NOAA Technical Memorandum NMFS-AFSC-12

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Alaska Fisheries Science Center

April 1993

by

Robin C. Harrison

Data Report: 1991 Bottom Trawl

Survey of the Aleutian Islands Area
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:

 Harrison, R.C. 1993. Data report: 1991 bottom trawl survey of the 

Aleutian Islands area. U.S. Dep. Commer., NOAA Tech. Memo. 

NMFS-AFSC-12, 144 p.

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

National Marine Fisheries Service, NOAA.
NOAA Technical Memorandum NMFS-AFSC-12

Data Report: 1991 Bottom Trawl

Survey of the Aleutian Islands Area

by Robin C. Harrison

Alaska Fisheries Science Center

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

Seattle, WA 98115-0070

U.S. DEPARTMENT OF COMMERCE

Ronald H. Brown, Secretary

National Oceanic and Atmospheric Administration

John A. Knauss, Administrator

National Marine Fisheries Service

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

April 1993
This document is available to the public through:

National Technical Information Service

U.S. Department of Commerce

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Springfield, VA 22161
Notice to Users of this Document 

This document is being made available in .PDF format for the convenience of users; however, the 

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iii

ABSTRACT

The Resource Assessment and Conservation Engineering (RACE) Division of the

Alaska Fisheries Science Center, Seattle, Washington, conducted a groundfish resources

survey of the Aleutian Islands region from July to September 1991. Previous surveys in

this region occurred in 1980, 1983, and 1986. The survey area covered the southern

Bering Sea, from long. 165 o W to 170° W and the Aleutian Islands waters, from long.

170° W to 170o30' E. Two chartered vessels, the Green Hope and Ocean Hope 1,

completed 377 preselected stations covering the continental shelf and slope from 16 m

to 521 m in depth. Both vessels were equipped with standard RACE Division

Noreastem high- opening bottom trawls rigged with rubber bobbin roller gear. ’

 The primary survey objectives were to define the distribution and relative

abundance of the principal groundfish and commercially important invertebrate species

inhabiting the Aleutian Islands region from near shore to approximately 500 m in depth

and to collect data to define selected biological parameters for age, growth, length-weight

relationships, feeding habits, and size, sex, and age composition. The survey also

collected ancillary data and specimens requested by other research groups.

Survey results are presented, including estimates of biomass and catch per unit

of effort, species distribution, length frequency distributions, and length-weight

relationships for important commercial species.

A total of 111 fish species were identified from the survey catches.” Walleye

pollock, Pacific cod, Atka mackerel, Pacific ocean perch, and northern rockfish were the

dominant species within the survey region. Sablefish, Pacific halibut, arrowtooth

flounder, and giant grenadier were locally abundant in some areas. The only abundant
i v

invertebrate in the survey region was red (magistrate armhook) squid, which was the

sixth most abundant species in the Southwest Aleutian Islands area.
V

CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..l

Methods ........................................................ ...7

Vessels and Gear ............................................ ...7

Survey Area and Sampling Design ................................. .8

Collection and Processing of Samples .............................. 11

Data Analysis ................................................ 12

Results .......... . ............................................. ..15

Survey Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..15

Distribution, Abundance, and Biological Data ........................ 18

Catch Results by Area ..................................... 18

Catch Results by Species ................................. .22

Walleye polIock ................................... .22

Pacific cod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..2 8

Sablefish ......................................... .34

Atka mackerel .................................... .40

Arrowtooth flounder ................................ .46

Kamchatka flounder ................................ .52

Pacific halibut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..5 8

Rock sole ........................................ .64

Greenland turbot .................................. .70

Other flatfish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76

Pacific ocean perch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84

Northern rockfish .................................. .90

Rougheye rockfish ................................. .96

Shortraker rockfish ................................. 102

Shortspine thornyhead .............................. 108

Other rockfish .................................... 114

Sculpins.............................................................119

Skates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..119

Cephalopods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Crabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..120

Citations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...122

Appendix A. Gear Specifications and Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Appendix B. Lists of Species Encountered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Appendix C. Length-Weight Regressions for Major Species . . . . . . . . . . . . , . . . . . 133
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vii

PREFACE

This document is the third of three standard reports1

 presenting data from the

1991 Aleutian Islands groundfish survey conducted by the National Marine Fisheries

Service (NMFS). These reports are:

1) A Cruise Report, outlining the survey objectives, documenting itinerary, and

personnel, and summarizing the major accomplishments:

2) A Report to the Industry, containing a fishing log consisting of raw haul

and catch data for each haul made during the survey as well as species-based

summaries of catch per unit effort by haul; and

3) This document, a Data Report, containing a detailed description of the

planning and implementation of the survey, distribution and abundance charts, length

frequency plots, tables of estimated biomass, catch per unit effort, average weight and

length estimates, and length versus weight regression parameters.

1 Available from Director, Resource Assessment and Conservation

Engineering Division, Alaska Fisheries Science Center, National

Marine Fisheries Service, 7600 Sand Point Way N.E., Building 4, BIN

C15700, Seattle, WA 98115-0070.
INTRODUCTION

The Resource Assessment and Conservation Engineering (RACE) Division of the

Alaska Fisheries Science Center (AFSC) conducted a groundfish resources trawl survey

of the Aleutian Islands region from July to September, 1991.

The survey objectives were to

1) Define the distribution of the principal groundfish and commercially important

invertebrate species inhabiting the Aleutian Islands region from near shore to

approximately 500 m in depth:

2) Obtain data from which to estimate the abundance of the principal groundfish

species:

3) Collect data to define selected biological parameters for age, growth, lengthweight relationships, feeding habits and size, sex, and age composition;

4) Collect accurate net mensuration data on trawls used by the vessels involved

in the survey; and

5) Obtain ancillary data and collect specimens requested by other research

groups, including incidence of Pacific lamprey (Lampetra tridentata) predation on

walleye pollock (Theragra chalcogramma), pollock blood samples for DNA stock

identification studies, whole fish specimens for the University of Washington’s fish

collection, whole specimens of skates for Bucknell University, and specimens of snails

for the NMFS Observer Program of the AFSC’s Resource Ecology and Fisheries

Management (REFM) Division.

Previous major surveys in this region, made in cooperation with the National

Research Institute for Far Sea Fisheries, Fisheries Agency of Japan, occurred in 1980,

1983, and 1986 (Ronholt et al. In prep.). In 1991, two chartered vessels, the Green Hope

and Ocean Hope 1, sampled preselected stations covering the continental shelf and slope
2

from 16 m to 521 m in depth (Fig. l), and two additional stations at 697 m and 711 m to

collect specimens. The survey area covered a portion of the southern Bering Sea, from

long. 165oW to 170°W and the Aleutian Islands, from long. 170°W to 170o30’E (Fig. 2).
Figure l.--Stations sampled during the 1991 Aleutian Islands bottom trawl survey.
Figure 2.--Area surveyed during the 1991 Aleutian Islands bottom trawl survey.
Figure 2.--Continued.
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7

METHODS

Vessels and Gear

Two chartered commercial stem trawlers were used throughout the survey. The

Ocean Hope 1 is 32.9 m (108 feet) in length and powered by a single main engine with

850 continuous horsepower. Deck equipment included paired hydraulic winches with

1,100 m (600 fathom) of 2.2 cm (7/8 inch) cable per drum, two hydraulic net reels (one

mounted over the stem ramp and the other mounted forward on the working deck), and

two winches (one moveable) mounted on the main boom for lifting. The Green Hope is

30.7 m (100 feet) in length and powered by a single main engine with 565 continuous

horsepower. Deck equipment included paired hydraulic trawl winches with 1,463 m

(800 fathoms) of 1.91 cm (3/4 inch) cable per drum, two hydraulic net reels (one

mounted over the stem ramp and the other mounted forward on the working deck), and

two stationary winches mounted on the main boom for lifting. Electronic equipment on

both vessels consisted of Global Positioning System (GPS) and Loran C receivers with

converters for geodetic positions, Loran C video plotters, two radars, single band and

VHF radios, color video fish finders, and auto-pilots.

Both vessels used standard RACE Division Poly-Nor’eastem, hard bottom, highopening bottom trawls constructed of 12.7 cm (5 inch) stretched mesh polyethylene web

with a 3.2 cm (l-1/4 inch) stretched mesh nylon liner in the codend to retain smaller

specimens. Each trawl was rigged with rubber bobbin roller gear and towed with

54.9 m [30 fathom) triple dandylines and 1.83 m x 2.74 m (6 feet x 9 feet), 800 kg

( 1,800 lbs) steel V-doors. An acoustic net mensuration system, consisting of headrope

and wing units transmitting to a towed hydrophone, was used to measure the horizontal
and vertical dimensions of the survey trawls used by each vessel. Complete gear

specifications and diagrams are presented in Appendix A.

Survey Area and Sampling Design

The geography of the Aleutian Islands presented several problems in survey

station selection. Unlike the Bering Sea and Gulf of Alaska, where the continental shelf

is wide enough to allow selection of stations on a grid, the shelf in the Aleutian Islands is

narrow to nonexistent. Where the shelf does exist, areas rich in coral and sponge which

are associated with a rocky irregular substrate present difficulty in sampling with

standard survey trawls. These considerations, along with a reduction of available vessel

tune compared to previous surveys, influenced the decision to not select station

locations in a completely random manner since a majority of stations would likely occur

on untrawlable ground.

Limited vessel time and the need to achieve a reasonable level of sampling

intensity weighed heavily on the decision to use successfully trawled stations from

previous surveys as a pool from which 1991 survey stations would be selected.

The Aleutian Islands survey region was divided into five major geographical

units: the Southern Bering Sea Area and the Northeast, Northwest, Southeast, and

Southwest Aleutian Islands Areas. Each of these areas was divided longitudinally into

two to three subareas (Fig. 3). A depth zone (l-100 m, 101-200 m, 201-300 m, and

30l-500 m) within a subarea defines a stratum for planning and analysis purposes. This

sampling design was used in 1991 to provide consistency with previous surveys. Data

from triennial surveys conducted in 1980 and 1983 were analyzed to determine the

number of stations required in each strata to provide the lowest variance for abundance
Figure 3. --Areas and subareas used for the 1991 Aleutian Islands bottom trawl survey. A stratum is de

zone within a subarea.
10

estimates of major species throughout the survey area ( Ronholt et al. In prep.). This

sample allocation scheme was used in 1986, and again for the 1991 survey.

Successfully sampled stations from all previous years were pooled and distributed

among subareas by geographic location based on sample allocation units. The allocation

units were essentially longitudinal subdivisions of each stratum (depth zone in a

subarea) resulting in regions of approximately equal area. This ensured that selected

stations were well distributed throughout each subarea. Within each sample allocation

unit, the allocated number of stations were selected at random from the unit’s pool of

previously sampled stations. These selected stations were then randomly prioritized to

three levels of importance, which allowed rapid selection of stations by Chief Scientists

as survey progress was monitored and remaining stations needed to be selected on a

priority basis. Half of the stations were assigned top priority and the remaining stations

were evenly split between medium and low priority. If an odd number of stations were

split, the leftover station was assigned medium priority. If a sample allocation unit

contained only two stations, they were both assigned top priority. A total of 452 stations

were selected, which resulted in 372 possible stations if all high and medium priority

stations were sampled. Completion of the high priority stations would represent the

minimum number of observations necessary to meet the survey objectives. After

selection, stations were then divided between the two participating vessels.

Assignment of stations to each vessel was evenly distributed to allow the vessels

to operate together throughout much of the survey area. During the course of the

survey, some stations were reallocated between vessels by the Chief Scientists to

minimize running time between stations.
11

Collection and Processing of Samples

Catches weighing less than 1.1 metric tons (t) were completely sorted and

weighed by species. Larger catches were subsampled after obtaining total weight with a

load cell or estimating it volumetrically. The dominant species were subsampled prior

to sorting. Whenever possible, all non-dominant fish and large invertebrate species in

the catch were completely sorted, counted, and weighed. All fish and commercial crabs

were identified to species whenever possible. Some fish, such as certain skates

(Rajidae), for which taxonomic information was scarce or under revision, were identified

to family or genus if positive species identification was impossible.

Data collection effort was concentrated on 13 species selected based on their

commercial value or high abundance in the sampling area. The priority species were

walleye pollock

Pacific cod

Atka mackerel

sablefish

Pacific ocean perch

northern rockfish

rougheye rockfish

shortraker rockfish 

shortspine thornyhead

rock sole

arrowtooth flounder

Pacific halibut

Greenland turbot

Theragra chalcogramma

Gadus macroce

Pleurogrammus monopterygius

Anoplopoma fimbria

Sebastes alutus

Sebastes polvspinis Sebastes aleutianus.

Sebastes borealis

Sebastolobus alascanus

Pleuronectes bilineatus

Atheresthes evermanni

Hippoglossus stenolepis

Reinhardtius hippoglossoides

Less sampling effort was applied to other commercial species with patchy or

limited distributions, such as

rex sole Errex zachiru 

Dover sole Microstomus pacificus

flathead sole Hippoglossoides elassodon

Kamchatka flounder Atheresthes stomias

yellowfin sole Pleuronectes asper

Pacific herring Clupea pallasi

other rockfish species Sebastes spp.
12

A random sample of each commercial species was sorted by sex and individual

fork lengths (FL) were measured. Age structures (otoliths, scales, or both) and

individual weight and length (FL) data were randomly collected for the priority species.

International Pacific Halibut Commission biologists participating in the survey collected

age structures and other biological data for Pacific halibut throughout the cruise.

Biologists from the AFSC’s Trophic Interactions Program collected stomach samples

from the priority species throughout the survey.

Data Analysis

Biomass estimates were calculated using the area-swept method (Alverson and

Pereyra 1969). Each catch was standardized by dividing catch weight by the area swept

by the trawl during each tow. This method ‘produces catch per unit of effort (CPUE),

with units of kilograms per square kilometer trawled.. Mean CPUE was estimated for

each species as the arithmetic mean of observed CPUE values from all successfully

trawled stations within each stratum. Mean CPUE for the entire survey region was

estimated as an area weighted mean of the stratum estimates. Mean CPUE values for

areas within the survey region were also calculated in this way.

Biomass estimates were calculated for each stratum by multiplying the mean

CPUE by the stratum area. Population numbers for each stratum were calculated by

dividing the station CPUE by the mean weight of individuals at each station and then

multiplying the arithmetic mean of population numbers from all stations in a stratum by

the stratum area. Estimates of biomass and population numbers by area and region

were calculated by summing strata estimates.

Size composition for each stratum was estimated by first expanding the length

frequency sample for each station to the total catch (in numbers) per square kilometer
13

for that station. The stratum population within a sex-length category was calculated by

multiplying the stratum population by the proportion of fish in that category from the

summed station data. Population size composition estimates were summed over strata

to create estimates by area. A detailed description of the analytical procedures is

presented in Wakabayashi et al. (1985).
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15

RESULTS

Survey Results

Of the 452 stations allocated for the 1991 groundfish survey, 377 stations were

attempted and 340 of these were considered successful and were included in biomass

and size composition analysis (Table 1). Successful tows fell into two categories. The

first category included tows in which there were no noticeable problems such as net

damage or abnormal behavior of the net or vessel during the tow: 80% of the successful

tows fell into this category. The second category included tows where the net briefly

hung up on the bottom or was found to be tom, but the problems were not substantial

enough to affect the catch. This category contributed 10% of the successful tows. The

remaining 37 tows were considered unsuccessful due to either severe hang up,

significant trawl damage or other abnormality in the tow procedure which could affect

the quality of the tow.

Because of good weather and generally trouble-free vessel operations, most

selected stations in the Southern Bering Sea and Northeast and Southeast Aleutian areas

were attempted during the first two-thirds of the survey period. In the Southern Bering

Sea Area, only one station was bypassed (98% attempted), while in the Northeast and

Southeast Areas over 84% of the stations were attempted. In the western Aleutian

Island areas, the last one-third of the survey period was marked by deteriorating weather

conditions, the expenditure of additional running time to procure fuel, and generally

poor bottom conditions, which combined to reduce the sampling density. In the

Northwest and Southwest Areas, 58% and 70% of the allocated stations were attempted,

respectively. In both western areas, less than 44% of the l-100 m stations were

attempted.
16

Table 1. -Number of allocated, attempted, and successfully completed stations and sampling density

during the 1991 Aleutian Islands groundfish survey.
17

Overall, 90% of the tows were successful, ranging by area from 86% to

92% successful. Many of the successfully towed stations from previous surveys had

been sampled by larger Japanese vessels using trawls equipped with automobile tire

roller gear more suitable for the rough bottom conditions encountered. In 1991, the U.S.

trawls equipped with smaller roller gear were not as successful at some of those stations.

Unsuccessful tows were most prevalent in the 101-200 m strata in the Northeast Area

(14%), the combined l-100 m and 101-200 m strata in the Southeast Area (15%),

301-500 m strata in the Southeast Area (20%), and the 301-500 m strata in the

Southern Bering Sea (34%). More than 75% of the hauls attempted in the l-100 m

strata in the Northwest and Southwest Areas were successful, even though bottom

conditions in those areas contributed to a low percentage (less than 33%) of attempted

hauls.

The low number of attempted stations and relatively low success rate for

stations in the shallow strata, particularly in the western Aleutian Islands, suggests the

need to evaluate the merits of expending additional effort to locate trawlable locations.
18

Distribution, Abundance, and Biological Data

Catch Results bv Area

A total of 111 fish species representing 28 families were identified during

the 1991 Aleutian Islands groundfish survey. Appendix B presents lists of fish and

invertebrate species encountered.

Relative abundance estimates, reported as CPUE; are presented in Table 2

for the 20 most abundant groundfish species in each of the five reporting areas. The

four areas comprising the Aleutian Islands region were generally dominated by 5

species: Atka mackerel, Pacific ocean perch, waIleye pollock, northern rockfish, and

Pacific cod, which as group accounted for 86% of the 20 most abundant species. These

five species were also the most dominant species in the Northeast and Southwest Areas.

In the Northwest Area, giant grenadiers were the fifth most abundant species, followed

by northern rockfish. Northern rockfish were relatively uncommon in the Southeast

Area, where sablefish were fifth in relative abundance. Atka mackerel was the most

abundant species in all but the Northeast Area, contributing over 39% of the CPUE of

the 20 most common groundfish in each of the other Aleutian Islands Areas.

The Southern Bering Sea region had a noticeably different species

composition, dominated by walleye pollock, which contributed almost 50% of the total

CPUE in this area. The 5 dominant species in this area were walleye pollock,

arrowtooth flounder, Pacific cod, rock sole, and Pacific halibut, which together

accounted for 82% of the total CPUE of the 20 most dominant species. Northern

rockfish and Pacific ocean perch were both present in low densities, while Atka mackerel

were encountered in only trace amounts.
19

Table 2. -Mean CPUE (kg/km) by area for the 20 most abundant groundfish encountered during the

1991 Aleutian Islands groundfish survey.
20

Individual weight and length measurements were collected for most of the

dominant fish species present in the survey area. These data were used to estimate the

relationship between weight and length using a non-linear regression of weight on length

for each species. The equation used for the regression was

Weight(grams) = a • Length (mm)

b

.

Plots and parameters from this regression analysis are presented in Appendix C.
2 1

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Catch Results bv Species

22

Walleye pollock--Walleye pollock were distributed throughout the survey area,

occurring at 70% of the Aleutian Islands stations, but at only 48% of the Southern

Bering Sea stations (Fig. 4 and Table 3). Approximately 64% of the total survey area

biomass of 264,830 t was distributed in the Northeast Aleutian Islands and Southern

Bering Sea Areas. Over 80% of the estimated biomass in the Aleutian Islands region

was found between 101 and 300 m, while over 90% of the Southern Bering Sea biomass

occurred in depths shallower than 200 m.

Several length modes were noted for fish from both the Aleutian Islands and

Southern Bering Sea areas. The most distinctive were a juvenile mode of 15-25 cm (FL),

an intermediate mode of 25-40 cm (FL) fish and the largest mode composed of fish

greater than 40 cm (FL) (Fig. 5). Clear separable modes were not evident for larger fish.

In the Southern Bering Sea and Northeast Aleutian Islands Area, most fish smaller than

40 cm (FL) were found in the l-100 m depth interval. Only trace amounts of pollock

were found in this depth interval in the remaining Aleutian Islands region.
23

Table 3. -Total number of survey hauls, hauls containing walleye pollock, estimated biomass, CPUE,

mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.

Figure 4. --Continued.
26

Figure 5. --Size composition of wolleve pollock from the 1991 Aleutian Islands survey
27

Figure 5. --Continued.
28

Pacific cod--Pacific cod were distributed relatively evenly throughout the survey

area, occurring at over 70% of the stations in the Aleutian Islands region and 67% of

stations in the Southern Bering Sea (Fig. 6 and Table 4). Over 80% of the total

estimated biomass of 183,756 t was distributed in depths shallower than 200 m with the

remainder occurring in the 200-300 m depth interval. High concentrations of cod

(greater than 21,500 kg/km2

) occurred at several stations in the Northeast area.

The length distribution of Pacific cod ranged from 15 to 115 cm (FL). A strong

length mode of 25-45 cm (FL) fish occurred in the two shallowest strata throughout the

survey area (Fig. 7). An additional mode of smaller. 15-30 cm (FL) fish was also evident

in the l-100 m depth interval of the Southern Bering Sea. In general, Pacific cod

average length and weight increased with depth.
29

Table 4. --Total number of survey hauls, hauls containing Pacific cod, estimated biomass, CPUE, mean

weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
Figure 6. --Distribution and relative abundance of Pacific cod, 1991 Aleutian Islands bottom trawl survey

Abundance is categorized by catches below the mean (3,100 kg/km2), between the mean and 

deviations above the mean, and greater than two standard deviations above the mean.
Figure 6. --Continued.
LENGTH IN CENTIMETERS

Figure 7.--Size composition of Pacific cod from the 1991 Aleutian Islands survey.
Figure 7. --Continued
34

Sablefish-Sablefish were sparse in the survey area, with significant catches

occurring only in the Southeast Area (Fig. 8). Sablefish occurred at less than 6% of all

stations, although they were found in 33% of the stations in the 301-500 m strata

(Table 5). Biomass was estimated to be 20,846 t in the Aleutian Islands region and only

228 t in the Southern Bering Sea. Most of the estimated biomass of sablefish in the

survey area was a result of relatively high abundance in a limited area south of Atka

Island. All sablefish were found at depths greater than 200 m, except in the Southern

Bering Sea, where two stations contained sablefish in the 101-200 m depth interval. In

all areas, sablefish were most abundant ‘in the 301-500 m depth interval. Because the

survey was limited to depths of less than 500 m, an important portion of sablefish

habitat was not surveyed, and estimates of CPUE and biomass are not representative of

the entire Aleutian Islands region population.

The only length observations were from the Southeast Area 301-500 m depth

interval where sablefish ranged in length from approximately 45 to 85 cm (FL) (Fig. 9).
35

Table 5. --Total number of survey hauls, hauls containing sablefish, estimated biomass, CPUE, mean

weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
Figure 8.--Distribution and relative abundance of sablefish, 1991 Aleutian Islands bottom trawl survey

Abundance is categorized by catches below the mean (200 kg/km2), between the mean and t

deviations above the mean, and greater than two standard deviations above the mean.
Figure 8.--Continued
38

Figure 9.--Size composition of sablefish from the 1991 Aleutian Islands survey
Figure 9.--Continued.
Atka mackerel--The distribution of Atka mackerel was extremely patchy

throughout the survey area (Fig. 10). This species occurred at 42% of the stations in the

Aleutian Islands region, and at 65% of the stations in the Northwest and Southwest

Areas combined (Table 6). Concentrations were extremely high at some stations, with

the largest catch of 10,262 kg occurring during- a 23-minute tow in Tanaga Pass. Atka

mackerel occurred at only 18% of the stations in the Southern Bering Sea where catch

rates were very low. Nearly 60% of the estimated biomass of 688,239 t was found in the

Southwest Aleutian Islands Area. Atka mackerel was concentrated in the l-200 m

depth intervals, with only trace amounts occurring between 201 and 300 m.

Data from the l-100 m depth strata indicated two length modes of 25-35 cm (FL)

and 35-45 cm (FL), but the separation of these modes was not clear in the 101-200 m

depth intervals where a similar size range was evident (Fig. 11). Due to the small

number of fish caught in the Southern Bering Sea, no length frequency data were

available for that area.
41

Table 6.-Total number of survey hauls, hauls containing Atka mackerel, estimated biomass. CPUE,

mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey. by

geographical areas and depth Intervals.
Figure l0.--Distribution and relative abundance of Atka mackerel, 1991 Aleutian Islands bottom trawl 

Abundance is categorized by catches below the mean (8,900 kg/km2), between the mean an

deviations above the mean, and greater than two standard deviations above the mean.
Figure l0.--Continued.
Figure 11.--Size composition of Atka mackerel from the 1991 Aleutian Islands survey.
Figure 11 --Continued
46

Arrowtooth flounder--Arrowtooth flounder were evenly distributed throughout the

survey area (Fig. 12), occurring at 64% of the stations in the Aleutian Islands region and

74% of the stations in the Southern Bering Sea (Table 7). The estimated biomass of

16,971 t in the Southern Bering Sea was similar to the estimate of 16,159 t for the entire

Aleutian Islands region.

Length frequency data for arrowtooth flounder show a wide size range of

11-82 cm (FL) with no easily separable modes (Fig. 13). There was a general trend

toward larger fish at deeper depths.
47

Table 7.--Total number of survey hauls, hauls containing arrowtooth flounder, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth intervals.

Figure 12.--Continued.
Figure 13.--Size composition of arrowtooth flounder from the 1991 Aleutian Islands survey.
Figure 3.--Continued
52

Kamchatka flounder--During the 1991 survey, Kamchatka flounder was

consistently identified and separated from arrow-tooth flounder. Previous surveys

generally grouped these two species together as arrowtooth flounder.

The Kamchatka flounder was distributed throughout the Aleutian Islands, but

was found only in trace amounts at the extreme western boundary of the Southern

Bering Sea (Fig. 14), where the estimated biomass was only 742 t (Table 8). The

estimated biomass for Kamchatka flounder in the Aleutian Islands region was 17,395 t.

The biomass of Kamchatka flounder (6,764 t) was significantly higher than for

arrowtooth flounder (2,356 t) in the Northwest Area, although overall biomass in the

Aleutian Islands region was similar (16,159 t for arrow-tooth flounder and 17,395 t for

Kamchatka flounder).

The length range for Kamchatka flounder was even greater than for arrowtooth

flounder, ranging from 15 to 93 cm (FL) (Fig. 15). There was a very distinct trend in

size at depth, with fish larger than 45 cm (FL) absent from the shallowest strata, and

fish smaller than 35 cm (FL) scarce at greater depths.
53

Table 8.--Total number of survey hauls, hauls containing Kamchatka flounder, estimated biomass.

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey,

by geographical areas and depth intervals.
Figure 14.--Distribution and relative abundance of Kamchatka flounder, 1991 Aleutian Islands bottom t

survey. Abundance is categorized by catches below the mean (200 kg/km2), between the me

two standard deviations above the mean, and greater than two standard deviations above th
Figure l4.--Continued.
Figure 15.--Size composition of Kamchatka flounder from the 1991 Aleutian Islands survey.
Figure 15.--Continued
58

Pacific halibut--Pacific halibut were frequently encountered in the Southern

Bering Sea, occurring at 77% of the stations, but were less common in the Aleutian

Islands region, occurring in only 46% of these stations (Fig. 16 and Table 9). The

estimated biomass of Pacific halibut was 33,892 t in the Aleutian Islands region and

10,219 t in the Southern Bering Sea. In the Aleutian Islands region, halibut were least

common in the Southwest Area, where they occurred at only 25% of the stations but

occurred relatively frequently in the Southeast Area (63%), where over 50% of the total

estimated biomass in the Aleutian Islands region were found. Most halibut were found

in depths less than 200 m, but this species occurred at all depths in the survey.

Pacific halibut had the widest length range of all species encountered in the

survey, ranging from 15 to 180 cm (FL) (Fig. 17). Because they were generally returned

to the sea alive, Pacific halibut were usually not sexed during the survey, so length data

are presented for both sexes grouped. A strong mode in the 30-40 cm (FL) range was

evident in the Southern Bering Sea Area, but there were no clear modes in data from the

Aleutian Islands region. There was a strong trend toward larger fish at deeper depths.
59

Table 9.--Total number of survey hauls, hauls containing Pacific halibut, estimated biomass, CPUE,

mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth Intervals.

Figure 16.--Continued.
Figure 17.--Size composition of Pacific halibut from the 1991 Aleutian Islands survey
Figure 17.--Continued.
64

Rock sole--Rock sole were common throughout the survey area (Fig. 18),

occurring at 72% of the stations in the Aleutian Islands region and 80% of the stations

in the Southern Bering Sea (Table 10). Nearly 90% of the total estimated rock sole

biomass of 42,832 t occurred in depths less than 200 m.

The length distribution of rock sole increased with depth (Fig. 19). Males were

numerically dominant in the shallow strata, while catches of rock sole observed deeper

than 200 m were composed primarily of larger females.
65

Table l0.--Total number of survey hauls, hauls containing rock sole, estimated biomass, CPUE, mean

weight. and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
Figure 18.--Distribution and relative abundance of rock sole, 1991 Aleutian Islands bottom trawl surve

Abundance is categorized by catches below the mean (800 kg/km2), between the mean and 

standard deviations above the mean, and greater than two standard deviations above the m
Figure 18.--Continued.
Figure l9.--Size composition of rock sole from the 1991 Aleutian Islands survey
Figure l9.--Continued.
70

Greenland turbot--With a total estimated biomass of only 14,000 t (Table 11),

Greenland turbot was sparsely and unevenly distributed throughout the survey area

(Fig. 20). Over 50% of the total estimated biomass (6,541 t) in the Aleutian Islands

occurred in the Northeast Area, followed by the Northwest Area with 28% of the

biomass. Only trace amounts were found in the Southeast Area. The greatest biomass

of Greenland turbot occurred at depths greater than 300 m. Since the survey covers

only part of the depth range of this species, the biomass estimate is useful only for those

depths surveyed, and will not adequately reflect total abundance.

All Greenland turbot caught during the survey were large fish, with no

individuals less than 55 cm (FL) (Fig. 21). The average length for females was

consistently greater than for males. In two area-depth intervals (Northeast Area

101-200 m and Southern Bering Sea Area 301-500 m) only female turbot were captured,

while in all other areas with data, males dominated the numbers caught.
71

Table 11.--Total number of survey hauls, hauls containing Greenland turbot, estimated biomass, CPUE,

mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth Intervals.
Figure 20.--Distribution and relative abundance of Greenland turbot, 1991 Aleutian Islands bottom traw

Abundance is categorized by catches below the mean (200 kg/km2), between the mean and t

deviations above the mean, and greater than two standard deviations above the mean.
Figure 20.--Continued.
74

Figure 21.--Size composition of Greenland turbot from the 1991 Aleutian Islands survey.
Figure 21.--Continued.
76

Other Flatfish- Eight other flatfish species were encountered during the survey.

Flathead sole, rex sole, and Dover sole were encountered in moderate numbers in

various locations. Flathead sole was the seventh most abundant groundfish species in

the Southern Bering Sea with an estimated biomass of 6,461 t (Table 12), and was the

twentieth most abundant species in the Aleutian Islands region, with an estimated

biomass of 4,273 t. Rex sole was the thirteenth most abundant species in the Southern

Bering Sea, with an estimated biomass of 1,367 t (Table 13). In the Aleutian Islands

region rex sole had an estimated biomass of 1,552 t, but it was not among the 20

dominant species. Dover sole was found at several deepwater stations, but at low

abundance, with an estimated biomass of less than 450 t throughout the survey region

(Table 14). In previous surveys, this deepwater species was encountered most

frequently below the 500 m maximum depth sampled during 1991.

Several shallow-water species, English sole (Pleuronectes vetulus), butter sole

(Pleuronectes isolepis), yellowfin sole (Pleuronectes asper), and starry flounder

(Platichthys stellatus) were encountered only in the Southern Bering Sea Area (Tables

15-18 respectively). Biomass estimates were very low (less than 400 t) for each of these

species. Pacific sanddab (Citharichthys sordidus) was also encountered in trace

amounts during the survey (less than 1 t).
Table 12.--Total number of survey hauls, hauls containing flathead sole, estimated biomass, CPUE, mean weight, and mean length based on the 1991 Aleutian islands groundfish survey, by

geographical areas and depth intervals.
78

Table 13.--Total number of survey hauls, hauls containing rex sole, estimated biomass, CPUE, mean

weight. and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
79

Table 14.--Total number of survey hauls, hauls containing Dover sole, estimated biomass, CPUE, mean

weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
80

Table 15.--Total number of survey hauls, hauls containing English sole, estimated biomass, CPUE,

mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
81

Table 16.--Total number of survey hauls, hauls containing butter sole, estimated biomass, CPUE, mean

weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
82

Table 17.--Total number of survey hauls, hauls containing yellowfin sole, estimated biomass, CPUE,

mean weight. and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth Intervals.
83

Table 18.--Total number of survey hauls, hauls containing starry flounder, estimated biomass, CPUE,

mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
84

Pacific ocean perch-- With an estimated biomass of 405,366 t, Pacific ocean perch

were common throughout the Aleutian Islands region, occurring at 60% of all stations,

but they were rare in the Southern Bering Sea, occurring at 28% of the stations and in

relatively low abundance (2,274 t) (Fig. 22 and Table 19). Over 99% of all Pacific ocean

perch occurred in the 101-300 m depth range. Very high CPUE values were found at

stations located throughout both western areas, on Petrel Bank and in both eastern

areas immediately east of Atka Island. Over 69% of the estimated biomass in the

Aleutian Islands region occurred in the Southwest Area, followed by the Northeast Area

with 25%.

Most Pacific ocean perch observed in the l-100 m strata in both the Aleutian

islands and Southern Bering Sea areas were juveniles of 10 to 25 cm (FL) (Fig. 23). This

size group was rare at deeper depths (101-200 m) and absent below 200 m. The mean

lengths of Pacific ocean perch were generally highest in the western Aleutian Islands

region and exhibited a distinct increasing size trend with increasing depth in all areas.

In most areas the average size of females was slightly larger than males.
85

Table 19.--Total number of survey hauls, hauls containing Pacific ocean perch, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth intervals.
Figure 22.--Distribution and relative abundance of Pacific ocean perch, 1991 Aleutian Islands bottom t

survey. Abundance is categorized by catches below the mean (8,700 kg/km2), between the 

two standard deviations above the mean, and greater than two standard deviations above 

Figure 23.--Size composition of Pacific ocean perch from the 1991 Aleutian Islands survey.
Figure 23.--Continued.
90

Northern rockfish-- Northern rockfish were scattered in pockets of high

concentration, mainly in the western Aleutian Islands and on Petrel Bank (Fig. 24). This

species occurred at only 38% of all Aleutian Islands stations, but CPUE at some of these

stations was high (Table 20). Over 84% of the total estimated biomass of 182,494 t was

found in the Southwest Aleutian Islands Area. Northern rockfish were uncommon in the

Southern Bering Sea, occurring at 21% of these stations, and in low abundance, with an

estimated biomass of under 800 t. Over 99% of northern rockfish sampled occurred in

depths of l-200 m.

Northern rockfish varied from less than 20 cm to 40 cm (FL) in length.

Individuals of less than 20 cm were restricted to l-100 m in depth (Fig. 25). The

average length of females was slightly greater than males in each area-depth interval.
91

Table 20.--Total number of survey hauls, hauls containing northern rockfish, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth Intervals.
Figure 24.--Distribution and relative abundance of northern rockfish, 1991 Aleutian Islands bottom tra

survey. Abundance is categorized by catches below the mean (2,100 kg/km”), between the 

two standard deviations above the mean, and greater than two standard deviations above t
Figure 24.--Continued.
Figure 25.--Size composition of northern rockfish from the 1991 Aleutian Islands survey
PERCENT FREQUENCY WITHIN AREA AND DEPTH
96

Rougheye rockfish--Rougheye rockfish is a deepwater species sporadically

distributed throughout the survey area (Fig. 26). They occurred in 57% of the Aleutian

Islands stations deeper than 200 m; and in 85% of the Southern Bering Sea stations at

the same depths (Table 21). Most of the 13,625 t biomass of this species was found

below 300 m. Large CPUE values were found from stations in the Southern Bering Sea.,

Southwest and Southeast Areas, and on Petrel Bank

Although smaller fish tend to be associated with shallower depths, size

segregation with depth does not appear to be strong (Fig. 27). Most of the sampled

rougheye rockfish were in the 30-50 cm (FL) range
97

Table 21.--Total number of survey hauls, hauls containing rougheye rockfish, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth intervals.
Figure 26.--Distribution and relative abundance of rougheye rockfish, 1991 Aleutian Islands bottom tra

survey. Abundance is categorized by catches below the mean (100 kg/km2), between the m

two standard deviations above the mean. and greater than two standard deviations above t
Figure 26.--Continued.
Figure 27.--Size composition of rougheye rockfish from the 1991 Aleutian Islands survey
Figure 27.--Continued
102

Shortraker rockfish- Shortraker rockfish were sparsely scattered throughout the

survey area in deeper water (Fig. 28). They were found at over 70% of all stations in the

301-500 m depth range, which contained 93% of the total shortraker rockfish biomass in

the Aleutian Islands region and 100% of the biomass in the Southern Bering Sea

(Table 22). Only trace amounts of shortraker rockfish were found in depths less than

200 m. The total estimated biomass of shortraker rockfish was 26,808 t. Over 73% of

the estimated biomass occurred in the Southwest Area,- but relatively high CPUE values

were found at stations on Petrel Bank, west of Tanaga Island, south of Atka and Amlia

Islands, north of the Islands of Four Mountains, and east of Umnak Island.

A wide length distribution (ranging from 18 to 88 cm (FL)) of shortraker rockfish

were observed in most areas (Fig. 29). A higher proportion of larger fish were found in

the 201-300 m strata than in the 301-500 m strata, but this could be an artifact of small

sample size in the shallower strata.
103

Table 22.--Total number of survey hauls, hauls containing shortraker rockfish, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth intervals.
Figure 28.--Distribution and relative abundance of short-raker rockfish, 1991 Aleutian Islands bottom t

survey. Abundance is categorized by catches below the mean (200 kg/km2), between the m

two standard deviations above the mean, and greater than two standard deviations above 
Figure 28.--Continued.
106

Figure 29.--Size composition of shortraker rockfish from the 1991 Aleutian Islands survey.
Figure 29.--Continued
108

Shortspine thornyhead-- Shortspine thornyhead were patchily distributed with low

abundance over most of the areas and depths sampled (Fig. 30). Estimated biomass was

5,853 t in the Aleutian Islands region, but only 469 t in the Southern Bering Sea.

Thornyheads occurred at 50% of all stations in the 301-500 m strata, and were

increasingly rare at shallower depths (Table 23). The highest observed abundance was

found in the Southwest Area, with 72% of the estimated survey biomass, and on Petrel

Bank, which spans the boundary between the Northwest and Northeast Areas. Over

75% of the estimated biomass of this species was found in depths greater than 300 m.

Because this survey did not cover the entire depth range of thornyheads, estimates can

only be considered to reflect abundance in the depths sampled.

In most area-depth intervals, length frequencies were fairly evenly distributed

over a wide 15-50 cm (FL) range (Fig. 31). There was no clear relationship between

depth and size, except that the few fish found in the 101-200 m depth range were

generally smaller fish.
109

Table 23.--Total number of survey hauls, hauls containing shortspine thornyhead, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth intervals.

Figure 30.--Continued.
112

Figure 31.-- Size composition of shortspine thornyhead from the 1991 Aleutian Islands survey
Figure 31.--Continued
114

Other rockfish--Four other rockfish species occurred in the survey region. Dusky

rockfish (Sebastes ciliatus), harlequin rockfish (Sebastes variegatus), redbanded rockfish

(Sebastes babcocki), and sharpchin rockfish (Sebastes zacentrus) were encountered at

least once during the survey. Dusky rockfish were distributed throughout the entire

survey area (Table 24). Total estimated biomass was 564 t. Abundance was low in the

southern Aleutian Islands region and extremely low in the Southern Bering Sea Area

and northern Aleutian areas. Harlequin rockfish occurred in all areas of the Aleutian

Islands, but were low in abundance throughout this region, with a total estimated

biomass of only 29 t (Table 25). Redbanded rockfish were found at one station in the

Southern Bering Sea Area, but with an estimated biomass of approximately 1 t

(Table 26). Sharpchin rockfish were found at two shallow stations in the Southern

Bering Sea Area in low abundance with an estimated biomass of 3 t (Table 27).
115

Table 24.--Total number of survey hauls, hauls containing dusky rockfish, estimated biomass, CPUE,

mean weight, and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
116

Table 25.--Total number of survey hauls, hauls containing harlequin rockfish, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth intervals.
117

Table 26.--Total number of survey hauls, hauls containing redbanded rockfish, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth Intervals.
118

Table 27.--Total number of survey hauls, hauls containing sharpchin rockfish, estimated biomass,

CPUE, mean weight, and mean length based on the 1991 Aleutian Islands groundfish

survey, by geographical areas and depth intervals.
119

Sculpins-- Several species of sculpins were encountered frequently during the

1991 survey. The genus Myoxocephalus was among the 20 dominant taxa in all of the

areas sampled (Table 2). It is unlikely that any given species from this group would

have been among the dominant groundfish groups in the Aleutian Islands region, but

the great sculpin (Myoxocephalus polyacanthocephalus) was the dominant

representative of the genus in the Southern Bering Sea Area, where the genus

Myoxocephalus was the tenth most abundant taxa. Darkfin sculpins (m

zonurus) and blackfin sculpins (Malacocottus kincaidi) also appeared frequently among

the 20 dominant taxa in the Aleutian Islands and Southern Bering Sea regions. These

small fish were numerically significant at many stations, and occurred in moderate

numbers at all depths sampled during the survey. The genus Hemilepidotus was also

widely distributed throughout the survey region. The yellow Irish lord (Hemilepidotus

jordani) was frequently encountered in the Aleutian Islands region, although its biomass

was relatively low. They were more common in the Southern Bering Sea, where they

were the ninth most abundant groundfish species. Most other Cottidae found during the

survey (Table B-l) were sparsely distributed and encountered only occasionally in small

numbers.

Skates--Skates of the genera Bathyraja, Raja, and Rhinoraja were encountered

throughout the survey. As a group, skates were important in the Aleutian Islands

region, ranking fourteenth in overall abundance (Table 2). This taxa has commercial

potential, but further research is needed to adequately describe each species.
120

Cephalopods-Red (magistrate armhook) squid (Berryteuthis magister) was

encountered throughout the survey (Table 28). Red squid was the sixth most abundant

species in the Southwest Aleutian Islands Area, however only trace amounts were found

in the other Aleutian Islands areas and in the Southern Bering Sea. Two other squid

species (Rossia pacifica and Moroteuthis robusta and two species of octopus [Octopus

dofleini and Octopus leioderma) were caught in the survey, but in trace amounts

(Table B-2).

Crabs--Six species of commercially important crabs were caught during the 1991

survey: golden king crab (Lithodes aequispina), scarlet king crab [Lithodes couesi), red

king crab (Paralithodes camtschatica), Tanner crab [Chionoecetes bairdi), snow crab

(Chionoecetes opilio), and hair crab (Erimacrus isenbeckii). None of these species were

estimated to be in high abundance in any area, nor were these species found at any

station in significant quantities. The sampling gear used for the survey was not

designed to efficiently capture crab, so this survey will not provide representative

results.
121

Table 28.--Total number of survey hauls, hauls containing red squid, estimated biomass, CPUE, mean

weight. and mean length based on the 1991 Aleutian Islands groundfish survey, by

geographical areas and depth intervals.
122

CITATIONS

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

northeastern Pacific Ocean - An evaluation of exploratory fishing methods and

analytical approaches to stock size and yield forecasts. J. Fish. Res. Board Can.

26: 1985-200 1.

Ronholt, L., K. Teshima, and D. Kessler. In preparation. The groundfish resources of

the Aleutian Islands, 1980- 1986. Alaska Fisheries Science Center, 7600 Sand

Point Way NE, Seattle, WA 98115.

Wakabayashi, K., R. G. Bakkala, and M. S. Alton. 1985. Methods of the U.S.-Japan

demersal trawl surveys. p. 7-29. In R. G. Bakkala and K. Wakabayashi (editors),

Results of cooperative U.S.-Japan groundfish investigations in the Bering Sea

during May-August 1979. Int. North Pac. Fish. Comm., Bull. 44.
123

APPENDIX A

Gear Specifications and Diagrams

Figure A- 1 illustrates the Poly-Nor’eastem high-opening bottom trawl used in the

1991 Aleutian Island groundfish survey.
124

POLY-NOREASTERN

Figure A- 1 .--Schematic diagram of the bottom trawl, roller gear and accessory gear used

by the chartered trawlers Ocean Hope 1 and Green Hope during the 1991

Aleutian Islands bottom trawl survey.
125

APPENDIX B

Lists of Species Encountered

Tables B-l and B-2 list fish and invertebrate species encountered and identified

during the 1991 Aleutian Island groundfish survey. Fish are listed in phylogenetic

order. Most common and scientific names are from Robins et al. (1991), except as noted

by superscripts Invertebrates are listed in phylogenetic order by phylum. Order of

listings and common names are provided for convenience, and do not imply adherence

to a particular phylogenetic system.

List of tables Page

Table B- 1 .--List of fish identified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Table B-2.--List of invertebrates identified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
126

Table B-1.--List of fish identified during the 1991 Aleutian Island groundfish survey.
127

Table B-l .--Continued.
128

Table B-1.--Continued.
129

Table B-l .-Continued.

1

Allen, M. J. 1983. Provisional key to the skates (Rajidae) of the Bering Sea. Unpublished manuscript.

Northwest and Alaska Fisheries Center, RACE, 7600 Sand Point Way NE, Seattle, WA 98115,

9 P.

2

Baxter, R. 1989. Annotated key to the fishes of Alaska. Unpublished manuscript. Center for Alaskan

Coastal Studies, P.O. Box 2225, Homer, Alaska 99669,716 p.

3

Hart. J. L. 1973. Pacific Fishes of Canada, Fish. Res. Board Can., No. 180. Ottawa 740 p.

4

Raschi, W.. and J. D. McEachran. 1991. Rhinoraja longi, a new species of skate from the outer

Aleutian Islands. with comments on the status of Rhinoraja (Chondrichthyes, Rajoidei).

Can. J. Zool. 69: 1889-1903.

5

Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea, and W. B. Scott. 1991.

Common and scientific names of fishes from the United States and Canada. Fifth edition. Am.

Fish. Soc. Spec. Publ. No. 20. 183 p.

 6

Yabe, M. 1991. Bolinia euryptera, a new genus and species of sculpin (Scorpaeniformes: Cottidae)

from the Bering Sea. Copeia 1991(2):329-339.
130

Table B-2.--List of invertebrates idenified during the 1991 Aleutian Island groundfish survey.
131

Table B-2.--Continued.
132

Table B-2.--Continued.
133

APPENDIX C

Length-Weight Regressions for Major Species

Length-weight relationships for major species were calculated using a non-linear

least-squares regression algorithm. The equation used for the regression was

Weigh(grams) = a · Length(mm)

b

.

List of plots Page

Walleye pollock ................................................... 134

Pacific cod.. ................................................... .....135

Atka mackerel .................................................. ..136

Arrowtooth flounder ............................................. ..137

Rock sole........................................................................................................................ 138

Greenland turbot .................................................. 139

Pacific ocean perch ................................................ 140

Northern rockfish........................................................................................ ................... 141

Rougheye rockfish ................................................. 142

Shortraker rockfish ................................................ 143

Shortspine thornyhead .............................................. 144
134

WALLEYE POLLOCK

length vs. weight regression (weight(grams) = a·length b

(mm) ) 
135

PACIFIC COD

length vs. weight regression (weight(grams) = a·length b

(mm) )
136

ATKA MACKEREL

length vs. weight regression (weight (grams) = a · lengthb

(mm) )

138

ROCK SOLE

length vs. weight regression (weight (grams) = a · lengthb

(mm) )
139

GREENLAND TURBOT

length vs. weight regression (weight (grams) = a·length b

(mm) )
PACIFIC OCEAN PERCH

length vs. weight regression (weight (grams) = a • length b

(mm) )
141

NORTHERN ROCKFISH

length vs. weight regression (weight (grams) = a • length b

(mm) )
142

ROUGHEYE ROCKFISH

length vs. weight regression (weight (grams) = a • length b

(mm) )
143

SHORTRAKER ROCKFISH

length vs. weight regression (weight (grams) = a • length b

(mm) )
144

SHORTSPINE THORNYHEAD

length vs. weight regression (weight (grams) = a • length b

(mm) )
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. 

AFSC11 LIVINGSTON, P. A., A. WARD, G. M. LANG, and M-S. YANG. 1993. Groundfish food habits and

predation on commercially important prey species in the eastern Bering Sea from 1987 to 1989,

192 p. NTIS No. PB93-184703. 

10 KINOSHITA, R. K., and J. M. TERRY. 1993. Oregon, Washington, and Alaska exports of edible fishery

products, 1991, 47 p. NTIS No. PB93-159101.

9 KARINEN, J. F., M. M. BABCOCK, D. W. BROWN, W. D. MACLEOD, JR., L. S. RAMOS, and J.W.

SHORT. 1993. Hydrocarbons in intertidal sediments and mussels from Prince William Sound, Alaska,

1977-1980: Characterization and probable sources, 69 p. NTIS No. PB93-159093.

 8 WING, B. L. 1993. Winter oceanographic conditions in the eastern Gulf of Alaska, January-February

1986, 53 p. NTIS No. PB93-158335.

7 ARMISTEAD, C. E., and D. G. NICHOL. 1993. 1990 bottom trawl survey of the eastern Bering

Sea and continental shelf, 190 p. NTIS No. PB93-156677.

6 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-

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

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