kachemak Bay, mean catch by species per nautical mile, C, weightedby the surface area of each stratum,A was 3 pc A a=1 A where A = the coinbined surface area. The standard error of C, either in nutnbers of individuals or by weight, was similar to that given by Sokal and Rohlf 969!:
sc ,i g A~!~s~. A Total catch, T, by speciesin numbers of individuals or weight for the entire study area was calculated from C and the combined surface area, A, in square nautical miles:
T = 151.9CA, 9!
The associated variance was Sr g 51.9A! s~. Lower and upper 95% confidence limits, which do not accountfor measurement errors when total catch was extrapolated from 2-bushel sub samples,were T 1.96sz< T < T+1.96sr.
Results Three successful tows were made in the Inner Kachemak, five in the Outer Kachemak Shallow, and three in the Outer Kachemak Deep 504 Bechtol A Yuen Flasfssh Abundance in Kachesnak Bay, Alaska
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DD O Cd 0 g Id CI 0 Id P ID CC g CO A Ol crI cn 508 BeChrolIcc Yuen Flatfish Abrtndanee in KachemakBay, Alatka LCJ IPJ 0, CO O Cdlm ~ Nr- 0, mO mm N co m O + cd g Cd 0 4cd I Ol O O O O O O O 0 C P 0 "0C4 CO Id & Cd o 4 c I H 0> cD cd Oo d cd ~ w p m co IXI OOmcdccIOOOO 0 0, cO m cd C 0 Cl Cdg o O O O O o O O O O cdIcl 0 50 O 4 I4 O O O O O N 0 O CII CO O Id Cd Q Il! N m m cd m cd cO cd W m M cd cd o mo CO O C O w CD N 0 0,V D 0 cll O O O CD O O O O O Kl CO N O CO O Q rA O 4 N ID m co oO .cll N cd N m c o 'cc' N N m N Id cd Id CD g0 0CIc N IU O bc' CO O O O ~ O O O O 'Id' O 0 O 4 Cg O v N 4Pl m 8Q 0 0CI 0 co 4' 0 Cl 4 0 0 0 cgdI 0 cn Id0 VCCI so dl COV 0 4 0 0 0 0 cd d! 0 cd 4 Cc IX C/3 Proceedingsof the International Symposiumon Ãorth Pacific Flatfish 509 Table 7. Length-at-ageof arrowtoothflounder caught during October 1989 in KachemakBay, Alaska. Sample Percent Age Mean SD size oftotal Station 302 297 41.6 10.7 354 41.5 16 57.1 399 50.9 9 32. 1 Total 363 53.0 28 100.0 Station 102 178 12.6 57.1 325 7,1 28.6 390 O.O 14.3 Total 250 93.5 100.0 Station 105 192 15.2 15 41.7 218 39.6 36.1 314 65.5 137 1 19.4 360 0.0 2.8 Total 230 62.8 36 100.0 Station 218 97 5,8 3 1 1.5 164 20.9 65.4 298 9.6 174 2 154 340 28.3 7.7 Total 190 74.0 26 100.0 Station 215 206 10,8 34 60.7 278 30.1 l.8 32.1 338 25.0 4 7.1 To'tal 238 47.8 56 100.0 Station 220 210 8.2 4 7.0 302 43,6 17 29,8 346 31.1 28 49.1 406 67.8 7 12.3 380 0,0 1 1.8 Total 331 60.5 57 100.0 Station 303 300 14.1 22.2 346 45.1 55,6 435 21.2 22.2 Total 356 59,2 100.0 Combined 97 5.8 3 1.4 stations 192 22.3 74 33.8 276 48.0 59 26,9 344 39.8 62 28.3 403 52.0 20 a.t 380 0.0 1 0.5 Combined total 276 84.4 219 100.0 510 Bechtol & Yuen Flatfish Abundance in Kachemak Hay, Alaska Figure2. Arrowtoothflounder abundance 'fishinm! and agecomposition by Kachemak Bay sample station duri ng ! 989. Figure3. Doversole abundance fishlnm! and agecomposition by KachemakBay sample starion during !989. Proceedingsof the International Symposiumon ivorth Panjic Flatfish Table 8. Length-at-age of Dover sole caught during October l989 in Kachemak Bay, Alaska, Length mm! Sample Percent Age size of total Station 302 324 20.9 20.0 350 22.3 17 56,7 384 19.1 7 23.3 Total 353 29.0 30 100.0 Station 215 298 33,1 10.9 327 25.3 56.4 342 29.7 l4 25,5 370 29.4 7.3 Total 3313 l.5 55 100.0 Station 215 290 28.3 2 328 21.5 28 45,2 354 21 33.9 381 28.4 11 17.7 Total 345 31.0 62 100,0 Combined 296 30.2 8 5.4 stations 327 23.1 65 44.2 23.2 52 35.4 380 25.3 22 15,0 Combined total 341 3!,8 147 100.0 ages3 and 4 Table 8; Figure 3!. Dover sole averaged341 mm in length and 545 g in weight. Individual weights were not tneasured for other species.Flathead sole ages 1 through12 were found in the samples but tnost were between ages2 and 6 Table 9; Figure 4!. Schnute's 981! general four-parameter size-agegrowth inodel produceddifferent growthcurves for eachspecies. Arrowtooth flounder length-age was best described by a logistics type curve Figure 5!. In our initial fit of the arrowtooth flounder data, a was positiveand b was 0.56;b wasconstrained to 1 in our final fit as is required for the logistic curve. The Dover sole length-age relationship appeared to be an exponential curve for the ages examined as a was negative and b = 1 in our first and only fit Figure 6!. Dover sole weight-age relationship also appeared to be an exponential curve Figure 7!. In our initial fit, a was negative and b = 1.11; b was con- 5I2 Bechfol & yuen F/arfish Abundance in Kachemak Bay,Alaska Table 9. Length-at-ageof flathead solecaught during October i989 in KachemakBay, Alaska. Lenrth lrnml Sample Percent Age a1 ac oftotal Stat!all 11 130 0.0 193 15 53.6 258 11.7 21.4 270 OD 3.6 280 00 3.6 315 71 9 390 0.0 13 380 0,0 Total 233 63.1 28 100.0 Station102 188 32.4 22.2 245 28.1 267 33.3 285 52.8 10 18.5 320 43.4 11.1 85.4 7.4 368 61.8 7.4 8 9 400 !.0 1.9 10 380 56.6 3.7 380 56.6 3.7 12 320 00 1 1.9 '1'otal 281 76.9 54 1DD.O Station105 220 O.D 2.5 253 33.5 7 17.5 286 31.0 136 32,5 298 40 7 ! 5.0 340 66.8 ! 0.0 375 21.2 5.0 343 208 1D 375 21.2 5.0 11 390 0.0 2.5 13 420 0.0 1 2.5 Total 305 56.0 40 !DD.D Station218 250 0.0 20.0 360 0.0 20.0 390 26.5 60.0 Total 356 1000 Station215 180 60.8 5.4 175 55.4 10.7 228 38.6 33.9 257 24.5 11 19,6 264 13.0 8 143 Proceedingsof the Internationtsi Symposium on¹rth PacificFlatfish Table 9. ct313tinuetL! Satnpje Percent Age Mean sD sjze of total jah 12.5 Boo 0.0 1.8 27jl 0.0 1.8 Total 242 481.2 100.0 Stari Figure 4, Flatheadsole abundance fish/am! and agecomposition by Kachemak Bay sample station during 1989. strained to a value of 1 in our flinal fit. The flathead sole length-age model was a von Bertalanffy type curve where a and b were both positive and initial parameter values were retained as the final values Figure 8!. Lengthfrequency data indicatedhalibut were generallylarger than 270 mm except for Outer Kachemak stations 202 and 208 where a greaterfrequency of smaller fish were found Figure 9!. Across all stations, halibut lengths ranged from 90 to 1,200 mm. Most of the rex sole length samples were from one station where fish rangedfroin 240 to 410 rnrn Figure 10!. Rock sole from Outer Kachernak Shallow ranged from 80 to 440 mm, although there appeared to be segregation by size between stations Figure 11!. Discussion Halibut were caught in 100%of our tows versus 68% of the tows by Blackburn 978! and 67% of the successful NMFS tows Payneand Stark 1991!, Our studyfound flathead soleto be the predominant Proceedingsof the International Symposiumon IAIorthPacific Flatfish 4D0 2 SDDE 200 100 Figure5. Schnute'sgeneral four-parameter length-age model for arrowtooth flounderin KachemakBay describes a logisticgrowth curve where a = 0.78, b = -1.00, y, = 114.30,and ys = 432.18. 450 4DD 350 300 Ecm200250 15D 10D 50 Age Figure6. Schnute'sgeneral four-parameter length-agemodel for Doversole in I achemakBay describesan exponentialgrowth curve wherea = 112.14, b = 1.00,y, = 334.26,and y, = 379.66. 526 Bechtol & yuen Flatfish Abundance in Kachemak Bay, Alaska 1000 900 000 000 500 l% 400 300 200 10D Age Figure 7. Schnute's general four- parameter weight-age model for Dover sole in Kachemak Bay describes an exponential growth curve where a = -0.88, b = l.00, y, = 4l2.l3, and ys = 719.29. flatfish species in Kachemak Bay,Alaska, with arrowtooth flounder ranked second in both abundance and biomass Tables 3-6!. In contrast, flathead sole was not predominant in a NMFS survey involv- ing six tows in lower Cook Inlet during August I 990 Payne and Stark 1991!. Instead, the NMFS study found arrowtooth flounder as the predominant flatfish biomass in two deep water tows, followed by halibut, Dover sole, and rex sole, whereas halibut predominated the shallow tows, followed by starry flounder, rock sole, and Alaska plaice, The averagecatch rate kg/ntn! of flatfish from the shallow NMFS taws was < 8% of that from the deep tows. Our study, on the other hand, found similar averagecatch rates in the Outer Kacheinak Deep and Outer Kacheinak Shallow strata. The Inner Kachemak stratum catch rates were nearly half that of Outer Kachemak Table 5!. Our more consistent catch rates relative to the NMFS study are mainly attributed to flathead sole catches which were relatively consistent across afl areas. In addition, greater catch rates of starry flounder and yellowfin sole moderated a lack of arrowtooth flounder in the Inner Kachernak stratum. Proceedingsof the International Symposium on IvorthPacific Flatfish Si 7 450 400 350 300 E E 250 031 200 150 100 50 0 2 5 10 12 14 Age Figure8. Schnute'sgeneral four-parameter length-age model for flatheadsolein KachemakBay describesa eon Bertalanffygroruth curue where a = 0.J7, b = I.46, y, = 249.87.and yr = 386.60. Blackburn's 978! 58 otter trawl tows madeduring the summerof 1976and 18 otter haulsmade during March 1977 found yellowfin sole to be the most abundant flatfish,followed by rock sole and halibut. In bothour surveysand those conducted by NMFS,yellowfin sole was generallyfound at depths< 35fathoins 4 m!,including all the Inner Kachemak stratumtows. This is consistentwith observationsin the easternBering Sea that yellowfin sole tend to be at depths> 50 fathoms 91 m! in winter and < 50 fathoms 91 m! in summer Wilderbueret al, 1992!.It is notablethat the locationof greatest yellowfiinsole abundance during Blackburn's Cook inlet studycorre- spondedto the locationof a relativelyintense, but short-term, com- mercialfishery for this speciesin the mid-1980s unpublished data!. Thegrowth curves developed by Schnute'sgeneral four-parameter mode!represent an initialanalysis of size-at-age for the availabledata, Thevon Bertalanffy curve described for flatheadsole appeared to be a reasonable fit to the data Figure 8!. On the other hand, the Dover sole size-agecurves, especially the length-age curve, were of limited usefulnessin describingthe size-agerelationships because so few 5l8 Bechtoi g Yuen Flatfish Abundance in Kachemak Bay, Alaska Figure9. Halibut lengthfrequency by KachemakBay sample station during 1989. Figure 10, Rex sole length frequency by Kachemak Bay sample station during l 989. Proceedingsof the international Symposiumon Ãorth Pacific Flatfish 519 Figurel l. Rocksole length frequency by Kachemak Bay sample station during l989. ageswere represented Figures 6 and7!. Largersatnple sizes over a wider rangeof agesis neededto adequatelymodel the growthcharac- teristics of Dover sole. While several studies have examined bias associated with the use of trawl gear,trawl gearremains one of the more comprehensiveand leastselective gear types for resourceassessinent Klein 1986;Dickson 1993!.Our study did not take gearbias into account.In addition, flatfish resourcesat depths < 18 m were not examinedin this study Figure1!. Forthe areasurveyed, the variationin abundanceand biomass, both betweenstrata and between stationswithin strata,and asevidenced by the wide 95%confidence intervals, indicated patchy distributionsfor most flatfishspecies Tables3-6!. Figures 9 and 11 also providedevidence of station-specificsize distributions for halibut and rock sole. Studieseinphasizing habitat use are needed to better understand flatfish production and distribution in this area. Conclusions Thisstudy advanced our understandingof flatfishin nearshore areas.Because halibut has produced the only major flatfish fishery in 520 Bechtol A Vuen Flatfish Abundance in Kachemak Bay, Alaska southcentral Alaska, little was known about other flatfish in this area. Concerns about the iinpacts of fishing mortality on low-value, high- volume groundfish species, such as flatfish, continue to increase Pacific Associates 1994!. Fishing fleets are increasingly capable of removing surplus production, and the removal is often poorly defined for species that are not retained. This study provided a "snapshot" of the flatfish in Kachemak Bay,Alaska. However, surplus production was not determined, and the flatfish contribution to the Kachemak Bay resource energy budget remains unknown. Although marine ecosys- tems are rarely static, having a view of the past will lead to a better understanding of how an ecosystein evolves and a better evaluation of potential "risk" of a particular fishing strategy,While unveiling inany new questions about the interactions and distributions of flatfish resources, this study will provide input into future management decisions and direction for future studies. Acknowledgments We thank Brian Bue for reviewing our statistics, Kris Munk and Joan Brodie for otolith ageing, Jeff Bromagin for developing the spreadsheet to solve Schnute'ssize-age model, and several anonymous reviewers. References Bechtol, W.R. 1994, Review of the 1993 groundfish fisheries in the Central Region. Alaska Department of Fish and Game, Division of Commercial Fisheries, Regional Inforinaiion Report 2A94-19, Anchorage. Bechtol, W.R., and R. Morrison. In press! Development and management of the sablefish fishery in Prince Wilharn Sound, Alaska. In: Proceedings of the International Sablefish Syxnposiurn, National Marine Fisheries Service, Seattle. Blackburn, J.E. 1978. Pelagic and demersal fish assessment in the lower Cook Inlet estuary system. Alaska Departinent of Fish and Garne, Outer Continental Shelf Environinental Assessment Project, Research Unit 512, Final Report, Kodiak. Blackburn, J., B. Bracken, and R. Morrison. 1983, Gulf of Alaska Bering Sea groundfish investigations. Alaska Department of Fish and Game, Technicai report for the period September29, 1981to June30, 1982;prepared for the National Oceanic and Atmospheric Association, Project 5-49-R-I, Juneau. Chilton, D.E., and R.J. Beainish. 1983. Age deterinination methods for fishes studied by the Groundfish Program at the Pacific Biological Station. Canadian Special Publication, Fisheries and Aquatic Sciences 60. 'ochran, W.G. I964. Sampling Techniques. John Wiley and Sons, New York. Proceedingsof the internationalSymposium on NorthPacific Flatfish 52! Dickson,W, 1993.Estiination of the captureefficiency of trawl gear,I!i Testingof a theoretical model. Fisheries Research 16:255-272. Hart,J,L, 1973. Pacific fishes of Canada.Fisheries Research Board of Canada, Bulletin !80. Klein.S,J. 1986, Selectivity of trawl,trap, longline, and set-net gears to sablel1sh, Anoplopomafimbria. NationalOceanic and Atinospheric Association, Northwestand AlaskaFisheries Center, Report 86-06, Seattle. Kramer,D.E., and VIVI.O' Connell, 1986.Guide to northeast Pacific rockfishes; GeneraSebastes and SebastolobutcAlaska Sea Grant, University of Alaska, Marine Advisory Bulletin 25, Fairbanks, Lee,R.S. 1979. White Bsh identification guide. Alaska Sea Grant, University of Alaska,Marine Advisory Bulletin 9. Fairbanks. Lees,D.C J,P. Houghton, D.E. Erickson, W.B. Driskell, and D,E, Boettcher, 1980. Ecologicalstudies of intertidaland shallow subtidal habitats in lowerCook inlet, Alaska,U.S. Department of Commerce,Outer Continental Shelf Environmental Assessment Program, Final Report 44 986!. Pacific Associates,1994. Discards in the groundfish fisheries of the Bering Sea/ Aleutian Islands and the Gulf of Alaskaduring 1993,Prepared I'or the Alaska Department of Fish and Game, Juneau. Payne,R., and J. Stark. 1991. Report to the industry:Results of the 1990cooperative bottomtrawl survey of the centraland western Gulf of Alaska.National Oceanicand Atmospheric Association, Northwest and Alaska Fisheries Center, Processed Report 91-05. Quinn,T.J. 111, E.A. Best, L. Bijsterveld,and I.R.McGregor. 1983, Sampling Pacific halibut Hippoglossusstenolepis! landings for agecomposition: History, evaluation,and estimation. International Pacific Halibut Commission, Scientific Report 68, Schnute,J, 1981.A versatilegrowth model with statistically stableparameters. CanadianJournal of Fisheriesand Aquatic Sciences38:1128-1! 40. Soka!,R.R and EJ.Rohlf, 1969.Bioinetry. W.H. Freeman and Coinpany,San Francisco, Wilderbuer,T.K., G,E, Walters, and R.G.Bakkala, 1992. Ye!lowfin so!e, Pleuronectes asper,of the easternBering Sea: Biological characteristics, history of exploita- tion, and management.Marine FisheriesReview 54 !:1-18,