NOAA Technical Memorandum NMFS-AFSC-7

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Alaska Fisheries Science Center

January 1993

by

Claire E. Armistead and Daniel G. Nichol

1990 Bottom Trawl Survey

of the Eastern Bering Sea

Continental Shelf
NOAA Technical Memorandum NMFS

The National Marine Fisheries Service's Alaska Fisheries Science Center

uses the NOAA Technical Memorandum series to issue informal scientific and

technical publications when complete formal review and editorial processing

are not appropriate or feasible. Documents within this series reflect sound

professional work and may be referenced in the formal scientific and technical

literature.

The NMFS-AFSC Technical Memorandum series of the Alaska Fisheries

Science Center continues the NMFS-F/NWC series established in 1970 by the

Northwest Fisheries Center. The new NMFS-NWFSC series will be used by

the Northwest Fisheries Science Center.

This document should be cited as follows:

Armistead, C. E., and D. G. Nichol. 1993. 1990 bottom trawl survey of

the eastern Bering Sea continental shelf. U.S. Dep. Commer., NOAA

Tech. Memo. NMFS-AFSC-7, 190 p.

Reference in this document to trade names does not imply endorsement by

the National Marine Fisheries Service, NOAA.
NOAA Technical Memorandum NMFS-AFSC-7

1990 Bottom Trawl Survey

of the Eastern Bering Sea

Continental Shelf

Claire E. Armistead and Daniel G. Nichol

Alaska Fisheries Science Center

7600 Sand Point Way N.E., BIN C-15700

Seattle, WA 98115-0070

U.S. DEPARTMENT OF COMMERCE

Barbara Hackman Franklin, Secretary

National Oceanic and Atmospheric Administration

John A. Knauss, Administrator

National Marine Fisheries Service

William W. Fox, Jr., Assistant Administrator for Fisheries

January 1993
This document is available to the public through:

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iii

ABSTRACT

 The Resource Assessment and Conservation Engineering

Division of the Alaska Fisheries Science Center conducts annual

bottom trawl surveys to monitor the condition of the demersal

fish and crab stocks of the eastern Bering Sea continental shelf.

The standard study area, surveyed each year since 1979,

encompasses a major portion of the eastern Bering Sea shelf

between the 20-m and the 200-m isobaths and from the Alaska

Peninsula north to approximately the latitude of St. Matthew

Island (lat. 60° 50' N). In 1990, this area of 463,000 km2

 was

again surveyed by two chartered trawlers, the 30.5 m Alaska and

the 33.5 m Ocean Hope 3.

Demersal populations were sampled by trawling for 30 minutes

 at stations centered in 20 x 20 nautical mile grids covering the

survey area. At each station, species composition of the catch

 was determined and commercially important species were sampled to

obtain length distributions and age structure samples.

Survey results presented in this report include relative

fishing powers of the survey vessels, abundance estimates for

fish and invertebrates, geographic distributions of economically

important fish species and major fish families, size composition

of principal fish species, and age and growth information for

selected species. Surface and bottom temperatures recorded at

each sampling station are also presented.

Appendices provide detailed station data and computer

listings of the analyses of abundance and biological data of the

sampled populations.
V

CONTENTS

Introduction .............................................

Methods ..................................................

Survey Area and Sampling Design........................

Vessels and Fishing Gear ...............................

Data Collection .......................................

Data Analysis ..........................................

Special Studies .......................................

Results ...................................................

Environmental Conditions ...............................

Relative Fishing Powers of Survey Vessels .............

Estimated Biomass of Major Fish and Invertebrate

Groups ..............................................

Relative Abundance of Individual Fish Species .........

Abundance, Distribution, and Size and Age Composition

of Principal Species and Species Groups .............

Walleye pollock .....................................

Pacific cod .........................................

Yellowfin sole ......................................

Rock sole ...........................................

Hippoglossoides spp. ................................

Alaska plaice .......................................

Greenland turbot ....................................

Atheresthes spp. ....................................

Pacific halibut .....................................

Miscellaneous Species Groups ........................

Citations ................................................

Appendix A.

Appendix B.

Appendix C.

Appendix D.

Station Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Schematic Diagram of Trawl Gear..............

Appendix E.

Appendix F.

List of Species Encountered . . . . . . . . . . . . . . . . .

Rank Order of Relative Abundance of Fish

and Invertebrates . . . . . . . . . . . . . . . . . . . . . . . . .

Abundance Estimates for Principal Fish

Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Population Estimates by Sex and Size Groups

for Principal Fish Species . . . . . . . . . . . . . . . .

Appendix G. Age-Length Keys for Principal Fish Species . .

Appendix H. Population Estimates by Age for Principal

Fish Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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I

INTRODUCTION

The eastern Bering Sea continental shelf supports one of the

most productive groundfish fisheries in the world (Bakkala 1988).

Since 1970, annual commercial catches of groundfish have ranged

from 1.2 to 2.2 million metric tons (t) (North Pacific Fishery

Management Council 1990). Although many species are caught

commercially, the most abundant has been walleye pollock

(Theragra chalcogramma) which, since 1970, has comprised more

than 70% of the total landings. The next most abundant species

have been yellowfin sole (Pleuronectes asper) and Pacific cod

(Gadus macrocephalus) which have comprised 8 and 5%,

respectively, of the commercial landings.

Since 1971, the Resource Assessment and Conservation

Engineering (RACE) Division of the Alaska Fisheries Science

Center (AFSC) has conducted annual bottom trawl surveys of the

eastern Bering Sea continental shelf. In 1975, the first

large-scale survey of the eastern Bering Sea shelf was conducted

under contract to the Bureau of Land Management in response to a

need for baseline data to assess the potential impact of proposed

offshore oil exploration and development on fishery resources

(Pereyra et al. 1976). During this baseline survey, sampling was

conducted over the Bering Sea shelf between the 20 m and 200 m

isobaths and from the Alaska Peninsula north to approximately

62°N lat. (Fig. 1). Following 1975, the areal coverage of the

annual surveys was reduced until 1979 when an even more

comprehensive survey of the Bering Sea shelf than in 1975 was

undertaken in cooperation with the Japan Fisheries Agency (Fig.
Figure l.--Sampling stations and survey stratificationused for

analyses of data from the 1975 baseline survey on the

eastern Bering Sea shelf, with approximate locations of

oil lease areas (from Pereyra et al. 1976).

N

Figure 2. --Sampling stations and survey stratification used for

analyses of data from the 1979 expanded triennial survey

on the eastern Bering Sea shelf and slope (from Bakkala

and Wakabayashi 1985).
3

2 , Bakkala and Wakabayashi 1985). The 1979 survey encompassed

the entire region sampled in the 1975 baseline study, and in

addition, the continental slope waters between the Aleutian

Islands and the U.S.-U.S.S.R. convention line, and the region

between St. Matthew and St. Lawrence Islands. A hydroacoustic

survey was also conducted in 1979 to assess the midwater

component of the walleye pollock population. Subsequent annual

bottom trawl surveys have essentially resampled the stations

established during the 1975 survey, with slight modifications

each year. This region has been found to encompass the major

portion of economically important eastern Bering Sea groundfish

populations, except those primarily located in continental slope

waters. Every third year (1979, 1982, 1985, 1988) an extended

survey has been conducted, including hydroacoustic assessment of

midwater pollock, bottom trawl sampling of the continental slope,

and bottom trawl sampling in the region between

St. Lawrence Islands. The information gathered

surveys serves to: 1) provide the North Pacific

St. Matthew and

by the annual

Fishery

Management Council with annual fishery-independent estimates of

abundance and biological condition of commercially exploited

stocks, 2) provide distribution and abundance information to

commercial fishermen, and 3) develop a time-series data base

contributing to our understanding of the population dynamics and

interactions of groundfish species.

This report presents information collected by the AFSC in

the eastern Bering Sea during the 1990 bottom trawl survey. The
4

groundfish/crab survey and several ancillary projects were

conducted from 1 June to 8 August by two U.S. vessels. The

survey area was also sampled by the Soviet research vessel

Novokotovsk from 18 May to 17 July 1990. The survey data

collected by the Soviet and the U.S. vessels have not been

combined due to differences in survey timing and sampling gear.

Results of the Soviet survey will be presented in a future

report. Also, detailed information on principal crab species is

not included here but can be found in a report by Stevens and

Macintosh (1990).

METHODS

Survey Area and Sampling Design

A total of 352 standard and 28 special study stations were

successfully sampled during the 1990 survey (Fig. 3). The

standard station pattern was based on a systematic 20 x 20

nautical mile grid. In areas surrounding St. Matthew and the

Pribilof Islands, grid block corners were also sampled to better

assess blue king crab (Paralithodes platupus) concentrations.

Starting with the eastern stations, the two vessels fished

alternate north/south lines of stations such that coverage of the

survey area was similar for each vessel. This sampling design

facilitated the computation of relative fishing powers (or catch

efficiencies) of the two vessels., The progression from east to

west was established to prevent multiple encounters of yellowfin

sole, Alaska plaice (Pleuronectes quadrituberculatus), and
Figure 3.--Standard and special study stations sampled during the 1990

eastern Bering Sea bottom trawl survey, and stratification used

for analyses of the data. Boxed areas s&rounding the

Pribilof Islands and St. Matthew Island indicate locations

of high-density sampling.
6

perhaps other species which may be migrating eastward during the

course of the survey (Smith and Bakkala 1982). Tows were usually

30 minutes in duration and fishing was limited to daylight hours.

For data analysis, the survey region was divided into six

subareas bounded by the 50 m, 100 m, and 200 m isobaths and by a

line separating the northwest and southeast portions of the study

area (Fig. 3). This stratification scheme was designed to reduce

the variances of population and biomass estimates by conforming

to oceanographic domains which seem to relate to distributions of

fishes (Bakkala 1988). The presence of high-density sampling for

blue king crab in subareas 3, 4, and 6 necessitated a further

division of these subareas into high-density and standard-density

sampling strata, resulting in a total of 10 geographic strata.

Of the 356 total standard survey stations, 352 were

successfully sampled in 1990 (Appendix A). The overall sampling

density for the entire survey area was one station per 1,316 km2

(Table 1). However, because of the high-density sampling in

subareas 3, 4, and 6, and the irregular subarea boundaries,

sampling density among the six subareas varied from one station

per 1,147 km2 to one per 1,492 km2.
7

Table l.--Size of subareas and sampling densities by subarea

for the 1990 eastern Bering Sea bottom trawl survey

(see also Fig. 3).

Vessels and Fishing Gear

For the third consecutive year, the annual eastern Bering

Sea bottom trawl survey was conducted aboard the 30.5 m

University of Washington research vessel Alaska and the 33.5 m

fishing vessel Ocean Hope 3 (Table 2). As in previous years,

both vessels were equipped with 83-112 eastern otter trawls which

have 25.3 m (83 ft) headropes and 34.1 m (112 ft) footropes

(Appendix B). These nets were attached to tail chains with

54.9 m (30 fathoms) paired dandylines. Each lower dandyline had

a 0.61 m chain extension connected to the lower wing edge to

improve bottom tending characteristics. Steel "V"-doors

measuring 1.8 x 2.7 m and weighing 816 kg were used.
8

Table 2. --Characteristics of vessels used during the 1990 eastern

Bering Sea bottom trawl survey.

SCANMAR1 net mensuration systems were used aboard each

vessel to measure net height and width. Net width was measured

by the distance between two sensors attached to the upper

dandyline, about 0.61 m in front of the net. For most tows, a

mean net width was calculated from observations recorded during

the tow. These data were also used to establish a net widthscope (wire-out) relationship for each vessel to enable

prediction of net width for tows where net width data were not

available (Fig. 4) as described by Rose and Walters (1990).

Estimates of net width were used in area-swept calculations.

Data Collection

Sampling procedures used in RACE eastern Bering Sea

assessment surveys are described in detail by Wakabayashi et al.

(1985). A brief summary follows.

Samples were collected by trawling at the center of each 20

x 20 nautical mile grid block (or corner station, in the case of

high-density strata) for 30 minutes (timed after the net had

1

 Reference to trade names does not imply endorsement by the

National Marine Fisheries Service, NOAA.
Figure 4. --Relationship between net-width and scope

(wire-out) for the two vessels participating

in the 1990 eastern Bering Sea bottom trawl

survey.
10

settled on the bottom), towing at a speed of 1.54 m/sec

(3 knots). If the bottom appeared to be untrawlable at the

specified location, the nearest trawlable site within the same

grid square was used. If the net was ripped or "hung up" on some

object on the bottom during the tow, the catch was discarded and

a new sample obtained.

Catches of less than approximately

processed entirely while larger catches

1,150 kg (2,500 lb) were

were subsampled.

Economically important fish and invertebrates were sorted to

species with the exception of four species of flatfish. Similar

features between arrowtooth (Atheresthes stomias) and Kamchatka

flounder (Atheresthes evermanni), and flathead sole

(Hippoglossoides elassodon) and Bering flounder (Hippoglossoides

robustus) made identification of these species difficult within

the time constraints of the survey; thus, these species were

grouped by genus for purposes of this report. Minor species of

fish and invertebrates were sorted to the lowest taxonomic level

practicable. Catch weights and numbers by species or species

group were estimated directly or, when subsampled, estimated by

extrapolating the proportion in the subsample to that of the

entire catch weight. Pacific halibut (Hippoglossus stenolepis)

and crab species of the genera Paralithodes (red and blue king

crabs, camtschatica and platypus, respectively), Chionoecetes

(snow and Tanner crabs, opilio and bairdi, respectively), and

Erimacrus (hair crabs, isenbeckii) were usually weighed and

enumerated from the entire catch.
11

Size composition data were collected for each commercially

important species. Pacific halibut, walleye pollock, Pacific

cod, and yellowfin sole were measured whenever caught while other

species were measured as time permitted (Table 3). Pacific

halibut were measured immediately upon capture and returned to

the sea in an effort to reduce sampling mortality for this

species. Random samples of the remaining species of up to

approximately 200 individuals (300 in the case of walleye

pollock) were sexed and measured to the nearest centimeter from

the tip of the snout to the end of- the middle rays of the caudal

fin (fork length).

Sagittal otoliths were collected from seven commercially

important species (Table 4). In both the northwestern and

southeastern divisions of the survey area, three otolith pairs

per sex/centimeter interval were collected for Pacific cod and

rock sole (Pleuronectes bilineatus), and five pairs per

sex/centimeter interval for all other species. Scales as well as

otoliths were taken from Pacific cod to aid in ageing young fish.

Individual weight data were collected from Alaska plaice in

conjunction with otolith sampling. In the case of the

Hippoglossoides, otoliths were collected only from individuals

that were identified with certainty as flathead sole. Age

structures for roundfish were preserved in 50% ethanol/water;

flatfish otoliths were preserved in 50% glycerol/water.

Temperature profiles were taken at each station with an

expendable bathythermograph cast; surface temperatures were taken

by bucket thermometer.
12

Table 3.--Number of length measurements taken during the 1990

eastern Bering Sea bottom trawl survey.

a

Some length measurements were made in hauls that fell outside the standa

survey area, thus, the numbers taken in the six subareas of the standard

survey area do not add to the total.
13

Table 4. --Number of fish in which age structures were collected,

by species and subarea, during the 1990 eastern Bering

Sea bottom trawl survey.

Data Analysis

A brief description of the procedures used in analysis of

PACE Bering Sea survey data follows (for a detailed description

see Wakabayashi et al. 1985). Many of the species collected were

grouped by family for data analysis because of their

insignificant commercial value or questionable identification.

Since 1979, the Bayesian technique of Geisser and Eddy

(1979) was used to compare the relative fishing powers of the two

survey vessels. If the distribution of catch-per-unit-effort

(CPUE) values for any one species were statistically different

between vessels, catch rates of the less efficient vessel were

expanded by the ratio of the mean CPUEs (more efficient divided
by less efficient) of the

determined that the ratio

14

two vessels. Recent work at the AFSC

of means was extremely unstable and too

sensitive to abnormally large values of CPUE. Consequently, a

new method developed by Kappenman (1992) was used to compare CPUE

'distributions and determine a scaling factor for correction. All

stations sampled by the two vessels during the standard survey

(Fig. 3) were used in the analysis.

Mean CPUE values for each species were calculated in

kilograms per hectare and number per hectare for each of the 10

strata; area swept (hectares) was computed as the distance towed

multiplied by the mean net width (Alverson and Pereyra 1969).

Mean CPUE values, weighted by strata areas, were calculated for

individual subareas and for the overall survey area. Biomass and

population estimates were derived for each stratum by multiplying

the stratum mean CPUE by the stratum area. Stratum totals were

then added together to produce estimates for each subarea and for

the total survey area.

In estimating the size composition of populations of

principal commercial species, length-frequency data obtained at

each station were expanded to the station catch by proportion and

then extrapolated to the stratum population by the weighted CPUE.

Stratum estimates were summed to derive the estimated size

composition by subarea and for the overall survey area.

Otolith and scale samples collected during the survey were

read by the Age and Growth Determination Unit of the AFSC's

Resource Ecology and Fisheries Management (REFM) Division. From
15

each centimeter interval. Population age composition was

estimated by apportioning ages to the estimated population at

each length interval. Age composition in terms of biomass was

estimated by first calculating biomass at length using the

equation:

where BL = biomass at length L in grams,

PL

= population number at length L,

L = fork length in mm, and

A and B = constants based on the regression of previous

species-specific length-weight data obtained

from the RACE eastern Bering Sea database.

Values used for the constants A and B are as follows:

After converting weight in grams into metric tons, BL was then

apportioned to biomass at age using the age-length key for each

species.

Growth characteristics of principal species were described

with von Bertalanffy (1938) growth curves fitted to age-length
16

data collected in this survey.

Special Studies

In addition to the 352 standard survey tows, 28 tows were

made for special studies (Fig. 3). Nearshore sampling for

juvenile crab and fish was conducted at three stations in Port

Heiden, and at one station in Kvichak Bay. In addition, 2 tows

each were made in Togiak and Kuskokwim Bays to assess the

abundance and spawning condition of yellowfin sole inshore of the

standard survey area, and 20 tows were made to assess the

abundance of snow crab northwest of St. Matthew Island. Catches

from these 28 tows were used to define geographic distributions

of fish groups but were not used to estimate population

parameters in order to maintain comparability with estimates from

previous standard annual survey areas.

Stomach samples from several of the most prevalent

commercial species in each haul were collected and preserved in

formalin for later examination by the Food Habits Program of the

AFSC's REFM Division (Table 5).

Additional activities included tagging Pacific cod (Table

5) , collecting specimens or tissue samples for observer training

programs and crab pathology studies, and fulfilling requests from

academic institutions.
17

Table 5. --Biological samples collected for special

studies and number of Pacific cod tagged

during the 1990 eastern Bering Sea bottom

trawl survey.

RESULTS

Environmental Conditions

Sea surface temperatures recorded during the survey ranged

from 2.3° to 10.8°C (Fig. 5). As in most previous years, surface

temperature increased from east to west across the shelf,

probably reflecting the progression of summer warming as the

survey proceeded from east to west.

Bottom temperatures ranged from -1.5° to 6.8°C (Fig. 5).

The warmest temperatures (above 4°C) occurred in shallow waters

along the Alaska mainland, in the vicinity of the Pribilof

Islands, and in the southern portion of the outer shelf just
18

Figure 5. --Distribution of surface water (top panel) and bottom

water (lower panel) temperatures ("C) observed during

the 1990 eastern Bering Sea bottom trawl survey.
19

north of Unimak Pass. The coldest bottom temperatures observed

were in the northern portion of the mid-shelf at depths between

50 and 100 m.

The mean bottom water temperature for the total survey area

in 1990 was 2.3°C (Fig. 6). Historically, this is below average

for mean summer bottom water temperatures in the standard survey

area (range in annual means 1.8° to 5.1°C, average of annual

means 2.9°C). Mean bottom temperatures observed over a more

limited region of the southeast Bering Sea, which has been

sampled annually since 1971, have ranged from 1.2° to 4.8°C; the

1990 value for this area was 3.2°C, near the long-term average

(3.1°C). The distribution of bottom water temperatures was

somewhat unusual in 1990 in that there was a relatively broad

distribution of O°C and colder water on the northern midshelf,

but the 2°C isotherm did not extend as far south as it normally

does when the O°C and colder water is as extensive as it was in

1990. This would account for the total survey area mean in 1990

falling below average while the mean for the southeast Bering Sea

was near average.
20

Figure 6. --Mean summer bottom water temperatures based on

bathythermograph casts made during Alaska Fisheries

Science Center bottom trawl surveys. The 1971-90 means

(dashed line) are from the southeast Bering Sea (see

inset) and the 1975 and 1979-90 means are from the

larger survey area outlined on the inset. The 1975 data

point for the overall survey area is based on data

collected from August through September, while

those in all other years and areas were collected from

June through early August.
21

Relative Fishing Powers of Survey Vessels

A total of 352 alternate-row tows were used in the

statistical comparison of vessel catch rates developed by

Kappenman (1992). Based on this analysis, the Alaska was

significantly more efficient than the Ocean Hope 3 at capturing

the following species and species groups: walleye pollock,

Pacific cod, Hippoglossoides spp., Alaska plaice, Atheresthes

spp., Pacific halibut, Myoxocephalus spp., skates (Rajidae),

Tanner crab, and snow crab. The Ocean Hope 3 was more efficient

at catching rock sole. Fishing power corrections were applied to

catches (by species) of the less efficient vessel (Table 6).

Table 6. --Species for which fishing power corrections were

applied, and scaling factors determined by the method

of Kappenman (1992).
22

Estimated Biomass of Major Fish and Invertebrate Groups

Total demersal animal biomass for the overall survey area

was estimated at 18.2 million t, of which fish species accounted

for 80% (14.6 million t), and invertebrates 20% (3.6 million t).

Concentrations of fish biomass were located in Bristol Bay and

along the Alaska Peninsula, around the Pribilof Islands, and

northwest of the Pribilofs (Fig. 7). Although 18 families and

70 species of fish were identified in the catches (Appendix C),

the fish biomass was dominated by cods (Gadidae, 8.4 million t)

and flatfishes (Pleuronectidae, 5.4 million t) (Table 7).

The biomass of invertebrates was comprised primarily of the

phyla Crustacea (1.6 million t), Mollusca (0.4 million t), and

Echinodermata (1.2 million t). A total of 96 invertebrate

species were identified in the survey (Table 8, Appendix C).
Figure 7.--Distribution and relative abundance in kg/ha of total

fish, 1990 eastern Bering Sea bottom trawl survey.
Table 7 .--Biomass estimates (metric tons) for major fish species and fish groups taken during the

1990 eastern Bering Sea bottom trawl survey.

aDifferences in sums of estimates and totals are due to rounding.

bProportion of total estimated biomass,

Total estimated biomass = 18,199,154 t.

fish and invertebrates combined, for the total survey area.
Table 8.--Biomass estimates (metric tons) for major invertebrate species and invertebrate groups

taken during the 1990 eastern Bering Sea bottom trawl survey.

aDifferences in sums of estimates and totals are due to rounding.

bProportion of total estimated biomass,

Total estimated biomass = 18,199,154 t.

fish and invertebrates combined, for the total survey area.
26

Relative Abundance of Individual Fish Species

The 11 most abundant species and species groups of fish are

shown in Figure 8. These taxa accounted for 79% (309 kg/ha) of

total animal mean CPUE (393 kg/ha) and 98% of total fish mean

CPUE (316 kg/ha). Overall, but particularly in water deeper than

50 m, walleye pollock were the most dominant species in the catch

with a mean CPUE of 165 kg/ha. Similarly, Pacific cod were more

abundant at depths exceeding 50 m, but their overall mean CPUE

was only 15 kg/ha. Yellowfin sole and rock sole, with overall

mean catch rates of 47 kg/ha and 30 kg/ha respectively, dominated

catches in water less than 50 m. Alaska plaice, butterfly

sculpins (Hemilepidotus papilio) and Myoxocephalus sculpins were

most prominent at depths less than 100 m. Conversely,

Hippoglossoides spp., Atheresthes spp., and skates were most

abundant in water greater than 100 m. Pacific halibut were

present at low levels in all depth zones. See Appendix D for a

descending rank of all organisms caught.
27

Figure 8. --Relative abundance (%CPUE in kg/ha) of principal

groundfish species by depth zone and for all depths

combined, 1990 eastern Bering Sea bottom trawl survey.
28

Abundance, Distribution, and Size and Age Composition of

Principal Species and Species Groups

Geographical distributions, population numbers and biomass

estimates, and size composition are presented for each of the

following commercially important eastern Bering Sea groundfish:

walleye pollock, Pacific cod, yellowfin sole, rock sole,

Hippoglossoides spp., Alaska plaice, Greenland turbot,

Atheresthes spp., and Pacific halibut (Tables 9-29 and Figs.

9-43). Estimated biomass, population number, and mean size (by

length and weight) are summarized by subarea and for the entire

survey area. Size composition data are illustrated in histograms

relating the population percentage of length by centimeter

interval for each subarea and in population numbers for the total

survey area. Age composition and von Bertalanffy growth

parameters are given for walleye pollock, Pacific cod, yellowfin

sole, and rock sole. Geographical distributions for

noncommercial fish groups are presented in Figures 44 to 49;

biomass estimates for these groups are found in Table 7.

Appendices to the report contain detailed results of the

analysis. CPUE, population, and biomass estimates are given for

each species by stratum in Appendix E. Population estimates by

sex and size class are listed for the total survey area in

Appendix F. Age-length keys and population estimates by age are

given in Appendices G and H, respectively.
Figure 9. --Distribution and relative abundance in kg/ha of walleye

pollock, 1990 eastern Bering Sea bottom trawl survey.
30

Table 9. --Abundance estimates and mean size of walleye pollock

by subarea, 1990 eastern Bering Sea bottom trawl

survey.

Variances of abundance estimates are given in Appendix E.

differences in sums of estimates and totals are due to rounding.
31

Figure 10. --Estimated relative size composition of walleye

pollock (sexes combined) by subarea, 1990 eastern

Bering Sea bottom trawl survey.
Figure 11. --Estimated size composition of walleye pollock (sexes

combined), all subareas combined, 1990 eastern

Bering Sea bottom trawl survey.
Table l0.--Estimated population numbers (millions of

group and subarea,

fish

1990 eastern Bering Sea bott

of walleye pollock by age

om trawl survey.

'Differences in sums of estimates and totals are due to rounding.
34

Table 11. --Estimated biomass (metric tons) of walleye

pollock by age group, 1990 eastern Bering Sea

bottom trawl survey.

'Differences in totals are due to rounding.
Figure 12. --Population number and biomass (metric tons)

estimates by age for walleye pollock, 1990 eastern

Bering Sea bottom trawl survey.
36

Table 12. --Von Bertalanffy growth parameter estimates

for walleye pollock by sex, based on

otolith age readings and length data from

the 1990 eastern Bering Sea bottom trawl survey.
Figure 13. --Von Bertalanffy growth curves and mean lengths at age

(symbols) for male and female walleye pollock, 1990

eastern Bering Sea bottom trawl survey.
Figure 14. --Distribution and relative abundance in kg/ha of Pacific

cod, 1990 eastern Bering Sea bottom trawl survey.
39

Table 13.--Abundance estimates and mean size of Pacific cod by

subarea, 1990 eastern Bering Sea bottom trawl survey.

aVariances of abundance estimates are given in Appendix E.

bdifferences in suns of estimates and totals are due to rounding.
4 0

Figure 15. --Estimated relative size composition of Pacific cod

(sexes combined) by subarea, 1990 eastern Bering Sea

bottom trawl survey.
41

Figure 16. --Estimated size composition of Pacific cod (sexes

combined), all subareas combined, 1990 eastern

Bering Sea bottom trawl survey.
Table 14.--Estimated population numbers (millions of fish) of Pacific cod by age group

and subarea, 1990 eastern Bering Sea bottom trawl survey.

*Differences in sums of estimates and totals are due to rounding.
43

Table 15. --Estimated biomass (metric tons) of Pacific

cod by age group, 1990 eastern Bering Sea

bottom trawl survey.

Differences in totals are due to rounding.
Figure 17. --Population number and biomass (metric tons)

estimates by age for Pacific cod, 1990 eastern

Bering Sea bottom trawl survey.
45

Tab1e 16. --Von Bertalanffy growth parameter estimates

for Pacific cod by sex, based on

otolith age readings and length data from

the 1990 eastern Bering Sea bottom trawl survey.
46

Figure 18.--Von Bertalanffy growth curves and mean lengths at age

(symbols) for male and female Pacific cod, 1990 eastern

Bering Sea bottom trawl survey.
Figure 19.--Distribution and relative abundance in kg/ha of

yellowfin sole, 1990 eastern Bering Sea bottom trawl

survey.
48

Table 17. --Abundance estimates and mean size of yellowfin sole

by subarea, 1990 eastern Bering Sea bottom trawl

survey.

variances of abundance estimates are given in Appendix E.

differences in sues of estimates and totals are due to rounding.
49

Figure 20. --Estimated relative size composition of yellowfin

sole (sexes combined) by subarea, 1990 eastern

Bering Sea bottom trawl survey.
50

Figure 21. --Estimated size composition of yellowfin sole (sexes

combined), all subareas combined, 1990 eastern

Bering Sea bottom trawl survey.
Table 18.--Estimated population numbers (millions of fish) of yellowfin sole by age group

and subarea, 1990 eastern Bering Sea bottom trawl survey.

*Differences in sums of estimates and totals are due to rounding.
52

Table lg.--Estimated biomass (metric tons) of yellowfin

sole by age group, 1990 eastern Bering Sea

bottom trawl survey.

'Differences in totals are due to rounding.
Figure 22. --Population number and biomass (metric tons)

estimates by age for yellowfin sole, 1990 eastern

Bering Sea bottom trawl survey.
54

Table 20. --Von Bertalanffy growth parameter estimates

for yellowfin sole by sex, based on

otolith age readings and length data from

the 1990 eastern Bering Sea bottom trawl survey.
55

Figure 23.--Von Bertalanffy growth curves and mean lengths at

(symbols) for male and female yellowfin sole, 1990age

eastern Bering Sea bottom trawl survey.

57

Table 21. --Abundance estimates and mean size of rock sole by

subarea, 1990 eastern Bering Sea bottom trawl survey.

aVariances of abundance estimates are given in Appendix E.

differences in sues of estimates and totals are due to rounding.
Figure 25. --Estimated relative size composition of rock sole

(sexes combined) by subarea, 1990 eastern Bering Sea

bottom trawl survey.
59

Figure 26. --Estimated size composition of rock sole (sexes

combined), all subareas combined, 1990 eastern

Bering Sea bottom trawl survey.
Table 22. --Estimated p opulation numbers

1990 eastern Bering s

millions of fish) of rock sole by age group and

ea bottom trawl survey.

*Differences in sums of estimates and totals are due to rounding.
61

Table 23. --Estimated biomass (metric tons) of rock sole

by age grop, 1990 eastern Bering Sea bottom

trawl survey.

*Differences in totals are due to rounding.
Figure 27. --Population number and biomass (metric tons)

estimates by age for rock sole, 1990 eastern Bering

Sea bottom trawl survey.
63

Table 24. --Von Bertalanffy growth parameter estimates

for rock sole by sex, based on otolith age

readings and length data from the 1990

eastern Bering Sea bottom trawl survey.
Figure 28.--Von Bertalanffy growth curves and mean lengths at age

(symbols) for male and female rock sole, 1990 eastern

Bering Sea bottom trawl survey.
Figure 29.--Distribution and relative abundance in kg/ha of

Hippoglossoides spp.,

trawl survey.

1990 eastern Bering Sea bottom
66

Table 25. --Abundance estimates and mean size of Hippoglossoides

spp. by subarea, 1990 eastern Bering Sea bottom trawl

survey.

aVariances of abundance estimates are given in Appendix E.

bdifferences in sum of estimates and totals are due to rounding.
67

Figure 30. --Estimated relative size composition of

Hippoglossoides Spp. (sexes combined) by subarea,

1990 eastern Bering Sea bottom trawl survey.

Figure 32.--Distribution and relative abundance in kg/ha of

Alaska plaice, 1990 eastern Bering Sea bottom trawl

survey.
Table 26. --Abundance estimates and mean size of Alaska plaice

by subarea, 1990 eastern Bering Sea bottom trawl

survey.

aVariances of abundance estimates are given in Appendix E.

bdifferences in sums of estimates and totals are due to rounding.
7 1

Figure 33. --Estimated relative size composition of Alaska plaice

(sexes combined) by subarea, 1990 eastern Bering Sea

bottom trawl survey.

Figure 35. --Distribution and relative abundance in kg/ha of

Greenland turbot, 1990 eastern Bering Sea bottom trawl

survey.
74

Table 27. --Abundance estimates and mean size of Greenland turbot

by subarea, 1990 eastern Bering Sea bottom trawl

survey.

Variances of abundance estimates are given in Appendix E.

Differences in suns of estimates and totals are due to rounding.
Figure 36. --Estimated relative size composition of Greenland

turbot (sexes combined) by subarea, 1990 eastern

Bering Sea bottom trawl survey.
76

Figure 37. --Estimated size composition of Greenland turbot

(sexes combined), all subareas combined, 1990

eastern Bering Sea bottom trawl survey.
Figure 38.--Distribution and relative abundance in kg/ha of

Atheresthes spp., 1990 eastern Bering Sea bottom trawl

survey.
78

Table 28.--Abundance estimates and mean size of Atheresthes spp.

by subarea, 1990 eastern Bering Sea bottom trawl

survey.

Variances of abundance estimates are given in Appendix E.

Differences in suns of estimates and totals are due to rounding.
79

Figure 39. --Estimated relative size composition of Atheresthes

spp. (sexes combined) by subarea, 1990 eastern

Bering Sea bottom trawl survey.
80

Figure 40. --Estimated size composition of Atheresthes spp.

(sexes combined), all subareas combined, 1990

eastern Bering Sea bottom trawl survey.
Figure 41. --Distribution and relative abundance in kg/ha of

Pacific halibut, 1990 eastern Bering Sea bottom trawl

survey.
82

Table 29. --Abundance estimates and mean size of Pacific halibut

by subarea, 1990 eastern Bering Sea bottom trawl

survey.

aVariances of abundance estimates are given in Appendix E.

bdifferences in suns of estimates and totals are due to rounding.
8 3

Figure 42. --Estimated relative size composition of Pacific

halibut (sexes combined), by subarea, 1990 eastern

Bering Sea bottom trawl survey.
8 4

Length (cm)

Figure 43. --Estimated size composition of Pacific halibut

(sexes combined), all subareas combined, 1990

eastern Bering Sea bottom trawl survey.
Figure 44. --Distribution and relative abundance in kg/ha of

skates, 1990 eastern Bering Sea bottom trawl survey.
Figure 45. --Distribution and relative abundance in kg/ha of

sculpins, 1990 eastern Bering Sea bottom trawl survey.
Figure 46.--Distribution and relative abundance in kg/ha of

eelpouts, 1990 eastern Bering Sea bottom trawl survey.
Figure 47.--Distribution and relative abundance in kg/ha of

poachers, 1990 eastern Bering Sea bottom trawl survey.
Figure 48.--Distribution and relative abundance in kg/ha of

snailfish and lumpsuckers,

bottom trawl survey.

1990 eastern Bering Sea
Figure 49. --Distribution and relative abundance in kg/ha of

smelts, 1990 eastern Bering Sea bottom trawl survey.
91

CITATIONS

Alverson, D. L., and W. T. Pereyra. 1969. Demersal fish

explorations in the northeast Pacific Ocean--An evaluation

of exploratory fishing methods and analytical approaches to

 stock size and yield forecasts. J. Fish. Res. Board Can.

26:1985-2001.

Bakkala, R. G., and K. Wakabayashi (editors). 1985. Results of

cooperative U.S. -Japan groundfish investigations in the

Bering Sea during May-August 1979. Int. North Pac. Fish.

comm., Bull. 44, 252 p.

Bakkala, R. G. 1988. Structure and historical changes in the

groundfish complex of the eastern Bering Sea. Ph.D. Diss.,

Hokkaido Univ., Hakodate, Japan, 187 p.

Geisser, S., and W. F. Eddy. 1979. A predictive approach to

model selection. J. Am. Stat. Assoc. 74(365):153-160.

Kappenman, R. F. 1992. Robust estimation of the ratio of

scale parameters for positive random variables. AFSC

Processed Rep. 92-01, 10 p. Alaska Fish. Sci. Cent., Natl.

Mar. Fish. Serv., 7600 Sand Point Way NE, BIN C15700,

Seattle, WA 98115.

North Pacific Fishery Management Council. 1990. Stock

assessment and fishery evaluation document for groundfish

resources in the Bering Sea/Aleutian Islands region as

projected for 1991, 281 p. Available from North Pacific

Fishery Management Council, P.O. Box 103136, Anchorage, AK

99510.

Pereyra, W. T., J. E. Reeves, and R. G. Bakkala. 1976. Demersal

fish and shellfish resources of the eastern Bering Sea in

the baseline year 1975. Processed Rep., 619 p. Northwest

and Alaska Fish. Cent., Natl. Mar. Fish. Serv., NOAA, 2725

Montlake Blvd. E., Seattle, WA 98112.

Rose, C. S., and G. E. Walters. 1990. Trawl width variation

during bottom trawl surveys: causes and consequences. In L.

Low (editor), Proceedings of the symposium on application of

stock assessment techniques to gadids, p. 57-67. Int. North

Pac. Fish. Comm., Bull. 50.

Smith, G. B., and R. G. Bakkala. 1982. Demersal fish resources

of the eastern Bering Sea: Spring 1976. U.S. Dep. Commer.,

NOAA Tech. Rep. NMFS SSRF-754, 129 p.

Stevens, B. G., and R. A. Macintosh. 1990. Report to industry

on the 1990 eastern Bering Sea crab survey. AFSC Processed

Rep. 90-09, 50 p. Kodiak Facility, Alaska Fish. Sci. Cent.,
92

Natl. Mar. Fish. Serv., P.O. Box 1638, Kodiak, AK 99615.

von Bertalanffy, L. 1938. A quantitative theory of organic

growth. Hum. Biol. 10:181-213.

Wakabayashi, K., R. G. Bakkala, and M. S. Alton. 1985. Methods

of the U.S.-Japan demersal trawl surveys. In R. G. Bakkala

and K. Wakabayashi (editors), Results of cooperative

U.S.-Japan groundfish investigations in the Bering Sea

during May-August 1979, p. 7-29. Int. North Pac. Fish.

comm., Bull. 44.
93

APPENDIX A

Station Data, 1990 Eastern Bering Sea Bottom Trawl Survey

Appendix A contains station data by vessel for the 352

successfully completed standard survey stations. In using the

tables the following should be noted:

1. Time represents the nearest hour at the start of the

tow.

2. Haul numbers are not always sequential because special

study and unsatisfactory hauls were omitted.

List of Tables

Table Page

A-l. Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

A-2. Ocean Hope 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
94

Table A-1. --Haul data for stations sampled by the RV Alaska

during the 1990 eastern Bering Sea bottom trawl

survey.
95

Table A-l. --Continued.
96

Table A-l. --Continued.
97

Table A-l. --Continued.
98

Table A-2. --Haul data for stations sampled by the FV Ocean

Hope 3 during the 1990 eastern Bering Sea bottom

trawl survey.
99

Table A-2. --Continued.
100

Table A-2. --Continued.
101

Table A-2. --Continued.
102

APPENDIX B

Schematic Diagram of Trawl Gear

List of Figures

Figure Page

B-l. Schematic diagram of trawl used during the

1990 eastern Bering Sea bottom trawl survey . . . . . . . . . . 103
103

Figure B-l.--Schematic diagram of trawl used during the 1990

eastern Bering Sea bottom trawl survey.
104

APPENDIX C

List of Species Encountered

Appendix C contains a computer listing of all fish and

invertebrate species taken during the 1990 eastern Bering Sea

bottom trawl survey.

List of Tables

Table Page

C-l. Fish species encountered during the 1990 eastern

Bering Sea bottom trawl survey ........................ 105

C-2. Invertebrate species encountered during the 1990

eastern Bering Sea bottom trawl survey . . . . . . . . . . . . . . . . 108
105

Table C-l.-- Fish species encountered during the 1990 eastern

Bering Sea bottom trawl survey.
106

Table C-l. --Continued.
107

Table C-l. --Continued.
108

Table C-2.--Invertebrate species encountered during the 1990

eastern Bering Sea bottom trawl survey.
109

Table C-2. --Continued.
110

Table C-2. --Continued.
111

Table C-2. --Continued.
112

Table C-2. --Continued.
113

APPENDIX D

Rank Order of Relative Abundance of Fish and Invertebrates

Appendix D ranks all fish and invertebrates caught during the

1990 eastern Bering Sea bottom trawl survey by descending CPUE.

List of Tables

Table Page

D-l. CPUE rank order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Table D-l. --Rank order of fish and invertebrate taxa by relative abundance (kg/ha) from the

1990 eastern Bering Sea bottom trawl survey.
Table D-l. --Continued.
Table D-l. --Continued.
Table D-l. --Continued.
Table D-l. --Continued.
Table D-l. --Continued.
120

APPENDIX E

Abundance Estimates for Principal Fish Species

Appendix E presents estimates of catch-per-unit-effort

(CPUE), population numbers and biomass for the principal fish

species. Estimates of variance and confidence intervals do not

incorporate variation associated with fishing power corrections or

measurements of effort. CPUE is measured in kilograms (kg) and

numbers (no.) per hectare. Estimates are given separately for

each of the 10 geographic strata used in the analysis; estimates

for each of the six standard subareas are presented as subtotals

of the component strata. Stratum codes correspond to subareas as

follows:

Subarea Stratum

1 10

2 20

3 31

32 (Pribilof Island high density)

4 41

42 (Pribilof Island high density)

43 (St. Matthew Island high density)

5

6

50

61

62 (St. Matthew Island high density)
121

List of Tables

Table

E-l.

E-2.

E-3.

E-4.

E-5.

E-6.

E-7.

E-8.

E-9.

Walleye pollock ...................................... 122

Pacific cod .......................................... 124

Yellowfin sole ....................................... 126

Rock sole ............................................ 128

Hippoglossoides spp. ................................. 130

Alaska plaice ......................................... 132

Greenland turbot ..................................... 134

Atheresthes spp. ..................................... 136

Pacific halibut ...................................... 138
122

Table E-l --CPUE, population, and biomass estimates for walleye pollock.
123

Table E-l .--Continued.
124

Table E-2.--CPUE, population, and biomass estimates for Pacific cod.
125

Table E-2.--Continued.
126

Table. E-3.--CPUE, population,and biomass estimates for yellowfin sole.
127

Table E-3.--Continued.
128

Table E-4.--CPUE, population,and biomass estimates for rock sole.
129

Table E-4.--Continued.
130

Table E-5.--CPUE, population,and biomass estimates for Hippoglossoides
131

Table E-5.--Continued.
132

Table E-6.--CPUE, population,and biomass estimates for Alaska plaice.
133

Table E-6.--Continued.
134

Table E-7.--CPUE, population, and biomass estimates for Greenland turbot.
135

Table E-7.--Continued.
136

Table E-8.--CPUE, population,and biomass estimates for Atheresthes spp.
137

Table E-8.--Continued.
138

Table E-9.--CPUE, population,and biomass estimates for Pacific halibut.
139

Table E-9.--Continued.
140

APPENDIX F

Population Estimates by Sex and Size

Groups for Principal Fish Species

Appendix F presents estimates of the numbers of individuals

within the overall survey area by sex and size group for principal

fish species.

List of Tables

Table Page

F-l. Walleye pollock ...................................... 141

F-2. Pacific cod .......................................... 143

F-3. Yellowfin sole ....................................... 145

F-4. Rock sole ............................................ 146

F-5. Hippoglossoides spp. ................................. 147

F-6. Alaska plaice ........................................ 148

F-7. Greenland turbot ..................................... 149

F-8. Atheresthes spp. ..................................... 150

F-9. Pacific halibut ...................................... 151
141

Table F-l .--Population estimates by sex and size group for walleye

pollock.
142

Table F-l. --Continued.
143

Table F-2. --Population estimates by sex and size group for Pacific cod.
144

Table F-2. --Continued.
145

Table F-3. --Population estimates by sex and size group for yellowfin
146

Table F-4. --Population estimates by sex and size group for rock sole.
147

Table F-5. --Population estimates by sex and size group for

Hippoglossoides spp.
148

Table F-6 .--Population estimates by sex and size group for Alaska

plaice.
149

Table F-7. --Population estimates by sex and size group for Greenland

turbot.
150

Table F-8. --Population estimates by sex and size group for Atheresthes

spp.
151

Table F-9. --Population estimates by sex and size group for Pacific

halibut.
152

Table F-9. --Continued.
153

APPENDIX G

Age-Length Keys for Principal Fish Species

Appendix G presents age-length keys for principal species of

fish by sex and sexes combined. Lengths are expressed in

millimeters. Asterisks indicate ages affected by the linear

interpolation used to assign age distributions to length classes

(in the age-length key) not represented by collected age data.

List of Tables

Table Page

G-l. Walleye pollock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

G-2. Pacific cod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

G-3. Yellowfin sole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

G-4. Rock sole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171







Table G-2 .--Continued.


Table G-2. --Continued.

FEMALE KEY
Table G-2 .--Continued.

Table G-2 .--Continued.

Table G-3 .--Continued.

FEMALE KEY
Table G-3 .--Continued.

Table G-4. --Continued.
173
174

APPENDIX H

Population Estimates by Age for Principal Fish Species

Appendix H presents population estimates and mean lengths at

age by sex and for sexes combined. Population estimates listed

as "below minimum key length" and "above maximum key length"

refer to fish lengths that lack age observations. Asterisks

indicate ages affected by the linear interpolation used to assign

age distributions to length classes (in the age-length key) not

represented by collected age data.

List of Tables

Table Page

H-l. Walleye pollock .............................. . . . . . . . . 175

H-2. Pacific cod ........................................ 179

H-3. Yellowfin sole . . . . . . . . . . ............................ 183

H-4. Rock sole .......................................... 187
Table H-l .--Population estimates of walleye pollock by age (years), derived from data

collected during the 1990 eastern Bering Sea bottom trawl survey.

are presented in millimeters.

Mean lengths
Table H-l .--Continued.
Table H-l .--Continued.
Table H-l .--Continued.

MALES, FEMALES, AND UNSEXED
Table H-2 .--Population estimates of Pacific cod by age (years), derived from data collected

during the 1990 eastern Bering Sea bottom trawl survey. Mean lengths are

presented in millimeters.
Table H-2 .--Continued.

FEMALES
Table H-2 .--Continued.

UNSEXED
Table H-2. --Continued.

MALES, FEMALES, AND UNSEXED
Table H-3 .--Population estimates of yellowfin sole by age (years), derived from data

collected during the 1990 eastern Bering Sea bottom trawl survey.

are presented in millimeters.

Mean lengths

MALES
Table H-3 .--Continued.

FEMALES
Table H-3 .--Continued.

UNSEXED
Table H-3 .--Continued.
Table H-4 .--Population estimates of rock sole by age (years), derived from data collected

during the 1990 eastern Bering Sea bottom trawl survey. Mean lengths are

presented in millimeters.
Table H-4. --Continued.

FEMALES
Table H-4.--Continued.

UNSEXED
Table H-4 .--Continued.

MALES, FEMALES, AND UNSEXED
RECENT TECHNICAL MEMORANDUMS

Copies of this and other NOAA Technical Memorandums are available from the

National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22167

(web site: www.ntis.gov). Paper and microfiche copies vary in price. 

AFSC6 WOLOTIRA, R. J., JR., T. M. SAMPLE, S. F. NOEL, and C. R. ITEN. 1993. Geographic and bathymetric

distributions for many commercially important fishes and shellfishes off the West Coast of North America,

based on research survey and commercial catch data, 1912-84, 184 p. NTIS No. PB93-167682. 

5 GUTTORMSEN, M., R. NARITA, J. GHARRETT, G. TROMBLE, and J. BERGER. 1992. Summary

of observer sampling of domestic groundfish fisheries in the northeast Pacific Ocean and Eastern Bering

Sea, 1990, 281 p. NTIS No. PB93-159085.

4 GUTTORMSEN, M., R. NARITA, and J. BERGER. 1992. Summary of U. S. observer sampling

of joint venture fisheries in the northeast Pacific Ocean and Eastern Bering Sea, 1990, 78 p. NTIS No.

PB93-127546.

3 JOHNSON, P. A., S. D. RICE, and M. M. BABCOCK (compilers). 1992. Impacts of oil pollution

and Prince William Sound studies: Bibliography of 1960-91 publications and reports, Auke Bay Laboratory,

98 p. NTIS No. PB93-114064.

2 KAJIMURA, H., and E. SINCLAIR. 1992. Fur seal investigations, 1990, 192 p. NTIS No. PB93-

109080.

1 MERRICK, R. L., D. G. CALKINS, and D. C. MCALLISTER. 1992. Aerial and ship-based surveys

of Steller sea lions (Eumetopias jubatus) in southeast Alaska, the Gulf of Alaska, and Aleutian Islands

during June and July 1991, 41 p. NTIS No. PB92-235928. 

F/NWC216 ZENGER, H. H., JR., and M. F. SIGLER. 1992. Relative abundance of Gulf of Alaska sablefish

and other groundfish based on National Marine Fisheries Service longline surveys, 1988-90, 

103 p. NTIS No. PB92-222843.

215 KINOSHITA, R. K., B. M. K. BROOKE, L. E. QUEIROLO, and J. M. TERRY. 1992. Economic status of

the groundfish fisheries off Alaska, 1990, 99 p. NTIS No. PB92-187699.

214 ANTONELIS, G. A. 1992. Northern fur seal research techniques manual, 47 p. NTIS No. PB92-191824.

213 BAKKALA, R. G., W. A. KARP, G. F. WALTERS, T. SASAKI, M. T. WILSON, T. M. SAMPLE,

A.M. SHIMADA, D. ADAMS, and C. E. ARMISTEAD. 1992. Distribution, abundance, and biological

characteristics of groundfish in the eastern Bering Sea based on results of U.S.-Japan bottom trawl and

hydroacoustic surveys during June-September 1988, 362 p. NTIS number pending. 

212 WILSON, M. T., and C. E. ARMISTEAD. 1991. 1989 bottom trawl survey of the eastern Bering Sea

continental shelf, 212 p. NTIS No. PB92-135607.

211 LOW, L-L. (editor). 1991. Status of living marine resources off Alaska as assessed in 1991, 

95 p. NTIS No. PB92-145713.