NOAA Technical Memorandum NMFS-AFSC-31

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Alaska Fisheries Science Center

February 1994

by

L. L. Ronholt, K. Teshima, and D. W. Kessler

The Groundfish Resources

of the Aleutian Islands Region

and Southern Bering Sea

1980,1983 and 1986
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:

Ronholt, L. L., K. Teshima, and W. D. Kessler. 1994. The 

groundfish resources of the Aleutian Islands region and southern

Bering Sea 1980, 1983, and 1986. U.S. Dep. Commer., NOAA 

Tech. Memo. NMFS-AFSC-31, 351p.

 

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

the National Marine Fisheries Service, NOAA.
The Groundfish Resources

of the Aleutian Islands Reg ion

and Southern Bering Sea

1980,1983 and 1986

by 

L. L. Ronholt, K. Teshima, and D. W. Kessler

Alaska Fisheries Science Center

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

Seattle, W A 98115-0070

Shimonoseki Branch

Seikai Regional Fisheries Research Laboratory

20, 2 Cherne Higashiyamatocho

Simonoseki 750

Japan

s. DEPARTMENT OF COMMERCE

Ronald H. Brown, Secretary

National Oceanic and Atmospheric Administration

D. James Baker, Under Secretary and Administrator

National Marine Fisheries Service

Rolland A. Schmitt en, Assistant Administrator for Fisheries

February 1994
This document Is available to the public through:

National Technical Information Service

S. Department of Commerce

5285 Port Royal Road

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 

accuracy and correctness of the document can only be certified as was presented in the original hard 

copy format. 

iii

ABSTRACT

During the summer and fall of 1980, 1983, and 1986, the

National Marine Fisheries Service and the Fisheries Agency of

Japan conducted comprehensive trawl surveys of the groundfish

resources of the Aleutian Islands. The survey area included the

continental shelf and upper slope from Stalemate Bank to Unimak

Pass, including Bowers Ridge and a portion of the southern Bering

Sea.

The maj or obj ecti ves of these surveys were to define the

distribution and abundance of commercial groundfish species and

to assess changes in stock abundance and biological conditions

over the 6-year survey period. Results of each of these yearly

surveys include distribution information, biomass and population

estimates, size and age composition, and length weight data for

most species of commercial fish. This paper presents and

compares the data from each of the three surveys.

The average total biomass estimate for the three surveys was

4 million metric tons. Fish made up over 96% of this biomass

and included 161 species representing 40 families. Nineteen

species made up over 90% of the total available biomass.

Accounting for 23% of the available biomass, walleye pollock

Theragra chalcogramma ) with a similar biomass estimate each year

was the most abundant species. Giant grenadier Albatrossia

pectoralis ), a non-utilized species was the second most abundant

species with an increasing biomass which accounted for 18% of the

available resource. The other abundant species were Atka

mackerel EJeurogrammus monopterygius ), Pacific ocean perch

Sebastes alutus ), and Pacific cod Gadus macrocephalus

accounting for 16, 8, and 7% of the resource, respectively.

CONTENTS

INTRODUCTION. . . . . 

METHODS AND MATERIALS..

Vessels and Survey

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Per iods. . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gear. . . . . . . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Trawl Mouth Height and width Measurements..................

Sampling Design and Rationale..............................

station Sampling Procedures................................

Catch and Biological Data Collection

Length Frequency Measurement...............................

Age Structure Collection...................................

Relative Fishing Power comparisons.........................

Survey Precision...........................................

Environmental Data.........................................

Da ta Management

............................................

Species Groupings..........................................

Data Analysis Procedures...................................

RESULTS. . . . . . 

. . . . 

Sampling Effort............................................

Survey PrecJ.sJ.on...........................................

Fishing Power Comparisons..................................

Length Frequency Measurements.. 

Age Structure..............................................

Length-Weight Measurements.................................

Trawl Measurements.........................................

BIOMASS ESTIMATES...............................................

SPECIES ACCOUNTS................................................

Walleye Pollock............................................

Atka Mackerel..............................................

Pacific Ocean Perch.......................................

Pacif ic

Northern Rockf i sh. . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Arrowtooth Flounder.......................................

Sablef ish. . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Greenland Turbot..........................................

Rougheye Rockf ish. . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Pac i f i c Ha Ii bu t. 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Shortr aker Rockf i sh. . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Shortspine Thornyhead.....................................

Rock Sole.................................................

Skates. . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Flathead Sole.............................................

Re)C Sole..................................................

Dover Sole................................................

Giant Grenadier...........................................

Red squid.................................................

CITATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

APPENDIX A 

APPENDIX B

APPENDIX C

Procedures. . . 

. . . . . . . . .

Cod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . .

Indices of Abundance..............................

Water Temperatures................................

Species Inventory.................................

Paqe

101

126

144

159

178

198

212

227

237

252

267

284

289

296

304

309

319

325

329

337

345

INTRODUCTION

since 1979, the Alaska Fisheries Science Center (AFSC),

National Marine Fisheries Service (NMFS), Seattle, Washington

and the National Research Institute of Far Seas Fisheries

(NRIFSF), Fisheries Agency of Japan, Shimizu, Japan, have conducted triennial groundfish resource assessment surveys in

Alaska waters. Beginning with the eastern Bering Sea in 1979,

the surveys were expanded to the region around the Aleutian

Islands in 1980 and further to the Gulf of Alaska in 1984. Prior

to the cessation of cooperative surveys following the 1987 field

season , surveys were completed for the Aleutian Islands region in

1980 , 1983, and 1986, in the Gulf of Alaska in 1984 and 1987, and

in the Bering Sea in 1979 , 1981, 1982 , and 1985.

The principal objectives of these surveys were to 

establish a benchmark database to assess stock condition and

changes over time , 2) define the distribution and relative

abundance of the principle groundfish and commercially important invertebrate species, and 3) collect data to define the

biological parameters of each major groundfish stock. A

description of the survey methods and results obtained from the

earlier research surveys have already been published in various

papers or reports (Bakkala et ale 1985; Wakabayashi et ale 1985;

Brown 1986; Ronholt et ale 1986; Sample et ale 1985; Wilderbuer

et ale 1985).

The Aleutian archipelago consists of 47 maj or islands

extending westward in a nearly 1, 500 km arc from the Alaska

Peninsula to Attu Island. The larger islands and numerous

smaller islands are separated into five major groupings. These

island groups going from east to west are 1) The Fox Islands,

including Unimak, Akutan, Unalaska, and Umnak Islands; 2) The

Islands of Four Mountains , including Chuginadak , Yunaska, and

Amukta Islands; 3) The Andreanof Islands , including Seguam,

Amlia, Atka, Adak , Kanaga , Tanaga , and Gareloi Islands; 4) The

Rat Islands, including Amchi tka, Kiska, and Buldir Islands; and

5) The Near Islands , including Shemya, Agattu, and Attu Islands

(Figs. 1 and 2). Located among the western islands are several banks and

reefs; the most prominent are Petrel Bank north of Semisopochnoi

Island; Buldir Reef , Tahoma Reef, and Walls Plateau which form an

arc to the south of Buldir Island; and Stalemate Bank, located to

the west of Attu Island. Bowers Ridge rises in a northwesterly

arc approximately 400 km long north of the Rat Islands and

contains the Ulm Plateau at its northwestern tip and Bowers Bank

with depths shallower than 100 

The bathymetry of the sea floor in the area reflects the

volcanic origin of the islands and is characterized by an

extremely irregular bottom, narrow continental shelf , and abrupt continental slope. The Aleutian Trench defines the limit of the

continental slope approximately 120 km to the south of the chain

with depths ranging from 4 000 to 7, 500 m. Separated by Bowers

Ridge, the northern continental slope is 30 to 75 km wide and

bounded by Bowers Basin in the west and the Aleutian Basin in the

east.
Oceanographic studies of the Aleutian Islands are scarce and

have primarily concentrated on the interchange of waters between

the North Pacific Ocean , Bering Sea , and Gulf of Alaska (Favorite 1974, Favorite et ale 1976, Favorite and Ingraham 1972,

Hood 1983, and Reed and Schumacher 1986). The surface waters of

the maj or passes between the islands are characterized by strong

and complex currents which are prone to rapid changes.

Influenced by strong winds opposing the tidal flow, sea

conditions can deteriorate rapidly and be extremely hazardous.

Tidal cycles generally flood to the north and ebb to the south.

Historically, the Aleutian Islands have been an important

fishing ground for foreign vessels , with total catches averaging

over 73, 000 t per year from 1962 to 1986 (Bakkala 1987). The

modern era of foreign fisheries in the region can be traced to

the early 1960s with the expansion of Japanese and Soviet

fisheries to the eastern Bering Sea and Aleutian Islands region

for yellowfin sole Pleuronectes aspera ) and Pacific ocean perch Sebastes alutus ) (Forrester et ale 1978). Fisheries conducted

by Japan, the former U. R., the Republic of Korea, and Poland

have accounted for the majority of catches in the area, with the

largest fishery in the Aleutian Islands region concentrating on

Pacific ocean perch, with catches of 285, 000 metric tons (t) from

1964 to 1966 (Table 1). Following the decline of the Pacific

ocean perch fishery after 1972, walleye pollock Theragra

chalcogramma ) and Atka mackerel Pleuroqrammus monopterygius

emerged as the dominant fisheries. Incidental catches of sablefish Anoplopoma fimbria ), Pacific cod Gadus

macrocephalus ), and turbots (arrowtooth flounder Atheresthes

stomias ; Kamchatka flounder, A. evermanni ;, and Greenland turbot

Reinhardtius hippoglossoides ) in the trawl fisheries have made

important contributions to the catches for the area along with

directed longline fisheries for sablefish and Pacific cod

(Forrester et al. 1978, Forrester et ale 1983).

with the enactment of the Magnuson Fisheries Conservation

and Management Act (MFCMA) in 1976, the importance of U.

vessels in the fisheries of the area has increased (Table 2).

Due primarily to U. s. joint venture efforts commencing in 1981,

and intensified effort by the U. S. domestic fishery for sablefish

and Greenland turbot, coupled with reductions in foreign

groundfish quotas, the foreign fisheries have shifted from

demersal trawling throughout the Aleutian chain to midwater trawl

fisheries targeting on pelagic pollock in the international

waters of the Aleutian Basin (Sasaki and Yoshimura 1987).

This report presents and compares the results of groundf ish

assessment surveys conducted in the Aleutian Island region in

1980 , 1983, and 1986. Repeated surveys of the area have made it

possible to evaluate and track trends in species distribution and

abundance , size and age composition , and length-weight relationships.
1700 E' 1750 1800

520

55O

NORTHWEST AREA

f:J 0;001

NORTHEAST AREA

55O

BOWERS RIDGE AREA

540 540

BERING SEA

(9.:- .s-

'i'

?

530

510 DELAROF ISLANDS 510

SOUTHWEST AREA SOUTHEAST AREA

1700 E'

Figure 

1750 180'

Western areas sampled during the U. S. -Japan 1980 , 1983, and 1986 Aleutian

Islands groundfish surveys.

1'\'
55ON'

1750 W' 1700

\ 

200

SOUTHERN BERING SEA AREA 

rn~

J~/0

C;ooo m /

;

~ ,oQ'.s- .sA~~slan

/~nalaska of- 

;;.

Unalaska Is Ian ' /r/" 

Makushin Bar. ~ Q . , r:~~/ '

, 

\

tr'- /

ISLANDs OF 

ak jla~ 

., ,

Zr/J '" 

FQUR MOUNT AINV, .

. . 

O'j. 

/

--'1/

/

530 ~~ / a

, 

. 

, / ...

oOO

q; ,

0 s 

...../ 

Uunaska Island~ 9- Chugmadak Islang/ ' S LAN 

/

;

) 

t"---- ::1~rF)

/:::::!j

f\ \:. 

p. N O At~a I I. . d

(

ZOO Seguam Island (J/

./ . .

P. NO . 4 Amukta Isl~ndC) 

Great S tkin Island 

. 

' mhalsland .s'eul.lq'17 

...... ; 

520 J Q. 

/.

.:; ;)\ / 

~J 

200 m_____

::

:::

~::J NORTH PACIFIC OCEAN

/

1 000 r

. Adak Island""-

'~n Trench AleuNORTHEAST AREA 540 BERING SEA Aleutian Basin

SOUTHEAST AREA

510

1750 W' 17.00

Figure 2. Eastern areas sampled during the U. -Japan 1980

Islands groundf ish surveys.

1983 , and 1986 Aleutian

1650

55O

540

530520510

1650
Table 1. Annual groundfish catches (metric tons) in the Aleutian

Islands and Southern Bering Sea areas for foreign

J.s erJ.es , 1962-76 

Year

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

Walleye

pollock

359

560

697

277

833

677

512

179

3, 197

442

10, 475

22, 661

13, 785

290

Pacif ic

cod

601

278

459

171

374

294

222

284

085

438

971

350

824

171

Species

Turbots

374

475

305

210

102

559

331

14, 197

12, 371

11, 983

757

437

Sablef ish

639

534

248

338

651

673

673

247

936

531

902

477

709

619

Pacific

ocean

perch

Atka

Mackerel

200

800

300

109, 100

85, 900

55, 900

44, 900

800

900

21, 800

33, 200

11, 800

22, 400

16, 600

14, 000

515

604

377

078

20, 092

a Compiled from Forrester et el. 1978 and Forrester et ale 1983

except as noted.

1970-1976 data for turbots from Bakkala et el. 1987. Cod from

Thompson and Shimada 1987. 1971-1976 data includes soviet

catches for walleye pollock , Pacific cod , sablefish, and Atka

mackerel.

Includes arrowtooth flounder , Greenland turbot , and Kamchatka flounder.

d Data may contain rockfish species other than Pacific ocean perch,

from Ito 1987.

e Less than 1 metr ic ton.
Table 2. Annual groundfish catches (metric tons) in the Aleutian

Islands and Southern Bering Sea areas for foreign, R.

joint venture , and u. S. domestic fisheries, 1977-86 

Species

Year

Walleye

pollock

Pacific Greenland cod turbot

Arrowtooth

flounder

Sablefish

Pacific

ocean

perch

Atka

mackerel

Foreign Vessels

1977 625 262 453 035 897 080 975

1978 282 291 766 782 821 286 250

1979 504 591 411 436 782 487 264

1980 156 905 696 603 267 700 337

1981 55,516 914 398 624 377 618 273

1982 56,040 996 316 356 808 012 320

1983 56,479 2~271 115 700 575 272 187

1984 249 277 802 404 725 356

1985 51,447 839

1986 956

S. Joint Venture Vessels

1977

1978

1979

1980 196

1981 749 156 388

1982 983 280 118 226

1983 547 700 407

1984 694 390 272 273 943

1985 283 638 215 856

1986 261 115 160 31,978

S. Domestic Vessels

1977

1978

1979

1980 797

1981 779

1982 250

1983 984

1984 891 14,459

1985 583 213 956

1986 777 319 048 053 178

a Compiled from individual species accounts in Bakkala et ale

1987 .

b Estimated values for foreign and U. S. joint-venture , catches

1980-83.
METHODS AND MATERIALS

Vessels and Survey Periods

A total of five U. S. and three Japanese vessels were used

during the 1980 , 1983 , and 1986 Aleutian Islands surveys. Two

U. S. and one Japanese trawler were chartered by the AFSC and by

the NRIFSF in 1980. Both U. S. vessels , the M/V Half Moon Bay and

M/V Ocean Harvester were 32. 9 m west coast combination trawlercrabbers, while the Japanese vessel the Hatsue Maru No. was a

50. 6 m land-based stern trawler. Two NOAA ships, the R/V Miller

Freeman (65. 5 m) and the R/V Chapman (38. 5 m), and a Japanesechartered land-based trawler, Daito Maru No. 38 (51. 8 m),

participated in the 1983 survey. A U. S. combination crabbertrawler, Lets Go (25. 9 m), and a Japanese land-based trawler,

Ginryu Maru No. (55. 3 m), were chartered for the 1986 survey.

The Japanese land-based trawlers were of similar type and equipped with similar fishing and .navigational systems.

Specifications for the D. S. and Japanese vessels are listed in Table 3.

Table 3. Characteristics of the vessels used during the U. S.

Japan 1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.

Vessel

Name

Overall length (m)

Gross

Tonnage

Horsepower

Half Moon Bay

Ocean Harvester

Hatsue Maru No. 

Mi ller Freeman

Cha man

Daito Maru No. 38

Lets 

Ginr u Maru No.

32.

32.

50.

65.

38.

51.

25.

55.

197

197

350

515

427

349

145

350

850

150

000

2, 150

150

800

565

000

The survey period extended from July through November in

1980 and 1983 , and from May through September in 1986, with the

most extensive coverage of the survey area being performed by the

Japanese charter vessels (Table 4).
Table 4. Sampling periods of the survey vessels participating in

the U. -Japan 1980 , 1983 , and 1986 Aleutian Islands groundfish surveys.

Months

Years Vessels May June July Aug. Sept. Oct. Nov.

1980 Half Moon Ba

Ocean Harvester

Hatsue Maru No. 

6/30--------8/20

7/22--8/22

7 / 6----------------------11/4

7/26--8/14

8/16--9/5 /16---------------------11/4

1983 Miller Freeman

Cha man

Daito Maru No. 38

1986 Lets 

Ginr u Maru No.

7 / 2 0--------9 /26 5/14-------------------9/19

The Hatsue Maru No. attempted 217 stations in two legs

(7/6-11/14). The M/V Half Moon Bay attempted 129 stations (6/30-

8/20) and the M/V Ocean Harvester attempted 89 stations (7/29-

8/22) . In the 1983 survey, 263 stations were attempted by the

Daito Maru No. 38 (7/16-11/4), and 99 and 63 were attempted by

the NOAA ships Miller Freeman (7/26-8/14) and Chapman (8/16-9/5),

respectively. The Ginryu Maru No. attempted 364 stations (5/14-

9/19) and the Lets Go attempted 135 stations (7/20-9/26) during

the 1986 survey.

Gear

From 1980 to 1987 , all bottom trawl surveys by U. s. vessels

were conducted with a standard nylon Noreastern trawl (headrope

length 27 m , footrope length 32 m), a four-seam trawl with a

total length of 50. 2 m (Fig. 3). Because the waters surrounding

the Aleutian Islands are known for their rough trawling bottom,

the Noreastern trawl was fished with roller gear constructed of

45. 7 cm rubber rollers in the throat and 35. 6 cm rubber bobbins

along the wings. Triple dandylines were 54. 9 m long (Fig. 4). A

2 cm liner in the cod end was used to retain small fish. Steel

V-type otter boards were 1. )C 2. 7 m and weighed approximately

409 kg each. This net was characterized by horizontal mouth

openings ranging from approximately 14 to 18 m and a vertical

opening of approximately 7 

The si)C-seam and eight-seam trawls used by the Japanesechartered land-based trawlers were provided by the vessels and

were those normally employed during commercial fishing operations. The trawls used during each survey were of various
TOP

-0 39.

34M!

150'

5" me5h in all wing

panels; #48 thread

60, Intermediate

, 3.5" mesh 

#60 thread

120

M Codend

5" mesh

#96 th read

Double thickness

64:

.::x:

0..

.::x:

a..

20M

Top Seam

8M 8M

End view of codend

showing the spacing

of the rings of the 

splitting gear around

the circumference 

Figure 3. Schematic diagram of the 27/32 m Noreastern trawl used

by the U. s. vessels during the U. s. -Japan 1980 , 1983

and 1986 Aleutian Islands groundfish surveys.
ROLLER GEAR

)\t - 8 an ,\t - 8cm ~17.8 cm

 

178cm~ --+-15.24cm

 (

/24 an 

............... . / 

~ 35.Washer Eye6 em wing bobbin

10.2 an \-

'cI

25.4 em connector chain Clamp \ 35.6 em wing bobbins

Rubber spacers

10.2 an

6 an

Total Length = 31.1 m 1.6 em cable

Headrope

1\ \ ~~crl ~ Q

~~X

. .

asdine

'Hammer- lock Y-'

Detail view of permanent 106.7 em headrope

extension. 190.5 em center panel extension

is similar.

+

54.9 m

Breastlines

(4)

190.5 em

Danleno

Footrope

Figure 4. Schematic diagram of the roller gear and dandyline configuration used by the u. s. vessels during the U.

Japan 1980, 1983, and 1986 Aleutian Islands groundfish

surveys.
designs. Several modifications and improvements were made on

these trawls , depending on the fishing master' s experience , to

increase the fishing efficiency. During the 1980 survey, two

different trawls were used on the Hatsue Maru No. The

32/44/73 trawl (headrope length 32 m , footrope length 44 m and

total length 73 m) used during leg 1 was replaced during leg 2 by

the 55/65/83 trawl (Figs. 5 and 6).

Both trawls were fished with roller gear constructed of used

57 cm automobile tires in the throat and rear wings and 53 cm

steel and rubber balls in the forward wings. Figure 7 shows the

roller gear used during the first half of the survey. This same

configuration was also used during the second half , except that

the length of the center wing section was increased by 10. 5 m to

accommodate the larger trawl. Both trawls were fished with 82 m

dandylines consisting of a single 32 m section branching to a

double 50 m section , and 2. 2 x 3. 4 m otter boards weighing 2. 4 t

each in water. The 32/44/73 trawl had an estimated trawl mouth

opening of approximately 5. 2 m vertically and 28. 8

horizontally; the 55/65/83 trawl opened 4. 5 m vertically and

21. 6 m horizontally.

During the 1983 survey a 47/58/71 trawl was used by the

Daito Maru No. for all sampling (Fig. 8). This trawl was also

fished with roller gear, although quite different from that 'used

by the Hatsue Maru No. in 1980 being constructed of 53 and

35 cm gum bobbins and 30 and 41 cm gum discs (Fig. 9). The Dai 

Maru No. 38 also used 80 m dandylines consisting of a 40 m single

section branching to 40 m doubles, and 2. 25 )C 3. 45 m otter boards weighing 2. 4 t each in water. The mouth opening of this trawl

measured approximately 5. 0 m vertically and 28. 3 m horizontally.

The Ginryu Maru No. conducted all sampling during the 1986

survey with a 38/54/84 otter trawl fished with roller gear

constructed as in 1980 i. e., 57 cm car tires in the throat and

rear wings and 53 cm rubber and steel balls in the forward wings

(Figs. 10 and 11). Other accessories included 100 m dandylines

with a 50 m single section branching to a 50 m double section

and 2. 25 x 3. 5 m otter boards weighing 2. 9 t each in water. The

estimated average horizontal and vertical openings of the trawl

mouth while fishing were 22. 8 m , and 4. 5 m respectively.

The general characteristics of the trawls used by the U. S.

and Japanese research vessels during the triennial survey are

shown in Table 
c:c

6. Om

....

(42)

150 150

150

15 Omm

135 135 135

13 Smm

a.n 13 Smm

,...

L. L

I.t\

,..,

13Smm

12Omm I.t\

0 90mm

....

:11

....

G. R

lJ1

180 l80N

180 -..J

r--

(66)

126

15Omm &l'I

c.?6

106

13 5mm &l'I

135mm 5;

120mm

90mm 0

9 C:mn

Figure 5. Schematic diagram of the 32/44 m trawl used by the

Hatsue Maru No. during the first half of the U.

Japan 1980 Aleutian Islands groundfish survey.

135 135 0&l'I

...

:JO

135

:nn &l'I

:JU

120

mm 1.0

:mIl

....

90mm
L. L

r--

r--

....

Lt1

r--

:: ....

(80)

15Omm

150

120mm

133

120mm

117

12 Omm

107

120mm

88'

12 Omm

LI1

90mm

E)O

90r::n

G. ~

-.J

r--

U"I

12 Omm

180 180

r--

:13

U"I 12Omm

Il1

110

120mm

U"I

U"I 120Ir.m

g 9Omm

r"'

90n-;m

Figure 6. Schematic diagram of the 55/65 m trawl used by the

Hatsue Maru No. during the second half of the U. s. -

Japan 1980 Aleutian Islands groundfish survey.

120

12Cmm 120

r'1

106

\D 120 12Omm \C

U"I

120am

Il1

12Omm

\tI

120

\tI Lt1
Front wing: Length; 3. 5 m

Weight in water; 125. 4 kg

connected to

dandy-line

. . . . .. 

connected to B

Steel d=53

bobbin Wt=25kg

Center wing: Length;

Weight in water; 181. 2 kg

Rubber d=53 em

bobbin wt=10. 8kg

. connected to

each side of C

Rubber Steel Rubber Steel Rubber Steel

Rear wing and Center: Length; 23 m Size of used-tire

5 m

Rear wing

(Q)

13-15 cm

Average weight; 6. 

chain: Length; 47. 0 em

Weight; 1 . 5 kg

: :: ::: :...

AI -- V. ~ ~!E ~f X~.-.-.-.-.-.- 

.::.

Steel

bobbin

19 nun Chain

            

u_------------- -- u_-_u- - 

    

. ...--u- ------E!..t!:.':~'rI!._- 

      

compound rope; Diameter; 26 nun

Figure 7. Schematic diagram of the footrope used by the Hatsue

Maru No. during the first half of the U. S. -Japan

1980 Aleutian Islands groundfish survey.
0 m

,...

134

150 rom V'I

,...

\t1

118

120 tOIm

\t1

V'I 120 Ir.n1

,...

\t1

,...

\t\ 120mm

100 IM1

"'I'

100 mm

,...

.-c

90 t:1m

tS'

0 m

.1::U mm

t'I

150 tam

11\

120 mm 11\

120 mm \t\

~ 120 mm

100 ma:I

100 mm

90 IM1

Figure 8. Schematic diagram of. the 47/58 m trawl used by the

Daito Maru No. 38 during the U. -Japan 1983 Aleutian

Islands groundf ish survey.

leo C'~

120 mm 150 mm

29 

~ 120 11".:11

22 

100 r.m
Bridle

40m

Front wing Central wing

Ste~l Gum Gum GU:i1

bobbin bobbin bobbin bobbin

$2153 ern fa 35 ern 053 ern 03S crn

Gum dise Gum

0' 30 CU1 disc

(0 41 cm

Drooce=

.. 

ehain

Length: 35 ern

Otter door

width: 2. 25 m

Height: 3. 45 m

weight in water: 2. 4 t

,/ Fishing

line Connected to

le,ft wing

Warp 2 m

Bridle: 40 m

Figure 9. Schematic diagram of, the roller gear and dandylines

used by the Daito Maru No. 38 during the U. -Japan

1983 Aleutian Islands groundfish survey.
Length (in meters)

Numbers of mesh

Mesh size

(in millimeters)

180 180 180

Length

165 a

150 b 150 150

141 a

165

150 150 150 150

1 3 143

137 159

135 135 135 135

s...

117 135

....

135 135 135

135

..c.

112

....

....J 135 135 135

101

120 120 120

20. 120

120

120

...

Figure 10. Schematic diagram of the 38/54 m trawl used by the

Ginryu Maru No. during the U. -Japan 1986 Aleutian

Islands groundfish survey.
SOm

Bridle Front wing Central wing

Gum disc

'30 em

Dropper chain

length 35 em

32 used tires

" 57 em

Belly

Fishing line

Connected to left wing

Otter door

Width: 2.25 m

Height: 3.50 m

Weight in water: 2.9 t

Warp

Bridle: 50 m

Figure 11. Schematic diagram of the roller gear and dandylines

used by the inryu Maru No. dur ing the U. S . -Japan

1986 Aleutian Islands groundfish survey.
Table 5. Characteristics of demersal trawls used

during the U. s. -Japan 1980, 1983, and 1986

Aleutian Islands groundfish surveys.

Length Mesh Size Net opening

Tr awl Head - Foot Wing Inter- Cod- Hor i - vertirope rope body mediate end zontal cal

(m) (m) (mm) (mm) (mm) (m) em)

Noreastern 1980 27. 32. 127 16. Noreastern 1983 27. 32. 127 18.

Noreastern 1986 27. 32. 127 16.

Japanese 1980 31. 44. 135-180 90, 120 21.

Japanese 1980 54. 65. 120-180 90, 120 28.

Japanese 1983 45. 58. 120-180 100 120 28.

Japanese 1986 38. 54. 120-180 100, 120 22.

a Codend was constructed of three layers of webbing.

Trawl Mouth Height and width Measurements

The area swept technique was used to estimate the biomass of the

groundf ish resources. The area swept by a trawl was obtained by

measuring the distance the net was towed using loran or radar

readings , the net width, defined as the distance between the wing tips , and the trawl mouth height or vertical opening.

For the Japanese vessels, the trawl mouth height was measured

using a net monitor transducer (Furuno FQ1) attached to the midportion

of the head rope of the trawl during all three surveys. During the

1980 and 1983 surveys the wing spread (horizontal opening) was

estimated using the methods developed by Koyama (1974) based on the

relationship of the distance between the trawl cables measured at the

trawling block and measured again approximately 1 meter aft. In 1986

direct measurements were obtained using a Furuno FQ1 transducer

attached to one wing tip and entwining reflective material in the

opposite wing tip as described by Wakabayashi and Teshima 1986.

Headrope height for the U. S. vessels was measured with a third

wire net transducer system attached to the middle of the headrope in

1983 and by a Scanmar net mensuration system in 1986. Headrope height

in 1980 and wing spread estimates for the 1980 and 1983 surveys were

estimated from a small number of measurements obtained using a net

moni tor ing system developed by the AFSC Resource Assessment and

Conservation Engineering (RACE) Division, on vessels of similar size

and horsepower. In 1986 , direct measurements were obtained using a

Scanmar net mensuration system.
Sampling Design and Rationale

The original objectives of this research program were to

conduct a mul tispecies groundf ish assessment survey and delineate

commercial fish concentrations throughout the Aleutian Island

region from 1650 W long. to 1700 E long. , including Bowers Ridge.

Operations were to be conducted in a dual mode; that is , the

groundfish survey would proceed normally until a significantly

large concentration of a commercially important species was

encountered, then additional non-survey stations (reconnaissance

sampling) would be conducted to delineate the geographic and

bathymetric distribution and abundance of the species. When the

aggregation had been adequately described , operations would

return to the mul tispecies survey mode.

To assure a wide geographic and bathymetric distribution of

the sampling effort, a stratified systematic sampling pattern was developed. The continental shelf and upper slope of the Aleutian

Islands and southern Bering Sea except Bowers Ridge was divided into 30' wide longitudinal strips. Bowers Ridge was divided into

30 minute longitudinal strips where it runs east to west and 

latitudinal strips where it runs north to south. Each strip was

further divided into sampling units based on six depth intervals:

1) 1-100 m

2) 101-200

3) 201-300

4) 301-500

5) 501-700

6) 701-900

(1-54 fm)

m (55-109 fm)

m (110-164 fm)

m (165-273 fm)

m (274-382 fm)

m (383-492 fm).

Because only a small number of stations were eventually completed

in the two deepest depth intervals , and of the similarity of

fauna , these were eventually combined into a single depth

interval, 501-900 m, for the 1980 analysis and for future

surveys.

One station was allocated to each sampling unit with

additional sites added when sampling units were greater than 5 nautical miles (nmi) wide between depth boundaries following the criteria:

1) 5-10 nmi wide- 2 stations

2) 10-15 nmi wide- 3 stations

3) 15-20 nmi wide- 4 stations.

Once survey operations were underway, it became readily

apparent that the time, manpower, and sampling resources were not

adequate to allow completion of both the mul tispecies survey and

the reconnaissance survey and the addition of extra stations.

Therefore the priority was established to place major emphasis on

completing the mul tispecies survey and to limit reconnaissance

sampling.
For data analysis the survey area was initially divided into

three maj or regions based upon the International North Pacific

Fisheries Commission (INPFC) management areas, 1) the Aleutian Islands , 1700 E - 1700 W long. (part of Bering Sea INPFC area V),

2) the southern Bering Sea , 1700-1650 W long. north of the Aleutian Islands (part of Bering Sea INPFC area III) and 3) the

western Shumagin, 1700-1650 W long. south of the Aleutian Islands

(part of the Gulf of Alaska Shumagin INPFC area). Because of the

extreme distance between the eastern and western survey

boundaries the survey area was again divided into five major

areas to better describe species distribution and abundance:

1) Southwest area 180-1700E long. south of the chain.

2) Northwest area 180-1700E long. north of the chain.

3) Southeast area 180-170 oW long. south of the chain. 4) Northeast area 180-1700W long. north of the chain. 5) Bowers Ridge 176OE - 179OW long. north of 52O30'N lat.

Prior to the 1983 survey, an optimum sampling allocation analysis (Cochran 1977) was conducted to decide which

distribution of the 1980 sampling effort would have provided the

lowest variance of the biomass estimate for the following five

major species: walleye pollock, Pacific cod , Atka mackerel,

Pacific ocean perch , and giant grenadier Albatrossia pectoralis

). 

The analysis indicated that for an expected

sampling effort of 300 stations , the precision of the biomass

estimates could be improved from 13% to 39% by using the

suggested distribution of the sampling effort; however , this

distribution did not provide adequate protection against possible

maj or shifts in the geographical distribution of these species. Therefore , the distribution of the sampling effort was adopted

with the following modifications:

1) All areas were divided into sampling units 10 of longitude wide. Minimum sampling effort was set at one station per depth interval wi thin each sampling unit.

2) The sampling effort for Bowers Ridge would remain

approximately the same as during the 1980 survey.

The stations in excess of these minimum requirements were then

allocated based on the results of the optimum allocation of

effort sampling analysis.

Prior to the 1983 survey, it was also decided to restratify

the survey area to allow a more detailed examination of the

biomass distribution. with the exception of Bowers Ridge each

major area was divided into subareas from 2-50 of longitude wide.

The actual dimensions of each subarea were primarily based on

dividing each maj or area into two or three subareas representing

relatively equal bottom areas. These divisions resulted in 

subareas which when overlaid by the 100-500 m and 900 m depth

contours formed the survey strata.
1) Southwest area

Subarea 1 170-175OE long.

Subarea 2 175-178 OE long.

Subarea 178OE long. - 1800

2) Northwest area

Subarea 1 1720-177 OE long.

Subarea 2 177 OE long. - 1800

3) Southeast area

Subarea 1 1800-177OW

Subarea 2 1770-174 ow

Subarea 174 0-1700W

4) Northeast area

Subarea 1 1800-177 ow

Subarea 2 1770-174 ow

Subarea 174O-1700W

5) Southern Bering Sea

Subarea 1 1700-168OW long.

Subarea 2 168O-165OW long.

For the 1986 survey the sampling units and stratification

schemes remained unchanged from 1983. Development of the 1986

survey plan utilized data from both the 1980 and 1983 surveys.

An optimum sampling allocation analysis was conducted on both

data sets to again determine which distribution of the sampling

effort would have resulted in the lowest variances of the biomass

estima tes for the dominant species for each survey. For the 1986

survey, 11 species were considered which included the same 5

species as in 1983 with the exception of giant grenadier, but

also including sablefish , northern rockfish Sebastes polys~inis ), shortraker rockfish Sebastes borealis ) rougheye rockfish Sebastes aleutianus ), shortspine thornyhead

Sebastolobus alascanus ), arrowtooth flounder, and Greenland turbot.

The allocation analyses based on the 1980 and 1983 data sets

provided the optimum distribution of sampling effort between the

si)C major areas. within each major area, the sampling effort was

then allocated equally between subareas with the following constraints:

long.

long.

long.

long.

long.

long.

1) The maximum sampling

one station per 85.

2) The minimum sampling trawl stations.

3) Additional stations would be added to selected strata to

equalize sampling densities so strata could be combined

for analysis.

4) Strata that were initially allocated an odd number of

sampling stations received an additional station so that

the u. S. and Japanese sampling effort could be divided

equally.

densi ty for any station would be 2 (25 nmi 2

) .

densi ty for a strata would be two
station Sampling Procedures

The procedure for selecting sampling sites remained constant

throughout all three surveys. No predetermined locations were sampled. The sampling units were bounded on the east and west by

longitudes and the north and south by depth interval boundaries.

The vessel' s fishing master or captain had the option to place

the station anywhere within these boundaries and usually searched

near the center of the sampling unit-depth interval. Once a

position had been selected, the bottom characteristics would be

evaluated with an echo sounder recording changes in bottom

topography and hardness. The echo sounding transect was

approximately 3 miles long for the U. S. vessels during all the

surveys and for the Japanese vessel in 1986 and approximately 5

miles long for the Japanese vessel during the 1980 and 1983 surveys. If the bottom appeared trawlable the vessel would

reverse course and set the trawl. Fish presence or absence was

never a criteria for deciding to sample or not, only the

trawlability of the station. During the 1980 and 1983 surveys

the Japanese research vessel towed the trawl for 1 hour, and in

1986 for 30 minutes while the U. s. vessels attempted 30 minute

tows throughout all surveys. The duration and distance of the

tows were measured from the time the net reached bottom as

indicated by a net sound unit until the retrieval of the trawl

was started. The distance was determined by computer

calculations of the differences in loran readings or measuring

the difference in radar bearing when plotted on hydrographic charts (U. S. vessels) or measuring the distance on a flatbed plotter (Japanese vessels). If the selected site proved to be

untrawlable or the probability of gear damage too high the vessel

was allowed 30 minutes to find an alternate trawling site in

close proximity to the original station. If no trawlable site

was found , the station was abandoned and the vessel would transit

to the next sampling site. Variations in the time trawled were

caused by hang-ups or sudden discovery of changes in the bottom

topography to hard -rough conditions after the tow was started.

All vessels attempted to follow a uniform depth contour once a

station was started , but again sudden changes in the bathymetry

caused occasional large changes in depth during a tow. 

special attempts were made to sample previously successful

stations in subsequent surveys. All sampling was conducted

during daylight hours to eliminate possible biases caused by

diurnal changes in the depth distribution of any of the species.

Towing speed varied by vessel and was much faster for the

Japanese vessels (Table 6).
Table 6. Mean towing speeds of research vessels participating in

the U. S. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.

Vessel Name Nautical miles/hour

Half Moon Bay

Ocean Harvester

Miller Freeman

Chapman

Lets Go

Hatsue Maru No. 

Daito Maru No. 38

Ginryu Maru No.

Catch and Biological Data Collection Procedures

Data collection procedures were quite similar on vessels of

both nations. On the Japanese vessel, all catch sorting,

splitting, weighing, and measuring was accomplished in the fish

processing facilities below the main deck. Catches of less than approximately 1, 500 kg were completely sorted by species while

larger catches were extrapolated volumetrically; that is , the

volume of the total catch was measured in holding bins , then approximately 1, 500 kg was removed from the bins by the factory

conveyor belts and sorted by species directly into plastic baskets. Hanging scales were used to weigh the baskets. Commercially important species of f ish in the sorted portion of

the catch were sexed and measured to obtain length frequency data

and counts. Selected baskets of each species (not measured) were

weighed and counted to determine a ratio for estimating the total

number of individuals in the sorted part the catch. Total catch

weight and numbers were extrapolated using a ratio of the volume

of the total catch to volume of the sorted portion.

On the U. s. vessel, all catch sorting, splitting, weighing,

and measuring was done on the main fishing deck. Catches less than 1, 150 kg were completely sorted while larger catches were

extrapolated volumetrically; that is, the volume of the total

catch was measured in the deck bin. Approximately 1, 150 kg was

then lifted out of the bin and dumped onto a sorting table using

a splitting net as described by Hughes (1976). Each major

species was sorted into several baskets simultaneously and set

aside in a group and a second set of baskets filled and set aside. This procedure was followed until every species was entirely sorted. Then all baskets were weighed on platform

scales and one basket of each species was randomly selected.

Length frequency measurements were made for all commercially

important species and all other selected baskets were weighed and counted. The ratio between the number of individuals and the
weight of the subsample basket was used to estimate the number of

each species in the sorted portion of the catch. Total catch

weight and numbers were extrapolated using a ratio of the volumes

of the total catch to the sorted portion.

One hundred percent of all prohibited species were counted

and returned to the water as soon as possible. Pacific halibut

were counted and measured but not weighed or se)Ced. On the

Japanese vessel they were usually removed as the catch was dumped

into the holding bin. All Pacific salmon, king crab and tanner

crab were weighed, sexed, and measured.

Length Frequency Measurements

Length frequency measurements were taken for all

commercially important species. The total length (TL) of fish

was measured, from the tip of the snout to the end of the center

of the caudal fin, except for grenadiers which were measured from

the tip of the snout to the anus. Red squid Berryteuthis

magister) were measured from the forward edge of the mantle to

the end of the center of mantle. Crabs were measured to the

nearest millimeter using stainless steel calipers. Carapace lengths (CL) were recorded for king crabs, and carapace widths

(CW) for snow crabs (chionoecetes spp.

On Japanese vessels , all commercially important species from the sorted catch were measured. Each fish was placed on a

measuring board equipped with a waterproof paper length frequency

strip marked in . 5 cm increments. The measurement was completed

by punching a hole into the paper strip at the end of the caudal fin. The total number of holes in each . 5 cm increment was

recorded as the length frequency for the sample. The 10 cm line

of the paper strips was aligned 9. 5 cm from the left end of the

measuring board. This had the effect of rounding all

measurements up to the nearest . 5 cm interval; that is , a 49. 6 cm

measurement would be recorded as 50 cm, and a 50. 4 would 

recorded as 50. 5 cm.

On U. s. vessels , length frequency measurements were taken

from random basket subsamples taken when the catch was sorted. Each fish was placed on a measuring board, fitted with a

plastic reusable strip marked in 1 cm increments. A pencil mark

was made on the plastic strip at the end of the caudal fin. The

total number of pencil marks in each centimeter increment was

recorded as the length frequency. The 10 cm line of the plastic

strips was aligned at 9. 5 cm on the board. This had the effect

of rounding all measurements to the nearest whole centimeter.
Age structure Collection

otoliths were taken from randomly selected samples of most

commercially important fish during all 3 years. In 1980 and

1983, otoliths were only collected from hauls with fairly large

catches of the desired species. This strategy resulted in more

otoliths than could be processed, so the 1986 collections were

allocated to each of the vessels and distributed throughout the

entire survey area (Table 7).

Table 7. Age structure collection allocation scheme used during

the U. S. -Japan 1986 Aleutian Islands groundfish survey.

Number of otoliths

u. s. Japan

Aleutian Southern Aleutian Southern Species Islands Bering Sea Islands Ber ing Sea

Walleye pollock 1120 280 1120 280

Pacific ocean perch 1120 210 1120 210 Sablefish 1120 210 1120 210

Atka mackerel 1120 210 1120 210

Shortraker rockfish 560 140 560 140 Rougheye rockf ish 560 140 560 140

Northern rockfish 560 140 560 140

Shortspine thornyhead 560 140 560 140 Rock sole 560 140 560 140 Arrowtooth flounder 560 140 560 140

Greenland turbot 280 140 280 140

During the 1980 and 1983 surveys , only one otolith was taken from each specimen. otoli ths at each station were usually placed

in vials by species sex cm-Iength categories. That is , for each station , all otoliths of each sex of each species of each length

category were stored in one vile. However, composite otolith

collections were made aboard the Hatsue Maru No. and the Ocean Harvester for certain species. For these collections, all

specimens of a single sex size-length interval were combined for

all sampling stations wi thin a subarea into a single otolith vial. In 1986 both otoliths were taken from each specimen and stored in a single vile.

During all three surveys , rockfish and roundfish otoliths

were cleaned and stored in 50% ethyl-alcohol. Flatfish otoliths

were cleaned and stored dry during the 1980 and 1983 surveys.

During the 1986 survey, flatfish otoliths were stored in a

solution of 50% glycerine and 50% water with the addition of
8 g of thymol, dissolved in a minimum of ethanol, per liter of

solutions to retard growth of undesirable organisms.

Length-weight measurements were taken for most commercially

important species during all three surveys. Lengths were

measured to the nearest centimeter. For species weighing less than 2, 600 g, individuals were weighed on magnetically dampened

triple-beam platform scales to the nearest whole gram or 10 grams

depending on the sea conditions and vessel stability. Larger

species were weighed on hand-held hanging scales of the

appropriate weight capacity. Each capacity scale had different

weight calibration intervals; therefore , weights were usually

recorded to the nearest 25, 50 , or 100 grams. Under good weather

and sea conditions , extrapolations could be made to one-half the

calibrated interval. All specimens were weighed without removal

of stomach contents , which for the larger species in particular

added variability.

Relative Fishing Power Comparisons

Each year, during these groundf ish resource assessment

surveys , an attempt was made to determine the relative fishing

power of one of the U. s. vessels compared to a Japanese vessel so

that data from both vessels could be combined for analysis. For

each comparison , catches were selected based on the original 30

minutes of longitude sampling units used to establish the

sampling design of the 1980 survey. Only paired stations

completed in the same sampling unit by each vessel/gear

combination , or in most instances , adjoining sampling units were

selected for these analysis. If an unequal number of stations

were available for each vessel/gear combination , paired

observations were selected based on the similarity of sampling

depths.

A fishing power coefficient was calculated for each selected

species as the ratio of the mean catch per unit of effort (CPUE)

obtained from each vessel/gear combination.

Survey precision

Throughout these analyses the measure of precision of the

biomass estimates has been the confidence interval expressed as a

percent of the biomass estimate (This measure of precision will

be referred to as the confidence interval). since the fish

species being dealt with in this report are not randomly

distributed, and the most abundant and important species are in

fact very gregarious , the variance is proportional to the mean

biomass estimates and the resulting confidence intervals are very

large , reflecting a low degree of precision in the biomass estimates. The confidence intervals of the most abundant species

in the survey area were examined to determine if the changes in
the sampling patterns had in reality increased the precision of

the biomass estimates as intended.

Environmental Data

During all trawling operations, echo sounding traces of the

bottom topography were recorded and used to determine mean trawling depths. Surface water temperatures were taken from

pilothouse readouts of engine intake water or with thermometers

and surface water samples obtained with buckets. Surface to

bottom water temperatures profiles were taken with expendable

bathythermographs (XBTs).

Data Management

Data collected during the 1980, 1983, and 1986, groundfish

resource assessment surveys of the Aleutian Islands were

maintained in four separate files:

Haul - station-specific data such as date, time, latitude, longitude, depth, sampling gear, temperature,

and gear performance.

position - file type containing more details on position

(e.g., latitude and longitude at the start and end of

net tows) 

Catch - species code, weight, and number.

Length-frequency - species code , sex, length, and

frequency.

Specimen - species code, sex, age-length, length-weight,

reproductive condition, age structures, and stomach

contents.

2 )

3 )

4 )

Data was usually recorded on preprinted forms and logged

magnetic tape or computer disk at sea; however, all data

Hatsue Maru No. and all specimen data forms were data

at the AFSC after the cruise was completed. 

After the data files were entered into the database at the

AFSC they were scrutinized for errors utilizing diagnostic

programs. All suspected errors were checked against original

data sheets and corrected. Following correction of the data

bases , copies were sent to the Groundfish group, Fishery Agency

of Japan, Far Seas Fisheries Research Laboratory, Shimizu , Japan.

from the

logged

Species Groupings

During these surveys, scientists from both nations sometimes

encountered unfamiliar species which could not be identified to

species, or more familiar species which occurred together with an

extremely similar species in high abundance. Therefore, for the
data analysis , certain faunal elements were combined at genus

family, or higher taxonomic levels (Table 8).

Table 8. Species groupings used for analysis of the U. S. -Japan

1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.

Group Name

Skates

Coryphaenoides sp.

Triglo~s sp.

Irish lords

Malacocottus sp.

Myoxocepha 1 sp.

Arrowtooth flounder

Squids

octopuses

Year

Species included 1980 1983 1986

All Rajidae

All Coryphaenoides

All Triglops

All Hemilepidotus

All Malacocottus

All Mvoxocepha Ius

All Atheresthes

All Squids

All octopuses

Data Analysis Procedures

Relative Fishing Power Comparisons

Since direct side-by-side trawling was not feasible, it was necessary to develop an al ternati ve method of estimating relative

fishing power differences between the U. S. and Japanese vessel/gear combinations. It was decided that the U. S. and

Japanese vessels would sample alternate sampling units in the

same time period so that catch rates at adj acent stations could be compared. Al though this plan was attempted the actual number

of paired stations which were completed in the same relative time

and place was small because vessel communications were inadequate

for close coordination and the vessels did not operate together for the entire survey. Catch rates at paired stations in the

same or adj acent sampling units conducted wi thin a 1 month period

were compared. In 1980, only 36 paired observations were

available because the U. S. vessel did not have time to fish the entire area. In 1983 , vessel communications and simultaneous

schedules improved and although the time available to the U. s.

vessels decreased the number of comparable stations increased to 42. In 1986, they increased to 59.

Data analysis to determine relative fishing power coefficients (RFPC) by species included calculation of the ratio

of the mean CPUE of the U. S. vessel-trawl combination and the

Japanese vessel-trawl combination in catch per unit area
(kg/hectare (Distance towed (km) x trawl width (km) )C . 01)) for

each species where

RFPC

Mean CPUE (U. S. kg/hectares

Mean CPUE (Japan) kg /hectares

Mean Catch Per unit Effort and Biomass

Before any computations were conducted, several adjustments

to the haul and catch files were made. The catch files for the

Japanese trawl were divided by the ratio of the U. s. trawl width

for a survey by the mean trawl width of the Japanese trawl of the

same survey to standardize these data to one trawl width, a

requirement of the computer program. In 1986 , when trawl width

by depth data were available for the Japanese trawl, the data

were adjusted to reflect these differences. This adjustment was

accomplished by selecting the shallowest depth interval trawl

width as the standard and dividing the distance fished in the

other depth intervals by the ratio of the trawl widths in each

depth interval by the trawl width in the shallowest standard depth interval.

Biomass estimates were computed based on the most efficient

trawl during each survey. Therefore, when the u. s. trawl was the

most efficient at capturing a species , the Japanese catch data

was multiplied by the appropriate RFPC coefficient. When the Japanese trawl was the most eff icient the U. s. catches were

divided by the ratio of the U. s. catches divided by the Japanese

trawl catches.

For all analyses the vulnerability, or the portion of

individuals in front of the trawl which were caught , was unknown

and was therefore assumed to be equal to 1.

Mean CPUE was obtained by standardiz ing all catches to

kilograms/square kilometer (kg/km ), and then summing the catches

and dividing by the number of stations (Wakabayashi et ale 1985).

variances of the means were also calculated.

Biomass estimates and their variances and confidence

intervals were calculated using the methods developed by Alverson

and Pereyra (1969). Biomass was calculated by strata , as defined

in the survey design and rationale section of this paper for

1983, and the subarea or area totals were obtained by addition of

the strata totals (Wakabayashi et ale 1985). The population

numbers were calculated in a similar manner.

Length Frequencies and Popul~on Size Composttign

For this analysis the Japanese length frequency data were

converted to the U. S. data format of 1 cm intervals by

subtracting 1 mm from each length and rounding to the nearest centimeter. A relative length frequency distribution was

calculated for each stratum by weighting each length frequency

sample by the ratio of the station CPUE (numbers/ha) representing

the sample to the sum of all the CPUEs within the stratum and
then summing the weighted frequencies for each length interval.

A population size composition was constructed for each stratum by

mul tiplying the total strata population estimate by the ratio of

the relative number of frequencies in a size-sex category to the

total number of relative frequencies. Subarea and area totals

were obtained by addition of strata size-sex interval totals.

Age Composition

All age interpretations were accomplished by trained

specialists at the Age and Growth unit of the AFSC or by

scientists at the Far Seas Fisheries Research Laboratory. These

age interpretations are based upon the assumption that annuli are

formed on otoliths or scales and they represent annual marks

(Wakayabashi et ale 1985). For all species except Atka mackerel,

the age was determined by the actual count of the annuli. For

Atka mackerel, which is a late summer-fall spawner, it was

determined that an annuli was not formed the first winter;

therefore, 1 year was added to the age obtained by the age readers. otoliths were used for ageing all species except

Pacific cod for which scales were read.

Age data were combined by subarea or area depending upon how

the data were collected to form age-length keys. Age composition

was calculated by proportioning the size composition to age

groups based upon the percentage of each age group in that sizesex category with the age-length key.

Growth Characteristics

Growth characteristics of the principle species were

estimated by fitting the mean length-at-age data to the

von Bertalanffy growth curve using a nonlinear least-squares technique (von Bertalanffy 1938).

Length-Weight

Relationships of the weight at length of the principle

species were calculated using a regression analysis and curve fit

of the length-weight data. A linear least square was calculated

on the log-transformed data.

RESULTS

Sampling Effort

The total number of attempted stations decreased from 435 in

1980 to 425 in 1983 but increased to 499 in 1986 (Table 9, Figs.

12 and 13). Of the 435 stations attempted in 1980, 31 were

unsuccessful , 64 were for special sampling, 48 were placed in the

shumagin INPFC area, (sampled only during 1980), and 45 were from

an area adjacent to Adak Island which was not sampled during the

1986 survey leaving 247 1980 stations for data comparison.

During 1983 , 18 of the 425 attempted stations were unsuccessful,

30 were used for special sampling and 58 were conducted in the

area not sampled during 1986 leaving 319 valid stations for

comparison with other years. In 1986 , 438 of the 499 attempted

stations were used for comparison with 18 being unsuccessful and

34 being used for special sampling. The amount of total effort

available for the comparison analysis increased from 57% in 1980

to 75% in 1983 and 88% in 1986. The Japanese research vessels

completed 66-78% of the total sampling effort during the three

survey years.

Table 9. Summary of sampling effort expended during the U. S.

Japan 1980, 1983, and 1986 Aleutian Islands groundfish

surveys.

Years

stations 1980 1983 1986 Attempted 435 Unsuccessful Special sampling West Shumagin 

Adak mi I i tary z one

Used for comparison 247

a 1 7 6 0 3 0 ' W - 178 0 3 0 ' W four

stations were also in the

425

319

499

438

special sampling

Adak mi I i tary zone)

The total number of comparative sampling stations in the

Aleutian Islands region increased from 211 in 1980 to 278 in

1983, and 367 in 1986 (Table 10). During all three surveys, the

Japanese research vessels provided the majority of the sampling effort. In 1980, 62% of the stations were completed by the

Hatsue Maru No. The Daito Maru No. 38 completed 73% of the

stations in 1983, and the Ginryu Maru No. 75% in 1986. Most

of the deep water sampling, (~300 m) was completed by the

Japanese research vessels , while the U. S. research vessels worked
~STALEMATE BANK

1986

SURVEY VESSELS

LET' S GOGINRYU MARU NO.

~STALEMATE BANK (J~

1983

SURVEY VESSELS

CHAPMANMI LLER FREEMANDAI TO MARU NO. 3B 

~STALEMATE BANK

1980

SURVEY VESSE

OCEAN HARVESTERHALF MOON BAYHATSUE MARU NO. 62 .

Figure 12. Survey stations used for data analysis in the Aleutian Islands areas of the

u. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
1986

SURVEY VESSELS

LET' S GO

GINRYU MARU NO.

1 983

SURVE Y VESSELS

CHAPMAN

DAlTO MARU NO. 38

1980

SURVEY VESSE

OCEAN HARVESTER

HATSUE MARU NO. 62 .

IX)

1.0

1986

SURVEY VESSEL

I GINRYU MARU NO.

IX)

1.01

1983

SURVEY VESSEL

I DAlTO MARU NO. 38 

(:)

IX)

I~d

1.0

BOWERS

BANK

1980

SURVEY VESSEL

I HAT SUE MARU NO. 62 . 

Survey stations used for data analysis in the Southern

Ber ing Sea and Bowers Ridge areas of the U. S. -Japan

1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.

Figure 13.
primarily in shallower waters. Japanese vessels completed 100% of

the stations in Bowers Ridge during all three surveys. In 1980

the U. s. vessels conducted sampling operations in all but the

500-900 m depth interval, but in 1983 and 1986 most u. s. sampling

occurred at depths shallower than 300 

Table 10. Number of stations successfully completed in the

Aleutian Islands areas during the U. S. -Japan 1980

1983, and 1986 groundf i sh surveys.

1980 1983 1986

Area Depth (m) Japan Total Japan Total Japan Total

Southwest 1-100

101-200

201-300

301-500

501-900

1-900 107

Southeast 1-100

101-200

201-300

301-500

501-900

1-900

Northwest 1-100

101-200

201-300

300-500

501-900

1-900

Northeast 1-100

101-200

201-300

301-500

501-900

1-900 116

Bowers 101-200

Ridge 201-300

301-500

501-900

1-900

Aleutian 1-100 Islands 101-200 103 151 Total 201-300

301-500

501-900

1-900 131 211 204 278 275 367
In 1980 and 1983, the effort was more concentrated in the

western area of the Aleutian Islands , but in 1986 the sampling

effort was more evenly distributed throughout the entire Aleutians Island region (Table 11). During 1980, 24-28% of the

effort from each area was distributed in the intermediate depth

intervals with the shallowest depth interval accounting for only

2% of the effort. In 1983 , the percentage of the sampling effort

increased in the two shallowest and the deepest depth interval

and in 1986 the percentage increased again in the two shallowest depth intervals.

Table 11. Distribution of sampling effort and sampling density

in the Aleutian Islands areas during the U. s. -Japan

1980 1983, and 1986 groundf ish surveys.

Percent stations per 1, 000 kIn

Area Depth (m) 1980 1983 1986 1980 1983 1986

Southwest 1-100

101-200 30. 37. 56.

201-300 31. 25. 16. 10. 10.

301-500 29. 15. 13.

501-900 18.

1-900 100. 100. 100.

Southeast 1-100 10.

101-200 43. 32. 41.

201-300 25. 35. 23.

301-500 18. 17. 17.

501-900 12.

1-900 100. 100. 100.

Northwest 1-100 10. 18.

101-200 16. 25. 33.

201-300 25. 22. 23. 10. 15.

300-500 29. 10. 13.

501-900 25. 31. 11.

1-900 99. 100. 100.

Northeast 1-100

101-200 31. 40. 37. 11.

201-300 29. 23. 23. 11.

301-500 21. 17.

501-900 12. 22. 16.

1-900 100. 100. 100.

Bowers 101-200 10.

Ridge 201-300 10. 17.

301-500 12. 25. 23.

501-900 81. 55. 52.

1-900 100. 100. 100.

Aleutian 1-100 Islands 101-200 28. 33. 41. Total 201-300 27. 24. 21.

301-500 24. 14. 16.

501-900 17. 23. 12.

1-900 100. 100. 100.
Sampling densi t~ in the Aleutian Islands varied from 0.

station per 1, 000 km in the 1-100 m depth interval in 1980 to

1 stations per 1, 000 km2 in the 101-200 m depth interval in 1986. Overall sampling densit~ for all depths combined increased

from 2. 6 stations per 1, 000 km in 1980 to 4. 5 stations per 1, 000 2 in 1986. This improvement occurred in all but the deepest

depth interval, but the greatest improvement occurred in the 1-

100 m depth interval.

In the Southern Bering Sea the number of stations completed

doubled from 1980 to 1986 with the u. s. research vessels

accounting for 61% of the total sampling during both the 1980 and

1983 surveys (Table 12).

Table 12. Number of stations successfully completed in the

Southern Bering Sea area during the U. S. -Japan 1980

1983, ' and 1986 Aleutian Islands groundfish surveys.

1980 1983 1986

Depth (m) s. Japan Total u. S . Japan Total S. Japan Total

1-100

101-200

201-300

301-500

501-900

Total

During 1986, however , they completed 48% of the sampling.

As in the Aleutian Islands region , the U. S. vessels completed

more shallow stations while the Japanese research vessels

completed more of the deeper stations , particularly during 1983 and 1986. By percentage , the distribution of the sampling effort

increased in the shallowest depth interval and decreased in all

others between 1980 and 1986. The overall sampling density for

the Southern Bering Sea increased from 2. 8 stations per 1, 000 Km

in 1980 to 5. 7 stations per 1 000 km2 in 1986 (Table 13).

Table 13. Distribution of sampling effort and sampling density

in the Southern Bering Sea area during the U. S. -Japan

1980, 1983 , and 1986 Aleutian Islands groundfish

surveys.

Percent Sampling density

Depth (m) 1980 1983 1986 1980 1983 1986

1-100 30. 31. 43.

101-200 33. 34. 31.

201-300 13. 19. 11.

301-500 13.

501-900

All Depths 100. 100. 100.
Survey precision

The change in the sampling design for the 1983 survey was

based primarily on the 1980 distribution of five of the most

dominant species. In 1983, the confidence intervals of the

biomass estimates for four of the species improved: moderately for three species, walleye pollock (26%) giant grenadier (26%)

and Pacific cod (13%) ; substantially for Atka mackerel (47%);. and

declined slightly for Pacific ocean perch (6%) (Table 14).

Table 14. Conf idence intervals expressed as a percent of the

mean biomass estimate for important species

encountered during the U. -Japan 1980 , 1983, and 1986

Aleutian Islands groundfish surveys.

Species 1980

Aleutian Islands

1986

Walleye pollock

Pacific cod

Atka mackerel

Pacif ic ocean perch

Giant grenadier

Northern rockf ish

Sablef ish

Arrowtooth flounder

Greenland turbot

Shortraker rockf ish

Rougheye rockf ish

Shortspine thornyhead

104

266

163

1983

, 41

107

140

276

121

1980

Southern Ber ing Sea

1986

124

268

329

943

129

741

214

105

101

1983

128

156

183

152

109

622

308

375

174

106

792

181

169

342

188

713

For the other seven species which occur at lower abundance,

three species, northern rockfish , shortspine thornyhead , and

rougheye rockfish improved while arrowtooth flounder and

Greenland turbot remained relatively unchanged and sablefish and

shortraker rockfish declined in precision. A closer examination

of the sablefish data showed that over 63% of the total

variability could be attributed to the Northeast area' s, 201-

300 m depth interval, which also contained 46% of the total

biomass estimate for the Aleutian Islands region. For shortraker

rockfish the Southwest area' s 301-500 m depth interval

contributed 52% to the total variance and 19% to the total

biomass. If the high variation of these two area-depth intervals

are discounted , the new sampling design and the increased

sampling effort showed excellent overall improvement in the

confidence intervals for most of the important species during the

1983 survey.

Dur ing the 1986 survey, the new

improve the precision of the biomass 1983. Of the 11 species included in analysis , the conf idence interval of

sampling design did not

estimates as much as in

the sampling allocation

four species , northern
rockfish, walleye pollock, shortspine thornyhead, and Pacific cod

remained relatively unchanged. Four species , shortraker rockfish

(101%), sablefish (53%), Greenland turbot (19%), and Pacific

ocean perch (15%) improved, while three species , Atka mackerel,

rougheye rockfish , and arrowtooth flounder had larger confid~nce intervals. The large improvements in sablef ish and shortraker

rockfish estimates are attributable to the fact that in 1986

these species had a more even distribution than in 1983 which

resulted in a lower variance associated with the biomass

estimates.

For three of the four species with improved confidence intervals , the same situation was apparent as occurred in the

1983 survey; that is, one area-depth interval had extremely large

catches which contributed to high variation of the biomass estimates. These are: (1) arrowtooth flounder, Northeast area,

301-500 m depth interval , 51. 9% of total biomass but 98. 8% of

total variance; (2) Atka mackerel , Southwest area , 1-100 m depth

interval, 75. 9% of total biomass , 77. 6% of total variance; and

(3) giant grenadier, Northwest area, 501-900 m depth interval,

41. 4% of total biomass , and 79. 1% variance.

Confidence intervals for the Southern Bering Sea have always

been very large for most species. Since the size of the survey

area is quite small, the number of sampling stations has also

been small, which when combined with large catches for many

species , leads to extremely large estimates of variance. During

the 1983 survey, the confidence intervals for four of five

dominant species decreased (Pacific cod, Atka mackerel, Pacific

ocean perch, and giant grenadier) and remained relatively

constant for one , walleye pollock. Of the other important

species the confidence intervals for Greenland turbot, shortraker

rockfish, and rougheye rockfish increased indicating a general

decrease in precision. Results of the 1986 survey were not as clear. six species , walleye pollock, Pacif ic ocean perch,

sablef ish, Greenland turbot , Pacif ic halibut, and shortraker

rockfish showed improvement; one species , Pacific cod , remained

relatively unchanged, and six species, Atka mackerel, giant grenadier , northern rockfish , arrowtooth flounder , and shortspine thornyhead decreased.

Fishing Power Comparisons

During the 1980 survey, 36 paired observations were

available between the Half Moon Bay (27/32 m Northeastern trawl)

and the Hatsue Maru No. (32/44 and 55/65 m trawls). The Half

Moon Bay was more effective at capturing five fish species:

Pacific halibut, flathead sole Hi~?oglossoides elassodon), Atka

mackerel, rougheye rockfish, and Pacific ocean perch. It was also

more effective at capturing red king crab Paralithodes camtschatica

). 

Both vessels were equally effective at capturing

Greenland turbot and golden king crab Lithodes aequispina

). 

The

Hatsue Maru No. was more effective at capturing the remaining species (Table 15).
Table 15. Estimates of relative fishing power differences (CPUE

of u. s. vessel divided by CPUE of Japanese vessel) for

vessels participating in the U. s. -Japan 1980, 1983,

and 1986 Aleutian Islands groundfish surveys.

Year

Spec ies 1980 1983 1986

Skates

Arrowtooth flounder

Greenland turbot

Pacif ic halibut Flathead sole

Dover sole

Rex sole

Rock sole

Sablef ish

Giant grenadier

Pacific cod

Walleye pollock

Atka mackerel

Shortspine thornyhead

Rougheye rockf ish

Pacif ic ocean perch

Northern rockf ish

Short raker rockf ish

Tanner crab

Golden king crab

Red king crab

Red squid

In 1983, 42 observations were available between the NOAA

ship Miller Freeman (27/32 m trawl) and the Daito Maru No. 38

(45/58 m trawl). The NOAA Ship Miller Freeman was more effective

at capturing rougheye rockfish, skates (Rajidae), and all species

of flatfish with the exception of Dover sole Microstomus pacificus

) .

In 1986, 59 comparable stations were available between the

Lets Go (27/32 m trawl) and the Ginryu Maru No. (38/54 m trawl). The Lets Go was more effective in capturing Dover sole,

flathead sole , and all species of crab.

The mean catch rates used to compare relative fishing power

were influenced by (1) the clumped , irregular distribution of

the species; (2) the ability of the fishing masters to trawl on

extremely rough substrates; and (3) differences in the roller

gears, trawl design , and construction materials which also

allowed sampling in areas of rough substrate.
Length Frequency Measurements

Length frequency measurements were taken for all

commercially important species. These measurements totaled over

126 000 in 1980 , 132 000 in 1983 and 129 000 in 1986 with over

80% of the collection being taken on the Japanese research vessels (Table 16).

Table 16. Number of length frequency measurements collected

during the U. S. -Japan 1980 , 1983 , and 1986 Aleutian

Islands groundfish surveys.

Species

Arrowtooth flounder

Greenland turbot

Pacific halibut Flathead sole

Dover sole

Rex sole

Rock sole

Sablef ish

Giant grenadier

Popeye

Pacif ic cod

Walleye pollock

Atka mackerel

Shortspine thornyhead

Rougheye rockf ish

Pacific ocean perch

Northern rockf ish

Shortraker rockf ish

Red squ id

Golden king crab

Red king crab

Alaska snow crab

Total

510

420

226

222

191

754

232

378

079

337

271

650

264

217

126

25, 008

1980

Japan

10, 637

656

497

613

1, 408

114

624

626

295

229

17, 227

973

027

029

14, 456

767

767

308

101, 332

619

180

544

468

926 

347

594

432

567

384

338

197

951

259

385

23, 439

Years

1983

Japan

488

476

593

750

776

107

170

5, 691

4, 126

335

20, 483

205

613

717

19, 922

276

129

299

565

108, 872

668

453

887

193

031

785

567

109

175

754

19, 725

1986

Japan

623

327

916

713

2, 099

12, 794

484

226

524

11, 797

18, 615

124

012

362

12, 629

127

222

948

640

197

109, 473
Age structures

A total of 14, 005 otoliths were collected in 1980, 25, 468 in

1983 and 10, 774 in 1986 (Table 17).

Table 17. Summary of otoliths collected dur ing the U. S . -Japan

1980, 1983, and 1986 Aleutian Islands groundfish

surveys.

1980 1983 1986

Species Japan Japan Japan

Arrowtooth flounder 154 520 328

Greenland turbot 113 180 137 653 Flathead sole 216

Rex sole 128 163

Rock sole 110 154 500 278 620 480

Sablef ish 262 908 980

Pacific cod 654 580 396 480

Walleye pollock 842 312 397 500 840 496

Atka mackerel 208 428 143 951 120 670

Shortspine thornyhead 107 446 420

Rougheye rockf ish 298 371 415

Pacific ocean perch 667 184 565 517 439 330 Northern rockf ish 486 107 569 120 510 Shortraker rockf ish 224 435 650 Total 176 829 263 18, 205 139 605
Length-Weight Measurements

Dur ing the 1980 , 1983 , and 1986 surveys, 3, 790, 9, 731 and

382 individual length-weight measurements were taken (Table

18) .

Table 18. Summary of length-weight observations obtained during

the U. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.

Years

1980 1983 1986

Species Japan Japan Japan

Arrowtooth flounder 328

Greenland turbot 113 180 633 Flathead sole

Rex sole 163 Rock sole 400 319 620 525 Sablefish 161 307 983

Pacific cod 157 782 390 946

Walleye pollock 130 316 431 840 515

Atka mackerel 826 137 276 226 946

Shortspine thornyhead 510 499 Rougheye rockf ish 535

Pacific ocean perch 405 414 938 643 439 055 Northern rockf ish 241 304 120 511 Shortraker rockf ish 224 271 251 Red squid 161 Total 639 151 108 623 281 11, 101
Trawl Measurements

The wing spread estimates of the Japanese trawls during the

1980 and 1983 surveys showed a wide variation, especially at

water depths greater than 200 m. Wing spread measurements

obtained during the 1986 survey tended to increase as the depth

increased at depths less than 200 m, but remained constant at

depths greater than 200 m as shown below and in figure 14.

De th Interval

1-100

101-200

201-300

301-500

501-900

Mean width m

20.

22.

23.

24.

24. 73

26!

.. . .. . 

.11 ~::. 

..... . . . \\ .. . .. . 

CtS

.....

:r:

'No

u~~

...

Lets Go

1 observation

150 350 550 . 650

Depth (m)

250 450 750

. .

Ginru Maru

. 1 observation

* 2 observations

0 4 observations

. 5 observations

850 950 1050

Figure 14. Wing spread measurements of trawls used during the

u. S. -Japan 1986 Aleutian Islands groundfish survey.

BIOMASS ESTIMATES

Total biomass of all fish and invertebrates taken during the

three surveys averaged 2. 4 million t and estimates ranged from a low of 1. 5 million t in 1980 to 3. 3 million t in 1986 (Table 19).

Estimates for biomass increased 51% between 1980 and 1983, and

41% between 1983 and 1986. Fish dominated the catches all 

years, with invertebrates accounting for only 4% of the average biomass. The overall species composition in 1980 consisted of

124 species representing 35 families (Appendix C.

). 

The number

of pelagic species declined after 1980.

Biomass estimates for important fish species , from the

total survey area , based on the U. -Japan 1980 , 1983,

and 1986 Aleutian Islands groundfish surveys.

Table 19.

Species

Pollock

Atka Mackerel

Pacific Ocean Perch

Pacific cod

Northern Rockf ish

Arrowtooth flounder

Sablef ish

Greenland turbot

Rougheye rockfish

Halibut

Shortraker rockf ish

Shortspine thornyhead

Rock sole

Skates

Flathead sole

Rex sole

Dover sole

Giant grenadier

Other fish

All fish

All invertebrates

All s ecies

1980

308, 745

150, 346

88, 713

126, 445

43, 248

36, 860

142, 384

44, 990

19, 797

12, 554

13, 817

20, 214

27, 948

12, 295

837

796

534

314, 031

78, 216

446, 770

99, 697

546, 467

1983

778, 666

343, 312

214, 708

158, 767

45, 344

47, 795

78, 900

65, 845

24, 816

21, 130

37, 539

15, 401

19, 213

19, 437

325

207

486

351, 304

59, 074

289, 269

47, 827

337, 096

Biomass (t)

1986

550, 517

634, 651

262, 828

214, 923

188, 360

144, 946

136, 303

88, 276

59, 454

45, 074

31, 589

24, 139

25, 720

20, 736

845

496

1, 102

601, 583

110, 953

156, 495

107, 604

264, 099

Aver age

545, 976

376, 103

188, 750

166, 712

92, 317

76, 534

119, 196

66, 370

34, 689

26, 253

27, 648

19, 918

24, 294

17, 489

002

500

707

422, 306

82, 748

297, 511

85, 043

382, 554

% of

Total

Biomass

22.

15.

17.

96.

100.
Biomass estimates in the Aleutian Islands area were similar

to the total survey area with fish making up most of the catch

and invertebrates accounting for about 4% (Table 20).

Biomass estimates for important fish species, from the

Aleutian Islands area , based on the U. s. -Japan 1980 1983, and 1986 groundfish surveys.

Table 20.

Species

Pollock

Atka mackerel

Pacific ocean perch

Pacific cod

Northern rockf ish

Arrowtooth flounder

Sablef ish

Greenland turbot

Rougheye Rockf ish

Halibut

Shortraker Rockfish

Shortspine Thornyhead

Rock sole

Skates

Flathead sole

Rex sole

Dover sole

Giant grenadier

other fish

All fish

All invertebrates

All s ecies

1980

252, 013

130, 514

82, 710

52, 070

42, 907

26, 928

24, 192

31, 059

18, 875

853

12, 797

19, 135

12, 159

10, 122

966

574

344

313, 480

47, 646

089, 344

81, 423

170, 767

1983

495, 982

343, 302

117, 229

113, 143

43, 828

38, 272

69, 029

51, 812

21, 987

13, 826

24, 459

13, 987

15, 188

16, 262

631

765

369

349, 538

44, 045

774, 654

43, 321

817, 975

Biomass (t)

1986

448, 138

634, 006

208, 052

172, 625

124, 869

124, 855

111, 689

67, 757

55, 359

38, 856

23, 985

23, 213

19, 376

19, 492

836

037

047

600, 656

64, 158

747, 006

103, 569

850, 575

Average

398, 711

369, 274

135, 997

112, 613

70, 535

63, 352

68, 303

50, 209

32, 074

20, 845

20, 414

18, 778

15, 574

15, 292

811

792

587

421, 225

51, 950

870, 335

76, 104

946, 439

, of

Total

Biomass

20.

18.

21.

96.

100.
Eight families accounted for 99% of the fish biomass. The

two most abundant families were Gadidae and Macrouridae (Table

21) . Squids were the dominant (74% of the total) invertebrate

species group with an estimated biomass of. 21, 000 t.

Table 21. Biomass estimates for important fish and invertebrates

by family or species group, from the Aleutian Islands

area, based on the U. -Japan 1980, 1983 , and 1986

Aleutian Islands groundfish surveys.

Biomass (t)

Family or group 1980 1983 1986 Average

Gadidae 304, 473 609, 261 621, 038 511, 591

Macrouridae 322, 409 364, 110 618, 102 434, 874

Hexagrammidae 130, 511 343, 434 634, 055 369, 333

Scorpaenidae 176, 456 222, 278 435 780 278, 171

Pleuronectidae 82, 943 121, 902 260, 838 155, 228

Anoplopomatidae 24, 193 027 111, 690 303

cottidae 624 570 32, 211 30, 135

Squids 461 786 25, 982 21, 076

Ra j idae 123 259 19, 491 15, 291

Crabs 10, 784 976 786 515

Zoarcidae 432 586 845 621

octopuses 757 440 781 659

Osmer idae 854 615

Cyclopter idae 604 325 427 452

Agonidae 373 215 102 326

Shrimps 316 141

a Less than 1 metric ton.
Fish were distributed in all depth intervals and all

subareas of the Aleutian Islands (Table 22). The lower values in

the 1-100 m depth strata in 1980 and 1983 suggests inadequate

sampling of the shallow depth strata during those years. The

biomass estimate of over 1 million t in the Southwest area in

1986 reflects a strong year class of Atka mackerel which had an

estimated biomass of over 500, 000 t.

Table 22. Biomass estimates of total fish by areas and depth

intervals based on the U. s. -Japan 1980, 1983 , and 1986

Aleutian Islands groundfish surveys.

Biomass (t)

Area Depth (m) 1980 1983 1986

Southeast 1-900 248, 915 489, 947 010, 539 Southeast 1-900 162, 419 391, 858 383, 116 Northwest 1-900 196, 931 383, 937 520, 611 Northeast 1-900 376, 475 448, 045 702, 356

Bowers Ridge 1-900 104, 603 60, 868 130, 384

Aleutian 1-100 16, 588 244, 984 743, 628 Islands 101-200 422, 569 720, 685 555, 742 Total 201-300 159, 640 .242, 880 446, 829

301-500 108, 195 122, 588 246, 392

501-900 382, 351 443, 517 754, 415 1-900 089, 343 774, 654 747, 006

Southern

Ber ing Sea 1-900 357, 426 514, 615 409, 489
Total fish biomass estimates in the Southern Bering Sea ranged

from 357, 000 t in 1980 to approximately 515, 000 t in 1983, with an

average of 427 000 t (Table 23). Fish made up 98% of the catch in

this area while invertebrates contributed only 2%. Eight

families accounted for 98% of the average fish biomass , with

Gadidae and Scorpaenidae having the largest values (Table 24). The

families Macrouridae and Hexagrammidae , which accounted for over

40% of the fish in the Aleutian Islands area , accounted for only 2%

of the Southern Bering Sea fish biomass. Crabs and squids were the

dominant invertebrate species groups with average estimates of

000 t and 900 t, respectively.

Biomass estimates for important fish species , from the Southern Bering Sea area , based on the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.

Table 23.

Species

Pollock

Atka Mackerel

Pacif ic ocean perch

Pacific cod

Northern rockf ish

Arrowtooth flounder

Sablef ish

Greenland turbot

Rougheye rockfish

Halibut

Shortraker rockf ish

Shortspine thornyhead

Rock sole

Skates

Flathead sole

Rex sole

Dover sole

Giant grenadier

Other fish

All fish

All invertebrates

All s ecies

1980

56, 732

19, 832

003

74, 375

341

932

118, 192

13, 931

922

701

020

079

15, 789

173

871

222

190

551

30, 570

357, 426

18, 274

375, 700

1983

282, 684

97, 479

45, 624

516

523

871

14, 033

829

7 , 304

13, 080

414

025

175

694

442

117

766

15, 029

514, 615

506

519, 121

Biomass (t)

1986

102, 379

645

54, 776

42, 298

63, 491

20, 091

24, 614

20, 519

095

218

7 , 604

926

344

244

009

459

927

46, 795

409, 489

035

413, 524

Average

147, 265

829

52, 753

54, 099

21, 783

13, 182

50, 892

16, 161

615

408

235

1, 140

719

197

191

708

121

081

30, 798

427, 177

938

436, 115

% of

Total

Biomass

33.

12.

12.

11.

97.

100.
Table 24. Biomass estimates of important fish and invertebrates

by family or species group, from the Southern Bering

Sea area, based on the U. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.

Biomass (t)

Family or group 1980 1983 1986 Average

Gadidae 131, 107 328, 310 144, 677 201, 365

Scorpaenidae 381 116, 599 135, 625 87, 202

Anoplopomatidae 118, 192 871 24, 164 50, 742

leuronect idae 45, 925 40, 267 60, 186 48, 793

Cottidae 27, 425 471 298 13, 731

Clupeidae 461 30, 047 12, 838

Hexagrammidae 19, 844 658 838

Crabs 14, 280 207 423 970

Raj idae 172 175 244 197

Macrour idae 570 020 025 538

Zoarcidae 146 941 060

Squids 657 522 463 881

octopuses 451 504

Osmer idae 943 314

Cyc lopter idae

Agonidae

Shrimps

a Less than 1 metric ton.
SPECIES ACCOUNTS

Walleye Pollock

Distribution and Abundance

Al though walleye pollock Theragra chalcogramma ) are found

throughout the Aleutian Islands area , their distribution was

e)Ctremely clumped and uneven. Walleye pollock occurred in the

highest abundance category in all areas of the Aleutian Islands

but not in the southern Bering Sea (Figs. 15-16). They were

found at all depths surveyed, however the vast majority of the

stock was found between 101 and 300 m with the largest portion

occurring in the 101-200 m depth interval (Table 25). Compared

to the 1980 and 1983 surveys more pollock were taken in the 1-100

and 201-300 m depth zones during 1986.

The total estimated biomass of walleye pollock in the

Aleutian Islands increased from 252, 000 t in 1980 to 496 000 t in

1983 , then decreased to 448, 000 t in 1986 (Fig. 17). Increases

in the biomass estimates were noted in all areas in 1983, however

the most significant change occurred in the Southwest area where

the estimated biomass increased nearly fivefold from 37, 000 to

179 000 t. Substantial increases of 49 000 t and 39, 000 t also

occurred in the Northwest and Southeast areas , respectively. 

1986 the largest decreases occurred in the Southwest, Northwest and Northeast areas , but these were partially offset by increases

in the Southeast and Bowers Ridge areas. Population estimates

increased each year , ranging from 452. 5 million in 1980 to

720. 3 million in 1986. 

In the S9uthern Bering Sea area the trend was similar but

the decline was more severe than in the Aleutian Islands area.

Estimated biomass increased nearly fivefold from 57, 000 t in 1980

to 283 000 t in 1983, and population increased from 88. 3 to

409. 7 million fish during the same time period (Fig. 18). 

1986 , estimated biomass decreased by 64% to 102, 000 t and

population decreased to 130. 4 million fish. 

Estimates of mean CPUE and mean lengths and weights are

summarized in Table 26. In the Aleutian Islands area , pollock

were largest in 1983 averaging 46. 2 cm in length and 0. 62 kg in weight. In the Southern Bering Sea, pollock mean lengths were

greater in 1980 with a mean length of 45. 8 cm , but heavier in 1986 with a mean weight of 0. 8 kg (Figs. 19-20).

Size and Aqe Composition

During the 1980 survey, the walleye pollock stock in the

Aleutian Islands area was dominated by small fish 30-35 cm in

length , with small secondary modes of larger fish occurring at

45 and 51 cm (Fig. 21). These smaller fish were 3-year-old
PETREl BANK

1986

CATCH IN KG/KM

NO CATCH 1 - 1 . 000 

I. 001-1 O. 000 10. 000'

PETREl BANK

1983

CATCH IN KG/KM

NO CATCH I - 1 . 000 

001-10. 000

10. 000' AMCHI TKA I.

1980

CA TCH IN KG/KMNO CATCH I - 1 . 000 

001-10. 000

10. 000'

PETREL BANK

~STALEMATE BANK

Figure 15. Distribution and relative abundance of walleye pollock in the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
......

1. 000 

1986

CATCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000

10. 000=-

......

1983

CA TCH IN KG/

NO CATCH

1 -1 . 000

001-10. 000

10. OOO=-

......

1980

CA TCH IN KG/KM

NO CATCH 

1 -I .000 

001-10. 000

10. OOO=-

Figure 16.

ULM PLATEAU

1986

CATCH IN KG/KM

NO CATCH 

I - 1 . 000 

001-10. 000

10. ODD=- 

BOWERS

BANK

1983

CA TCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000 10. aDO=- 

1980

CATCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000

10. 000=- 

Distribution and relative abundance of walleye

pollock in the Southern Bering Sea and Bowers Ridge

areas during the u. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.
Table 25. Estimates of biomass , biomass sampling error, and

population for walleye pollock based on the U. s. -Japan 1980, 1983, and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleutian

Islands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

165

779

062

952

173

131

245

886

861

992

095

440

15, 833

389

283

160

943

110 435

189

137 402

566

597

259

252 013

Biomass (t)

1980

141

139 163

764

265

179 407

996

219

794

009

706

286

920

930

179

138 336

948

159 527

11 ,026

335 883

147 853

117

103

495 982

1983 1986 1980

66.

247.

96.

117.

Sampl ins Error 

(%)

1983

41.

136.

138.

86.

40.9 1 113.

90.

132.

78.

639. 1

59.

1-100 37 071 154 752 13 870

101-200 12 132 105 247 68 246

201-300 5 725 16 917 17 788

301-500 1 626 5 768 2 412 501-900 178 

1-900 56 732 282 684 102 379 124.

No sampl ins was conducted in this area-depth interval.

506

808

910

115 376

892

591

5 , 536

119 , 058

122

784

960

206

072

220

085

307

444

107

145 163

102

109

404

057

469

860

210 973

186 825

264

216

448 138

982.

50.

73.

228.

162.

38.

138.

409.

223.

37.

46.

72.

382.

29.

1986

42.

741.0

349.

659.

081.

830.

53.

972.

945 .

032.

951.2

411 .

076.

942.

59. 121 430.

77.

139 651.

63, 535.

148.

210 335.

741.

320 384.

106 217.

204.

452 547.

70.

460.

605.

415.

821.

302.

Population (1 000s)

1980 1983

678.

189 408.

957.

374.

103.

243 522.

475 .

017.

738.

100 232.

713.

048.

831.2

24.

126 616.

347.

175, 065.

825.

53.

10.

200 301.

335 .

347.

739.

454 333.

193 638.

166.

144.

671 020.

249 580.

131 729.

446.

925.

409 682.

1986

371.

114 693.

837.

84.

111.

202 099.

30.

651.

386.

513.

18.

147 599.

235.

907.

541.

274.

107 957.

650.

115 347. 1

469.

601.

124.

236 193.

216.

243.

12.

472.

109 288.

368 815.

233 478.

473.

266.

720 322.

349.

994.

813.

195.

81.

130 434.
THOUSANDS MilliONS

900 900

ALEUTIAN ISLANDS

.. 

Biomass (t) Population

300

600 600

300

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 17. Estimated biomass and population of walleye pollock

in the Aleutians Islands area during the U. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.

THOUSANDS

600 MilliONS

600

450 

_.

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION 450

300 300

150 150

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 18. Estimated biomass and population of walleye pollock

in the Southern Bering Sea area during the U. S. -Japan

1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.
Table 26. Estimates mean catch per unit effort, length and

weight for walleye pollock based the u. S. -Japan

1980, 1983 and 1986 Aleutian Islands groundf ish

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 508. 769. 260. 30. 37.

101-200 100. 309. 148. 43. 46. 36.

201-300 513. 842. 778. 43. 48. 43.

301-500 279. 77. 23. 44. 46.

501-900 24. 10. 10.

1-900 722. 078. 009. 41.2 46. 38.

Southeast 1-100

101-200 465. 834. 942. 43. 46. 50.

201-300 546. 148. 447. 49. 48. 51.6

301-500 316. 252. 764. 54. 49. 50. 1.22

501-900 1.47

1-900 574. 581.3 914. 46. 47. 50.

Northwest 1-100 146. 746. 31. 37.

101-200 370. 198. 478. 39. 38. 34.

201-300 17, 231. 992. 455. 45. 47. 46.

301-500 145. 92. 49. 52.

501-900

1-900 796. 184. 706. 40. 44. 38.

Northeast 1-100 10. 153. 196. 38. 47.

101-200 847. 410. 356. 38. 46. 33.

201-300 406. 577. 466. 49. 47. 49.

301-500 022. 17. 354. 53. 51. 1.07 1.23

501-900 17.

1-900 163. 313. 187. 41. 47. 39.

Bowers 101-200 326. 295. 33.

Ridge 201-300 14. 598. 36.

301-500

501-900

101-900 10. 825 . 34. 33.

Aleutian 1-100 198. 370. 730. 35. 37.

Islands 101-200 837. 174. 672. 41. 45. 36.

Total 201-300 694. 514. 339. 46. 48. 47.

301-500 837. 80. 752. 53. 48. 51.5 1.05 1.21

501-900

1-900 513. 497. 685. 42. 46. 40.

Southern 1-100 692. 112. 878. 50. 37. 39.

Bering 101-200 707. 164. 856. 43. 46. 42.

Sea 201-300 715 . 890. 760. 50. 45. 46.

301-500 1 , 277 . 532. 895. 52. 50. 48.

501-900 78. 27.

1-900 488. 365. 100. 45. 41. 41.

No sampling was conducted in this area-depth interval.
ALEUTIAN ISLANDS . ---_u_u - 1.

.. MEAN LENGTH MEAN WEIGHT

1980 1981 1982 1983 1984

YEARS

0.4

1985 1986

Figure 19. Mean length and weight of walleye pollock in the

Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

1980 1981 1982 1983 1984

YEARS

.. 0.

1985 1986

Figure 20. Mean length and weight of walleye pollock in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
1980

LENGTH (CM)

120 ..

80 '"

80 ,..

MALE FEMALE

16 0 16 

NUMBER (MILLIONS)

1983

LENGTH (CM)

20 . 120

90 ...

80 -,

30 ' MALE FEMALE

16 

NUMBER (MIWONS)

1986

LENGTH (CM)

-40

120

30 ' MALE FEMALE

15 

NUMBER (MILLIONS)

1980

NUMBER (MILLIONS)

SEXES COMBINED 

. ..........,.. :

30 .0 

LENGTH (CM)

1983

NUMBER (MILLIONS)

SEXES COMBINED 

_._

30 40 

LENGTH (CM)

1986

NUMBER (MILLIONS)

SEXES COMBINED r--

30 

LENGTH (eM)

Figure 21. Size composition of walleye pollock in the Aleutian

Islands area during the U. s. -Japan 1980 , 1983 , and 1986 groundf i sh surveys.
PERCENT

'-----"'U-

1-900 m

1980

-""""'--"-'._U 

............

30 

20 

'---.U"-_U_. "

10 .

  ............. ...... .......  ........... 

.---.-'u.

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

'----U"-"---'--'---

 

1-900 m 40 .

1983 '-"'--"",,-'_U_-- 

....

30 .

20 

10 .

.

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

_. 

1-900 m

1986

30 ,

20 

 ..

10 .

 .. 

_U_..._-----_._--

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

50'

40 .

1-900 m

1980 --

30 .

 ............

-......_--- -'--'----------'-"---'---"""U."'-"""" .-....---....

..............

20'

10 

10 

AGE (YEARS)

SOUTHERN BERING SEA

PERCENT

40"

30 

20 .

10 .

.-----------_U_-- 1-900 m

1983

--'--'---U_'-"--'-""---

.., ...

AGE (YEARS)

SOUTHERN BERING SEA

PERCENT

;:~9

.

1111111-.

10 

.. .

10 

AGE (YEARS)

SOUTHERN BERING SEA

Figure 22. Age composition of walleye pollock in the Aleutian

Islands and Southern Bering Sea areas during the U.

Japan 1980 , 1983 , and 1986 groundfish surveys.
pollock from the 1977 year class , which accounted for over 40% of the stock (Fig. 22). The 1978 year class , which was probably not

fully available to the trawl , and the 1976 year class were the

only other age groups contributing over 10% of the stock. Each

successively older age group contributed fewer fish to the total

stock, except for the 1968 year class of 12-year-old fish which

was slightly stronger.

In 1983, there was a strong size mode of pollock between 

and 52 cm that peaked at 46-47 cm. These 5-year-old fish

contributed nearly 50% of the total stock. Six-year-old fish

from the 1977 year class , which dominated in 1980 , were still

significant in 1983 contributing about 18%. Four-year-old fish

from the weaker 1979 year class contributed about 12%. There was

a weak showing of smaller 3 -year-old fish 30-35 cm in length.

Year classes prior to 1976 were only minor contributors.

In 1986 the size composition consisted of three size groups:

a strong mode 33-42 cm in length , peaking at 38-39 cm; a mode of

larger fish, 44-50 cm, peaking at 48-50 cm; and a weak incoming

mode of small fish , 26-30 cm , peaking at 29 cm. The 1986 age composition was dominated by 3-year-old fish from the strong 1983

year class which contributed almost 45% of the stock. Five-yearold fish contributed nearly 12%, 8-year-old fish from the 1978

age class added 11%, and 9-year-old fish from 1977 added another

7% .

In the Southern Bering Sea a different picture was portrayed. During 1980 , fish in the 35-43 cm size range were

dominant making up about 55% of the stocks (Fig. 23). These were

year-old fish from the 1977 age class which were also dominant

in the Aleutian Islands. Four-year-old fish from the 1976 age

class added another 12% to the Southern Bering sea pollock

stocks. No other year class contributed over 10% of the stocks

in 1980.

In 1983 the Southern Bering sea stock consisted primarily of

larger fish in the 41-53 cm size mode which peaked at 46-47 cm.

These 5-year-old fish made up about 43% of the stocks. Six-yearold fish from the 1977 year class still contributed 18% of the

stock in 1983. There was also a strong showing of extremely

small 8-10 cm pollock which were 1983 young of-the-year.

During 1986 , the stock consisted primarily of fish in the

43-55 cm size range and for the first time there was a showing of

19-23 cm fish. No single year class was strongly dominant in

1986, but 4-8-year-old fish from the 1978-1982 age classes made

up the bulk of the stocks each year contributing from 11 to 17%.

The strong year classes of 1978 and 1977 continued to contribute

to the stocks as 8 and 9-year-old fish; however, the 1983 year

class did not appear to be especially strong in 1986. The 1981

and 1980 year classes which did not appear in the age composition

in any strength in 1983 are present as 5 and 6-year-old fish

contributing about 17% and 12%, respectively. The 1983 year

class which was so strong in the Aleutian Islands area during

1986 was not nearly as strong in the Southern Bering Sea.
LENGTIi tCMt

LENGTH tCMJ

Ifi

LENGTH (CMJ

Figure 23.

1980 1980

NUMBER (MILLIONS)

80 

SEXES COMBINED 

46 .

.........,...

MALE FEMALE

NUMBER tMllllONSJ 30 40 

LENGTH (CM)

1983 1983

NUMBER (MILLIONS)

MALE FEMALE

18 

NUMBER tMIWONSJ 30 40 

LENGTH (CM)

1986 1986

NUMBER (MILLIONS)

80 

SEXES COMBINED 

46 __0-

____...........

30 -.-..-.-

MALE FEMALE

16 0 16

NUMBER (MILLIONSJ

30 40 

LENGTH (CM)

size composition of walleye pollock in the Southern

Bering Sea area during the U. -Japan 1980 , 1983 , and

1986 groundfish surveys.
Age composition of walleye pollock varied considerably with

water depth , but in general , stocks in the shallower depths were

made up of younger fish (Figs. 24-25). In 1980, in the 101-200 m

depth zone 82% of the fish were age 4 or younger. Three-year-old

fish were dominant contributing 50% to the stocks. Two-year-old

fish from 1978 contributed 22% and 4-year-old fish another 10%.

In the 201-300 m zone , 3-year-olds were still abundant but 4- 5-

6- and 7-year-olds from the 1972-76 year classes each made up

more than 10% of the stocks. In the 301-500 m depth zone there

were more older fish , with 5-year-old fish accounting for 20%, and 6-8-year-olds accounting for more than 10% each. Four-yearold fish still made up 10% of the stocks , but 3-year-old fish

were not abundant in that depth zone. Age data for the 1-100 m

depth interval in 1980 were not available.

In 1983 , younger fish were predominate in the 1-100 m depth

zone with 2-year-old fish making up about 38% of the stocks. Three and 4-year-olds each contributed a little more than 10% but

year-old fish from the 1978 age class contributed more than 23%. All three deeper depth zones had similar age compositions

in 1983 , with the 1978 age class of 5-year-old fish accounting

for more than 45% of the fish in each zone , and 4 and 6-year-old

fish each contributing more than 10%.

During the 1986 survey, 3-year-old fish were dominant in the

three shallowest depth zones , accounting for about 55% of the

stocks in the 1-100 m and 101-200 m zones , and more then 25% in

the 201-300 m zone. In the shallowest depth, 2-year-old fish

made up most of the rest of the stock. Five and 8-year-old fish

from the 1981 and 1978 age classes made up most of the rest of

the stocks in the 101-200 m and 201-300 m depth intervals. 

the deepest depth zone , 8-year-olds from the 1978 year class and

year-old fish from the 1979 class made up most of the stocks.

Substantial differences were apparent in the size and age

composition within the Aleutian Islands areas. In 1980 , small

fish in the 30-35 cm size mode dominated the size composition

along the north side of the Aleutian Islands (Figs. 26-27). In

the Northwest area , 3-year-old pollock were dominant

making up 43% of the stock. Fish from the 1978 age class contributed 21%, and 4-year-old fish from the 1976 age class made up another 12% (Fig. 28). In the Northeast area, 2-year-old fish

were dominant providing 50% of the stock and 3-year-old fish from

the 1977 age class contributed 14%. On the south side of the Aleutian Islands chain, small fish in the 32-40 cm size mode were

encountered in the Southwest , but not the Southeast area (Figs.

29-30). Three-year-old fish of the 1977 age class made up 45% of

pollock in the Southwest area (Fig. 31). Four-year-old fish from

the 1976 year class made up 22%, and 2-year-old fish from the

1978 age class contributed about 7%. In the Southeast area the

majority of fish were larger, mostly in the 47-56 cm size mode. Five-year-old fish from the 1975 age class were dominant

accounting for 30% of the stocks , 6-year-old fish made up 24% and

year-old fish contributed 17%.
PERCENT

...._. .....

1-100 f--

1980

--_-_un. ---"-'-"--'-

,......., ......................

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

50 

. "-------_u..-------...---....-.---..----...- 

1-100 

_-n

......

....-.......u..-...-

.., 

1983 

..

,--_u_------.-----.

....

10"

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

......................

50 . 1-100 m

1986 40"

...... ..

20 

...........

10 .

.

10 ~

AGE (YEARS)

ALEUTIAN ISLANDS

Figure 24.

PERCENT

101-200 m

1980 

........ ..........._.._,.

20.

10 

_.........

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

50 

.

101-200 m

1983 -- 40 -

30 .

.....

20 -

0 0 10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

....

101-200 m --

1986

50 

30 .

20 

................_._.._

0 0 10 

AGE (YEARS)

ALEUTIAN ISLANDS

Age composition of walleye pollock in the 1-100 m and

101-201 m depth intervals of the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986

groundf ish surveys.
PERCENT

60'

40'

30"

20'

201-300 m

1980

.....

JJJJlb ~

..

10 

AGE (YEARS)

AlEUTIAN ISLANDS

50 .

40 

30 .

10'

PERCENT

,

201-300 m

1983

........

-1l~

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

......

50 

201-300 m

.................

40' 1986

20 

.... .......

--'-'----'---'--_u_--,-

10 

AGE (YEARS)

AlEUTIAN ISLANDS

Figure 25.

PERCENT

40'

30 -

20"

10'

301-600 m

1980

..................

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

50 .

.......

40 

301-500 m

1983

.

---------'-""--....-....-u....---....- -"'-'-"--

20 ..

...........

10 

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

..

40'

30'

20'

10'

301-500 m

1986

__"_m.._-

10 

AGE (YEARS)

ALEUTIAN ISlANDS

Age composition of walleye pollock in the 201-300 m

and 301-500 m depth intervals of the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986

groundf ish surveys.
lENGTH (CMt

1980

MALE FEMALE

j .

NUMBER tMllllONS)

1983

LENGTH (CMJ

MALE FEMALE

NUMBER (MIWONSJ

lENGTH tCMJ

1986

Figure 26.

MALE FEMALE

NUMBER (MILlIONSJ

. 8

1980

NUMBER (MILLIONS)

SEXES COMBINED 

...

. I

........

30 40 

LENGTH (CM)

1983

NUMBER (MILLIONS)

18 .

SEXES COMBINED 

30 40 

LENGTH (CM)

1986

NUMBER (MILLIONS)

SEXES COMBINED 

8 -

30 40 

LENGTH (CM)

size composition of walleye pollock in the Northwest

area of the Aleutian Islands during the u. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.
lENGTH (CMJ

LENGTH (CMJ

lENGTH (CMJ

Figure 27.

1980 1980

NUMBER (MILLIONS)

MALE FEMALE

..J

SEXES COMBINED 

60"",

40..

20........

. 16

NUMBER tMllllONSJ

30 40 

LENGTH (CM)

1983 1983

NUMBER (MILLIONS)

60.

...

SEXES COMBINED 

40 ..

20... .

.................................

. 0 

NUMBER tMllLlONSJ

30 40 

LENGTH (CM)

1986 1986

NUMBER (MILLIONS)

MALE FEMALE

... 

SEXES COMBINED 

60 ..

40 ...

20 -

NUMBER (MilLIONS)

30 40 

LENGTH (CM)

size composi ~ion of walleye pollock in the Northeast

area of the Aleutian Islands during the U. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.
PERCENT

30 

.............

1-900 m 40 .

1980

..... ......... .. ...,.....

20 .

10 

10 

AGE (YEARS)

NORTHWEST SUBAREA

PERCENT

40 

30 

...

20"

10 "

10 

AGE (YEARS)

NORTHWEST SUBAREA

PERCENT

60'

50'

40 

30"

_..__..

20 

1-900 m

1983

1-900 m

1986

.....,,,,,,, .... ......... ......

10 ~

AGE (YEARS)

NORTHWEST SUBAREA

Figure 28.

PERCENT

......

1-900 m

1980 ,_u_"

.

40 

.......

10 

0 0 10 

AGE (YEARS)

NORTHEAST SUBAREA

PERCENT

60 .

......

1-900 m

1983 

........

50 .

40"

20 

.,.

10 .

10 

AGE (YEARS)

NORTHEAST SUBAREA

PERCENT

60 .

1-900 m

- 1986

50 -

40 -

.

30"

... ... _.. _... . ..,......_

10 

AGE (YEARS)

NORTHEAST SUBAREA

Age composition of walleye pollock in the Northwest

and Northeast areas of the Aleutian Islands during

the U. -Japan 1980 , 1983 , and 1986 groundfish

surveys.
Figure 29.

1980

LENGTH tCMt

MALE FEMALE I

. !

NUMBER (MILlIONSJ

lENGTH (CMJ

1983

_MALE

NUMBER tMIWONSJ

1986

lENGTH (CMJ

MALE ~ FEMALE

NUMBER (MILLIONSI

1980

NUMBER (MILLIONS)

SEXES COMBINED 

10.

30 40 

lENGTH (CM)

1983

NUMBER (MILLIONS)

30 '

SEXES COMBINED 

30 40 

LENGTH (CM)

1986

NUMBER (MILLIONS)

30 ---_.._-

,_

SEXES COMBINED 

20"-,-,,,-,

30 40 

LENGTH (CM)

size composition of walleye pollock in the Southwest

area of the Aleutian Islands during the U. S. -Japan

1980 , 1983, and 1986 groundfish surveys.
lENGTH tCMt

LENGTH (CMJ

LENGTH tCMJ

Figure 30.

1980 1980

NUMBER (MILLIONS)

MALE FEMALE 18 ...-----

SEXES COMBINED 

'----'----"'u_",-",

, ............

2:&

&

NUMBER (MILlIONSJ

30 

LENGTH (CM)

1983 1983

NUMBER (MILLIONS)

MALE FEMALE 18 .

SEXES COMBINED 

2.5 -

NUMBER (MILlIONSJ

30 

lENGTH (CM)

1986 1986

NUMBER (MILLIONS)

MALE FEMALE

..

SEXES COMBINED

0 - 2.~

NUMBER (MILlIONSJ

30 

LENGTH (CM)

size composition of walleye pollock in the Southeast

area of the Aleutian Islands during the U. s. -Japan 1980, 1983, and 1986 groundfish surveys.
PERCENT

......... 

1-900 m

1980

30 .

20 

....................................................

10 

AGE (YEARS)

SOUTHWEST SUBAREA

PERCENT

.............

1-900 m 40'

1983

30 

..... ..........................

20 .

10 .

10 

AGE (YEARS)

SOUTHWEST SUBAREA

PERCENT

40 .

... 

1-900 m

1986

30"

. _. 

20 .

10 

................  ... ...

10 

AGE (YEARS)

SOUTHWEST SUBAREA

Figure 31.

PERCENT

40 .

30 .

20'

10 '

.. 

1-900 m

1980

0 0

.......................

10 ~

AGE (YEARS)

SOUTHEAST SUBAREA

PERCENT

.......

50 - 1-900 m

...._.......... 

1983 

.....

30 

................

JJJ

..,........... ...

10 

10 

AGE (YEARS)

SOUTHEAST SUBAREA

PERCENT

40 . :~9

30"

..... _._. .. ...... .....

10 .

10 

AGE (YEARS)

SOUTHEAST SUBAREA

Age composition of walleye pollock in the Southwest

and Southeast areas of the Aleutian Islands during

the u. S. -Japan 1980 , 1983 , and 1986 groundfish

surveys.
In 1983 , the walleye pollock stock consisted primarily of

larger fish, 42-52 cm in length, and there was a greater

similarity in the size composition throughout the Aleutian

Islands area. Most fish were in the 40-55 cm size mode. These were 5-year-old fish from the strong 1978 year class and they

dominated the age composition in all areas. Six-year-old fish

were the second most abundant age group accounting for 12-24% of

the stock. Four-year-old pollock contributed an additional 10-

16% of the stock. In 1983 only the Northwest area contained

small pollock in the 30-35 cm size mode which consisted of 2- and

year-old fish from the 1980 and 1981 year classes.

In 1986 , the Northwest and Northeast areas contained a

dominant size mode of pollock in the 32-42 cm size range with a

strong secondary mode at 44-58 cm. However stocks from the

Northwest area contained an additional mode of smaller fish in

the 26-30 cm size mode. The age composition of both areas were

completely dominated by 3-year-old fish from the 1983 year class

which contributed nearly 60% of the total stock. There was a

small showing of 2 -year-old fish in the Northwest area.

On the southern side of the Aleutian Islands in 1986 there

was considerable difference between the size composition of the

two areas. In the Southwest area the principle mode was from 35-

55 cm, peaking at 43 cm , while in the Southeast area it ranged

from 43 - 58 cm peaking at 50 cm. Both areas had secondary modes

27-31 cm in the Southwest and 34-41 cm in the Southeast area.

The 1983 year class of 3-year-old fish was less dominant then on

the north side of the Aleutians, contributing 30% in the

Southwest and 25% in the Southeast areas. In the Southwest area

year-old fish contributed 22% to the stocks , and 2-year-old

fish from 1984 an additional 17%. In the Southeast area there

was a fairly large remnant of 8-year-old fish from the strong

1978 year class that made up 20% of the stocks. In addition,

year-old fish contributed 17%, and 7-year-old fish made up 12%

of the stocks.

Mean Lenqth-at-Age and Growth

Mean length-at-age data for walleye pollock for the three surveys do not demonstrate any def ini te trends wi thin or between

years (Table 27). within the Aleutian Islands area the mean size

at age appears smaller in the Southwest than other areas during

all three surveys , particularly at the younger ages (Table 28).

These data show that walleye pollock in the Aleutian Islands

area obtained a length of 19-21 cm by the second summer of their life. From age 1+ to 2+ they increased an average of

12 cm to around 32 cm and for the next 2 years the average annual

growth increment decreased to between 5 and 6 cm so that at age

4+ years they had obtained a length of 43-46 cm. From age 5+ to

9+ the average yearly growth increment was 2. 5-1. 7 cm per year

(Table 29. Al though individuals up to 14 years in the Aleutian
Table 27. Mean length (rom) at age for walleye pollock from all

areas sampled during the U. S. -Japan 1980, 1983, and

1986 groundfish surveys.

Aleutian Islands

1980 1983 1986

Age M+F M+F M+F

190 190 209 223 213

322 317 319 327 334 331 325 330 325

375 387 382 371 375 374 386 379 383

418 443 432 419 440 430 452 458 457

450 500 471 444 456 451 475 481 478

483 504 494 448 473 465 493 519 508

490 503 495 493 522 509 502 524 512

503 551 531 542 542 523 522 521

529 584 558 490 490 509 539 530

560 611 589 543 540 557

635 614 620 560 560 650 650

560 605 596

500 585 557 580 580

602 595

Southern Bering Sea

1980 1983 1986

Age M+F M+F M+F

206 205

336 339 338 297 301 299 294 295 294

390 395 392 380 380 380 384 386 385

422 436 429 442 453 446 413 431 418

476 499 490 455 472 464 444 466 450

477 504 495 472 494 486 466 485 474

482 503 496 495 526 512 480 503 492

519 536 531 499 532 516 489 516 504

521 541 536 501 533 520 504 527 518

507 524 513 516 553 534 518 539 532

493 515 504 549 544 545 530 530 530

491 523 515 532 566 551 519 567 540

490 542 529 480 578 554 530 578 568

510 533 525 650 650

500 500

500 500

M = males F = females
Table 28. Mean length (rom) at age for walleye pollock sampled in

the Aleutian Islands areas during the U. S. -Japan 1980 1983, and 1986 groundfish surveys.

1980

Southwest

Age M+F

Southeast

M+F

Northwest

M+F

Northeast

M+F

363 365 365

384 395 389

427 472 450

465 488 479

460 479 472

494 521 515

511 527 523

492 507 501

497 524 514

487 519 511

480 534 525

514 533 525

500 - 500

500 500

364 373 368

398 405 401

442 461 450

494 514 507

479 517 507

477 515 499

522 522

490 520 514

473 505 483

480 527 500

520 520

565 565

Southeast

M+F

328 330 329

387 401 394

431 441 437

480 497 491

483 506 495

500 526 516

543 563 555

530 566 552

592 570 580

510 490 500

520 520

500 - 500

1983

Northwest

M+F

438 444 439

443 463 450

485 495 490

457 500 487

476 480 478

502 510 505

541 571 563

528 600 568

503 497 498

530 550 543

Northeast

M+F

Southwest

Age M+F

320 328 324

395 411 404

433 447 439

461 472 467

478 485 482

496 507 501

487 504 497

519 540 534

526 538 531

546 573 560

564 - 564

564 564

Southeast

M+F

322 326 324

352 348 349

444 454 448

452 467 461

465 477 472

483 484 483

507 521 512

496 552 522

490 570 558

609 565 598

560 600 591

1986

Northwest

M+F

279 274 277

396 393 396

448 461 454

454 475 465

483 513 505

511 543 531

528 552 542

516 547 535

524 570 547

560 556 553

525 572 553

585 585

650 650

Northeast

M+F

205 - 205

312 322 317

380 354 368

445 441 444

453 463 458

464 471 467

468 504 494

477 508 489

479 502 493

497 513 508

513 517 516

500 530 520

480 - 480

320 327

399 409 403

416 460 421

449 470 459

476 498 489

472 515 488

486 511 501

473 532 513

485 570 528

510 500 505

490 - 490

560 560

290 291 288

374 379 377

406 419 413

448 467 455

487 493 489

479 508 496

491 516 503

496 546 526

552 588 576

540 540

510 530 520

660 660

350 360 357

371 376 373

395 425 399

453 481 468

470 493 476

497 503 500

496 527 512

514 532 523

533 533 533

525 537 530

532 573 523

530 - 530

Southwest

Age M+F

303 293 298

397 396 397

428 443 432

439 447 443

454 479 467

471 501 490

477 506 495

501 515 511

505 536 526

543 - 543

480 - 480

530 530

M = males F = females
Tab I e 29. Estimates of yearly incremental growth (cm) of walleye

pollock based on the U. s. -Japan 1980, 1983, and 1986

surveys.

Year

Age 1980 1983 1986 Average

1-2 12. 11. 12.

2-3

3-4

4-5

5-6

6-7

7-8

8-9
Islands area and 17 years in the Southern Bering Sea are included

in the samples, data after the ninth summer is lacking and too

scattered to provide meaningful estimates after the ninth year.

Growth curve estimates are shown in Table 30.

Table 30. Estimated von Bertalanffy growth curve parameters for

walleye pollock sampled during the U. S. -Japan 1980,

1983, and 1986 groundfish surveys.

Range von Bertalanffy

Growth Parameters

Age . Length

Area - Year Sex (Years) (cm) LINF

Aleutian Islands

1980 2-15 30-62 51. 390 -0. 592

2-17 30-67 54. 437 -0. 012

M+F 2-17 30-67 54. 374 -0. 452

1983 1-13 19-70 50. 469 -0. 082

2-14 23-71 55. 382 -0. 081

M+F 1-14 19-71 53 . 63 402 -0. 070

1986 2-13 27-64 50. 394 -0. 425

2-13 25-66 55. 324 -0. 635

M+F 2-13 25-66 53. 340 -0. 641

Southern Bering Sea

\...

1980 1-14 19-73 57 . 81 226 -1. 585

2-13 27-70 64. 206 -1. 323

M+F 1-14 19-73 63. 197 -1. 649

1983 2- 9 29-53 49. 365 -0. 934

2-11 29-58 56. 243 -1. 671

M+F 2-11 29-58 54. 266 -1. 491

1986 1-13 19-60 53. 422 -0. 193

2-13 19-65 56. 335 -0. 466

M+F 1-13 19-65 54. 400 -0. 253
Length -Weight

Length-weight data were collected for walleye pollock during

all three surveys (Fig. 32). Relationships were calculated using

linear regression analysis and the results provided the following

estimates of the parameters a and b for the sexes combined:

Weight (g) (1980) = . 0187 x Length(cm) s53

Weight (g) (1983) = . 0179 x Length (cm) 2.764

Weight (g) (1986) = . 0134 x Length(cm) s45

Length-weight relationships for walleye pollock were

extremely similar during all three surveys; however, in 1980, the

fish were slightly heavier for a given length than in 1983 and

1986 and for the larger fish over 45 cm they were slightly

heavier in 1983 than in 1986.

1980 N. 1142

1986 N. 2113

SEXES COMBINED

1983 N. 3599

WEIGHT (g)

2500

500

..... ..

2000

1500

1000

.... _._

30 40 

LENGTH (em)

Figure 32. Length-weight relationships for walleye pollock in the

Aleutian Islands area during the U. S. -Japan 1980,

1983 , and 1986 groundfish surveys.
Atka Mackerel

Distribution and Abundance

Atka mackerel Pleurogrammus mono~terygius ) had a 

discontinuous distribution in the Aleutian Islands and Southern

Bering Sea areas (Figs. 33-34). This species was found clumped

in extremely dense schools making precise abundance assessments difficult. Atka mackerel are primarily found in shallow water

less than 200 m. six major concentrations have been defined in the Aleutian Island area: 1) Stalemate Bank, 2) Buldir and Tahoma Reefs, 3) Kiska and Amchi tka Islands, 4) Petrel Spur on the

extreme northeast corner of Petrel Bank , 5) Tanaga Pass and

6) Seguam Pass.

The biomass estimate for Atka mackerel in the Aleutian

Islands area more than doubled from 130, 000 t in 1980 to

343 000 t in 1983 (Fig. 35, Table 31). Part of this increase was

related to the lack of sampling in the 1-100 m depth interval in

1980 (Tables 10 and 11). the 144, 000 t catch (1983) from the

shallow water zone is disregarded the biomass in the remaining

depth intervals increased by 69 000 t. This still represents a

65% increase above the 1980 Atka mackerel biomass. Biomass

estimates in 1983 increased in all areas sampled except the

Northeast area where it decreased by 25%.

In 1986 the biomass of Atka mackerel was 643, 000 t,

nearly double the 1983 estimate. However, 83% of the entire

biomass , 525 000 t , occurred in the 1-100 m depth zone of the

Southwest area. This enormous concentration of Atka mackerel was

primarily located in the shallow waters around Kiska and Amchitka Islands.

Removing the estimate for the 1-100 m depth interval in the

Southwest area leaves a 108 000 t biomass estimate for the rest

of the Atka mackerel resource in the Aleutian Islands. This

represents a 45% decrease from 1983 estimates and reflects a

decrease of biomass estimates in most areas and depth intervals.

In the Southern Bering Sea in 1980 , catches of Atka

mackerel near the Island of Four Mountains contributed to a

biomass estimate of nearly 20, 000 t (Fig. 36) Since then, only

incidental catches of Atka mackerel have been made in this area

and the biomass estimates decreased to 10 t in 1983 and 600 t in

1986.

In the Aleutian Islands area the largest mean length

(34. 9 cm) and mean weight (0. 57 kg) for Atka mackerel occurred

during the 1983 survey (Table 32 , Figs. 37-38).

Size and Age Composition

The following results assume that all Atka mackerel

are 1 year older than the actual otolith annulus count. (See

discussion on age composition in Methods and Materials section.
\

E BANK ~~"LEH" 

PETR" BANK

(-;r

~AT ru I. 

J,U ...1/

j

c-....

BULD IR I. 

.

~I+

/\../.

(.1",

:/

-;(;1+ N7 

. . 

1986 2 "

\-:J V ,J.~

KG/K" 

y 

CAT

AHCHITKA I. _

NO CATCH 1 - , . 000 

001-10. 000

10. 000-

1983 

pt(- CATCH IN KG/K +

NO CATCH

'-1. 000

01-10. 000

, 

10. 000-

PETREL BANK

BULD I R 

PETREL BANK

170

cO)

~.......it. 

,

't!

;:-:r1 . 000 

AGATTU I.

1980

CATCH I N KG/KH

NO CATCH 1 - 1 . 000 

001-10. 000

10. 000-

Figure 33. Distribution and relative abundance of Atka mackerel in the Aleutian Islands

area during the U. S. -Japan 1980 , 1983, and 1986 groundfish surveys.
1"-

1986

CATCH IN KG/KM

NO CATCH 

1 - 1 .000 

001-10. 000

10. OOO=-

1983

CA TCH IN KG/KM NO CATCH 

1 -1 . 000 

001-10. 000

10. OOO=-

1980

CATCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000

1 O. OOO=-

Figure 34.

1986

CATCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000 10. OOO=- 

1983

CATCH IN KG/KM

NO CATCH 1-1 . 000 

001-10. 000 10. OOO=- 

BOWERS

BANK

1980

CA TCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000 .

1 O. OOO=- 

Distribution and relative abundance of Atka mackerel

in the Southern Bering Sea and Bowers Ridge areas

during the U. S. -Japan 1980 , 1983 , and 1986 Aleutian

Islands groundfish surveys.
1982 1983 1984

YEARS

Figure 35. Estimated biomass and population of Atka mackerel in

the Aleutian Islands area during the U. -Japan 1980,

1983 , and 1986 groundfish surveys.

1983 1984

YEARS

Figure 36. Estimated biomass and population of Atka mackerel in

the Southern Bering Sea area during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.

THOUSANDS

750 

.... ...................... 

-..... -.-.. h 

_.... ... . 

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION

500

250

1980 1981 1985

THOUSANDS

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

1980 1981 1982 1985

BILLIONS

1986

MilliONS

1986
Table 31. Estimates biomass biomass sampling error, and population for Atka mackerel based on the U. S. -Japan

1980 1983 and 1986 Aleutian Islands groundf ish

surveys.

Biomass (t) Sampl ing Error 

(%)

Population (1 OOOs)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 322 482 546 210. 279. 3 1 186 003.

101-200 76, 646 117 812 720 145 485. 268 222. 130 831.

201-300 631 087 195 111. 961.7 624.

301-500 146 339. 19.

501-900

1-900 415 135 368 543 475 128. 78. 320. 146 807. 301 805. 5 1 317 479.

Southeast 1-100 814 537. 258.

101-200 043 690 048 648. 517. 944.

201-300 194 133. 390.

301-500

501-900

1-900 135 126 698 087 158. 131. 211. 782. 152 445. 209.

Northwest 1-100 075 785 052. 115- 368.

101-200 382 111 227 050. , 107. 335.

201-300 465 801. 47.

301-500 182 398.

501-900

1-900 033 213 013 303. 843. 153. 250. 296. 115 708.

Northeast 1-100 121 323.

101-200 695 449 191 131 600. 372. 744.

201-300 850 451 195 959. 588. 213.

301-500 290

501-900 51.2

1-900 929 021 431 228. 67. 118. 133 559. 284. 016.

Bowers 101-200

Ridge 201-300

301-500

510-900

101-900

Aleutian 1-100 190 144 332 525 365 274. 331. 210. 223 275. 7 1 301 634. Islands 101-200 126 766 196 064 108 186 107. 95. 63. 283 785. 368 229. 198 857. tots l 201-300 022 759 397 221. 112. 132. 005. 988. 849.

301-500 521 146 155. 244. 413. 398. 339. 22.

501-900 328. 277 . 220. 1 51.

1-900 130 514 343 302 634 006 104. 56. 275 . 290 399. 597 836. 5 1 501 414.

Southern 1-100 126 635 437.

Ber i ng 101-200 694 757. 14. 21.

Sea 201-300

301-500

501-900

1-900 832 645 268. 156. 174. 757. 14. 459.

No sampl ing was conducted in this area-depth interval.
Table 32. Estimates mean catch per unit effort, length, and weight for Atka mackerel based the u. S. -Japan 1980,

1983 and 1986 Aleutian Islands groundf ish surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 41. 212. 128 247. 31.9 34.

101-200 736. 040. 297. 34. 32. 35.

201-300 275 . 1 909. 85. 29. 33. 36.

301-500 42. 33.

501-900 1.5

1-900 590. 095. 596. 32. 32. 35.

Southeast 1-100 41 , 714. 12. 38.

101-200 929. 547. 154. 41. 39. 34.

201-300 24. 61. 34.

301-500

501-900

1-900 280. 064. 471. 41. 38. 34.

Northwest 1-100 406. 130. 30. 34.

101-200 208. 564. 86. 38. 33.

201- 300 368. 25. 34. 32.

301-500 82. 34.

501-900 1.0

1-900 183. 542. 370. 30. 34. 32.

Northeast 1-100 42. 968. 35.

101-200 952. 442. 287. 37. 38. 30.

201-300 347. 184. 79. 39. 32.

301-500 84.

501-900

1-900 674. 102. 280. 37. 36. 30.

Bowers 101-200

Ridge 201-300

301-500

501-900

101-900 0.0

Aleuti an 1-100 31.5 944. 172. 31.8 35.

Islands 101-200 153. 776. 498. 35. 34. 33.

Total 201-300 296. 270. 39. 29. 33. 33.

301-500 38. 10. 33. 34. 1.31

501-900

1-900 819. 497. 043. 32. 34. 33.

Southern 1-100 26. 131. 31.

Ber i ng 101-200 018. 33.

Sea 201-300

Total 301-500

501-900

1-900 569. 51. 31. 33.

No sampl ing was conducted in this area-depth interval.
ALEUTIAN ISLANDS

.. MEAN LENGTH MEAN WEIGHT

1980 1982 1983 1984

YEARS

1981 1985 1988

Figure 37. Mean length and weight of Atka mackerel in the

Aleutian Islands area during the u. S. -Japan 1980,

1983 , and 1986 groundfish surveys.

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

1980 1981 1982 1983 1984

YEARS

1985 1986

- 0.

Figure 38. Mean length and weight of Atka mackerel in the

Southern Bering Sea area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.
During 1980 , the Atka mackerel stock was characterized by a

bimodal size composition curve consisting primarily of females of

either 29-31 cm or 35-37 cm fork length (Fig. 39). Three year

classes contributed nearly 90% of the total biomass. The 1977

year class contributed 39%, the 1975 year class contributed 28%

and the 1976 year class contributed 19% (Fig. 40).

In 1983 , the stock was again characterized by a bimodal size

composition curve, however the sex ratio was nearly even. The

maj ori ty of the stock consisted of individuals from 33 to 40 cm,

with the primary female mode peaking at 36 cm and the primary

male mode peaking at 38-39 cm. The stock was dominated by the

same 1977 year class that was the major contributor in 1980,

followed by the 1978 and 1979 year classes that contributed 18% and 13%, respectively.

A uni-modal size composition was present during 1986 , and

again the sex ratio was nearly even. The stock was dominated by

a newly recruited 1983 year cl~ss. The 1982 through 1978 year

classes also contributed from 18 to 5%, with decreasing contribution with increasing age. The 1977 year class which

dominated the stock from 1980 and 1983 was still providing around

2% of the stock.

Examination of age data indicates several differences in age

composition by depth. In 1980 , 3-year-old fish dominated the stock , contributing nearly 40% in all depths for which data is available. These fish were strongly supported by 4- and 5-year

old fish in all depth intervals (Fig. 41).

In 1983 , the 1977 year class (age 6) was still dominating in

the 1-100 m and 101-200 m depth intervals , but in the 201-300 m

depth interval three year classes, 1977-1979, contributed nearly

equal portions , slightly over 20% each.

In 1986, the incoming 1983 year class was the largest

contributor, providing 42% and 48% of the Atka mackerel sampled

in the 1-100 m and 201-300 m zones , respectively. In the

101-200 m depth interval , six year classes (1978-1983)

contributed nearly equal portions to the total stock.

Size and age composition data analyzed by areas indicates

numerous differences within a survey year (Figs. 42-47).

In 1980 , stocks in the Southwest area consisted primarily of

larger fish in the 34-37 cm range. These fish were mostly

3- to 6 year-olds from the 1974 through 1977 year classes. The

1975 age group of 5-year-old fish was dominant making up 52% of

the stocks in that area. In the Southeast area length data were

not available in 1980, but age data indicate that the stocks were

made up primarily of 3 to 5-year-olds. In the Northeast area

fish were smaller , mostly in the 28-33 cm range. Size and age

data for the remaining areas were not available in 1980.

In 1983 the Southwest area contained nearly equal

proportions of males and females in the 29-36 cm size interval. These were dominated by 5-year-old fish with strong support of

year-old fish and a good showing of 4-year-olds. In the

Southeast area there were more males than females , and they were

in the 36-42 cm size category. Age data were not available for
1980 1980 LENGTH (CMJ

NUMBER (MILLIONS)

MALE FEMALE 300 SEXES COMBINED 

226 '-'-- u_--- 

..... .. 

160

160

......... ..

100 100 160 20 

NUMBER (MilLIONS) LENGTH (CM)

1983 1983 lENGTH tCMJ

NUMBER (MILLIONS)

MALE FEMALE

160

..... .......... ......... ............ ........... .........

300 

226 .--

160

160

SEXES COMBINED 

...........

100 . 50 

NUMBER (MIWONSJ

100 20 

LENGTH (CM)

1986 1986

LENGTH (CMJ

NUMBER (MilLIONS)

MALE FEMALE 300

SEXES COMBINED 

226.

150. 100 0- 6!) .

NUMBER (MilLIONS)

100 160

160..

76 -.--...---...-,----.---.-..--

20 

LENGTH (CM)

Figure 39. size composition of Atka mackerel in the Aleutian

Islands area during the u. s. -Japan 1980, 1983 , and

1986 groundfish surveys.
PERCENT

1-900 m

1980

30 .

......

10 .

AGE (YEARS)

10 

ALEUTIAN ISLANDS

PERCENT

1-900 m

1983

.......... .......

20 .

10 

...

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

 

1-900 m

1986

40 

30 

.....................................

0 0

AGE (YEARS)

10 

ALEUTIAN ISLANDS

PERCENT

 

1-100 m

1980

..,............

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

1-100 m

1983

10'

ALEUTIAN ISLANDS

........ 

AGE (YEARS)

PERCENT

1-100 m

1986

30 .

AGE (YEARS)

ALEUTIAN ISLANDS

Figure 40. Age composition of Atka mackerel in the 1-100 m depth

interval of the Aleutian Islands area during the

-Japan 1980 , 1983 , and 1986 groundfish surveys.
PERCENT

..................., 

101-200 

..._..

1980

30.

20.

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

101-200 m

40 1983

................

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

...

101-200 m

1986 40 .

30.

...

20 

. 2

AGE (YEARS)

ALEUTIAN ISlANDS

PERCENT

201-300 m."-.-

1980

.............. .,,,.,,

10 

201-300 m'--"'-

1983

...

10 

AGE (YEARS)

201-300 m .--

1986

..

10 

Figure 41. Age composition of Atka mackerel in the 101-200 m and

201-300 m depth intervals of the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986

groundf ish surveys.

.,....

30.

20 

10.

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

.

20 .

ALEUTIAN ISLANDS

PERCENT

40 

AGE (YEARS)

AlEUTIAN ISLANDS
1980 1980

lENGTH tCM)

MALE FEMALE

300 NUMBER (MILLIONS)

SEXES COMBINED 240

180

120

60-

20 

NUMBER (MllllONSJ LENGTH (CM)

1983 1983

lENGTH (CMJ

NUMBER (MILLIONS)

300

MALE FEMALE

240 SEXES COMBINED 

_..._:...._.._..__...

180

120

80 .

. 60 20 

NUMBER (MIWONSJ LENGTH (CM)

1986

LENGTH (CMt

MALE FEMALE

100 100

NUMBER (MIWONSJ

1986

NUMBER (MILLIONS)

300

240 SEXES COMBINED 

,_.

180 .

120 .-

20 

LENGTH (CM)

Figure 42. size composition of Atka mackerel in the Southwest

area of the Aleutian Islands during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.
MALE FEMALE I

lENGTH tCMt

LENGTH (CMJ

1980

NUMBER tMllLlONSJ

1983

MALE FEMALE

NUMBER tMIlLIONSt

1986

lENGTH (CMJ

MALE FEMALE

NUMBER (MILLlONSJ

Figure 43.

1980

NUMBER (MILLIONS)

40 -'-'.'-- SEXES COMBINED 

.._.

10 -..

. , ..

, T 

10 20 30 

LENGTH (CM)

1983

NUMBER (MILLIONS)

SEXES COMBINED 

_.__.._...

30 ..--.---

20 ---..

20 

LENGTH (CM)

1986

NUMBER (MILLIONS)

SEXES COMBINED

_.

I II

... .. ..,

20 

LENGTH (CM)

size composition of Atka mackerel in the Southeast

area of the Aleutian ~slands during the U. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
1980 1980

LENGTH (CMJ

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

12 ...

6 ...

20 

NUMBER (MllllONSJ LENGTH (CM)

1983

LENGTH (CMJ

MALE . FEMALE

NUMBER (MllllONSJ

1983

NUMBER (MILLIONS)

18.

.........

SEXES COMBINED 

.....

6...

1 2""

.

20 

LENGTH (CM)

1986 1986

LENGTH (CMJ

NUMBER (MILLIONS)

MALE FEMALE

18 .. SEXES COMBINED 

...........

12 ..

6 ...

20 

NUMBER (MilLIONS) LENGTH (CM)

Figure 44. size composition of Atka mackerel in the Northwest

area of the Aleutian Islands during the U. s. -Japan 1980, 1983, and 1986 groundfish surveys.
1980

lENGTH (CMJ

MALE FEMALE I

NUMBER tMllLlONSJ

1983

lENGTH (CMJ

MALE FEMALE

NUMBER (MILLIONSJ

1986

lENGTH (CMJ

MALE FEMALE

Figure 45.

NUMBER tMILLIONSJ

1980

NUMBER (MILLIONS)

39... SEXES COMBINED 

26 ..

13...

20 

LENGTH (CM)

1983

NUMBER (MILLIONS)

39 .......................-..-.....................,......

SEXES COMBINED 

.........,................................,...

26..

13 ...

20 

LENGTH (CM)

1986

NUMBER (MILLIONS)

39...

...

SEXES COMBINED 

26 ........

20 

LENGTH (CM)

size composition of Atka mackerel in the Northeast

area of the Aleutian Islands during the U. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.
PERCENT

..................

1-900 m

1980 

..... .....

40-

30.

AGE (YEARS)

10 

SOUTHWEST SUBAREA

PERCENT

1-900 m

1983

40 

30.

............................................. .....

20.

AGE (YEARS)

10 

SOUTHWEST SUBAREA

PERCENT

.:..

1-900 m

1986

40 

...

30 

20 

10.

AGE (YEARS)

10 

SOUTHWEST SUBAREA

Figure 46.

PERCENT

. .........................,. .................. 

1-900 m

1980

30.

........

10.

AGE (YEARS)

10 

SOUTHEAST SUBAREA

PERCENT

...... 

1-900 m

1983

40.

..  ...

30.

... . ......... . .........................  ..... ..... ......, ..... ..,........ .,.... .... ....,......................... .  ..._....... ...,....... ..

AGE (YEARS)

10 

SOUTHEAST SUBAREA

PERCENT

........ ..,,.,...,,,. ....... 

1-900 m

40 .

1986

 ................... ....

30.

..

10.

AGE (YEARS)

10 

SOUTHEAST SUBAREA

Age composition of Atka mackerel in the Southwest and

Southeast areas of the Aleutian Islands during the

u. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
PERCENT

.............................

1-900 m

40 

1980

...,.....,..

20 .

,..,...,.

10 .

AGE (YEARS)

10 

NORTHEAST SUBAREA

PERCENT

10 

..........

1-900 m

1983

40 .

30 

......

20 .

_..

AGE (YEARS)

10 

NORTHEAST SUBAREA

PERCENT

1-900 m

1986

.....................,......

30'

................,.

10 -

.

AGE (YEARS)

10 

NORTHEAST SUBAREA

Figure 47. Age composition of Atka mackerel in the Northeast

area of the Aleutian Islands during the U. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.
the Southeast area in 1983. In the Northwest area there were

more females than males , and they were in the 30-39 cm mode. 

age data were available. In the Northeast area there were

slightly more females than males and they were in the 35-40 cm size range. The 1977 year class of 6-year-old fish was dominant

with major contributions of greater than 10% from 3- , 4- , and

year-old fish from the 1980 , 1979, and 1976 year classes.

In 1986 the Atka mackerel stock in the Southwest area was

composed mainly of smaller fish (28-36 cm) and there were more

males than females. The age composition was dominated by

year-old fish with decreasing contributions from older year classes. In the three remaining areas of the Aleutian Islands

the fish were larger , mostly in the 38-46 cm range. In the

Southeast area most of fish were older than 5 years with

year-olds , and 10-year-old fish the largest contributors to the

stocks. No age data are available from the Northwest area in 1986. The Northeast area was composed of several ages with 3- to

year-old fish contributing nearly equal portions to the stock.

Size composition in the Southern Bering Sea in 1980 was

bimodal and dominated by smaller fish, mostly in the 30-35 cm range (Fig. 48). No size composition data were available for the

1983 and 1986 surveys and no age data were available from any of

the three surveys.

Mean Lenqth-at-Age and Growth

In view of the age composition and the variation in dominant

year classes between concentrations of Atka mackerel, mean length-at-age data were computed based upon the data available for the six concentrations. During the 1980 survey, mean lengthat-age seems quite similar for the three concentrations where age

data is available. However, there may be slightly larger size at

age in the Amchi tka and Kiska Islands concentration (Table 33). During 1983, a gradation of mean size-at-age is obvious with

the smallest sizes occurring at the west end of the Aleutian

Islands , Stalemate Bank; intermediate mean sizes in the central portion , Buldir-Tahoma Reefs and Petrel Spur; and the largest

mean sizes at the eastern end , Seguam Pass (Table 34).

In 1986, a similar situation was apparent, that is, a

gradation in mean size-at-age from west to east, with the largest

mean size again in the eastern Aleutian Islands , Seguam Pass (Table 35).

These data show that although the western Aleutian Islands

had fish of a smaller mean size-at-age during the 1983 and 1986

surveys , this has not always been the case. In 1980 the mean size-at-age was as large in the Stalemate Bank concentration as

in the more central portions of the Aleutian Islands.

Age data collected during these surveys indicate that Atka

mackerel on the average grow from 22 to 27 cm during their first

2 years after which the average annual growth increment decreased to 6. 1 cm from age 2 to 3 , 3. 1 cm from age 3 to 4 and from O. 6 

7 cm thereafter (Table 36).
1980

lENGTH tCM)

_MALE FEMALE

NUMBER (MllUONst

1983

LENGTH (CMJ

MALE FEMALE

NUMBER (MIWONSJ

1986

LENGTH (CMJ

MALE FEMALE

.fO

NUMBER (MlllIONSJ

Figure 48.

1980

NUMBER (MILLIONS)

.

SEXES COMIBNED 

6 ...

3-'--

20 

LENGTH (CM)

1983

NUMBER (MilLIONS)

9on

SEXES COMBINED 

3 -,

....

0 ..... I "

., 

20 I "

LENGTH (CM)

1986

NUMBER (MilLIONS)

. 3

SEXES COMIBNED 

on-

---.---r

, 

20 

LENGTH (CM)

size composition of Atka mackerel in the Southern

Bering Sea during the u. S. -Japan 1980 , 1983 , and 1986

groundf ish surveys.
Table 33. Mean length (cm) at age and age composition (%) for

high-densi ty Atka mackerel areas sampled during the

U. S. -Japan 1980 Aleutian Islands groundfish survey.

Area

Stalemate Buldir- Amchi tka - Petrel Seguam

Bank Tahoma Reefs Kiska Is. Spur Pass

Age Lgth Lgth Lgth Lgth Lgth

31. 12. 32. 31.

34. 35. 35. 26.

35. 55. 36. 62. 36. 58.

35. 13. 37. 16. 37.

36. 38. 39.

38. 38. 39.

38. 41. 40.

Table 34. Mean length (cm) at age and age composition

(%)

for

high-densi ty Atka mackerel areas sampled during the

-Japan 1983 Aleutian Islands groundfish survey.

Area

Stalemate Buldir- Amch i tka - Petre I Seguam

Bank Tahoma Reefs Kiska Is. Spur Pass

Age Lgth Lgth Lgth Lgth Lgth

26. 30.

28. 34. 34. 16. 34.

30. 11. 33. 27. 35. 18. 38. 13.

32. 33. 34. 23. 36. 10. 37.

35. 24. 35. 34. 36. 25. 38. 63.

38. 35. 36. 18. 40.

35. 37. 37. 39.

36. 37. 37. 41.

35. 40.
Table 35. Mean length (cm) at age and age composition

(%)

for

high-density Atka mackerel areas sampled during the

-Japan 1986 Aleutian Islands groundfish survey.

Area

Stalemate Buldir- Amchi tka - Petrel Seguam

Bank Tahoma Reefs Kiska Is. Spur Pass

Age Lgth Lgth Lgth Lgth Lgth

29. 27.

26. 30. 30. 53. 30. 23. 33.

28. 15. 34. 10. 32. 20. 33. 22. 39. 18.

31. 17. 36. 19. 35. 35. 15. 41.

33. 29. 35. 13. 36. 36. 14. 42. 12.

32. 16. 37. 31. 38. 36. 41.

32. 35. 15. 38. 38. 42. 19.

37. 37. 38. 43. 13.

40. 45. 42.

44.

Table 36. Estimates of yearly incremental growth (cm) of Atka

mackerel sampled during the U. -Japan 1980 , 1983, and

1986 Aleutian Islands groundfish surveys.

Year

Age 1980 1983 1986 Average

2-3

3-4

4-5

5-6

6-7

7-8 -0.

8-9
100

Length-Weight

Length-weight data were collected for Atka mackerel during

all three surveys. Analysis of these data (Fig. 49) provided

estimates for the constants for the sexes combined:

Weight (g) (1980) = . 0171 x Length(cm) 892

Weight (g) (1983) = . 0001 x Length(cm) 288

126 Weight (g) (1986) = . 0077 x Length(cm) 

Length-weight relationships for 1980 and 1986 were similar

at smaller lengths (~ 32 cm). However in 1986 , fish (~ 32 cm)

were slightly heavier for a given length than in 1980. In 1983 Atka mackerel (~ 40 cm) were somewhat lighter for a given length

than during 1980 and 1986 , but at lengths over 40 cm they were heavier . 

1980 N. 948

SEXES COMBINED

-+-1983 N .293 --- 1986 N -1073

WEIGHT (g)

900

_...._,

1200

600

300

20 

LENGTH (em)

Figure 49. Length-weight relationships for Atka mackerel in the

Aleutian Islands area during the U. S. -Japan 1980,

1983 , and 1986 groundfish surveys.
101

Pacif ic Ocean Perch

Distribution and Abundance

Pacific ocean perch Sebastes alutus ) are found from

Stalemate Bank to the Islands of Four Mountains, including Bowers

Ridge , in the Aleutian Islands area and in the Southern Bering

Sea area. Concentrations of high abundance were located during

all three surveys on both sides of the eastern Aleutian Islands

chain from Seguam Island to Great sitkin Island , around Buldir

Reef, and on Stalemate Bank in the western Aleutian Islands (Fig. 50-51). During the 1983 and 1986 surveys , additional highdensi ty concentrations were located on Walls Plateau and off the

southeast en~ of Amchitka Island and in 1986 around Kiska Island

Petrel Bank and on Bowers Ridge. Moderate density concentrations

were encountered off of Umnak Island during all three surveys and

off of Unalaska Island during the 1983 and 1986 surveys in the Southern Bering Sea area.

Between 1980 and 1983 the biomass estimate increased 141%

from 83 000 t to 117 00 t (Fig. 52). Nearly all of this 44 000 t

increase occurred in the Southeast area (Table 37). Biomass

estimates for the Southwest and Bowers Ridge ares were only

slightly higher in 1983 , and there was a decrease in the biomass

of the Northwest and Northeast areas.

In 1986 there was a 177% increase in the biomass estimate

from 117 000 to 208, 000 t. Most of this increase occurred on the

north side of the Aleutian Islands chain. There was an 87 000 t

increase in the Northeast area and a 24 000 t increase in the

Northwest areas. A smaller increase occurred on Bowers Ridge,

and moderate reductions of 14, 000 t and 8, 000 t occurred in the

Southwest and Southeast areas. A large portion of this increase

was probably attributed to the numerous large catches on Petrel Bank. There was also an increase in the number of high-density

catches in the Seguam Pass region.

During the 1980 and 1983 surveys , the largest portion of the

estimated biomass for Pacific ocean perch was located between

101-200 m, and lesser amounts between 201 and 300 m. In 1986 the si tuation was reversed with the largest portion of the biomass in

the 201-300 m depth interval.

In the Southern Bering Sea , the biomass estimates were also

highly variable , increasing from 6, 000 t in 1980 to 95, 000 t in

1983, then decreasing 57% to 55 000 t in 1986 (Fig. 53).

In both the Aleutian Islands area and the Southern Bering

Sea area , the population mean maximum length (32. 5 and 34. 6 cm)

occurred during the 1980 survey and the mean maximum weight (0.

and 0. 62 kg) during the 1986 survey (Figs. 54-55, Table 38).
1986

CATCH IN KG/KM NO CATCH I - I . 000 

OOI-'O' OOO

1 O. OOO~

PETREL BANK

PETREL BANK

1983

CATCH IN KG/KM NO CATCH I - , . 000 

001-10. 000 .

I O. OOO~

rov

..

PETREL BANK ~TA""ATE .~,

1980

CATCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000

10. OOO~ AHCHI TKA I. 

,

Figure 50. Distribution and relative abundance of Pacific ocean perch in the Aleutian

Islands area during the U. -Japan 1980 , 1983 , and 1986 groundfish surveys.

....
103

.....

I. 000 

1986

CA TCH IN KG/KM

NO CATCH 

I -I .000 

001-10. 000

I O. OOO=-

.....

1983

CA TCH IN KG/KM

NO CATCH I -I . 000 

I . 00 I -I O. 000

I O. OOO~

.....

1980

CA TCH IN KG/KM NO CATCH I -1 . 000 

001-10. 000

I O. OOO=-

Figure 51.

1986

CA TCH IN KG/KM

NO CATCH I - I . 000 

001-10. 000 10. OOO=- 

I. 000

1983

CA TCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 10. OOO=- 

(:)

BOWERS

BANK

1980

CA TCH IN KG/KM

NO CATCH I -1 . 000 

I . 00 I -I O. 000 

10. OOO=-

Distribution and relative abundance of Pacific ocean

perch in the Southern Bering Sea and Bowers Ridge

areas during the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.
1983

YEARS

Estimated biomass and population of Pacific ocean

perch in the Aleutian Islands area during the U. S.

Japan 1980 , 1983 , and 1986 groundfish surveys.

104

THOUSANDS

180 ---- ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION

120

1980 1981 1982 1984

Figure 52.

THOUSANDS

150

120

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

....

1880 1881 1982 1883 1984

YEARS

1986

MilliONS

360

240

- 120

1985 1986

MilliONS

300

240

180

120

1986

Figure 53. Estimated biomass and population of Pacific ocean

perch in the Southern Bering Sea area during the U. S. -

Japan 1980 , 1983 , and 1986 groundfish surveys.
105

Estimates of biomass, biomass sampling error , and

population for Pacific ocean perch based on the U. s. Japan 1980, 1983 , and 1986 Aleutian Islands groundfish

surveys.

Table 37.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleuti an

Islands

Total

Depth (m)

1-100

101-200

201- 300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201- 300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

Southern 1-100

Bering Sea 101-200 Total 201-300

301-500

501-900

1-900

885

645

993

32, 541

994

1 , 548

502

044

494

766

265

159

523

944

, 154

810

159

403

668

415

710

708 

047

169

, 003

Biomass (t)

1980

466

176

707

320

080

551

969

634

850

501

215

348

287

867

126

059

185

345

521

984

377

117 229

190

638

651

479

1983 1986 1980

101.

100.

27.

85.

55.

93.

42.

69.

102.

47.

328.

Sampl ing Error 

(%)

1983

89.

106.

103.

63.

25.

88.

49.

323.

277.

52.

182.

No sampl ing was conducted in this area-depth interval.

130

362

132

109

733

883

026

826

756

312

455

136

903

135

804

465

101 407

1 , 546

950

757

253

154

238

145 367

293

208 052

190

690

520

376

776

70.

191.

70.

47.

116.

37.

105.

1986

74.

419.

239.

478.

100 136.

68.

282.

065.

797.

146.

14.

639.

840.

87. 494.

69.

455.

125.

803.

461.

845.

32.

32.

455.

116 841.6

779.

577.

202 654.

500.

871.

950.

217 .

540.

Population (1 000s)

1980 1983

18.

101 284.

515.

120.

112 943.

197.

108.

199.

34.

147 540.

28.

120.

649.

12.

810.

339.

091.

690.

445 . 0

566.

189.

616.

865.

584.

195 794.

101 671.

612.

301 666.

176 166.

626.

161.

206 954.

1986

466.

022.

889.

244.

623.

399.

876.

416.

762.

454.

355.

621.

186.

163.

62.

689.

104 294.

222.

189 268.

243.

711.9

082.

037.

928.

136 187.

242 933.

498.

395 547.

804.

800.

309.

467.

382.
106

ALEUTIAN ISLANDS

.. MEAN LENGTH MEAN WEIGHT

1981 1982 1983 1984 1985 1986

YEARS .

Mean length and welght of Paclflc ocean perch ln the

Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.

1980

Figure 54.

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

1983 1984

YEARS

Figure 55. Mean length and weight of Pacific ocean perch in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 groundfish surveys.

1980 1981 1982 1985 1986
107

Table 38. Estimates mean catch per unit effort, length, and

weight for Pacific ocean perch based the U. S. -Japan

1980, 1983, and 1986 Aleutian Islands groundf ish

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 34. 26.

101-200 738. 430. 199. 30. 28. 29.

201-300 203. 255. 901.9 32. 31. 31.4

301-500 464. 17. 32. 33. 33. 35.

501-900

1-900 509. 832. 421.2 31.2 29. 30.

Southeast 1-100 203. 18.

101-200 831. 276. 798. 26. 28. 27.

201-300 490. 771. 505. 33. 29. 32.

301-500 184. 581.9 35. 34.

501-900

1-900 719. 718. 509. 31.8 28. 28.

Northwest 1-100

101-200 241. 260. 31.8 27.

201-300 396. 663. 852. 35. 33. 29.

301-500 602. 61. 37. 37. 38.

501-900

1-900 653. 274. 186. 34. 31. 35.

Northeast 1-100 71.9 14. 14. 31.4

101-200 973. 078. 457. 29. 29. 29.

201-300 709. 237. 764. 34. 35. 32.

301-500 501. 83. 360. 30. 36. 36.

501-900

1-900 1 , 942. 867. , 719. 32. 32. 31.2

Bowers 101-200 404. 952. 32.

Ridge 201-300 30. 962. 053. 34. 36. 37.

301-500 097. 38.

501-900 1.8

101-900 603. 804. 34. 36. 37. 1.53

Aleutian 1-100 26. 43. 14. 26. 18. 31.4

Is lands 101-200 534. 055. 257. 29. 28. 28.

Total 201-300 617. 808. 270. 34. 31. 31.9

301-500 226. 27. 607. 32. 36. 36.

501-900

1-900 1 , 153. 1 , 535 . 639. 32. 29. 30.

Southern 1-100 16. 39. 19. 22.

Ber i ng 101-200 216. 895 . 628. 33. 29. 25.

Sea 201-300 039. 612. 470. 36. 35. 34.

Total 301.,500 132. 083. 295. 39. 36. 33.

501-900

1-900 474. 712. 333. 34. 30. 32.

No sampl ing was conducted in this area-depth interval.
108

size and Age Composition

New annuli reading criteria and interpretations and age

verification have shown that Pacific ocean perch attain a much

older age than previously thought. These new ageing techniques

were used for all otoliths collected during the three Aleutian

Islands surveys. For the 1980 survey, 78 years was the maximum

age recorded. ish as old as 98 years and 92 years were recorded

in 1983 and 1986. However, the number of sampled individuals

which attained these old ages was quite small. In 1980, 67% of

the stock was less than 11 years old and 84% was less than 21

years old. Similar results were obtained in 1983: 81% were less

than 11 years and 91% were less than 21 years. In 1986, 69% were

less than 11 years and 87% were less than 21 years. Because so

few individuals reach these old ages , the age composition has

only been plotted for 50 years.

During 1980 the size range of Pacific ocean perch in the

Aleutian Islands extended from 20 to 42 cm and the size

composition was characterized by a uni-modal curve with the

majority of the stock being 26-34 cm with the peak at 29-34 cm (Fig. 56). with the exception of the 1969 year class , which

appears very weak , this stock was supported by the 1967-1976 year classes (Fig. 57). These nine year classes provided nearly 77%

of the total population with 8-year-old fish from 1972

contributing 17% and 10-year-olds from 1970 contributing 13%.

In 1983 the size range expanded slightly, from 17 to 44 cm.

The size composition curve. was again uni-modal with the majority

of individuals between 23 and 35 cm peaking at 28-31 cm. The

proportions of sm~ller fish (24-27 cm) increased and larger fish (32-35 cm) decreased.

Five year classes, 1973 and 1975-1978, dominated the stock

providing 75% of the total. Three year classes, 1976 , 1977, and

1975 were particularly strong contributing 23, 21, and 16% of the stock, respectively. The 1972 year class which was the dominant

year class during the 1980 survey contributed only 4% of the

population in 1983. The 1973 year class which appeared weaker

then either the 1972 or 1974 year classes in 1980 appeared

stronger than those year classes in 1983.

In 1986 the size composition curve continued to be uni-modal

with the largest portion of the stock in the 28-38 cm size range, and a higher percentage of larger f ish in the 33 -4 2 

range. The seven strongest year classes (1974 and 1976-81)

contributed 72% of the total population. The 1978 year class was particularly strong, contributing 26% of the stocks , more than

twice the percentage of the 1977 year class which contributed

12% .

In 1986 there were major reductions in the percentage

contribution of the dominant year classes of the 1983 survey.

The 1976 , 1977 , and 1975 year classes contributed only 7. 8, 11. and 2. 8%, respectively. In particular the 1975 year class which

appeared very strong in 1983 appeared weak in 1986. During all

three surveys the vast majority of the Pacific ocean perch stocks

were made up of 5- to 12-year-old fish.
109

1980 1980

LENGTH tCMJ

NUMBER (MILLIONS)

-45 .

............

SEXES COMBINED 

._.......................

30 .

..........,..........

20 

LENGTH (CM)

40-

MALE FEMALE

NUMBER tMllllONSJ

1983 1983

lENGTH (CMJ

NUMBER (MILLIONS)

80 -

.... 

SEXES COMBINED 

, . ..

-46-'.

..... ....

30 

MALE FEMALE

16 --

.__._,.

20 

NUMBER (MllllONSJ LENGTH (CM)

1986 1986

LENGTH (CMJ

NUMBER (MILLIONS)

10 

NUMBER (MllllONSJ

60 ...

46 ...

30 --

SEXES COMBINED 

.........

MALE FEMALE

20 

LENGTH (CM)

-40

Figure 56. Size composition of Pacific ocean perch in the

Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.
PERCENT

30 -

ALEUTIAN ISLANDS

PERCENT

30 

ALEUTIAN ISLANDS

PERCENT

.

ALEUTIAN ISLANDS

20 

AGE (YEARS)

20 

AGE (YEARS)

20 

AGE (YEARS)

1-900 m

1980

1-900 m

1983

1-900 m

1986

110

PERCENT

1-900 m

,..

1980

.................. .

:::3 

10 

.. .. .... ..........,

10 20 

AGE (YEARS)

SOUTHERN BERING SEA

PERCENT

30-- 1-900 m

........,.

1986

20 .

10 20 

AGE (YEARS)

SOUTHERN BERING SEA

Figure 57. Age composition of Pacific ocean perch in the Aleutian

Islands and Southern Bering Sea areas during the U.

Japan 1980 , 1983 , and 1986 groundfish surveys.

10 20 

AGE (YEARS)

SOUTHERN BERING SEA

PERCENT
111

Analysis of the age composition data by depth intervals

demonstrates considerable variability in age structure of the

stock by depth (Figs. 58-59). During the 1980 survey, 13% of the

stocks in the 1-100 m depth interval were 10-year-old fish from

1970, the strongest age class. The two strongest supporting year

classes were 1974 and 1968 , but there was a surprising contribution of older fish. In the 101-200 m depth interval the

1972 year class was strongest with the 1974 , 1975 , and 1971 being

the primary supporting year classes. In the 201-301 m interval

the 1972 year class was also the strongest , with the 1970 and

1971 year classes being next in importance. The 1970 , 1968 , and

1967 year classes were the largest contributors in the 301-500 m

depth zone , even though each contributed less than 10% of the stocks. There was also a surprisingly strong contribution from

fish 20 years and older. In all depth intervals the 1969 year

class was very weak, and the 1968 year class relatively strong.

In 1983 , 6-year-old fish were dominant in the shallowest

water depth interval and received strongest support from the 1980

and 1976 year classes. Unlike 1980 , there were no old fish found

in the shallowest depth interval. In the 101-200 m and 201-300 m

depth intervals the 1975-1977 year classes were dominant with the

1976 year class being strongest. In the deepest depth interval

10-year-old fish were most abundant. The 1975 , 1971 , and 1966

year classes were slightly stronger than the rest of the year

classes which were spread quite evenly throughout the stocks.

There continued to be a good showing of older fish in the deepest depth zone, however this was not quite as strong as in 1980.

During the 1986 survey, 2-year-old fish were dominant in the

shallowest depth interval. The 1978 year class of 8-year-old

fish was next followed by the 1981, 1977, 1976, and 1974 year classes. In the 101-200 m depth interval the 1978 year class of

year-old fish was the single most dominant year class

contributing 30% of the stock. The 1981, 1979, 1977, and 1980

year classes made up most of the rest of the stocks in that depth interval. In the 201-301 m depth interval , 8-year-old fish made

up 24% of the stocks , with support from the 1977 and 1976 year classes. In the deepest depth interval, 8-year-old fish were

still dominant making up 23% of the stocks. Five-year-old fish

made up another 13% of the stocks. The showing of older fish was

not as strong as in other surveys.

Size and age composition were different between areas within

survey years (Figs. 60-65). In 1980 the size composition was

bimodal in most areas. In the Southwest area , the principle mode

was at 29-34 cm and the secondary mode was at 24-29 cm. Both

modes consisted of males and females of approximately the same size. Most of the fish were 8- to 10-year-olds. In the

Southeast area the primary mode ranged from 25 to 30 cm and

consisted of nearly equal proportions of males and females. Most

of these fish were slightly younger fish of 6- to 8-years-old.

The size composition curve in the Northwest area was trimodal;

the principle mode ranged from 38 to 42 cm , and was mostly large
PERCENT

30 1-100 m

1980

20 

........, .....,.............,............................

20 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

1-100 m 

1983

20 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

:6 

20 

...................,.

20 

AGE (YEARS)

ALEUTIAN ISLANDS

112

PERCENT

101-200 m

30 

,,,,,, 

1980

20 

...... ..........................,......................

10 

 

20 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

101-200 m

1983

30 -

.......................,.,.

20 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

30 101-200 m

..

1986

20 

....  .............._.. ...._....... .. .. , ... ....

20 

AGE (YEARS)

ALEUTIAN ISLANDS

Figure 58. Age composition of Pacific ocean perch in the 1-100 m

and 101-200 m depth intervals of the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986

groundf ish surveys.
113

PERCENT PERCENT

201-300 m

1980

30 301-500 m

1980

20 

10 

..

20 

AGE (YEARS)

20 

AGE (YEARS)

ALEUTIAN ISLANDS ALEUTIAN ISLANDS

:~N

PERCENT PERCENT

201-300 m

,,

1---

1983

301-500 m 30 "'---------'--"'-------'--'---'-"'-'-""'" 

1983

20 

..

10 -

...

20 

AGE (YEARS)

20 

AGE (YEARS)

ALEUTIAN ISLANDS ALEUTIAN ISLANDS

PERCENT PERCENT

201-300 m

1986

301-500 m

1986

20 -

10 

., . 

20 

AGE (YEARS)

20 

AGE (YEARS)

AlEUTIAN ISLANDS ALEUTIAN ISLANDS

Figure 59. Age composition of Pacific ocean perch in the

201-300 m and 301-500 m depth intervals of the

Aleutian Islands area during the U. s. -Japan 1980

1983 , and 1986 groundfish surveys.
1980

lENGTH tCMJ

1986

LENGTH (CMJ

Figure 60.

114

1980

NUMBER (MILLIONS)

15 .. SEXES COMBINED 

5 ...

10.....

NUMBER tMllllON'SJ

20 30 40 .

LENGTH (CM)

1983 1983

lENGTH (CMJ

NUMBER (MILLIONS)

MALE FEMALE

16 .........

...,....................

SEXES COMBINED 

.........................

10 ..

NUMBER tMILUONSJ

20 30 

LENGTH (CM)

1986

NUMBER (MILLIONS)

16.................... SEXES COMBINED 

10......

5"""

10 20 30 NUMBER (MlllIONSJ LENGTH (CM)

size composition of Pacif ic ocean perch in the

Southwest area of the Aleutian Islands during the

-Japan 1980 , 1983 , and 1986 groundfish surveys.
1980

lENGTH (CM)

MALE FEMALE

115

1980

NUMBER (MILLIONS)

SEXES COMBINED 

.......................... ........,....... ......,...... ... .,........, ...,....

24 

.__.__..

-SEXES COMBINED 

, ..........,.......... .. .........

20 

LENGTH (CM)

SEXES COMBINED 

... . .

NUMBER (MILlIONSJ

1983

LENGTH tCMJ

MALE FEMALE

1983

NUMBER (MILLIONS)

18.

Figure 61. Size composition of Pacific ocean perch in the

Southeast area of the Aleutian Islands during the

-Japan 1980 , 1983 , and 1986 groundfish surveys.

NUMBER (MIWONSJ

1986

LENGTH (CMJ

MALE FEMALE

NUMBER tMIWONSt

20 

LENGTH (CM)

1986

NUMBER (MILLIONS)

20 

lENGTH (CM)
116

1980 1980

LENGTH (CMJ

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

6 ..

3...

6 ...

0 0.7 1.

NUMBER (MlllIONSt

20 

LENGTH (CM)

1983 1983

LENGTH (CMJ

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

........................

6.'" m...._.

.. ....

6 .........

-40 NUMBER tMILLlONSJ 20 

LENGTH (CM)

1986 1986

lENGTH (CMJ

NUMBER (MILLIONS)

MALE FEMALE

..........................,.............

SEXES COMBINED 

6 .

0 0.7 1.4 2. 10 20 NUMBER tMllllONSJ LENGTH CCM)

Size composition of Pacif ic ocean perch in the

Northwest area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.

Figure 62.
117

1980 1980 lENGTH (CM)

NUMBER (MILLIONS)

27..............

............

SEXES COMBINED 

....

9...

MALE FEMALE

NUMBER (MllllONSJ 20 30 

LENGTH (CM)

1983

LENGTH (CMJ

MALE

NUMBER CMfLUONS)

1983

NUMBER (MILLIONS)

SEXES COMBINED 

..,.................,...........,.......................

18 m

9..

20 30 

LENGTH (CM)

1986 1986

LENGTH tCMJ

NUMBER (MILLIONS)

27. SEXES COMBINED 

18...

9 .......,.

MALE FEMALE

NUMBER (MllllONSJ 10 15 10 20 

LENGTH (CM)

Size composition of Pacific ocean perch in the

Northeast area of the Aleutian Islands during the

u. S. -Japan 1980 , 1983, and 1986 groundfish surveys.

Figure 63.
PERCENT

30 

.....

20 

AGE (YEARS)

SOUTHWEST SUBAREA

PERCENT

1-900 m

1980

.....,,.

30 

.....

1-900 m

,..,,,,

1983

..........,...........

20 

AGE (YEARS)

SOUTHWEST SUBAREA

PERCENT

20 

.

20 

AGE (YEARS)

SOUTHWEST SUBAREA

1-900 m

1986

118

PERCENT

1-900 m

..............

1980

20 

.... .........

20 

AGE (YEARS)

20 

AGE (YEARS)

20 

AGE (YEARS)

1-900 m

........

1983

..

1-900 m

1986

Figure 64. Age composition of Pacif ic ocean perch in the

Southwest and Southeast areas of the Aleutian Islands

during the U. S. -Japan 1980 , 1983 , and 1986 groundfish

surveys.

SOUTHEAST SUBAREA

PERCENT

SOUTHEAST SUBAREA

PERCENT

SOUTHEAST SUBAREA
PERCENT

1-900 m

 

1980 

20 

.. .

20 

AGE (YEARS)

NORTHWEST SUBAREA

PERCENT

1-900 

. 

1983

..

20 

AGE (YEARS)

NORTHWEST SUBAREA

PERCENT

30--- 1-900 m

......, .

1986

20 

20 

AGE (YEARS)

NORTHWEST SUBAREA

119

PERCENT

10 

NORTHEAST SUBAREA

PERCENT

NORTHEAST SUBAREA

PERCENT

30 '

20 

NORTHEAST SUBAREA

1-900 m

1980

... .....,............,..

20 

AGE (YEARS)

1-900 m

1983

...,.

20 

AGE (YEARS)

1-900 m

........,....

1986

20 

AGE (YEARS)

Figure 65. Age composition of Pacific ocean perch in the

Northwest and Northeast areas of the Aleutian Islands

during the U. S. -Japan 1980 , 1983 , and 1986 groundfish

surveys.
120

females. There was a strong secondary mode at 28-33 cm, composed

mostly of males , and a third weak mode at 21-24 cm consisting of

both males and females. In the Southeast area the principle mode

was at 29-34 cm and consisted mainly of females. The secondary

mode was composed mainly of males in the 24-29 cm range. No age

data are available from 1980 north of the chain. During 1983 the size composition curves in most areas were flat without defining modes. In the Southwest area most fish

were 5- to 7-years-old from the 1978-1976 year class. In the

Southeast area a strong unimodal curve ranged from 23 to 34 cm.

These were mostly 6- to 8-year-old fish from the 1975-1977 year classes. In the Northwest area , there were no defining size

modes and no age data. There were also no defining size modes in

the Northeast area, but there was a surprising showing of older

year classes. However , 5- and 7-year-old fish from the 1978 and

1976 year classes were the only ages that comprised more than 10%

of the stocks of that area.

In 1986 the size composition curves by areas again lacked similarity. In the Southwest area the size curve was bimodal,

with the primary mode peaking at 44 cm and the secondary mode at 36 cm. Males and females were about equal. Eight-year-old fish

from the 1978 year class were clearly dominant, supported by 5-

to 7-year-old fish from the 1981-1979 year classes and 9- to 10-

year-old fish from the 1977-1976 year classes. In the Southeast

area the size curve for females was bimodal with a secondary

mode, primarily females , peaking at 40 cm with very few

individuals in the 36-38 cm range. Eight-year-old fish from the

1978 year class were dominant with strong support from 9-year-old

fish from the 1977 year class. In the Northwest area the size

composition curve was trimodal with the principal mode peaking at 34 cm. There were more large females. Eight-year-old fish from

the 1978 year class were dominant , but not as much as in the other areas. There was a stronger showing of older fish. The

Northeast area had a bimodal size distribution with the principle

mode peaking around 31-32 cm. The secondary mode consisted

primarily of females from 34 to 44 cm with the highest abundance

from 35 cm 40 cm. Eight-year-old fish from the 1978 year class

were dominant making up more than 35% of the stocks in this area.

In the Southern Bering Sea in 1980 the size composition samples were small and the resulting ' curve extremely flat

consisting mostly of fish in the 34-38 cm size range with fewer

smaller fish in the 23-25 cm range (Fig. 66). No age data were

available for 1980 (Fig. 57).

The 1983 size composition curve in the Southern Bering Sea

was trimodal and covered a full size range from 20 to 44 cm with

the principle mode in the 25-32 cm range. There were two

secondary modes: one was mostly males at 34-36 cm and the other

was mostly females at 39-41 cm. The age composition in 1983 was

overwhelmingly dominated by 7-year-old fish which made up 44% of the stock. This age group was supported by fish from the 1979 year class , which was probably not fully recruited to the trawl
121

1980

lENGTH tCMt

MALE FEMALE

. i

NUMBER (MilliONS)

1980

NUMBER (MILLIONS)

SEXES

.__...._,....._...

COMBINED

, . . ., . . ................. ,...

20 . I 

lENGTH (CM)

1983

LENGTH (CMJ 1983

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

NUMBER (MIWONSJ 20 

LENGTH (CM)

1986 1986 LENGTH (CMJ

! .

NUMBER (MilLIONS)

MALE FEMALE

SEXES COMBINED 

. !

5 . 

NUMBER (MllLlONSJ 20 

lENGTH (CM)

Figure 66. Size composition of Pacific ocean perch in the

Southern Bering Sea area during the U. S. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
122

and by the 1977 and 1975 year classes which added about 7% each. Fish older than 12 years were dominated by the 1967 and 1969

classes of 14- and 16-year-olds.

In 1986, most of the stock consisted of fish from 31 to

40 cm , peaking at 34 cm. There was a mode of males in the

32-37 cm range, and two modes of females: one at 32-35 cm and the

other at 37-40 cm. The age composition of this stock was

dominated by the 1979 year class which added 30% to the stock.

This year class was also quite strong during the 1983 survey.

The population was supported by the 1980 and 1978 year classes

which contributed 11% each. In 1986, the incoming 1983 year class , not yet fully available , appears quite strong. Also

there was a higher percentage of older fish, over 20 years old

than had been seen during previous surveys.

Mean Length-at-Age and Growth

Mean lengths at age were calculated for Pacific ocean perch

for all three surveys and it appears that the mean length is

slightly larger to age 17 during the 1986 survey (Table 39).

These data also indicate that this species obtains a length of

about 8 cm by the first summer and 14-17 cm by the second summer

(Table 40). The average yearly growth increment of 2 cm from

age 2-3 appears to be underestimated as the average increase in

mean length from age 3-4 was nearly 5 cm and for age 4-5 it was 5 cm. From age 5 to 8 the average increase dropped to about

2 cm per year and from age 8 to 13, growth averaged 1 cm per

year. These data indicate that Pacific ocean perch have

completed their growth by age 24.

Age data for Pacific ocean perch were also fitted to the

von Bertalanffy growth curve which provided estimates for sexes

combined of k from . 152- . 165, LINF from 38. 0-40. 5, and to from - 2 to -3. (Table 41).
Table 39.

123

Mean length (rom) at age for Pacific ocean perch

sampled during the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.

1980

Age M+F

133 135 138

180 170 171

209 221 215

240 250 241

261 261 261

280 284 282

296 301 298

308 298 304

317 309 313

310 330 325

329 336 332

346 343 345

347 353 350

335 360 347

326 343 335

352 352

340 340 340

330 346 341

355 370 365

360 350 352

345 358 355

340 370 355

330 355 340

340 365 356

335 380 350

350 385 367

400 400

355 365 361

350 390 370

350 365 362

335 377 363

380 380

355 377 373

350 383 381

365 376 372

350 385 382

390 395 394

398 398

401 401

398 398

380 405 403

400 400

420 420

415 415

430 430

393 393

360 380 370

380 390 385

M = males F = females

1983

M+F

75 - 

169 134 154

165 161 163

231 224 227

250 255 252

265 266 266

276 280 278

290 297 293

315 305 310

326 324 325

325 328 326

343 344 344

352 354 353

347 357 353

340 357 347

351 371 360

357 363 360

361 373 367

373 392 386

377 393 385

362 394 378

365 391 372

373 401 391

372 370 371

375 392 385

374 396 385

360 390 380

378 378

366 386 381

367 405 386

347 385 377

381 377 379

375 393 387

375 395 386

386 398 395

382 394 387

367 410 397

374 403 395

383 410 395

378 405 395

376 399 390

387 410 395

374 393 386

374 407 393

382 410 396

377 415 399

390 415 398

383 415 396

377 398 388

380 402 395

1986

M+F

167 - 167

191 197 194

217 233 228

253 253 253

276 277 277

295 293 294

313 317 315

323 328 326

337 350 341

348 360 355

351 366 359

352 368 360

355 383 367

375 378 377

367 389 379

361 401 380

364 393 375

362 404 381

378 406 397

376 410 395

373 400 388

356 400 383

350 412 405

370 415 392

370 420 398

360 414 405

382 408 395

365 430 386

370 376 374

380 433 402

400 460 430

350 407 388

373 406 390

405 417 413

430 426 427

390 418 410

380 408 401

405 400 401

386 415 403

383 403 393

387 413 402

410 415 414

403 425 408

410 416 414

397 423 410

400 415 406

391 427 406

376 413 395

402 416 409

1980

Age M+F

100

410 410

430 400 420

380 405 396

410 420 415

415 415

430 430

390 - 390

410 410

430 430

420 420

400 - 400

400 400

390 390

420 420

400 420 410

420 - 420

1983

M+F

380 390 387

372 407 386

386 - 386

378 383 380

386 393 390

380 - 380

382 430 388

377 400 387

391 400 393

356 400 381

376 400 382

385 390 387

360 395 383

370 390 380

382 - 382

387 - 387

365 - 365

380 445 410

380 400 383

360 - 360

387 390 388

375 416 404

400 - 400

380 - 380

375 400 387

385 - 385

395 - 395

380 410 400

415 415

380 - 380

400 - 400

370 410 390

400 - 400

390 390

370 - 370

390 - 390

410 - 410

390 - 390

420 420

1986

M+F

450 400 425

380 403 397

410 406 408

436 412 422

380 420 396

400 406 405

423 450 430

400 417 414

403 433 418

400. 432 413

406 400 404

430 430

410 410

390 390 390

375 - 375

460 460

390 400 393

400 430 415

390 400 393

390 430 403

410 410

400 - 400

405 405

396 396

410 410 410

400 400

!

400 400

400 - 400
, 124

Table 40. Estimates of yearly incremental growth (cm) of

Pacific ocean perch sampled during the U. S. -Japan 1980,

1983 , and 1986 Aleutian Islands groundfish surveys.

Year

Age 1980 1983 1986 Average

1-2

2-3

3-4

4-5

5-6

6-7

7-8

8-9

9-10

10-11

11-12

12-13

13-14

Table 41. Estimated von Bertalanffy growth curve parameters for

Pacific ocean perch sampled during the U. -Japan 1980

1983 and 1986 Aleutian Island groundfish surveys.

Range von Bertalanffy

Growth Parameters

Age Length

Area - Year Sex (Years) (cm) Linf

Aleutian Islands

1980 2-78 12-49 34. 219 -0. 200

2-74 12-43 30. 138 -1. 572

M+F 2-78 12-43 37 . 97 152 -1. 349

1983 1-92 7-45 37. 165 -1. 205

2-98 12-48 40. 141 -1. 650

M+F 1-98 7-48 39. O. 152 -1. 401

1986 2-92 15-45 39. 175 -1. 028

3-85 19-47 41. 163 -0. 871

M+F 2-92 15-47 40. 165 -1. 041 Southern Bering Sea

1983 5-59 26-41 37. O. 154 -3. 619

6-75 26-43 40. 139 -2. 718

M+F 5-75 26-43 39. 134 -3. 772

1986 4-74 24-43 37. 280 318

5-56 28-46 41. 168 -2 . 114

M+F 24-46 39. 221 -0. 504
125

Length-Weiqht Relationships

Length-weight data provided relationships for Pacific ocean

perch, sexes combined , that were very simila~ for all 3 years (Fig. 67). At larger sizes greater than 35 cm, Pacific ocean

perch were slightly heavier in 1986 for a given length than

during 1980 and slightly heavier at all comparable sizes than in 1983. Relationships for the 3 years are:

Weight (g) (1980) = . 0176 x Length(cm) 931

Weight (g) (1983) = . 0091 x Length(cm) o98

Weight (g) (1986) = . 0126 x Length(cm) o33

SEXES COMBINED

1980 N. 1142

1983 N. 1596

1986 N. 3161

WEIGHT (g)

1800

1500

1200

900

600

300

LENGTH (em)

Figure 67. Length-weight relationships for Pacific ocean perch

in the Aleutian Islands area during the U. S. -Japan

1980 , 1983, and 1986 groundfish surveys.
126

Pacif ic Cod

Distribution and Abundance

Pacific cod Gadus macrocephalus ) were distributed

throughout the Aleutian Islands and Southern Bering Sea areas

primarily at depths less than 200 m (Figs. 68-69). During all

three surveys , high densities of Pacific cod were found in the

eastern Aleutian Islands. In 1983 , high densities of Pacific cod

were observed on the north side of the Aleutian chain as far west

as Agattu Island , and on the south side of the Aleutian chain as

far west as Buldir Island. In 1986 , there was also an increase

in the number of high-density stations throughout the Aleutian

Islands , spreading to the west end of Attu Island on both sides

of the Aleutian chain and onto Petrel Bank. No concentrations of

Pacific cod were encountered on Bowers Ridge and no high-density

concentrations were found in the Southern Bering Sea area.

In 1980 the biomass estimate for Pacific cod in the Aleutian

Islands area was 52, 000 t , and the population estimate was

21. 8 million fish (Table 42 , Fig. 70). However the actual

biomass was probably much higher because the 1-100 m depth zone

was not sampled in some areas that year. In 1983 the biomass

estimate increased to 113, 000 t , and the population estimates to

36. 9 million fish.

In 1986 the biomass of Pacific cod increased by 152% to

173 000 t, a 60, 000 t increase over the 1983 estimate. The

population estimate increased to 78. 9 million fish. Biomass

estimates increased in all but three area-depth intervals.

However, there were substantial decreases in the 101-200 m zone

in the Northwest area and the 1-100 m zone in the Northeast area.

During the 1980 survey, 54% of the Pacific cod stock,

28, 000 t, was located in the Northeast area. In 1983 the biomass

shifted to the two northern areas which contained 69% of the

stock , 78 000 t , with the Northwest area having a slightly larger portion than the Northeast. In 1986 the biomass was concentrated

in the western areas which contained 65% of the stock , 113 000 t,

equally divided between the Northwest and Southwest areas.

During all three surveys , the largest portion of the biomass was

located in the 101-200 m depth intervals.

In 1980 the Southern Bering Sea biomass was 74 000 t. 

1983, it had decreased 39% to 46 000 t and in 1986 it decreased

7% more to 42, 000 t (Fig. 71). During 1980 and 1983 the largest

portion of the biomass was located in the 101-200 m depth

interval; however, in 1986 the 1-100 m depth interval contained

slightly more than the 101-200 m depth interval.

In both the Aleutian Islands and Southern Bering Sea areas

the largest mean length (61. 4 cm and 56. 8 cm) and mean weight

(3. 07 kg and 2. 62 kg) occurred during the 1983 survey (Table 43,

Figs. 72 and 73).
BANK

PETREL BANK

AREA NOT

SURVEYED

1986

CATCH IN KG/KH NO CATCH 1 -1 , 000 

001-10, 000

10, 000:. AHCH1TKA 1. 

~STAlEHATE BANK

(JCQ 

PETREL BANK

1983

CATCH IN KG/KHNO CATCH 1 -1 . 000 

001-10. 000

l- _

:

t\J

AHCHI TKA 1. 

PETREL BANK

1980

CATCH IN KG/KHNO CATCH 1 -1 , 000 

001-10, 000 .

10, 000:. AMCHITKA I.

Figure 68. Distribution and relative abundance of Pacific cod in the Aleutian Islands area

during the U. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
.....

1986

CA TCH IN KG/K

NO CATCH

I-I. 000

001-10. 000

10. 000::.

.....

1983

CA TCH IN KG/KM

NO CATCH

I-I. 000

001-10. 000

10. OOO=-

.....

1980

CATCH IN KG/KM

NO CATCH

I-I. 000

001-10. 000

I O. OOO=-

Figure 69.

128

1. 000 

200 M

(XI

BOWERS

BANK

1986

CATCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 I O. 000::. 

(XI

1983

CATCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000 I O. 000=- 

(XI

BOWERS

BANK

1980

CA TCH IN KG/KM

NO CATCH I - I . 000 

001-~0. 000 .

10. 000::. 

Distribution and relative abundance of Pacific cod in

the Southern Bering Sea and Bowers Ridge areas during

the u. s. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf i sh surveys.
129

Table 42. Estimates of biomass , biomass sampling error, and

population for Pacific cod based on the U. s. -Japan

1980 , 1983, and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleuti an

Islands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1980

1 , 158

250

475

891

168

886

500

554

754

695

509

967

17 ,954

805

390

116

, 125

, 126

861

958

070

593

856

606

320

375

Biomass (t)

1983

450

771

799

050

610

777

448

870

114

891

516

528

637

605

960

497

699

811

045

723

569

113 148

121

864

, 236

403

624

1986

166

986

573

692

417

039

071

995

671

776

759

085

182

340

366

811

055

912

288

066

775

197

662

991

172 625

445

905

832

116

298

1980

59.

73.

103.

110.

78.

73.

153.

56.

No sampl ing was conducted in this area-depth interval.

64.

Sampl ing Error 

(%)

1983

132. 1

52.

154.

26.

0 1 270.

143.

34.

49.

361.

43.

53.

217.

139.

110.

29.

24.

98.

48.

1986

76.

054.

926.

415.

397.

038.

540.

158.

737.

433.

525.

24.

982.

44.

803.

595.

142.

174.

714.

857.

993.

623.

358.

832.

59.

092.

957.

142.

261.

453.

Population (1 000s)

1980

258.

976.

402.

13.

651.

087.

334.

297.

16.

735.

912.

048.

643.

608.

467.

942.

291.

190.

11 ,871 .

726.

302.

613.

224.

867.

886.

502.

067.

111.

566.

1983 1986

643.

208.

249.

289.

390.

000.

959.

060.

267.

288.

527.

965.

039.

66.

598.

235.

487.

691.

163.

578.

406.

620.

040.

799.

855.

806.

503.

712.

39.

061.
1982 1983 1984

YEARS

Figure 70. Estimated biomass and population of Pacific cod in the

Aleutian Islands area during the U. S. -Japan 1980 1983, and 1986 groundfish surveys.

THOUSANDS

200

150

100

1980 1981

THOUSANDS

:\

1980 1981

130

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION

MilliONS

100

- 50

,- 25

1985 1986

MilliONS

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

1982 1983 1984

YEARS

1985 1986

Figure 71. Estimated biomass and population of Pacif ic cod in the Southern Bering Sea area dur ing the U. S . -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
131

Table 43. Estimates mean catch per unit effort length, and weight for Pacific cod based the u. S . -Japan 1980

1983, and 1986 Aleutian Islands groundf ish surveys.

Mean CPUE (kg/km Mean Length (em) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 505. 874. 891.1 40. 52.

101-200 569. 343. 591. 65. 63. 60.

201-300 206. 348. 557. 60. 51. 56. 90 -

301-500 203. 1 58.

501-900

1-900 551. 812. 449. 47. 57. 59.

Southeast 1-100 189. 283. 57.

101-200 579. 071. 994. 55. 59. 52. 1.85

201-300 280. 091. 264. 54. 62. 51. 1.63

301-500 183. 11. 213. 56. 64.

501-900

1-900 585 . 1 , 207. 580. 49. 59. 52. 1.72

Northwest 1-100 252. 696. 64. 61.

101-200 042. 712. 838. 54. 65. 55.

201-300 583. 285. 907. 69. 72. 62.

301-500 27. 153. 64. 1.60

501-900

1-900 495. 410. 416. 62. 64. 56.

Northeast 1-100 887. 978. 465. 43. 70. 35. 1.15

101-200 595. 762. 181. 57. 59. 59.

201-300 196. 621. 011. 58. 63. 65.

301-500 113. 144. 87. 51. 63. 57.

501-900

1-900 569. 025 . 034. 55. 62. 55.

Bowers 101-200

Ridge 201-300

301-500

501-900

101-900

Aleuti an 1-100 520. 446. 811.4 47. 59. 35.

Is lands 101-200 388. 426. 877 . 1 59. 62. 57.

Total 201-300 066. 150. 1 , 635 . 59. 63. 62.

301-500 71. 41. 145. 55. 63. 61.

501-900

1-900 726. 482. 190. 52. 61. 55.

Southern 1-100 348. 307. 242. 48. 49. 54.

Ber i ng 101-200 180. 126. 777. 61. 61. 55.

Sea 201-300 600. 229. 827. 66. 66. 61.6

Total 301-500 251. 317. 91. 67. 57. 1.23

501-900

1-900 884. 609. 346. 53. 56. 55. 41'

No sampl ing was conducted in this area-depth interval.
100

132

ALEUTIAN ISLANDS 

.. MEAN LENGTH MEAN WEIGHT

-_u- 4.

1982 1983 1984

YEARS

Figure 72. Mean length and weight of Pacific cod in the Aleutian

Islands area during the U. -Japan 1980 , 1983 , and

1986 groundfish surveys.

- 1980 1981

2.4

1985 1986

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

-- 4

1980 1981 1982 1983 1984

YEARS

- 2

- 1

1985 1986

Figure 73. Mean length and weight of Pacific cod in the Southern

Bering Sea ' area during the U. -Japan 1980 , 1983 , and

1986 Aleutian Islands groundfish surveys.
133

size and Age Composition

The 1980 size composition curve for Pacific cod was

extremely broad and flat, ranging from 30 to 90 cm , with less than 0. 5 million fish in any size category (Fig. 74). Small

modes were present , peaking at 35, 50 , and 68 cm. Age data from

otolith readings are available only from the 1980 survey when the

stock was dominated by 2-year-old fish, which contributed 38% of

the stock (Fig. 75). The 3 -year-old and 1-year-old age groups

contributed 20% and 14%, respectively, although the 1-year-old f ish were probably not fully available for sampling.

In 1983 the size composition curve was again broad but not

nearly as flat as in 1980, with several size categories

containing over 1 million fish. The stock was dominated by fish

greater than 48 cm with the strongest mode peaking at 53 cm and

smaller modes at 60 and 70 cm.

In 1986 the size composition curve was much stronger than in

1983 with some size categories containing over 2. 5 million fish.

The strongest modes occurred at 35 cm and at 46 cm, with smaller

modes at 69 cm and 79 cm.

During the Aleutian Islands surveys the size composition

varied considerably within areas (Figs. 76-79). In 1980 the

Southwest area size curve was broad and flat with no visible modes. In the Southeast area, there was one small mode that

peaked at 50 cm. In the Northwest area , there were small weak

modes that peaked at 42 , 55 , and 72 cm. The highest abundance

was found in the Northeast area where at least four modes were

evident; the first and strongest mode peaked at 38 cm, followed

by secondary modes at 54, 67 , and 86 cm 

During the 1983 survey, size compositions in the Southwest

and Southeast areas were similar in that both were broad and flat

without prominent modes. In the Southwest area a small mode was

evident at 52 cm and in the Southeast area there was a small mode

at 41 cm. There where four modes in the Northwest area peaking

at 52, 60, 68 , and 78 cm. This area contained a greater size

range of fish; smaller fish ranged from 30 to 40 cm and large

fish from 90 to 100 cm. In the Northeast area there were also

four modes peaking at 52, 62, 68 , and 77 cm.

During 1986 in the Southwest area there were large numbers

of smaller fish ranging from 30 to 42 cm, and not as many larger fish. The Southeast area was similar with smaller fish ranging

from 40 to 53 cm , and fewer larger fish. The Northwest area had

more larger fish ranging from 60 to 90 cm, and less smaller fish

with two modes peaking at 55 and 35 cm. In the Northeast area

there were more smaller fish ranging from 32 to 55 cm, and less

larger fish ranging from 60 to 100 cm.

In the Southern Bering Sea area the size composition curve

in 1980 was dominated by smaller fish. The primary mode of

43-53 cm fish peaked at 49 cm with few larger fish and one small

secondary mode at 80 cm (Fig. 80).
134

1980

LENGTH (CM)

100

110

120 MALE

130

NUMBER (MILLIONS)

1980

NUMBER (MILLIONS)

----_--____n__

SEXES COMBINED 

...

:z 

__

___--nn--_____----

- n_...____--...- --_--___..n______-----------..-----

1 ----

......................

-40 50 

LENGTH (CM)

1983

LENGTH (CM)

100

110

120 MALE

130

NUMBER (MILLIONS)

1983

NUMBER (MILLIONS)

,,,,,

_SEXES COMBINED 

2 -

,,

---___'.._n______---..-------------..-

........ ............

1 - ------------_

..__.._....

-40 60 

LENGTH (CM)

1986

LENGTH (CM)

-40

100

110

120 MALE

130

NUMBER (MILLIONS)

1986

NUMBER (MILLIONS)

...______

SEXES COMBINED 

_,

1 -------

_.._....__.._,

2 n______-----

.......

40 60 

LENGTH (CM)

Figure 74. size composition of Pacific cod in the Aleutian

Islands area during the U. S. -Japan 1980 , 1983 , and

1986 groundfish surveys.
, V

135

PERCENT

40 ,

1-900 m

1980

...... ,..

~ 3 

AGE (YEARS)

ALEUTIAN ISLANDS

Figure 75. Age composition of Pacific cod in the Aleutian Islands

area during the U. S. -Japan 1980 groundfish survey.
136

1980 1980

LENGTH (CM)

NUMBER (MILLIONS)

100

110

120

130

4 __..00.__'__..

SEXES COMBINED / ______00'_'__"--'----'---

1.8 ____m___'__------------_oo_-----,"------"--------,,-,,-------------- m__oo___---._---- ----oo...-

1.2 0000_'-_"_--

_..._....

MALE

_m_____m_.___oo - "______00______00_____'_"_00_"____---"-----------'______00..---..------.-

,,..., 

NUMBER (MILLIONS)

10 '20 30 40 60 60 70 80 110 100 110 120

LENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (MILLIONS)

110

100

110

120

130

4m_00,,_00_00_---------00-- SEXES COMBINED 

---m-m_._____oo_---------..

8---___00'00 -__00-

-----"-_""..-..00- 

2 -""-'00__-__'

--_oo--

MALE FEMALE

6-------_00

_..

40 60 

LENGTH (CM)

110

NUMBER (MILLIONS)

1986 1986

LENGTH (CM)

100

110

120

130

NUMBER (MILLIONS)

4 ---- SEXES COMBINED 

--_00___-

2 --..

___

00____- ____-_m- 

MALE FEMALE

30 40 60 

LENGTH (CM)

110

NUMBER (MILLIONS)

Figure 76. Size composition of Pacific cod in the Southwest area

of the Aleutian Islands during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.
1983

LENGTH (CM)

...::.

800 .00 200 200 .00

137

1980 1980 LENGTH (CM)

600

NUMBER (THOUSANDS)

12O0

------u-- SEXES COMBINED 

800

WIb'

200 200 .00

NUMBER (MILLIONS)

400 ----_u_------_u --

.00 600 30 .0 50 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

~0---_._--------- SEXES COMBINED 

.......

800 

____

__m______---------------------

,,_....__.._

.00 ---------- m_..--

....,...... ....

800

NUMBER (MILLIONS)

30 40 50 

LENGTH (CM)

1986

LENGTH (CM)

600 400 200

1986

NUMBER (THOUSANDS)

1200--

SEXES COMBINED 

800

400

.....

200

NUMBER (MILLIONS)

.00 600 30 40 60 

LENGTH (CM)

Figure 77. size composition of Pacif ic cod in the Southeast area

of the Aleutian Islands during the 1980 , 1983 , and

1986 groundfish surveys.
lENGTH (CM)

Figure 78.

600

1980

MALE FEMALE

.00 200 200

NUMBER (MilLIONS)

lENGTH (CM)

1983

600

MALE

.00 200 200

NUMBER (MilLIONS)

lENGTH (CM)

1986

600

MALE FEMALE

.00 200 200

NUMBER (MilLIONS)

.00 600

138

1980

NUMBER (THOUSANDS)

1200

900 -._____m... __

SEXES COMBINED 

400 600

600

..._....

.00 600

300

. 

30 .0 60 

lENGTH (CM)

1983

NUMBER (THOUSANDS)

1200

--.-------...-----____----m

SEXES COMBINED 

900 -

600

......... 

300-----

..........

30 .0 50 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

1200

SEXES COMBINED 

900 - -...-------------

.....

______m

__.___... .._

600 --------.----

......

300 ...--------------..-..

30 .0 60 

LENGTH (CM)

size composition of Pacific cod in the Northwest area

of the Aleutian Islands during the 1980 , 1983 , and

1986 groundfish surveys.
139

1980

LENGTH (CM)

,

600 400 200 200 400 600

1980

NUMBER (THOUSANDS)

900 

600

SEXES COMBINED'

300

NUMBER (MILLIONS)

30 40 60 

LENGTH (CM)

1983

LENGTH (CM)

600 400 200

LENGTH (CM)

: I

30 I

600

Figure 79.

1983

NUMBER (THOUSANDS)

900 1- SEXES COMBINED I

600

300 I

, lTaT 200

NUMBER (MILLIONS)

400 600 30 40 50 

LENGTH (CM)

1986 1986

NUMBER (THOUSANDS)

i_SEXES COMBINED 900 

600

400 200 200 400 600

NUMBER (MILLIONS)

30 40 60 

LENGTH (CM)

size composition of Pacif ic cod in the Northeast area

of the Aleutian Islands during the 1980 , 1983 , and

1986 groundfish surveys.
140

1980 1980

LENGTH (CM)

100

110

120

130

NUMBER (MilLIONS)

_SEXES COMBINED 

------_u_------

1 - -

2 -- - -------_--m_-__-_-------

..

----..___-m_______u----

.

MALE

40 50 

NUMBER (MilLIONS) LENGTH (CM)

1983 1983

LENGTH (CM)

100

110

120

130

NUMBER (MilLIONS)

SEXES COMBINED 

2 - ---------------

...._.._

1 - ------------ ---

-------------- ----_____-m_'_____-____m______

.,

MALE FEMALE

40 60 

NUMBER (MILLIONS) LENGTH (CM)

1986 1986

LENGTH (CM)

100

110

120

130

NUMBER (MilLIONS)

SEXES COMBINED 

2 - ___-m___

___.

----m______-----------.--------

1 -

1.6 0 0.

NUMBER (MILLIONS)

40 60 

lENGTH (CM)

Figure 80. Size composition of Pacific cod in the Southern Bering

Sea during the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.
141

In 1983 the abundance was considerably lower, with the

largest size category containing about 1 million fish. The

primary size composition mode ranged from 48 to 58 cm, peaking at

52 cm. Again , there were fewer larger fish with secondary modes

at 64 and 80 cm. There was also a small showing of extremely

small cod, 7-8 cm, probably young-of-the-year from the 1983 year class.

During 1986 the size composition curve was composed of three

weak modes, with all size categories less than about O. 7 million fish. The strongest mode ranged from 30-46 cm and peaked at 

, the second mode peaked at 57 cm and a third small mode

occurred at 72 cm.

Mean Lenqth-at-Aqe and Growth

Mean length-at-age data , which are only available from the

1980 Aleutian Islands area, indicate a very fast rate of growth for Pacific cod (Table 44). There was only one observation for

length-at-age for age 1+. By age 2+ , Pacific cod had attained a

mean length of 49 cm; by age 3 + , they were 61 cm, and by age 4 + ,

they were 70 cm. At age 4+ , sexual dimorphism became evident and

the mean length of the males and females began to diverge. At

age 5+ , males averaged 73 cm and females averaged 82 cm in length.

The yearly growth interval of Pacific cod tended to decrease with increasing age (Table 45). Pacific cod grew approximately 15. 1 cm between age 1 and 2, 11. 8 cm between age 2 and 3 , and 9 . 1 cm between age 3 and 4. From age 4 to 5 the year 1 y growth increment for males decreased to 3. 9 cm. 9 cm , but females remained at

The available age data were fitted to the van Bertalanffy

growth equation and the resulting estimates of to' k and ~NF are

presented in Table 46.

Table 44. Mean length (rom) age for Pacific cod sampled during the u. s. -Japan 1980 Aleutian Islands groundf ish survey.

Age Males Females Sexes combined

487 496 492

613 606 610

691 718 701

730 817 763

903 903
142

Table 45. Estimates of yearly incremental growth (cm) of Pacific

cod based on the U. S. -Japan 1980 groundfish survey.

Age Males Females Sexes combined

1-2

2-3

3-4

4-5

5-6

14.

12. 11.

11.

15.

11.

14.

Table 46. Estimated von Bertalanffy growth curve parameters for

Pacific cod sampled during the U. S. -Japan 1980 Aleutian

Islands groundf ish survey.

Range von Bertalanffy

Growth Parameters

Age Length

Area Sex (Years) (cm) LINF

Aleutian Islands

1-6 34-84 83. 430 -0. 065 2-6 37-94 127. 173 -0. 786

M+F 1-6 34-94 104. 240 -0. 637

Southern Bering Sea

2-6 40-93 99. 333 812 2-6 39-97 113. 238 -0. 286

M+F 2-6 39-97 105. 287 -0. 080
143

Length-Weiqht RelationshiR

Length-weight relationships were obtained for Pacific cod

for all three surveys (Fig. 81):

Weight (g) (1980) = . 0128 x Length(cm) 998

Weight (g) (1983) = . 0049 x Length(cm) 215

167 Weight (g) (1986) = . 0057 x Length(cm) 

During the 1983 survey the weight for a given length was greater

than during either the 1980 or 1986 surveys and in 1980 the

weight was slightly heavier then during 1986 survey.

,...

1980 N. 121

SEXES COMBINED

-+- 1983 N. 1179 -+- 1986 N. 858

WEIGHT (g)

18000

6000

--_u_--

15000 ._--_O_u_- nun____-u-O"O------------------

2000

9000

____._0__-

3000

40 50 eo 

LENGTH (em)

100

Figure 81. Length-weight relationships for Pacific cod in the

Aleutian Islands area during the U. -Japan 1980

1983 , and 1986 groundfish surveys.
144

Northern Rockfish

Distribution and Abundance

Northern rockfish Sebastes polyspinis ) are distributed from

Stalemate Bank to Unimak Pass primarily in waters less than 200 m deep (Figs. 82 and 83). In 1980, high densities were encountered

only in the Southeast area of the Aleutian Islands , south of the

Islands of Four Mountains and Amlia Island. In 1983, they were

encountered only in the western areas around Buldir and Tahoma

Reefs and north of Agattu Island. In 1986, high densities in the

eastern areas occurred south of the Islands of Four Mountains,

north of Seguam Island , and on Petrel Spur. In the western

areas , high densities were located off Amchitka and Kiska Islands , on Tahoma and Buldir Reefs , and on Stalemate Bank.

In 1980, the biomass estimate totaled 43, 000 t, and the

population estimate was 72. 1 million fish (Table 47 , Fig. 84).

Approximately 84% of the total biomass was located in the

101-200 m depth interval in the Southeast area.

The biomass estimate in 1983 was 44, 000 t , nearly equal to

the 1980 estimate, but the population estimate had increased to

118 million fish. The stock was more evenly distributed

throughout the areas. Approximately 41% occurred in the Southwest area , 20% in the Southeast area , and 30% in the Northwest area.

The biomass estimate was higher in the two shallowest

depth intervals of all areas except the 101-200 m depth interval

of the Southeast area where there was a substantial decrease.

Northern rockfish were taken on Bowers Ridge for the first time

but this may be because the 100-201 m zone was not sampled in

that area in 1980.

In 1986 the biomass estimate increased nearly threefold to

125, 000 t , and the population estimate rose to 347. 4 million fish. Substantial increases occurred in most areas. In the

Southwest area the biomass estimate increased by 443%, in the

Northeast area by 532%, in the Northwest area by 206%, and in

Bowers Ridge by 293%. The Southeast area which had declined 75%

from 1980 to 1983 declined another 75% to only 2, 300 t. The

biomass estimate in the 1-100 m depth interval was 48, 000 t

greater than in 1983. Biomass in the 101-200 m depth zone was

31, 000 t greater than in 1983 , but only slightly higher than the

1980 estimate.

In the Southern Bering Sea , the biomass estimate increased

445% from 300 t in 1980 to 1, 500 t in 1983 , then increased 4 200%

to 63, 000 t in 1986. The population estimate of 0. 3 million fish

in 1980 increased to 19. 0 million in 1983 and

rose to 107. 4 million fish in 1986 (Fig. 85).

Mean length and weight data for northern rockfish in the

Aleutian Islands area and Southern Bering Sea area show

inconsistencies and are probably inaccurate (Table 48, Figs. 86 and 87).
CATCH IN KG/KH NO CATCH 1 - 1 , 000 

001-10. 000

10. 000:.

PETREL BANK

~STAlEHATE BANK

AHCHITKA I.

.....1983

CATCH IN KG/KH NO CATCH 1 -1 , 000 

001-10. 000

10, 000:.

PETREL BANK

STAlEHATE BANK

(j

AHCHi TKA I.

1980

CATCH IN KG/KHNO CATCH 1 - 1 , 000 

001-10. 000

1 0, OOO~

PETREL BANK

~STALEHATE BANK

Figure 82. Distribution and relative abundance of northern rockfish in the Aleutian

Islands area during the U. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
146

.....

1986

CA TCH IN KG/KM

NO CATCH 

I -I .000 

001-10. 000

1 o. ooo=-

.....

1983

CATCH IN KG/KM

NO CATCH 

I -1 .000 

001-10. 000

I o. ooo=-

.....

1980

CA TCH IN KG/KM

NO CATCH 

, .

000 

001-10. 000

I o. ooo~

Figure 83.

BOWERS

BANK

1986

CATCH IN KG/KM

NO CATCH 

I - 1 . 000 

001-10. 000

I 0. 000::. .

(XI

BOWERS

BANK

1983

CATCH IN KG/KM

NO CATCH 

1 -I .000 

001-10. 000 . 1 O. ooo=- 

(XI

BOWERS

BANK

1980

CATCH IN KG/KM

NO CATCH 

1 -I .000 

001-10. 000 1 o. 000::. 

Distribution and relative abundance of northern

rockf ish in the Southern Bering Sea and Bowers Ridge

areas during the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys. 
147

Table 47. Estimates of biomass , biomass sampling error , and population for northern rockfish based on the U.

Japan 1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleutian

Islands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1980

945

213

164

196

213

121

123

916

461

1 , 407

057

810

907

235

341

Biomass (t)

061

736

173

255

225

829

248

198

280

748

229

257

457

677

144

1 , 004

004

1983

761

191

713

666

093

201

344

357

891

135

384

323

11 , 420

730

325

055

127

, 228

469

124 869

774

714

491

1986

Sampl ing Error (%)

1983

222.

313.

399. 1

116.

1980

281.

145.

0 1 152.

271 .

110.

80.

266.

No sampl ing was conducted in this area-depth interval.

128.

627

413

488

300

828

1 , 439

516

132.

57.

120. 1

205 .

69.

109.

65.

34.

146.

327.

103.

63.

298.

251.

63.

180.

1986

Population (1 000s)

1986

116.

990.

581.

575.

141.

368.

47.

423.

518.

518.

97.

51.

1 , 711 .

838.

601.

51.

070.

986.

11.

119.

259.

62.

321.

1980 1983

380.

380.

380.

666.

549.

912.

124.

226.

70.

333.

180.

134.

756.

071.

033.

420.

31.

487.

039. 1

039.

248.

098.

394.

739.

118 481.

788.

178.

966.

148 781.

568.

350.

228. 703.

65.

975.

684.

93.

818.

118.

721.

315.

158.

300.

213.

18.

533.

457.

688.

145.

228 965.

117 023.

251.

117.

347 358.

701.

105 704.

10.

107 416.
148

THOUSANDS MILLIONS

150 ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION

300

100 . 200

100

1980 1981 1982 1983 1984

YEARS

1985 198.

Figure 84. Estimated biomass and population of northern rockfish

in the Aleutian Islands area during the U. S. -Japan

1980, 1983 , and 1986 groundfish surveys.

THOUSANDS MILLIONS

SOUTHERN BERING SEA 120

.. 

BIOMASS (t) POPULATION

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 85. Estimated biomass and population of northern rockfish

in the Southern Bering Sea area during the U. S . -Japan

1980, 1983 , and 1986 Aleutian Islands groundfish

surveys.
149

Table 48.

weight

Estimates mean catch per unit effort length and for northern rockfish based the U. s. -Japan 1980 1983 and 1986 Aleutian Islands groundf ish surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 742. 225. 29. 27. 101-200 757. 490. 623. 29. 29. 30. 201-300 92. 75. 310. 29. 31.9 29. 301-500 74. 28. 501-900

1-900 239. 820. 502. 29. 28. 30.

Southeast 1-100 962. 24. 101-200 061.8 381. 639. 33. 35. 35. 201-300 24. 63. 36. 29. 301-500 14. 12. 33. 501-900

1-900 236. 658. 155. 33. 25. 35.

Northwest 1-100 204. 169. 28. 30. 101-200 284. 339. 32. 29. 201-300 113. 214. 125. 30. 27. 24. 301-500

501-900

1-900 11.0 038. 145. 28. 29. 24.

Northeast 1-100 391. 30. 101-200 234. 429. 898. 28. 28. 32. 201-300 188. 38. 28. 36. 301-500

501-900

1-900 78. 125 . 644. 28. 29. 33.

Ridge

Bowers 101-200 217. 339. 26. 201-300 904. 32. 301-500

501-900

101-900 97. 297. 32. 26.

Aleutian 1-100 559. 125. 28. 27.

Total

Islands 101-200 705. 865. 716. 29. 29. 34. 201-300 79. 48. 340. 31. 29. 29. 301-500 21. 28. 501-900

1-900 598. 574. 584. 29. 28. 34.

Bering

Southern 1-100 12. 160. 31. 25.

Sea

101-200 71. 439. 166. 41. 29. 31. 201-300 14. 76. 42. Total 301-500

501-900 11.

1-900 27. 119. 023. 41. 29. 26.

No sampl ing was conducted in this area-depth interval.
150

ALEUTIAN ISLANDS 

40 

_..__. 

.. MEAN LENGTH MEAN WEIGHT

1980 1981 1982 - 1983 1984

- YEARS

1985 1986

Figure 86. Mean length and weight of northern rockfish in the

Aleutian Islands area during the U. S. -Japan 1980 1983, and 1986 groundfish surveys.

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 87. Mean length and weight of northern rockfish in the

Southern Bering Sea area during the U. -Japan 1980 1983 , and 1986 Aleutian Islands groundfish surveys.
151

size Com~osi tion

The size composition of northern rockfish in the Aleutian

Islands during the 1980 survey was characterized by a nearly

equal distribution of size categories from 30 to 39 cm , and a sex

ratio slightly favoring the females (Fig. 88). During 1983 the

composition was bimodal with the major mode peaking at 28-31 cm

and a smaller mode of incoming fish peaking at 23-24 cm. As in 1980 the sex ratio slightly favored the females which made up a

larger percentage of the principle mode over 30 cm. In 1986

there was a strong unimodal curve from 24 to 34 cm, peaking at 29-30 cm. There were about as many males as females with the

mode for females approximately 1 cm larger than for males.

Size composition curves for each of the areas are shown in Figs. 89-92. In 1980, adequate size composition data were

available only from the Southeast area where northern rockfish

ranged from 30 to 41 cm.

In 1983 the size composition curves in the Southwest, Northwest , and Northeast , areas were unimodal peaking at 28-31 em. In the Southeast area, there was a strong showing of

incoming younger fish ranging from 21 to 27 cm , peaking at 24 cm.

Size composition curves were similar in most areas during 1986. The Southwest , Northwest, and Northeast areas had nearly

identical curves that were unimodal with the vast majority of the

fish in the 25-35 cm size range , peaking at 29-30 cm. The

Southeast area had a broad, flat , and weak size composition curve with specimens ranging from 29 to 39 cm and no small fish.

In the Southern Bering Sea area no size composition data

were available for northern rockfish for the 1980 survey. During

the 1983 survey, specimens ranged from 22 to 38 cm but were

primarily in the 25-32 cm size range , and there were more females than males (Fig. 93). In 1986 the size composition curve was

bimodal with tow strong principle modes. The first mode was at

24-31 cm and probably represented smaller fish not fully

available to the trawl. The second mode represented larger,

fully recruited fish in the 33-42 cm size range.

Ageing criteria for northern rockfish are presently being

developed at the AFSC using the otoliths coilected during all

three surveys.
LENGTH (CM)

LENGTH (CM)

LENGTH (CM)

152

1980 1980

MALE FEMALE 80 NUMBER (MILLIONS)

80 __n_________n

SEXES COMBINED 

_,,_..,,_

___n on.. 

NUMBER (MILLIONS)

20 

LENGTH (CM)

1983 1983

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

,,

" 80

10 10 

NUMBER (MIWONS)

20 

LENGTH (CM)

1986 1986

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

______,,

NUMBER (MILLIONS)

20 

LENGTH (CM)

Figure 88. Size composition of northern rockfish in the Aleutian

Islands area during the U. -Japan 1980 , 1983 , and

1986 groundfish surveys.
153

1980 1980

LENGTH (CM)

NUMBER (MilLIONS)

MALE FEMALE 40 m _hhm

SEXES COMBINED 

..

30._h20-'_h

10---

,

_m______-------- --h-'--__m_m______-----

NUMBER (MILLIONS)

, 21 20 

lENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (MilLIONS)

MALE FEMALE 40 -----------

SEXES COMBINED 

_h30 -

_mhm

1 0 __hh__h______-------hm _---________m____h__-h'h______-----'--hh______--- -_--___m__ __h'______h_-__m____

__

NUMBER (MIWONS)

20 

lENGTH (CM)

1986 1986

LENGTH (CM)

NUMBER (MilliONS)

MALE FEMALE 40 _hh__'_h..___ _h_hh..____mh_hm__

SEXES COMBINED 

mmhhhhhh__h__hm

30 -

20---

10 ---

20 

NUMBER (MILLIONS) lENGTH (CM)

Figure 89. Size composition of northern rockfish in the Southwest

area of the Aleutian Islands during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.
154

1980 1980 LENGTH (CM)

NUMBER (MILLIONS)

sa _u_--- SEXES COMBINED -_ono----------------_no_._O'

MALE FEMALE

---------_"'_0______---

16 0 1.

NUMBER (MILLIONS)

20 

LENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

.

30u--

20 

NUMBER fMIllIONS) LENGTH (CM)

1986

LENGTH (CM)

MALE FEMALE

NUMBER (MIUIONS)

1986

NUMBER (MILLIONS)

SEXES COMBINED 

_.

20 

LENGTH (CM)

Figure 90. Size composition of northern rockfish in the Southeast

area of the Aleutian Islands during the U. S. -Japan

1980, 1983 , and 1986 groundfish surveys.
LENGTH (CM)

LENGTH (CM)

30 .

. LENGTH (CM)

Figure 91.

10 NUMBER (MILLIONS) lENGTH (CM)

size composition of northern rockfish in the Northwest

area of the Aleutian Islands during the U. s. -Japan

1980 , 1983 , and 1986 grou~dfish surveys.

1980

MALE

NUMBER (MILLIONS)

1983

MALE FEMALE

NUMBER (MfUIONS)

1986

155

1980

NUMBER (MilliONS)

15-- SEXES COMBINED 

10---

5 --

lENGTH (CM)

1983

NUMBER (MilliONS)

15-mm--

SEXES COMBINED 

10 ---------

6 -

lENGTH (CM)

1986

NUMBER (MilLIONS)

15 --

SEXES COMBINED 

10---

5 m_m_____ ----------m-_--___------
156

1980 1980

LENGTH (CM)

NUMBER (MILLIONS)

MALE FEMALE 6 --

SEXES COMBINED 

6 ---

3 --

6 ---

NUMBER (MILLIONS) LENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (MILLIONS)

MALE FEMALE 6 ---

SEXES COMBINED 

6 ---

1.6 ---

- 0.9 1.

NUMBER (MILLIONS) LENGTH (CM)

1986 1986

LENGTH (CM)

NUMBER (MILLIONS)

MALE FEMALE 6 --

SEXES COMBINED 

3 ---

6 -

0 0.9 1.

NUMBER (MILLIONS) LENGTH (CM)

Figure 92. Size composition of northern rockfish in the Northeast

area of the Aleutian Islands during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.
157

1983 1983

NUMBER (MILLIONS)

MALE FEMALE

. I

SEXES COMBINED 

---______m_m-

-______m_-.m_-"

NUMBER NUMBER

20 

LENGTH (CM)

.to ISO

MILLIONS

1986 1986

MALE

NUMBER (MILLIONS)

FEMALE

SEXES COMBINED

ISO

8 -

NUMBER

2 .

.. 

NUMBER

20 

LENGTH (CM)

MILLIONS

Figure 93. Size composition of northern rockfish in the Southern

Bering Sea during the U. -Japan 1983, and 1986

Aleutian Islands groundf ish surveys.
158

Length-Weight RelationshiRe

Analysis of the weight at length data for northern rockfish

revealed nearly identical curves and provided yearly estimates of

the constants a and b (Fig. 94):

996 Weight (g) (1980) = . 0151 x Length(cm)

Weight (g) (1983) = . 0314 x Length(cm) 78o

Weight (g) (1986) = . 0158 x Length(cm) 982

During 1983, northern rockfish were slightly heavier at smaller sizes (20-26) cm than during 1980 and 1986.

1980 N. 240

SEXES COMBINED

-+- 1983 N. 260 -+- 1986 N. 451

WEIGHT (g)

1200

600

_._._.. .._

900 

.

300

10 20 

LENGTH (em)

Figure 94. Length-weight relationships for northern rockfish in

the Aleutian Islands area during the U. -Japan 1980

1983 , and 1986 groundfish surveys.
159

Arrowtooth Flounder

Distribution and Abundance

During 1980 and 1983, arrowtooth flounder Atheresthes stomias ) were found from low to medium densities throughout most

of the Aleutian Islands region and Southern Bering Sea (Figs. 95- 96). One concentration of higher density was encountered in the

Seguam Pass area in 1980 , but none were observed in 1983. In

1986, medium-density concentrations were more numerous throughout

the Aleutian Islands area particularly on the north side of the

Aleutian chain. High-density concentrations were found north of

the Islands of Four Mountains , south of Seguam Island, near the Delarof Islands , on Petrel Bank, north of Arnchi tka Islands, and

northwest of Agattu Island. During all 3 years , arrowtooth

flounder were more abundant at depths greater than 300 

In 1980 the biomass of arrowtooth flounder was estimated at

000 t, and the population at 20. 5 million fish. The species

was distributed primarily on the north side of the Aleutian

Islands chain, 38% in the Northeast, and 29% in the Northwest

areas (Table 49, Fig. 97).

In 1983 the biomass estimate increased 42% to 38 000 t, and

the population went to 23. 0 million fish. The largest increase,

over 200%, occurred in the Northeast area and there were minor

increases in the Northwest and Southeast areas. Small decreases

occurred in the Southwest and Bowers Ridge areas. Approximately

55% of the biomass was located in the 301-500 depth zone. Most

of the stock was on the north side of the Aleutian Islands, 54%

occurred in the Northeast and 24% in the Northwest areas.

In 1986 , total biomass increased 326% to 125, 000 t , and

population increased to 98. 0 million fish. Substantial increases

were noted in all depth intervals and all areas of the Aleutian

Islands area, with the exception of Bowers Ridge. The Northeast

area contained 67% of the total biomass with the remainder being

more equally divided between the other areas. The biomass

estimate in the 301-500 m depth interval of the Northeast area

increased over 500% to 65 824 

A similar situation occurred in the Southern Bering Sea

area al though the increase was not quite so dramatic. From

1980 to 1983 the biomass estimate remained unchanged at 10, 000 t

while the population estimate declined from 14. 4 to 10. 6 million fish (Fig. 98). In 1986 the biomass estimate increased over 200%

to 20 000 t and the population increased to 24. 2 million fish.

For both the Aleutian Islands area and the Bering Sea area

the maximum lengths and weights occurred during the 1983 survey

(Table 50 , Figs. 99 and 100). In the Aleutian Islands area the

maximum length was 52. 1 cm and the maximum weight was 1. 68 kg.

In the Southern Bering Sea the maximum length was 40. 0 cm and the

maximum weight O. 98 kg.
1986

rATCH IN KG/KH NO CATCH 

1 - 1 ,000 

001-10. 000

10, 000:.

PETREL BANK

~STAlEHATE BANK

AI1CH1 TKA 

PETREl BANK

1983 

CATCH IN KG/KH NO CATCH 

1 - I ,000 

001-10. 000

, 0, 000:.

0"1

1980

CATCH IN KG/KHNO CATCH 1 - 1 . 000 

001-10. 000 .

10, 000:.

PETREL BANK

~S"LfHATE eAN'

AHCHITKA 1.

Figure 95. Distribution and relative abundance of arrowtooth flounder in the Aleutian

Islands area during the u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
161

....

1986

CA TCH IN KG/KM

NO CATCH 

1 - 1 . 000 

001-10. 000 1 o. ooo=- 

....

1983

CA TCH IN KG/KM

NO CATCH 

1-1. 000

001-10, 000

1 0, ooo=-

.....

1980

CA TCH IN KG/KM NO CATCH 

1-1. 000

001-10. 000

10. 000::.

Figure 96.

(XI

BOWERS

BANK

1986 

CA TCH IN KG/KM

NO CATCH I -1 . 000 

001-10. 000 . 10, ooo=- 

(XI

BOWERS

BANK

000

1983

CATCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000 1 O. ooo=- 

(XI

BOWERS

/BANK

1980

CA TCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000

10.000::. 

Distribution and relative abundance of arrowtooth

flounder in the Southern Bering Sea and Bowers Ridge

areas during the U. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundf ish surveys.
162

Table 49. Estimates of biomass , biomass sampling error, and

population for arrowtooth flounder , based on the U. Japan 1980, 1983, and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleutian

I s lands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

977

730

143

1 , 711

617

1 , 079

884

578

170

711

441

646

645

732

093

430

068

641

242

363

203

626

149

, 545

798

370

928

1 , 439

933

910

317

333

932

Biomass (t)

1980 1983

333

176

356

1 , 209

1 , 107

181

1986

132

1 , 872

271

736

602

613

1 , 084

351

179

653

359

583

650

170

703

181

1 , 710

961

210

824

675

380

009

500

646

030

670

124 855

904

094

489

3, 263

341

091

1980

31.

44.

46.

69.

164

121

322 469.

Sampl ing Error 

(%)

1983

33.

33.

105.

64.

727.

628.

29.

42.

50.

47.

28.

No sampl ing was conducted in this area-depth interval.

34.

1 , 154

442

961

246

803

272

751

947

278

249

133

382

625

953

594

687

193

352

467

984

367

155

299

272

552

527

540

278

626

523

93.

45.

37.

260.

28.

214.

277 .

112.

111.

111.

89.

28.

60.

116.

77.

75.

169.

1986

Population (1 000s)

1980

105.

1 , 187.

674.

849.

759.

576.

70.

354.

023.

393.

82.

853.

304.

1 , 599.

389.

293.

51.

318.

073.

234.

890.

567.

10.

83.

73.

167.

156.

860.

086.

, 159.

194.

458.

032.

424.

449.

720.

782.

410.

1983

678.

686.

265.

439.

250.

320.

433.

040.

455.

97.

027.

273.

480.

768.

820.

347.

171 .

834.

721.

311.

241.

280.

36.

17.

18.

73.

854.

227.

544.

992.

429.

048.

363.

984.

452.

664.

188.

652.

1986

698.

514.

103.

899.

273.

489.

470.

590.

067.

418.

239.

784.

166.

698.

212.

068.

958.

104.

083.

805.

171.

766.

613.

439.

110.

66.

10.

187.

418.

608.

664.

218.

094.

005.

688.

474.

604.

238.

237.

243.
163

THOUSANDS MilliONS

-- 80

120 - ALEUTIAN ISLANDS 

.. 

BIOMASS (t) POPULATION

1980 1981 1982 . 1983 1984

YEARS

1985 1986

Figure 97. Estimated biomass and population of arrowtooth

flounder in the Aleutian Islands area during the U. S.

Japan 1980 , 1983, and 1986 groundfish surveys.

THOUSANDS MilliONS

SOUTHERN .BERING SEA

.. 

BIOMASS (t) POPULATION

- 18

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 98. Estimated biomass and population of arrowtooth

flounder in the Southern Bering Sea area during the

U. S. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys. 
164

Tab 1 e 50. Estimates mean catch per unit effort length, and weight for arrowtooth flounder based the u. S. -Japan

1980 1983, and 1986 Aleutian Islands groundf ish

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 24. 113. 35. 37.

101-200 149. 180. 286. 38. 40. 39.

201-300 318. 155. 989. 46. 45. 53.

301-500 628. 354. 975. 56. 60. 57.

501-900 243. 157. 654. 60. 65. 57.

1-900 260. 188. 677. 49. 45. 50.

Southeast 1-100 34.

101-200 329. 352. 331. 41. 46. 43.

201- 300 279. 456. 377. 43. 50. 43.

301-500 212. 306. 1 650. 57. 55. 47.

501-900 83. 87. 230. 58. 56. 55.

1-900 242. 272. 1 755. 47. 49. 44.

Northwest 1-100 31.9

101-200 103. 221. 45. 42.

201-300 412. 701. 542. 48. 54. 46. 1.40

301-500 645. 684. 979. 54. 51. 56.

501-900 811. 507. 938. 63. 61. 59.

1-900 696. 724. 032. 56. 52. 57.

Northeast 1-100 113. 891.9 27.

101-200 791 . 353. 757. 31. 41. 43.

201-300 995. 255. 905 . 1 40. 47. 41.

301-500 602. 772. 053. 50. 61. 51.

501-900 446. 905. 888. 60. 59. 60. 1.40

1-900 571. 1 , 207. 759. 45. 54. 46.

Bowers 101-200

Ridge - 201-300 49. 158. 134. 46. 74. 68.

301-500 226. 53. 75. 86. 67. 67.

501-900 28. 10. 69. 60.

101-900 62. 34. 31.4 61. 71. 64.

Aleutian 1-100 11. 58. 188. 27. 37.

Islands 101-200 331. 239. 390. 34. 42. 42.

ota l 201-300 446. 330. 1 , 045 . 1 44. 50. 44.

301-500 657. 1 , 533. 1 864. 50. 57. 54. 1.51

501-900 314. 336. 928. 61.2 60. 59.

1-900 375. 501. 584. 46. 52. 49.

Southern 1-100 298. 114. 187. 24. 28. 32.

Bering 101-200 202. 383. 556. 35. 38. 41.

Sea 201-300 906. 539. 485. 45. 46. 42. 1.21

Total 301-500 1 , 035. 1 , 004. 564. 61. 51. 52.

501-900 586. 154. 667. 56. 54. 54.

1-900 785. 753 . 589. 39. 40. 39.

No sampl ing was conducted in this area-depth interval. surveys.
165

80 

.

ALEUTIAN ISLANDS 1---- 2.4

.. MEAN LENGTH MEAN WEIGHT

1983

YEARS

Mean length and weight of arrowtooth flounder in the

Aleutian Islands area during the U. S. -Japan 1980,

1983 , and 1986 groundfish surveys.

1980 1981

Figure 99.

1$82 1984 1985 1986

SOUTHERN BERING SEA

60 -.------- .. MEAN LENGTH MEAN WEIGHT

20.

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 100. Mean length and weight of arrowtooth flounder in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
166

size and Age Composition

size composition curves must be interpreted with caution

because of the strong sexual dimorphism of arrowtooth flounder

which starts at a young age. This sexual dimorphism may cause a

strong year class to appear as two separate modes when the sexes

are plotted together. Also , some size composition curve modes

may consist of several year classes (see "Mean Length-at-Age and

growth" sections for details).

Arrowtooth flounder in the Aleutian Islands area ranged from

15 to 90 cm with both smaller and larger fish being encountered

in the 1986 survey. Nearly all fish over 65 cm were females.

During 1980 and 1983 the Aleutian Islands area size composition

curves were broad and flat with small modes (Fig. 101). All size

categories contained less than 1 million fish, and there were

more females than males. In 1980 the size modes peaked at 38,

44, and 55 cm. Most of these were 5- to 8-year-old fish, but

there was a small showing of 14- to 15-year-olds from the 1966-

1965 year classes (Fig. 102). Large fish older than 16 years

were measured but not found in the randomly collected age samples. These older fish that were not aged represent about 18%

of the stock.

In 1983 the size composition curve was again broad and flat

with small modes peaking at 40 , 46, 52, and 57 cm., These were

primarily 5- to 8-year-old fish , but there was also a strong

showing of 15-year-old fish that made up 8% of the stock. Fish

older than 16 years that were measured but not aged represented

about 35% of the stock in 1983.

In 1986 the size categories ranged upward to 4. 5 million

fish and the composition curve was at least trimodal. The stock

was dominated by fish in the 40-62 cm size range , which contained

at least two modes peaking at 47 cm and 54 cm. There was also a

relatively strong showing of incoming fish ranging from 24 to 35

cm. Age data were not available for the 1986 survey.

Size compositions of arrowtooth flounder throughout the

Aleutian Islands area varied considerably by area within survey

years. In 1980 in the Southwest area, arrowtooth flounder ranged

from 20 to 80 cm and the size composition contained numerous

peaks of relatively the same magnitude (Fig. 103). In the

Southeast, area most of the fish were in the 30-50 cm size range

and there were smaller numbers of fish over 50 cm (Fig. 104).

Arrowtooth flounder in the Northwest area ranged from 30 to 76 cm

and there were more large fish over 51 cm and fewer smaller fish Fig. 105). The size composition curve in the Northeast area was

similar to the Southeast area with most fish 30-50 cm in length

and less fish larger than 50 cm (Fig. 106).

In 1983, in the Southwest area the size composition curve

had a primary mode of smaller fish in the 30-45 cm size range.

In the Southeast area the size composition curve modes were less

prominent without the strong showing of smaller fish. The
150

100

110

LENGTH (CM)

100

110

LENGTH (CM)

150

100

110

LENGTH (CM)

Figure 101.

167

1980 1980

Millions

6 ... """..."..""""""""""' SEXES COMBINED 

 .. ...........

MALE FEMALE

2...

NUMBER (MILLIONS)

30 40 60 

lENGTH (CM)

1983 1983

NUMBER (MilliONS)

6 """'-""""""""

SEXES COMBINED 

4 ...

..................... ............ ........ ............

MALE FEMALE

NUMBER (MILUONSJ (

30 40 60 

lENGTH (CM)

1986 1986

NUMBER (MilliONS)

6 ....................

.... ........................

SEXES COMBINED 

4 ..

10 20 30 40 60 60 70 

NUMBER UVIILLlONSJ lENGTH (CM)

Size composition of arrowtooth flounder in the

Aleutian Islands area during the U. s. -Japan 1980 1983, and 1986 groundfish surveys.
Figure 102.

PERCENT

168

1-900 m

1980

,.

20'

10 

10 12 

AGE (YEARS)

16 

ALEUTIAN ISLANDS

PERCENT

1-900 m

_1983 30 .

.. ......,............... .....................................

20 .

. ................. . .................. .

10 

AGE (YEARS)

14 16 

ALEUTIAN ISLANDS

PERCENT

1-900 m

30 .

,\..................................

1986 

.... ......

10 .

10 12 14 16 

AGE (YEARS)

ALEUTIAN ISLANDS

Age composition of arrowtooth flounder in the

Aleutian Islands area during the U. s. -Japan 1980

1983 , and 1986 groundfish surveys. During the U. s.

Japan 1980 and 1983 surveys many older

, ,

larger

individuals occurred in the length frequency samples

but were not included in the age samples. In the age

composi tion figures , these specimens have been

grouped together as 19-year-olds.
169

1980 1980

LENGTH (CMI

100

110

NUMBER (THOUSANDS)

380 SEXES COMBINED

240

210 140 1-40 210 30 .w 50 

LENGTH (CM)

120

MALE FEMALE

NUMBER (MILLIONS I

1830 1983

LENGTH (CMI

NUMBER (THOUSANDS)

100

110

360--" SEXES COMBINED 

.

2.w

210 140 140 210

120

MALE FEMALE

30 .w 50 

LENGTH (CM) NUMBER (MILLIONS)

1986

LENGTH (CM)

100 MALE

110

210 140 140 210

NUMBER (MILLIONSI

1986

NUMBER (THOUSANDS)

380 SEXES COMBINED 

240

120 -

30 40 50 

LENGTH (CM)

Figure 103. Size composition of arrowtooth flounder in the

Southwest area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
170

1980 1980

LENGTH (CM)

NUMBER (THOUSANDS)

100

800 SEXES COMBINED 

800

. ,_.. ,_.. _. _.. _. _.. _. . . _.... .. 

400

.

MALE FEMALE

200

380 240 120 120 240 360

...

30 40 

NUMBER (MILLIONS) LENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (THOUSANDS)

100

800

SEXES COMBINED 

800

400

MALE FEMALE

200

380 240 120 120 240

NUMBER (MIWONS)

380 30 40 

LENGTH (CM)

1986 1986

LENGTH (CM)

NUMBER (THOUSANDS)

100

800

SEXES COMBINED

800

400

380 240 120 120 240 380

200

30 40 

NUMBER (MILLIONS) LENGTH (CM)

Figure 104. Size composition of arrowtooth flounder in the

Southeast area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
1980

'lENGTH (CMI

ISO

376

MALE FEMALE

21S0 126 1215

371

NUMBER IMllUONSI

1983

LENGTH (CMI

MALE FEMALE

376

21S0 1215 126 260

NUMBER (MJWONSI

1986

LENGTH (CMI

MALE L\\\\':J FEMALE

260 1215

171

1980

NUMBER (THOUSANDS)

800

460

SEXES COMBINED 

._____........

NUMBER (MllUONSJ

300

160

260 376 30 40 60 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

600

460 .

SEXES COMBINED 

__..._...

300

UiO .-

_.

376 30 40 60 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

800

460

SEXES COMBINED 

300

160

210 376 30 40 60 

LENGTH (CM)

Figure 105. Size composition of arrowtooth flounder in the

Northwest area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983, and 1986 groundfish surveys.
100

110

120

LENGTH (CM,

172

1980 1980

NUMBER (MilLIONS)

SEXES COMBINED I

LENGTH (CM)

100

110

120

130

IS .-

3 -

LENGTH (CM)

100

110

120

1.5"-'

.......... ...._

MALE FEMALE

uo&..

NUMBER (MILUONS)

30 ..0 ISO 

LENGTH (CM)

1983 1983

NUMBER (MilLIONS)

; , ._____.

SEXES COMBINED

.... ., ........ ,.,

1.5

MALE FEMALE

NUMBER (MllUONS)

30 40 60 

LENGTH (CM)

1986 1986

NUMBER (MilLIONS)

SEXES COMBINED

. I

3 .:.

MALE FEMALE

NUMBER (MILUONS,

30 ..0 60 

lENGTH (CM)

Figure 106. Size composition of arrowtooth flounder in the

Northeast area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
173

Northwest area size composition curve had several strong modes of

fish in the 40-59 cm size range. In the Northeast area, there

was a showing of larger fish in the 54-61 cm size range.

Even in 1986 when the biomass was considerably larger,

similarities were hard to find. In the Southwest area the

pr imary mode ranged from 38 to 46 cm, in the Southeast from 34 to

55 cm and in Northwest from 54 to 66 cm. In the Northeast area

which had the largest biomass, the size curve was bimodal with

the primary mode ranging from 38 to 62 cm and the secondary mode

from 22 to 36 cm.

In the Southern Bering Sea area the 1980 size composition

curve for arrowtooth flounder was trimodal with the primary mode

consisting of two peaks: one at 28 cm and a second at 36 cm and a

secondary mode of larger fish peaking at 48 cm (Fig. 107). 

1983, four modes are visible with the largest peaking at 35 cm, a

smaller mode at 26 cm, and two extremely small modes at 47 and 58 cm. In 1986, six modes are apparent: the first was a small

mode at 15 cm , the second was the largest mode peaking at 24 cm,

and the rest were generally declining smaller modes peaking at 28, 37, 4 6 , 50, and 57 cm 

Mean Length-at-Aqe and Growth

Mean length-at-age data for 1980 shows strong sexual

dimorphism in arrowtooth flounder starting early in their life history (Table 51). Even at age 3, the first age at which both

males and females were included in the samples, the average size

of females was nearly 6 cm greater than males. Throughout their

lives the differences in mean length-at-age continues to increase

until at age 15 the females are on the average 12. 8 cm longer

than the males.

Yearly growth increments also varied by sex (Table 52).

From age 3 to 8 , female arrowtooth flounder increase in size from

1 to 6. 0 cm per year; between age 8 and 10 the growth rate is

2-3 cm per year. Males show a similar yearly increase in size

only to age 5 when the growth rate drops to 2-3 cm per year until

age 10. After age 10 the yearly increase in size was generally

less than 2 cm for both sexes and continued to decrease with age.

These data were fitted to the von Bertalanffy growth curve

to obtain estimates of to' ~NF and k (Table 53).
LENGTH (CM)

040

100

110

800

LENGTH (CM)

040

100

110

800

LENGTH (CMt

040

100

110

800

100

800

800

174

1980

1200.

800.

300

1980

NUMBER (THOUSANDS)

SEXES COMIBNED 

.__.._

MALE FEMALE

.00 200 200 400 800 800

------ -_u_

.. ...,,...... _._,..,...

30 040 50 

NUMBER (MILLIONS) LENGTH (CM)

1983

MALE

1983

NUMBER (THOUSANDS)

1200 

_SEXES COMBINED 

_..__.

800 -

800

300

.

FEMALE

30 040 60 

LENGTH (CM)

.00 100 200 -400 800 800

1986

NUMBER (THOUSANDS)

SEXES COMIBNED 

...

30 040 60 

LENGTH (CM)

NUMBER (MIlUONS)

1986

1200

900

_MALE

800

Figure 107. Size composition of arrowtooth flounder in the

Southern Bering Sea during the U. -Japan 1980

and 1986 Aleutian Islands gro~ndfish surveys.

300

.00 200 200 400

NUMBER (MILLIONS)

800 800

1983
175

Table 51. Mean length (rom) at age for arrowtooth flounder sampled

during the U. s. -Japan 1980 Aleutian Islands groundfish

survey.

Age Males Females Sexes combined

197

253

293

321

354

382

410

433

447

459

475

486

494

492

220

254

317

365

425

471

512

538

569

579

604

607

616

622

632

220

226

281

316

365

411

442

459

506

520

545

533

529

534

518

Table 52. Estimates of yearly incremental growth (cm) of

arrowtooth flounder based on the U. S. -Japan 1980

Aleutian Islands groundfish survey.

Age Males

3-4

4-5

5-6

6-7

7-8

8-9

9-10

10-11

11-12

12-13

13-14

14-15

15-16

Females
176

Table 53. Estimated von Bertalanffy growth curve parameters for

arrowtaoth flounder sampled during the U. -Japan 1980

Aleutian Islands groundf ish survey.

Range van Bertalanffy

Growth Parameters

Area Sex

Age

(Years)

Length

(cm) Lmr

Aleutian Islands

M+F

3-16

2-16

2-16

18-54

22-66

18-66

55.

67.

145

188

205

-0. 089

611

1. 055
177

Length-Weight Relationship

Length-weight relationships (sexes combined) for arrowtooth

flounder in the Aleutian Islands area were determined for all

three surveys:

Weight (g) (1980) = 0. 0007 x Length(cm) 695

755 Weight (g) (1983) = 0. 0234 x Length (cm)

Weight (g) (1986) = 0. 0020 x Length(cm) 4o9

During 1980 arrowtooth flounder over 55 cm were slightly

heavier per given length than during 1986. In 1983, arrowtooth

flounder in the 45-58 cm size range were lighter than during the

other two survey years (Fig. 108).

;.

1980 N. 70

SEXES COMBINED

1983 N. 55 1986 N. 212

WEIGHT (g)

8000

6000

4000

2000

30 40 50 

LENGTH (em)

Figure 108. Length-weight relationships for arrowtooth flounder

in the Aleutian Islands area during the U. s. -Japan 1980, 1983, and 1986 groundfish surveys.
178

Sablef ish

Distribution and Abundance

Sablefish Anoplopoma fimbria ) were encountered from

Stalemate Bank to Unimak Pass including Bowers Ridge mostly at

depths greater than 200 m (Figs. 109-110). In 1980, high-density

concentrations were only found west of Seguam Island. In 1983,

similar concentrations were encountered , and there was an

additional high-density concentration south of Seguam Island. 

1986, high-density concentrations were located north, east, and

south of Seguam Island , and west of the Islands of Four

Mountains. An increase in the number of medium-density

concentrations occurred along both sides of the eastern Aleutian

Islands during the 1983 and 1986 surveys. In 1986 , they expanded

north to Petrel Bank and Bowers Ridge and almost as far west as

Agattu Island. There was an increase in the number of mediumdensity concentrations in the Southern Bering Sea particularly

between the Islands of Four Mountains and Umnak Island in 1986.

The biomass estimate for sablefish in the Aleutian Islands

area increased from 24, 000 t in 1980 to 69 000 t in 1983, and

112, 000 t in 1986 (Table 54, Fig. 111). The population estimate

rose from 17. 5 million fish in 1980, to 31. 1 million in 1983 and

40. 7 million in 1986.

In 1980, 83% of the sablefish stock was in the eastern

Aleutians Islands region , with 47% of the total biomass occurring

in the Northeast area. In 1983 , all areas showed increases , but

the most dramatic change occurred in the eastern Aleutian Islands

where the Southeast area biomass increased nearly 2. 5-fold and

the Northeast area 3. 6-fold. In 1986 the biomass estimate

increased again with the most significant increases occurring

along the south side of the Aleutian Islands , where the Southwest area increased 6, 000 t and the Southeast area 33 000 t. Smaller

increases occurred in the Northwest and Bowers Ridge areas , but

the Northeast area remained unchanged.

In 1980 the biomass of the Southern Bering Sea was estimated

to be 118 000 t. However this estimate may be much too high. It

is unlikely that the biomass of the Southern Bering Sea is higher

than the biomass of the Aleutian Islands. The lack of precision

of this estimate is reflected by the extremely high sampling

error of 741% (Table 14). At least part of the problem is

related to RFPCs which multiplied catches of the U. S. vessel by

20 to correct for relative fishing power differences. In 1983

the biomass estimate was 10 000 t, and in 1986 , it increased to

25, 000 t (Fig. 112).

The mean length of sablefish was 'highest in 1980 and

decreased each survey year, but the mean weight was lowest in

1980 and increased each survey year. (Table 55 , Figs. 113-114).
1986

CATCH IN KG/KH

NO CATCH 

1 -1 ,000 

001-10. 000

1 0, OOO~

PETREL BANK

~STAlEMATE BANK

1983

CATCH IN KG/KHNO CATCH 

I - I .000 

001-10, 000

10. 000:.

PETREl BANK

~STALEHATE BANK /:...) 'J0.,,-

... 

..J

1980

CATCH IN KG/KH

NO CATCH I - I , 000 

001-10. 000

10. 000:.

PETREL BANK

~STAlEMATE BANK

Figure 109. Distribution and relative abundance of sablefish in the Aleutian Islands area

during the U. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.

,.

:,
180

.....

000 M

1986

CA TCH IN KG/KM

NO CATCH I - I . 000 

1 . 001 -1 0, 000

1 O. ooo=-

1983

CA TCH IN KG/KM NO CATCH 

1 -1 ,000 

001-10. 000

1 O. OOO=-

.....

1980

CA TCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000

1 O. OOO=-

Figure 110.

(XI

BOWERS

BANK

1986

CA TCH IN KG/KM

NO CATCH 

) .

000 

001-10. 000 1 O. ooo=- 

(XI

BOWERS

BANK

1983

CA TCH IN KG/KM

NO CATCH 

1 -1 ,000 

001-10. 000 . 1 O. ooo=- 

(XI

BOWERS

BANK

1980

CATCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000 . 1 O. ooo=- 

Distribution and relative abundance of sablefish in

the Southern Bering Sea and Bowers Ridge areas during the u. S. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.
181

Table 54. Estimates of biomass , biomass sampling error, and

population for sablefish based on the U. s. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleuti an

I s lands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201- 300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1980

680

546

313

414

737

562

743

997

1 , 078

710

227

132

1 , 192

261

776

797

740

733

646

073

192

706

053

183

185

065

118 192

Biomass (t)

1983

244

245

884

850

223

716

114

693

864

387

350

958

310

1 , 958

306

643

190

097

192

820

012

918

667

762

682

029

704

453

174

851

689

871

1986

229

630

989

848

101

247

955

591

894

338

537

879

1 , 326

594

355

282

586

200

786

108

806

103

672

111 689

159

401

575

813

666

614

1980

210.

109.

75.

120.

108.

229.

140.

227.

67.

63.

No sampl i ng was conducted in th i s area-depth i nterva l.

741.4

Sampl ing Error 

(%)

1983

45.

126.

92.

178.

53.

204.

120.

58.

168.

107.

95.

107. 1

72.

185.

147.

45.

43.

54.

80.

1986 1980

96.

309.

316.

94. 722.

20.

854.

182.

954.

011.

47.

97.

333.

435.

231.

620.

795.

516.

53. 163.

186.

186.

252.

575.

385.

317.

17 ,520.

001.

231.

190.

300.

224.

948.

Population (1 000s)

1983

77.

105.

302.

809.

295.

, 227. 1

742.

827.

747.

544.

182.

351.

534.

092.

920.

1 , 205 .

248.

467.

39.

210.

249.

397.

769.

557.

366.

090.

646.

478.

87.

160.

147.

519.

1986

94.

557.

450.

102.

25.

826.

714.

024.

590.

103.

801.

906.

508.

393.

544.

451.

138.

495.

634.

30.

430.

907.

315.

684.

254.

278.

587.

852.

535.

508.
182

THOUSANDS

160 MilliONS

120

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION __m___...------.-.'.

,...

... 30

40 ---,- ..- 15

1980 1981 1982 1983 1984 1985 1986

YEARS

Estimated biomass and population of sablefish in the

Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.

Figure 111.

THOUSANDS

160 MilliONS

SOUTHERN BERING SEA

.. 

120 BIOMASS (t) POPULATION

text

............ ........ .....

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 112. Estimated biomass and population of sablefish in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
183

Table 55. Estimates mean catch per unit effort, length, and

weight for sablef ish based the u. s. -Japan 1980,

1983 and 1986 Aleutian Islands groundf ish surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100

101-200 37. 58.

201-300 38. 106. 100. 61. 58.

301-500 199. 259. 478. 63. 64. 50.

501-900 219. 405 . 1 277. 67. 63. 67.

1-900 107. 190. 471. 66. 63. 59.

Southeast 1-100

101-200 274. 30. 67. 49.

201-300 080. 669. 107. 63. 65. 49. 1.18

301-500 004. 176. 172. 63. 58. 52. 1.26

501-900 259. 719. 329. 66. 63. 61.

1-900 781. 1 , 530. 1 649. 63. 64. 52.

Northwest 1-100

101-200

201-300 49.

301-500 34. 158. 152. 65. 54. 54.

501-900 222. 213. 565. 64. 63. 63.

1-900 97. 102. 225. 64. 60. 61.

Northeast 1-100

101-200 461.6 501 . 55. 44.

201-300 321. 944. 543. 1 60. 61. 52. 1.25

301-500 329. 769. 141.6 61. 59. 63.

501-900 201. 531. 7 102. 60. 56. 57.

1-900 628. 399. 272. 60. 57. 48.

Bowers 101-200

Ridge 201-300

301-500 13. 119. 365. 71. 72.

501-900 109. 115. 309. 70. 70. 68.

101-900 80. 98. 271 . 70. 70. 68.

Aleuti an 1-100

Islands 101-200 369. 775. 64. 44.

Total 201-300 660. 458. 907. 63. 63. 50.

301-500 347. 562. 912. 62. 59. 54.

501-900 266. 579. 651. 62. 57. 62.

1-900 337. 904. 417. 63. 59. 50.

Southern 1-100 844. 146. 33. 52.

Bering 101-200 238. 444. 567. 59. 63. 1.82

Sea 201-300 086. 173. 572. 61. 55. 58.

Total 301-500 003. 240. 567. 63. 61. 54.

501-900 11 , 902. 062. 810. 61. 60. 54.

1-900 351 . 781. 947. 61. 60. 56.

No sampl ing was conducted in this area-depth interval.
100

184

ALEUTIAN ISLANDS 

.. 

MEAN LENGTH MEAN WEIGHT -....--.-- 4.

1980 1981 1982 1983 1984

YEARS

--- 3.

2.4

1985 1986

Figure 113. Mean length and weight of sablefish in the Aleutian

Islands area during the U. -Japan 1980 , 1983 , and

1986 groundfish surveys.

100

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 114. Mean length and weight of sablefish in the Southern

Bering Sea area during the U. -Japan 1980 , 1983

and 1986 Aleutian Islands groundfish surveys.
185

size and Age Composition

In 1980, sablefish in the Aleutian Islands area ranged from

34 to 78 cm. The size curve was bimodal, with the principle mode

extending from 46 to 57 cm and peaking at 49-50 cm. The

secondary mode of smaller fish ranged from 36 to 42 cm and peaked

at 39-40 cm (Fig. 115). No age data were available from the 1980

survey.

In 1983, there was an absence of small fish less than 47 em.

A strong mode of fish ranged from 51 to 64 cm , and peaked at

54-55 cm. There was an increase of fish in the 65-80 cm size

range. The stock in 1983 consisted primarily of eight year

classes, 1974-1981 , with the 1978 year class of 5-year-old fish

being particularly strong, contributing nearly 35% of the biomass (Fig. 116). six- and 4-year-old fish, were also abundant

contributing nearly 20% each.

In 1986 a much stronger size composition mode was evident.

A strong single mode peaked at 59-63 cm and was skewed

considerably toward larger fish , particularly in the 65-75 

range. The stock consisted of fish 2 to 4-years-old. Seven year classes , 1976-1982, dominated, accounting for over 73% of the

total stock with fish in the 9 to 5-year-old age groups being the

strongest.

The age composition of sablefish in the Aleutian Islands area varied with depth (Table 56). In 1983, 5- and 6-year-old

fish were dominant in the 101-200 m depth interval, and 4-6-yearolds dominated in the deeper depth intervals. Three-year-old

fish from the 1980 year class were more numerous in the two deeper zones. In 1986 , 9- to 5-year-old fish were dominant at

depths greater than 200 

In 1980, there was considerable similarity in the size

composition of sablefish throughout all areas of the Aleutian Islands (Figs. 117-120). The major mode was near 50 cm in all

four areas for which data are available. In the Southwest and

Northwest areas the secondary mode was between 64 and 70 cm, in

the Southeast area it peaked at 55-60 cm, and in the Northeast

area it peaked at 38-34 cm.

During 1983, the Southwest area size composition curve had

weak modes between 50 and 70 cm and evidence of fish larger than 80 cm. In the Southeast area , there were no distinct modes,

however there was a higher proportion of larger fish 63-73 cm in length. The Northwest area curve was somewhat similar to the

Southwest area in that there were several weak modes between 50

and 70 cm, but there was no evidence of fish over 80 cm. In the

Northeast area, there was a strong principle mode that ranged

from 53 to 62 cm , peaking at 55-56 cm. The sex ratio favored

males in the Southwest area , females in the Southeast area, was

fairly even in the Northwest area , and favored males in the Northeast area.

In 1986, the Southwest area size composition curve peaked in

the mid-60 cm range and was the only area which contained fish

over 80 cm. There were more males than females. Most fish were
fiO

fiO

fiO

186

1980

LENGTH CCMt

Millions

1980

MALE FEMALE 4 .

SEXES COMBINED 

'-"""'ou,--",-",--",-,,--,--,-

3 ---'-'

... 

2 -..

.,, ...,.,.........,...

30 40 60 

LENGTH (CM)

1983

SEXES COMBINED 

"---'-'-"-'-_ou_ou_--,

.......,....... ,..........,.......,............

NUMBER CMILLIONSt

1983

LENGTH CCMt

Millions

30 40 fiO 

LENGTH (CM)

1986

SEXES COMBINED 

30 40 fiO 

LENGTH (CM)

MALE FEMALE

Figure 115. Size composition of sablefish in the Aleutian

Islands area during the U. S. -Japan 1980, 1983 , and

1986 groundfish surveys.

NUMBER CMIWONSt

1986

LENGTH CCMt

Millions

MALE FEMALE

, 1

NUMBER CMILUONSt
PERCENT 187

30 .

,,,

1-900 m

1980

.................................... ...................,.....

20 

10 -

,.........

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

........... 

1-900 m

........ ...,...... 

1983

20 

. ..........,

1 O' 

.....

10 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

1-900 m

........

30 

1986

20 

. .._.__._...._._._,_._._._,_._,,_...,.

10 .

. ""'~'Wi'----" 10 15 20 

AGE (YEARS)

ALEUTIAN ISLANDS

Figure 116. Age composition of sablefish in the Aleutian Islands

area during the U. -Japan 1980 , 1983 , and 1986

groundf ish surveys.
188

Table 56. Age composition of sablefish by depth intervals during

the U. -Japan 1983 and 1986 Aleutian Islands

groundf ish surveys.

Depths (m)

101-200 201-300 301-500 501-900

Age 1983 1986 1983 1986 1983 1986 1983 1986

10. 13.

12. 19. 23.

43. 37. 12. 37. 12. 35. 12 . 11

17. 24. 17. 10. 19.

13. 10. 11.

10. 12. 12.

15. 13. 13 . 54

Table 57. Age composition of sablef ish by areas in the Aleutian

Islands based on the U. S. -Japan 1986 Aleutian Islands

groundf ish survey.

Subareas

Age Southwest Northwest Northeast

10. 15. 12 . 68

15. 30 11. 11.

11. 10.

29. 10.

10. 10. 10.

14.
1980

LENGTH (CM)

MALE

. i

FEMALE I

2.0

I '

180

NUMBER (THOUSANDS)

1983

LENGTH ICM)

MALE l\\\\') FEMALE

240 180 80 80 180

NUMBER (THOUSANDS)

1986

LENGTH leM)

189

1980

NUMBER (THOUSANDS)

380 SEXES COMBINED

MALE L\\\\'9 FEMALE

240 180 80 80. 180

NUMBER (THOUSANDS)

_n______-,..-.

...........

240

120

180 240 30 .0 &0 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

380 SEXES COMBINED

240

120

240 30 .0 &0 

LENGTH (CM)

1986

. ..

NUMBER (THOUSANDS)

240

380 SEXES COMBINED

120

240

I I 30 40 60 80 

LENGTH (CM)

Figure 117. Size composition of sablefish in the Southwest area

of the Aleutian Islands during the U. -Japan 1980

1983 , and 1986 groundfish surveys.
1980

LENGTH (CM)

150

I-MALE FEMALE I

190

1980

NUMBER (MILLIONS)

SEXES COMBINED 

5 .---------------..-,--------------..--..--,--....--..---------..--

...._

_h______---------

8 0. 0 0.

NUMBER (MILLIONS)

1983

LENGTH reM)

30 .0 60 

LENGTH (CM)

1983

MALE FEMALE

0.8 0. 0 0.3 0.

NUMBER (MIWONS)

NUMBER (MILLIONS)

2 -

SEXES COMBINED 

1986

LENGTH fCM)

1.6

......

MALE

.. I

0 0.3 - 0.

NUMBER (MIWONS)

0.6

1.2 30 .0 60 

LENGTH (CM)

1986

NUMBER (MILLIONS)

1.6

1 -

30 40 60 

LENGTH (CM)

Figure 118. Size composition of sablefish in the Southeast area

of the Aleutian Islands during the U. -Japan 1980

1983 , and 1986 groundfish surveys.
1980

LENGTH (CM)

MALE FEMALE

191

1980

NUMBER (THOUSANDS)

160--.--.---- SEXES COMBINED ----.-00_00_.---'

100----

60 -- .__00_-

NUMBER (THOUSANDS)

1983

LENGTH (CM)

30 .0 

LENGTH (CM)

MALE FEMALE

1983

NUMBER (THOUSANDS)

160"-...--_-'._.hOOO -hh-- SEXES COMBINED h.h'.

100

.

----'..._-'00_..

___.._00

20 20 

NUMBER (THOUSANDS)

1986

LI!N8TM (CM:'

MALE FEMALE

30 .0 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

160 -. SEXES COMBINED 

_._

100--

6000

20 0 20

NUMBER (THOUSANDS)

.-__h_-

30 .0 

LENGTH (CM)

Figure 119. Size composition of sablefish in the Northwest area

of the Aleutian Islands during the U. -Japan ~980

1983 , and 1986 groundfish surveys.
192

1980 1980

LENGTH (CM,

NUMBER (MILLIONS)

MALE FEMALE 6.. SEXES COMBINED 

7 ..u

-40

8 ..

9 .

0 0.6 1.

NUMBER (MILLIONst

30 40 60 

LENGTH (CM)

1983 1983

LENGTH fCM. NUMBER (MILLIONS)

6..

...

SEXES COMBINED 

7 .......

-40

8 ..

0 0.6 1.

NUMBER (M.WONa.

9...

30 40 60 

LENGTH (CM)

1986

LENGTH (CM.

MALE FEMALE

NUMBER (MILUONSt

1986

NUMBER (MILLIONS)

6 .. SEXES COMBINED 

8 ...

30 40 60 

LENGTH (CM)

Figure 120. Size composition of sablefish in the Northeast area

of the Aleutian Islands during the U. s. -Japan 1980 

1983 , and 1986 groundfish surveys.
193

5- to 9-years-old from the 1981-1977 year classes, with 6-yearold fish from 1980 making up the largest portion of the stock

(Table. 57). In the Southeast area the mode was considerably

stronger peaking around 60 cm, and slightly skewed toward fish in

the 60-70 cm size range. There were more females than males. age data were available.

The size composition curve for the Northwest area peaked in

the low 60 cm range. There were about as many males as females.

The stock was composed primarily of 5- to 9-year-old fish, but

year-old fish from 1978 were dominant. The size composition

curve in the Northeast area peaked in the high 50 cm range.

There were about as many males as females. The 1982-1976 year

classes of 4- to 10-year-old fish were the major contributors to

the stock , with the 1976 year class of 10-year-old fish and the

1981 year class of 5-year-old fish providing the largest portions.

In the Southern Bering Sea area in 1980 the size

composition was characterized by a unimodal curve ranging from 46

to 67 cm, peaking at 57 cm, with most of the fish between 50 and

62 cm (Fig. 121). In 1983 , few measurements are available so the

curve is extremely flat , ranging from 54 to 74 cm. In 1986 the

stock ranged from 50 to 73 cm with a peak at 59-61 cm. During

both 1980 and 1986 , females out-numbered males , but in 1986 the

sex ratio was nearly equal.

Mean Length-at-Age and Growth

The mean length-at-age data indicates an initial fast growth

rate for sablefish, which obtained a size of 43 to 47 cm by age 

(Table 58). Estimates of the yearly average growth increment

varied considerably between 1983 and 1986. The 1983 data

indicates that up until age 5 the average growth increment

remained high, decreasing from 6. 6 cm from age 2 to 3 , to 4. 0 

from age 4 to 5. From age 5 to 7 years the average growth

increment ranged from 1 to 2 cm per year (Table 59). The annual

growth increment data for 1986 shows an oscillating pattern.

These data were fitted to the von Bertalanffy growth curve

to provide estimate of to' ~~ , and k (Table 60).
194

1980 1980

LENGTH (CM) NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

8--

NUMBER (MIWONS)

30 40 

LENGTH (CM)

1983 1983

LENGTH (CM) NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 8 ---,

.. ,_. .

:2 --

:2 

NUMBER (MIWONS)

30 40 

LENGTH (CM)

1986 1986

LENGTH (eM) NUMBER (MILLIONS)

MALE FEMALE

SEXES COMalNED 

30 

8 '

NUMBER (MIWONS)

30 ..0 

LENGTH (CM)

Figure 121. Size composition of sablefish in the Southern Bering

Sea during the U. S. -Japan 1980, 1983 , and 1986

Aleutian Islands groundfish surveys.
195

Table 58. Mean length (rom) age for sablefish sampled dur ing

the U. s. -Japan 1983 and 1986 Aleutian Islands

groundf ish surveys.

Year

1983 1986

Age M+F M+F

429 443 434 470 470

494 508 500 505 505

548 553 550 555 607 582

583 602 590 578 604 592

585 624 601 587 610 599

612 635 619 592 646 621

640 720 660 611 661 635

726 735 612 664 641

657 657 628 665 644

820 820 627 672 648

619 675 643

697 700 644 710 669

644 677 659

660 697 680 680 710 695

Table 59. Estimates of yearly incremental growth (cm) of

sablefish based on the U. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.

Year

Age 1980 1983 1986 Average

2-3

3-4

4-5

5-6

6-7

7-8
196

Table 60. Estimated von Bertalanffy growth curve parameters for

sablefish sampled during the U. -Japan 1983 and 1986

Aleutian Islands groundf ish surveys.

Range von Bertalanffy

Growth Parameters

Age Length

Area - Year Sex (Years) (cm) Linf

Aleutian Islands

1983 . 2-15 39-70 65. 348 -1. 090

2-15 40-82 76. 214 -1. 911

M+F 2-15 39-82 71. 249 -1. 851

1986 2-54 46-77 66. 178 -5. 735 4-46 48-95 77. 091 -11. 765

M+F 2-54 46-95 69. o. 159 -7 . 051
197

Length-Weight Relationship

Length-weight data were collected during both the 1983 and

1986 surveys and the data analysis provided the yearly estimates

of the constants a and 

Weight (g) (1983) 0040 x Length(cm) 229

Weight (g) (1986) 0016 x Length (cm) 

458

From length categories 45-70 cm , data from both years provided

nearly identical relationships; however , above 70 cm the fish

were slightly heavier in 1986 for a given length than they were

in 1983 (Fig. 122).

SEXES COMBINED

--+--- 1983 N. 456 -.- 1986 N. 903

WEIGHT (g)

9000 

,.__

0._--------.---- -

.

----.---...- --- - - -U_-- --_h6000 

'---_0._------.-------- ---"'--_0._

3 0 0 0 -0.---'--'----'-'------- ---'--

.,

" - ~__'hh___--------_'-__'hh__'_hhhh'-h_"'_-"'--

30 40 50 

LENGTH (cm)

Figure 122. Length-weight relationships for sablefish in the

Aleutian Islands area during the 1983 and 1986

groundf ish surveys.
198

Greenland Turbot

Distribution and Abundance

Greenland turbot Reinhardtius hippoglossoides ) were

encountered throughout the Aleutian Islands area and the Southern

Bering Sea. Concentrations were located mostly on the north side

of the Aleutian chain at depths greater than 300 m. High

concentrations were found between Atka and Seguam Islands during

both 1980 and 1986, and from Seguam Island to the Islands of Four

Mountains, and on Petrel Bank in 1986 (Figs. 123-124). During

the 1986 survey there was an increase in the occurrence of

medium-density catches on Petrel Bank and Bowers Ridge , and along

both sides of the Aleutian Islands chain west of 1800 long. 

the Southern Bering Sea medium-density catches occurred west of

Umnak Island and northwest of Unalaska Island.

The biomass estimate of Greenland turbot in the Aleutian

Islands area increased from 31, 000 t in 1980 to 52, 000 t in 1983

and 68, 000 t in 1986. The population estimate went from

12. 6 million fish in 1980 to 13. 3 million in 1983 and

18. 6 million in 1986 (Table 61, Fig. 125). Each survey year,

over 80% of the total biomass was located along the north side of

the Aleutian chain with the largest portion located in the

Northeast area. In 1983 , 96% of the resource was on the north

side with 76% occurring in the Northeast area. Over 98% of the

Greenland turbot resource occurred at depths greater than 300 

In the Southern Bering Sea area the biomass estimate for

Greenland turbot was 14 000 t in 1980, remained relatively

unchanged at 14 000 t in 1983, and increased to 21, 000 t in 1986.

The population abundance decreased from 7. 0 million fish in 1980

to 3. 3 million in 1983 , then increased to 6. 6 million fish in

1986.

(Fig. 126).

Although population mean length irregularities , they were highest in

and Southern Bering Sea areas during

Figs. 127-128).

and weights show some

both the Aleutian Islands

the 1983 survey (Table 62

Size Composition

Size composition data indicate a substantial decline in the

recruitment of small Greenland turbot in the Aleutian Islands during 1983 and 1986 as compared to 1980 (Fig. 129). In 1980 the

size composition curve was trimodal with the largest mode made up

of smaller fish consisting of equal numbers of males and females.

This mode ranged from 40 to 60 cm, and peaked at 44-48 cm. The

second mode was dominated by males and ranged from 60 to 71 cm,

peaking at 65-68 cm. The third mode was dominated by females,

and ranged from 72 to 90 cm

, 

peaking at 79-86 cm.
r~STALEHATE 

BANK

1986

CATCH IN KG/KH NO CATCH 

1 - 1 ,000 

001-10, 000 .

10. 000:.

PETREL BANK

.

.

AMCH1 TKA 

..

 

 

~STALEMATE BANK

1983

CATCH IN KG/KP1NO CATCH 

1-1 .000 

001-10. 000

10. 000:.

PETREL BANK

AHCHITKA 1.

L_.--__-

~srALE"ATE 

.

,

1980

CATCH IN KG/KP1 NO CATCH 1 - 1 , 000 

001-10, 000

10, 000:.

PETREL BANK

AMCHITKA I.

Figure -i23- Distribution and relative abundanceof Greenland turbot in the Aleutian

Islands area during the U. s. -Japan 1980, 1983, and 1986 groundfish surveys.
200

.....

1986

CATCH IN KG/KM

NO CATCH .

1 -1 . 000 

001-10. 000

10. 000::.

.....

1983

CA TCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10, 000

1 a . OOO~

.....

1980

CATCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000 1 o. ooo=- 

Figure 124.

eX!

1986

CA TCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000 10. ooo=- 

eX!

BOWERS

BANK

000

1983

CA TCH IN KG/KM

NO CATCH 

1-1 .000 

001-10. 000 .

1 0. 000::. .

1980

CATCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000 .

1 o. ooo~ 

Distribution and relative abundance of Greenland

turbot in the Southern Bering Sea and Bowers Ridge

areas during the u. s. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundf ish surveys.
201

Tab 1 e 61. Estimates biomass biomass sampling error, and population for Greenland turbot ba s ed the u. S. -Japan

1980 1983 and 1986 Aleutian Islands groundf ish

surveys.

Biomass (t) Sampl ing Error 

(%)

Populati on (1 000s)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100

101-200

201-300 14.

301-500 605 638 065 299. 122. 637.

501-900 432 561 260 925. 118. 632.

1-900 042 261 385 87. 33. 73. 225. 253. 285.

Southeast 1-100

101-200

201-300 0 . 15.

301-500 468 526 372 81.9 105. 353.

501-900 720 494 567 135. 66. 73.

1-900 189 1 . 020 028 171 . 57. 70. 217. 171 . 445.

Northwest 1-100

101-200

201-300 10.

301-500 439 247 1 . 206 184. 919. 245.

501-900 661 548 195 028. 494. 478.

1-900 121 812 442 53. 76. 109. 225. 417. 730.

Northeast 1-100

101-200 47.

201-300 429 94.

301-500 433 12. 679 18. 418 755. 483. 814.

501-900 737 823 512 758. 967. 248.

1-900 313 570 359 76. 59. 34. 570. 470. 156.

Bowers 101-200

Ridge 201-300 408 355.

301-500 989 888 841 497. 444. 296.

510-900 997 254 658 549. 515. 677.

101-900 394 149 543 213. 45. 45. 401. 968. 980.

Aleut i an 1-100

Islands 101-200 134. 133. 41. 47.

Total 201-300 525 136 633 25. 88. 55. 375. 27. 136.

301-500 934 978 902 55. 109. 46. 818. 073. 347.

501-900 547 680 192 49. 66. 33. 396. 816. 108.

1-900 059 812 757 41. 44. 25. 12. 638. 271. 597.

Southern 1-100

Ber i ng 101-200

Sea 201-300 139 57. 12. 11.1

Total 301-500 415 1 . 320 150 667. 317. 336.

501-900 284 659 283 312. 962. 238.

1-900 931 033 519 22. 622. 342. 044. 292. 586.

No sampl ing was conducted in this area-depth interval.
THOUSANDS

202

MilliONS

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION 

..

.-..-... 30

1983 . 1984

YEARS

Figure 125. Estimated biomass and population of Greenland turbot

in the Aleutian Islands area during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.

20 -

1980 1981

THOUSANDS

-.-.-. 20

. 10

1982 1985 1986

MilLIONS

------ 9

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

1980 1981

- 3

1982 1983 1985 1986

YEARS

1984

Figure 126. Estimated biomass and population of Greenland turbot

in the Southern Bering Sea area during the U. S. -Japan

1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.
203

Table 62. Estimates mean catch per unit effort, length, and weight for Greenland turbot based the u. S. -Japan

1980, 1983 and 1986 Aleutian Islands groundf ish

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Wei ght (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100

101-200

201-300 23. 23.

301-500 177. 187. 605 . 68. 71. 54.

501-900 487. 79. 463. 79. 71. 66.

1-900 187. 56. 233. 74. 71. 63.

Southeast 1-100

101-200

201-300 20.

301-500 171 . 167. 437. 1 67. 71. 79.

501-900 354. 174. 200. 82. 73.

1-900 106. 73. 134. 67. 75. 75.

Northwest 1-100

101-200

201-300 19. 15. 38. 73. 58.

301-500 197. 014. 544. 75. 64. 56.

501-900 815. 567. 379. 73. 75. 67.

1-900 370. 377. 583. 1 73. 68. 65.

Northeast 1-100

101-200 13.

201-300 37. 23. 175. 71. 84.

301-500 708. 693. 611. 66. 71. 66.

501-900 489. 339. 451.2 71. 69. 56. 1.89

1-900 966. 310. 614. 68. 70. 57.

Bowers 101-200

Ridge 201-300 334. 36. 48.

301-500 617. 178. 149. 82. 71. 53.

501-900 420. 457. 654. 1 84. 84. 72.

101-900 441. 9 502. 638. 83. 78. 59.

Aleut i an 1-100

I s lands 101-200 1.10

ota l 201-300 51.5 13. 62. 71.5 73. 49.

301-500 368. 302. 824. 67. 70. 60.

501-900 960. 217. 525. 72. 71. 59.

1-900 433. 678. 859. 70. 70. 59.

Southern 1-100

Bering 101-200 18.

Sea 201-300 138. 53. 85. 63.

Total 301-500 897. 037. 190. 65. 73. 54.

501-900 962. 566. 961 . 70. 72. 57.

1-900 102. 110. 623. 68. 72. 56.

No sampl ing was conducted in this area-depth interval.
204

120 

.

00 

..

ALEUTIAN ISLANDS

MEAN LENGTH MEAN WEIGHT

.......-....---------- 6

-- 4

.- __h______----.-----------_--_'__ hO-

__.

1980 1981 - 198.2 1984

Figure 127.

1983

YEARS

Mean length and weight of Greenland turbot in the

Aleutian Islands area during the U. -Japan 1980,

1983 , and 1986 groundfish surveys.

1985 1986

140

120 SOUTHERN BERING SEA 

.. MEAN LENGTH MEAN WEIGHT

100

60 

"_0___0'_"__".--_--0-

...

-. --0--.'_,-

.-----. ______h__- 

..

40 -

- 1

1980 1981 1982 1983

YEARS

1984 1985 1986

Figure 128. Mean length and weight of Greenland turbot in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
; 

,::

fiO

fiO

LENGTH (CM'

LENGTH (CM)

LENGTH .CM1

205

1980 1980

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

___._..

0.8

0 0.

NUMBER (MIWONS,

30 40 60 

LENGTH (CM)

1983 1983

1.6

MALE FEMALE SEXES COMBINED 

2 -

0.8

0 0.

NUM8&R CMlWONSt

30 40 60 

LENGTH (CM)

1986 1986

NUMBER (MILLIONS)

1.8

MALE FEMALE

SEXES COMBINED 

0 0.

NUMBER (MILLIONS'

30 40 50 

LENGTH (CM)

Figure 129. Size composition of Greenland turbot in the Aleutian

Islands area during the U. S. -Japan 1980, 1983 , and

1986 groundfish surveys.
206

In 1983 the size composition curve was again trimodal, but

the large mode of smaller fish was not present. The principle

mode was composed of larger fish dominated by males ranging from

60 to 73 em. The secondary modes ranged from 74-84 em to

85-94 em and were dominated by females.

The 1986 size composition was bimodal with the strongest

principle mode ranging from 60 to 76 em , skewed toward larger

fish, and dominated by males. There is a single secondary mode

ranging from 77 to 100 em dominated by females.

Size composition curves for each survey area are shown in

Figs. 130-133.

No age composition data are available for Greenland turbot.
207

1980 1980

LENGTH (CM'

, 

fiO

100

110

120

130

NUMBER (THOUSANDS)

120

90 

_

SEXES COMBINED 

30 

NUMBER (THOUSANDS'

MALE FEMALE

30 40 60 

LENGTH (CM)

1983 1983

LENGTH (CM'

NUMBER (THOUSANDS)

120

100

110

120

130

SEXES COMBINED

MALE f&\\"I FEMALE

30 40 80 

NUMBER (THOUSANDS' LENGTH (CM)

1986

LENGTH (OM'

ISO

100

110

120 MALE

130

NUMBER (THOUSANDS'

1986 120 NUMBER (THOUSANDS)

SEXES COMBINED 

- i

30 40 ISO 

LENGTH (CM)

Figure 130. Size composition of Greenland turbot in the Southwest

area of the Aleutian Islands during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.
1980

LENGTH (CM'

MALE FEMAlE

208

1980

NUMBER (THOUSANDS)

46 -

SEXES COMBINED 

115 16 

NUMBER (THOUSANDS'

30 --

16 

.

1983

LENGTH ,CM)

MALE FEMAlE

16 1fi 

NUMBER (THOUSANDS'

30 40 60 

LENGTH (CM)

1986

LENGTH ,CM)

fiO

MALE FEMALE

1983

NUMBER (THOUSANDS)

46 -

SEXES COMBINED

30 -

16 1/5 

NUMBER (THOUSANDS'

30 40 150 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

45----

SEXES COMBINED I

30 ---

16 -------

,

30 40 150 

LENGTH (CM)

Figure 131. Size composition of Greenland turbot in the Southeast

area of the Aleutian Islands during the U. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.
209

1980 1980

lENGTH (CM'

ISO

NUMBER (THOUSANDS)

160

180--------- SEXES COMBINED 

...........

MALE FEMALE

120------"

............

eo -

100 ISO 60 100

NUMBER (THOUSANDS.

11S0 30 40 60 

LENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (THOUSANDS)

ISO

SilO

MALE FEMALE

180 SEXES COMBINED 

....

120

160 100 100 110

.........

30 40 ISO 

NUMBER (THOUSANDS. LENGTH (CM)

1986 1986

LENGTH tCM)

NUMBER (THOUSANDS)

ISO

MALE FEMALE

180 - SEXES COMBINED 

..

120 -

80.

HIO 100 ISO 10 100

NUMBER (THOUSANDS'

110 30 40 ISO 

LENGTH (CM)

Figure 132. Size composition of Greenland turbot in the Northwest

area of the Aleutian Islands during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.
210

1980 1980

LENGTH (CM'

NUMBER (THOUSANDS)

1060 SEXES COMBINED 

MALE FEMALE

700

............ . . 

800 800 300 300 800 900

...._-------_.0_

..... ..

360 ..--- '---__0_-_--_-----'.-..

.

30 40 60 

NUMBER (THOUSANDS' LENGTH (CM)

1983 1983

LENGTH 'CM'

NUMBER (THOUSANDS)

MALE FEMALE 1050 '---"---------------,,---,0-- SEXES COMBINED 

..

700 ---------___--__0___._..-..---__"__0....___---

...... ,.,,

---__----"0'----

360 -

...........

800 800 300 300

NUMBER CTHOUSANDS,

600 900 30 40 60 

LENGTH (CM)

1986 1986

LENGTH ICM"

NUMBER (THOUSANDS)

MALE FEMALE 1050 ---...-....--------

- SEXES COMBINED 

700

 .. ... ....

350 --

800 800 300 300

NUMBER (THOUSANDS'

800 800 30 40 60 80 -- 70

LENGTH (CM)

Figure 133. Size composition of Greenland turbot in the Northeast

area of the Aleutian Islands during the U. S. -Japan

1980 , 1983 , and 1986 groundfish surveys.
211

Length-Weight RelationsbiR

Greenland turbot length-weight relationships for the

Aleutian Islands area are presented below:

Weight (g) (1980) = . 0007 x Length (em) &009

Weight (g) (1983) = . 0012 x Length(cm) 493

Weight (g) (1986) = . 0004 x Length(cm) 722

These relationships were very similar for all 3 years;

however, the weight for a given length was slightly lighter

during the 1980 survey (Fig. 134).

1980 N. 113

SEXES COMBINED

-+- 1983 N. 180 -4E- 1986 N. 496

WEIGHT (g)

12000

9000

,,,

6000 ----------_._-_._..__._.__.._..

_._

3000 ---'------------____".m"""

.,,

'-------"'_--_.m

40 50 

LENGTH (em)

Figure 134. Length-weight relationships for Greenland turbot in

the Aleutian Islands area during the U. -Japan 1980,

1983 , and 1986 groundfish surveys.
212

Rougheye Rockf ish

Distribution and Abundance

Rougheye rockfish Sebastes aleutianus ) were found

throughout the Aleutian Islands area and the Southern Bering Sea

in all depth intervals , but were most prevalent in the 301-500 

depth interval (Figs. 135-136). During 1980 and 1983 , no highdensity concentrations of rougheye rockfish were encountered, but

medium-densities were found in waters of both the eastern and

western Aleutian Islands. In the eastern areas medium-densities

were found north of the Islands of Four Mountains , in Seguam Pass , south of Atka Island , northwest and south of Adak Island

and northwest of the Delarof Islands.

In the western areas , medium-density concentrations were

found near Buldir Island and on Tahoma and Buldir Reefs. In

1986 , several high-density concentrations were defined in both

the eastern and western portions of the Aleutian Islands: north

of Amlia Island , south of Atka Island , south of Kiska Island , on

Tahoma Reef, and south of Buldir Island.

The biomass estimates for rougheye rockfish followed the

same pattern as northern rockfish; the estimates were similar in

1980 and 1983, but there was a large increase in 1986. The

biomass estimate went from 19 000 t in 1980 to 22 000 t in 1983,

and increased 252% to 55 000 t in 1986. The population went from

23. 3 million in 1980 to 20. 9 million in 1983 and 47. 3 million in 1986. (Table 63, Fig. 137).

In 1983 the biomass estimate increased moderately in the

Southwest, Northeast , and Bowers Ridge areas and decreased 50% in

the Southeast and 41% in the Northwest areas. In 1986 , there

were large increases in biomass in several areas. The estimate

for the Southwest area increased by 733%, the Northwest area

increased by 217 %, and the Southeast area increased by 205%. A

moderate decrease of 27% occurred in the Northeast area and the

estimate for Bowers Ridge decreased by 21%.

In the Southern Bering Sea area , biomass increased from

900 t in 1980 to 2, 800 t in 1983 and 4, 100 t in 1986 (Fig. 138). Population went from 0. 9 million in 1980 to 2. 8 million in 1983

to 4. 0 million in 1986.

Mean population lengths and weights for rougheye rockfish

showed some irregularities (Table 64 , Figs. 139-140). In the

Aleutian Islands area the largest mean length occurred during the

1980 survey and the largest mean weight in the 1983 survey. 

the Southern Bering Sea area the largest mean length occurred

during the 1986 survey and the largest mean weight during the

1980 survey.
1986

CATCH IN KG/KHNO CATCH 

I -I .000 

001-10. 000

10. OoO~

PETREL BANK

~STALEHATE BANK Q~ATTU 

p

... 

# 

. . 

AGATTU 1.

PETREL BANK

~STALEHATE BANK ~I'

1983

CATCH IN KG/KHNO CATCH 

, -I .000 

001-10. 000

10. 000~

....

AHCHITK~ 1.

1980

CATCH IN KG/KH

NO CATCH 1 - I . 000 

001-10. 000

10. OOO~

PETREL BANK

~STALEHATE BANK

Figure 135. 'Distribution and relative abundance of rougheye rockfish in the Aleutian

Islands area during the U. -Japan 1980 , 1983 , and 1986 groundfish surveys.
214

.....

1986

CA TCH IN KG/KM NO CATCH I -I . 000 

001-10. 000

I O. OOO~

.....

1983

CA TCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000

I 0 . OOO~

.....

1980

CA TCH IN KG/KM

NO CATCH I - I . 000 

001-10. 000

I a . OOO~

Figure 136.

1986

CA TCH IN KG/KM

NO CATCH 

I - I .000 

001-10. 000 10. OOO~ 

1. 000

1983

CA TCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 .

I O. OOO=- .

BOWERS

BANK

1980

CA TCH IN KG/KM

NO CATCH I - I . 000 

001-10. 000 I O. OOO~ 

Distribution and relative abundance of rougheye

rockfish in the Southern Bering Sea and Bowers Ridge

areas during the U. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundf ish surveys.
215

Table 63. Estimates of biomass , biomass sampling error, and

population for rougheye rockfish based on the U. s. Japan 1980, 1983 , and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleutian

Islands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

5.01-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1980

450

038

525

155

168

256

598

991

361

785

167

297

362

570

132

361

188

188

837

017

666

355

875

Biomass (t)

1983

258

825

551

139

852

133

541

342

016

287

891

1 , 277

191

363

305

9.02

895

940

874

922

673

911

131

182

987

986

768

829

1986

955

283

144

575

1 . 243

973

231

316

320

294

836

766

292

047

. 120

473

1980

Sampl ing Error 

(%)

37.

368.

33.

1.00.

113

2.01

314 1 270.

578

0.06

41 . 732

948

359

256

761

000

095

1983

44.

140.

100.

192.

944.

0 1 116.

102.4 75.

52. 1 560.

195.4 146.

71. 0 149.

162.8 66.

No sampling was conducted in this area-depth interval.

375.

186.

142.

430.

142.

98.

157.

137.

121.

712.

1986 1980

Population (1 000s)

846.

641.

964.

124.

578.

67.

254.

4717 .

4972.

593.

779.

73. 373.

83.

562.

807.

946.

317.

78.

78.

409.

297.

487.

124.

319.

15.

847.

863.

1983

73.

635.

183.

254.

100.

244.

193.

144.

364.

702.

13.

132.

446.

633.

226.

252.

427.

1058.

33.

871.

831.9

23.

857.

87.

215.

034.

430.

134.

901.

59.

315.

419.

11.

805.

1986

112.

863.

323.

519.

69.

888.

16.

401.

525.

942.

348.

570.

047.

612.

579.

289.

058.

118.

13.

479.

756.

699.

456.

112.

517.

110.

910.

695.

346.

373.

525.

032.

42.

974.
216

THOUSANDS MILLIONS

- 45

ALEUTIAN ISLANDS

45 ..-------....-----------

 .. 

BIOMASS (t) POPULATION 

15 - -. 15

1983

YEARS

Figure 137. Estimated biomass and population of rougheye rockfish

in the Aleutian Islands area during the U. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.

1980 1981 1982 1984 1985 1986

THOUSANDS MILLIONS

.

SOUTHERN -BERING SEA

.. 

BIOMASS (t) POPULATION --

- 1.

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 138. Estimated biomass and population of rougheye rockfish

in the Southern Bering Sea area during the U. S. -Japan

1980 , 1983, and 1986 Aleutian Islands groundfish

surveys.
217

Table 64. Estimates mean catch per unit effort length, and weight for rougheye rockfish based the u. S. -Japan

1980, 1983, and 1986 Aleutian Islands groundf ish

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 26. 25. 37.

101-200 68. 345 . 911. 35. 37. 31.8

201-300 452. 359. 123. 38. 34. 31.

301-500 447. 455. 548. 43. 41.6 35. 1.21 1.35

501-900 22. 19. 13. 41. 36.

1-900 147. 218. 544. 41. 37. 33.

Southeast 1-100

101-200 27. 40. 35.

201-300 81. 804. 393. 36. 36. 42. 1.01

301-500 789. 427. 221. 43. 40. 28.

501-900 22.

1-900 714. 287. 547. 1 42. 37. 28.

Northwest 1-100

101-200 33. 120. 37. 32.

201-300 337. 268. 299. 31. 33. 28.

301-500 805 . 402. 583. 42. 42. 37. 1.41

501-900 186. 42. 1.36

1-900 195 . 1 100. 1 216. 39. 38. 35. 1.04

Northeast 1-100

101-200 76. 48. 74. 39. 35. 29.

201-300 148. 148. 247. 38. 38. 29. 1.01

301-500 331. 419. 950. 44. 44. 41.

501-900 22. 40. 1.27

1-900 299. 519. 365. 40. 43. 38. 1.31

Bowers 101-200

Ridge 201-300 370. 911. 43. 43.

301-500 117. 26. 750. 46. 44. 42. 1.80

501-900

101-900 19. 286. 225 . 45. 43. 42.

Aleuti an 1-100 11. 37.

Islands 101-200 53. 160. 395 . 1 35. 36. 30.

Total 201-300 198. 678. 589. 37. 37. 31.

301-500 170. 879. 057. 43. 43. 35.

501-900 13. 34. 42. 41.3 36. 1.35 1.36

1-900 263. 288. 702. 41.3 40. 33. 1.05

Southern 1-100

Bering 101-200 18. 78. 33. 33.

Sea 201-300 22. 984. 759. 30. 36.

Total 301-500 686. 389. 357. 44. 43. 40. 1.48

501-900 34. 1.39 1.80

1-900 72. 223. 323. 38. 39. 40. 1.02

No sampl ing was conducted in this area-depth interval.
218

ALEUTIAN ISLANDS 

.. MEAN LENGTH MEAN WEIGHT

-.--- 1.

1983

YEARS

Figure 139. Mean length and weight of rougheye rockfish in the

Aleutian Islands area during the U. S . -Japan 1980

1983 , and 1986 groundfish surveys.

1980 1981 . 1982 1984 1985 1986

60 

SOUTHERN BERING SEA

.. MEAN WEIGHT MEAN LENGTH

.

1980 1981 1982 1983

YEARS

1984 1985 1986

Figure 140. Mean length and weight of rougheye rockfish in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
219

size Composition

size composition data indicate that there was a decline in

the proportion of smaller rougheye rockfish taken during the

three survey years. In 1980 there was a bimodal size curve with

the principle mode ranging from 21 to 26 em and the secondary

mode from 27 to 42 em (Fig. 141). Both modes consisted of nearly

equal proportions of males and females. In 1983 the size range

shifted to larger size categories (24-49 em) and the curve was

skewed heavily toward larger fish (36-47 em), peaking at 42-43 em. In 1986 the size range shifted further toward larger

size categories (30-53 em), and again the curve was heavily

skewed toward the larger fish, peaking at 45 em.

within areas , major differences in the size composition

occurred most dramatically during the 1980 survey (Figs.

142-145) . In the Southwest area the size range extended from 21

to 42 em with most specimens occurring in the 27-41 em size

range , with peaks at 33-35 em. In the Southeast area, most

individuals were in the 21-31 em size range. In the Northwest

area , sizes ranged from 19 to 48 em with the majority of the fish

in the 31-48 em size range. Four modes peaked at 22, 26, 35, and

42 em with each successively larger mode being stronger. The

size composition curve in the Northeast area is similar to the

curve in the Southwest area ranging from 21 to 42 em, with most

individuals in the 27-41 em size range. During 1983 the Southwest area was characterized by equal

numbers of fish in most size categories from 30 to 45 em. In the

Southeast area , sizes ranged from 16 to 56 em , with most fish 

the 31-50 em size range. Fish in the Northwest area ranged from

25 to 53 em with two modes evident , 28-34 em and 37-44 em. The

Northeast size composition curve was heavily skewed toward fish

in the 38 -4 9 em range.

In 1986 , greater similarity was noted for the size

compositions of all areas , most of which had unimodal curves

skewed toward larger fish peaking around 43-45 em. The Southwest

area which dominated the 1986 size composition was bimodal and

showed a strong incoming group of fish , 32-37 em.

In the Southern Bering Sea area in 1980, the size range

extended from 31 to 47 em with a single mode from 35 to 44 em,

peaking at 40-41 em (Fig. 146). In 1983, a much larger size

range was present extending from 20 to 56 em. The curve was

bimodal with the principle mode ranging from 36 to 50 em, peaking

at 40 em , and the secondary mode ranging from 27 to 34 em

peaking at 31 em. There were nearly equal numbers of males and females. In 1986 the size ranged from 17 to 58 em. The curve

was trimodal with a primary mode from 37 to 52 em , and secondary

modes from 21 to 29 em and from 30 to 36 em. Males were dominant

in the secondary modes but males and females were nearly equal in

the principle mode.
220

1980 1980

LENGTH (CM) NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

6 h.___h__.__..---

NUMBER (MILLIONS'

30 

LENGTH (CM)

fiO

1983 1983

LENGTH ICM' NUMBER (MILLIONS)

8-.------.-------- SEXES COMBINED 

................

MALE FEMALE

. .

NUMBER (MIWONS) 30 

LENGTH (CM)

fiO

1986 1986

LENGTH lCU)

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

4.6

6.-."

NUMBER (MIWONS,

30 

LENGTH (CM)

Figure 141. Size composition of rough eye rockfish in the Aleutian

Islands area during the U. S. -Japan 1980, 1983 , and

1986 groundfish surveys.
1980

LENGTH fCM'

NUMBER (MILLIONS'

, 

LENGTH feM'

LENGTH fCM'

. 

221

1980

NUMBER (MILLIONS)

SEXES COMBINED 

,

1.2 .--

..

30 

LENGTH (CM)

1983 1983

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED

.., . _._,

1.2

0 0.

NUMBER (MILLIONS'

1.8 30 

LENGTH (CM)

1986 1986

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

,

1.2 --

30 

LENGTH (CM)

~ 0.

NUMBER (MILLIONS'

1.8

Figure 142. Size composition of rougheye rockfish in the

Southwest area of the Aleutian Islands during the

u. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
222

1980 1980

LENGTH (CM'

NUMBER (THOUSANDS)

1200

800 

......................

SEXES COMBINED 

..._..:............

MALE FEMALE

800 

..................................

300 -"'----

..

316 126 126 260

NUMBER (THOUSANDS'

316

20 30 

LENGTH (CM)

1983 1983

LENGTH CCM'

NUMBER (THOUSANDS)

1200

900 

._

SEXES COMBINED 

..._.__...............

800

............... .

175 250 125 125 210 3715

300 -"-----'---------

,.

20 30 

LENGTH (CM)

fiO

NUMBER (THOUSANDS'

1986 1986

LENGTH (CM' 10 MALE FEMALE

NUMBER (THOUSANDS)

1200

800

SEXES COMBINED 

__.._..........

800

375 250 126 126 260

NUMBER (THOUSANDS'

376

300,,--

20 30 

LENGTH (CM)

Figure 143. Size composition of rougheye rockfish in the

Southeast area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
1980

LENGTH (CM)

MALE FEMALE

fiO

120 40 

NUMBER (THOUSANDS'

-- 120

1983

LENGTH (eM)

MALE FEMALE

. 30

120 40 40 

NUMBER (THOUSANDS)

1986

LENGTH (CM'

MALE FEMALE

120 40 

NUMBER (THOUSANDS'

223

1980

NUMBER (MILLIONS)

240

SEXES COMBINED 

_0----____----------

180

20 . ~O 

LENGTH (CM)

1983

NUMBER (MILLIONS)

240

SEXES COMBINED 

_._._

180

120 20 30 

LENGTH (CM)

1986

NUMBER (MILLIONS)

240 SEXES COMBINED 

180

120 20 30 

LENGTH (CM)

Figure 144. Size composition of rougheye rockfish in the

Northwest area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
224

1980 1980

LENGTH (CM'

NUMBER (THOUSANDS)

MALE FEMALE I 1050 

SEXES COMBINED 

700.

360...'--

800 400 200 200

NUMBER (THOUSANDS'

400 600 20 30 

LENGTH (CM)

1983 1983

LENGTH (CMf

NUMBER (THOUSANDS)

MALE FEMALE

800 400 200 200 400

NUMBER (THOUSANDS'

1060,,-.

700

360 

...

800

.....

SEXES COMBINED 

fiO

20 30 

LENGTH (CM)

1986 1986

lENGTH (CM.

NUMBER (THOUSANDS)

MALE FEMALE

1050 u.-.

SEXES COMBINED 

..

700 

...

600 400

Figure 145.

350-

200 200 400 800 10 20 30 NUMBER (THOUSANDS' LENGTH (CM)

size composition of rougheye rockfish in the

Northeast area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
1980

LENGTH (CM'

MALE FEMALE

fiO

160 100 fiO 60 100

NUMBER (THOUSANDS'

1983

LENGTH (CM'

MALE FEMALE

160 100 60 60 ,

NUMBER mtOUSANOS'

100

1986

LENGTH (CM'

~FE"'ALE i

160 100 60 fiO. 100

NUMBER (THOUSANDS'

160 200

225

1980

NUMBER (THOUSANDS)

300 - --.l

SEXES COMBINED 

----------_u226 _un -------_u_-------- u__u_----_u-u--..---_u..--.

160 Un

...

150

76 

20 30 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

300

SEXES COMBINED 

226 . .---_u..---u---

160

76 u

160 20 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

300

SEXES COMBINED 

226

160 -

76--

20 30 

LENGTH (CM)

Figure 146. Size composition of rough eye rockfish in the Southern

Bering Sea during the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.
226

Age determination criteria and techniques for ageing

rougheye rockfish were not established at the AFSC at the time of

these surveys, therefore , age data for this species are not available. 

Length-Weight Relationship

Length-weight data were collected for rougheye rockfish

during all three surveys; however , the sample sizes during 1980

and 1983 were quite small. These data show good agreement

between the weight at length for smaller fish at sizes less 31 em. In 1983 the fish were slightly heavier than in 1986

in 1980 they were slightly lighter (Fig. 147). Analysis of

data provided yearly estimates of the constants a and 

Weight (g) (1980) = . 0071 x Length(cm) &l~

Weight (g) (1983) = . 0027 x Length(cm) 49o

Weight (g) (1986) = . 0056 x Length (em) S.272

than

and

these

1980 N. 36

SEXES COMBINED

+-- 1983 N. 

.

1986 N. 432

WEIGHT (g)

3500

7 00 

........

2800 ---'---"---------'---------.-"-.'--".

....... ,... .. ... ..... ... ............ ........

2 1 00 --------..----.---

. ........... ...........

1400 --"------

.......

20 30 

LENGTH (em)

Figure 147. Length-weight relationships for rougheye rockfish in

the Aleutian Islands area during the U. s. -Japan 1980,

1983 , and 1986 groundfish surveys.
227

Pacific Halibut

Distribution and Abundance

Pacific halibut Hippoglossus stenolepis ) were found in most

depth zones from Attu Island to Unimak Pass including Bowers

Ridge (Figs. 148-149). High-density concentrations were not

found during the 1980 and 1983 surveys. In 1980 , intermediate

densities were found near Buldir Island in the western Aleutians,

on both sides of the eastern Aleutian Islands chain, and near the

Islands of Four Mountains , Umnak Island, and Unimak Pass in the

Southern Bering Sea area. In 1983 the number of intermediate

density concentrations increased substantially along both sides

of the eastern Aleutian Islands from the Island of Four Mountains

to Adak Island. In the waters around the western Aleutian Islands , medium densities were found on both sides of the chain

from Amchi tka to the Buldir Islands. In the Southern Bering Sea

area , medium densities were found north of the Islands of Four

Mountains and north of Umnak and Unalaska Islands. In 1986, one

high-density concentration was found on Bowers Ridge.

Intermediate density concentrations of Pacific halibut increased

slightly in the Southern Bering Sea and on both sides of the

Aleutian Islands chain from Seguam Pass to Adak Islands in the

eastern Aleutian Islands , and all the way to Attu Island in the western Aleutian Islands.

Throughout the three surveys there was a study increase in

the biomass estimates of Pacific halibut in the Aleutian Islands

area (Table 65, Fig. 150). The Pacific halibut biomass estimate

increased from 9 900 t in 1980 to 13, 800 t in 1983, and then

increased nearly three-fold to 39, 000 t in 1986. The population increased from 1. 5 million fish in 1980 to 1. 6 million in 1983 and 4. 8 million in 1986. The most significant increase occurred

in the Bowers Ridge area which increased from no catch to 300 t

in 1983 and then 16 000 t in 1986. The remaining portion of the

1983-1986 increase was fairly evenly spread among the remaining

areas.

In the Southern Bering Sea area the biomass estimate of

Pacific halibut increased from 2, 700 t in 1980 to 7 300 t in 1983

and then decreased slightly to 6 200 t in 1986 (Fig. 151).

Population abundance stayed at approximately 1. 1 million fish in

1980 and 1983 and increased slightly to 1. 8 million in 1986.

For both the Aleutian Islands area and Southern Bering Sea

area the largest mean length and weight occurred during the 1983

survey although abnormalities occurred for other years (Table 66 Figs. 152-153).
1986

CATCH IN KG/KtNO CATCH 1 -1 . 000 

001-10. 000

10. OOO~

PETREl BANK

~STAl EHATE BANK (de

000 M

..

1983

CATCH IN KG/KMNO CATCH 1 -1 . 000 

001-10. 000

10. OOO~

PETREl BANK

~STAlEHATE BANK

l\)l\)

AMCHrTKA I.

1980

CA TCH IN KG/KH

NO CATCH 1 - 1 . 000 

001-10. 000

10. OOO~

PETREl BANK

~STAlEHATE BANK

AHCHI TKA

Figure 148. Distribution and relative abundance of Pacific halibut in the Aleutian Islands

area during the U. S. -Japan 1980 , 1983 and 1986 groundf ish surveys.

.,;
229

.....

1986

CATCH IN KG/KM

NO CATCH 

1 - 1 .000 

001-10. 000

10. 000=-

I ~ );

.....

1983

CA TCH IN KG/KM

NO CATCH 

1 - 1 . 000 

001-10. 000

10. OOO=-

.....

1980

CA T CH IN KG/KM

NO CATCH 

1 -1 .000 

1 . 001 -1 0. 000

10. OOO=-

Figure 149.

BOWERS

BANK

1986

CA TCH IN KG/KM

NO CATCH 

1-1 .000 

001-10. 000 .

1 O. OOO=- 

(:)

1983

CATCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000

10. 000::. .

(:)

BOWERS

BANK

1980

CATCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000

10. 000=- .

Distribution and relative abundance of Pacific

halibut in the Southern Bering Sea and Bowers Ridge

areas during the U. S. -Japan 1980, 1983 , and 1986

Aleutian Islands groundfish surveys.
230

Table 65. Estimates biomass biomass sampling error, and population for Pacific halibut based on the U. S . -Japan

1980 1983 and 1986 Aleutian Islands groundf ish

surveys.

Biomass (t) Sampl i ng Error (%) Population (1 000s)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 326 489 55. 194.

101-200 331 475 913 101. 108. 513.

201-300 103 362 11. 116.

301-500 234 871 23. 112.

501-900 279 41.

1-900 403 138 914 73. 108. 43. 109. 197. 977.

Southeast 1-100 415 217 44. 302.

101-200 760 193 075 231. 236. 740.

201-300 151 1 . 845 108 91. 92. 107.

301-500 1 . 875 663 487 66. 64. 80.

501-900

1-900 786 116 887 145. 45. 56. 388. 438. 230.

Northwest 1-100 360 857 130. 218.

101-200 377 . 185 431 278. 174. 201.6

201-300 321 257 510 43. 30. 41.

301-500 385 115 526 42. 125.

501-900

1-900 083 917 324 88. 383. 64. 364. 339. 587.

Northeast 1-100 438 1 , 323 851 370. 202. 685.

101-200 978 784 875 194. 344. 453.

201-300 708 622 592 30. 34. 58.

301-500 457 597 839 18. 21. 80.

501-900 050 42.

1-900 581 383 207 53. 31. 80. 613. 603. 320.

Bowers 101-200

Ridge 201-300 520 663.

301-500 259

510-900

101-900 272 524 264. 414. 668.

Aleuti an 1-100 438 424 414 287. 90. 370. 432. 400.

Islands 101-200 446 650 298 70. 31. 20. 805. 865. 912.

Total 201-300 231 827 092 104. 75. 355. 171. 168. 988.

301-500 738 868 723 288. . 72. 71. 128. 115. 399.

501-900 329 236. 125. 84.

1-900 853 13. 826 856 67. 27. 167. 476. 583. 784.

Southern 1-100 582 697 261 693. 585 . 258.

Bering 101-200 1 . 905 235 711 330. 519. 532.

Sea 201-300 183 194 204 16. 24.

ota l 301-500 11. 18.

501-900 128 11.

1-900 701 304 218 76. 59. 36. 051.3 130. 834.

No sampling was conducted in this area-depth interval.
THOUSANDS

231

MILLIONS

ALEUTIAN ISLANDS 

.. 

BIOMSS et) POPULATION

1980 1981 1982 ' 1983 1984

YEARS

1985 1986

Figure 150. Estimated biomass and population of Pacific halibut

in the Aleutian Islands area during the U. s. -Japan

1980 , 1983 , and 1986 groundfish surveys.

THOUSANDS MILLIONS

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

1980 1981 1982 1983 1984

YEARS

- 1

1985 1986

Figure 151. Estimated biomass and population of Pacific halibut

in the Southern Bering Sea area during the U. S. -Japan

1980 , 1983, and 1986 Aleutian Islands groundfish

surveys.
232

Table 66. Estimates mean catch per unit effort length, and weight for Pacific halibut based the u. S. -Japan

1980, 1983, and 1986 Aleutian Islands groundf ish

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest . 1-100 110. 129. 50. 66.

101-200 50. 72. 293. 56. 55. 63.

201-300 22. 45. 157. 60. 86. 87. 10.

301-500 68. 255. 73. 89. 91. 12.

501-900 39. 80.

1-900 18. 51. 170. 58. 64. 65.

Southeast 1-100 263. 460. 93.

101-200 538. 670. 245. 70. 81. 80.

201-300 364. 584. 350. 86. 100. 92. 12. 20. 11.

301-500 688. 211. 473. 103. 91. 112. 28. 10. 16.

501-900

1- 900 427. 366. 524. 72. 87. 88. 12. 11. 82

Northwest 1-100 576. 363. 61. 88. 10.

101-200 749. 451 . 544. 79. 73. 67.

201-300 300. 240. 476. 76. 81. 66. 11.

301-500 173. 52. 688. 94. 77. 27. 12.

501-900

1-900 187. 228. 338. 76. 80. 68.

Northeast 1-100 197. 134. 965. 55. 67. 43.

101-200 250. 456. 736. 77. 66. 71.

201-300 290. 254. 242. 84. 98. 111. 24. 18.

301-500 133. 174. 255. 91. 107. 126. 23. 29. 10.

501-900 169. 118. 131. 32. 21.

1-900 144. 255. 406. 68. 69. 58.

Bowers 101-200 42. 12. 85.

Ridge 201-300 710. 117. 23.

301-500 162. 185. 83.

501-900

101-900 26. 513. 117. 149. 56. 23.

Aleuti an 1-100 73. 425 . 413. 57. 76. 43. 1.18

Islands 101-200 285. 339. 618. 68. 70. 71.

ota l 201-300 219. 277. 776. 103. 95. 88. 12. 17. 18.

301-500 204. 135. 346. 90. 95. 103. 21. 16. 11 .

501-900 48. 100. 131. 32. 14.

1-900 137. 181. 493. 74. 76. 69.

Southern 1-100 120. 767. 676. 46. 62. 44.

Bering 101-200 582. 988. 828. 64. 70. 70.

Sea 201-300 182. 193. 203. 85. 101. 79. 11. 22.

Total 301-500 24. 39. 33. 50. 65. 10.

501-900 56. 11.

1-900 213. 577. 491 . 53. 65. 54.

No sampl ing was conducted in this area-depth interval.
120

233

...__--0--_"_- 1 2

100

ALEUTIAN ISLANDS

.. MEAN LENGTH MEAN WEIGHT 

1980 1981 1982 ' 1983 1984

YEARS

1985 1986

Figure 152. Mean length and weight of Pacific halibut in the

Aleutian Islands area during the U. -Japan 1980 1983, and 1986 groundfish surveys.

100

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

40 -

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 153. Mean length and weight of Pacific halibut in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
234

size Composition

size composition curves for the Aleutian Islands area were

quite similar for 1980 and 1983, however, there was a slight

increase in the number of fish in the 60-99 em size range in 1983

and fewer fish less than 50 em (Fig. 154). In 1986 there was a

strong increase in the number of fish less than 40 em in length,

and a substantial increase in the number of fish from 41 to

160 em.

In the Southern Bering Sea area , the size composition curves

lacked similarity throughout all three surveys (Fig. 155). 

1980 , fish measured from 20 to 95 em with a good showing of small f ish from 30 to 44 em , peaking near 36 em. In 1983 there was an

increase in the number of fish between 100 and 140 em and the

pr imary mode extended from 45 to 70 em and peaked around 52 - 5 4

em. By 1986 , the primary mode in 1983 had shifted to 52-69 em

and peaked near 62 em and there was a strong showing of incoming

small fish 25-45 em in length.

No age data is available for Pacific halibut during these

surveys.
1980

NUMBER (THOUSANDS)

1150 .___0____-

--1 SEXES COMBINED O_._----

100 ------.."".__0-0__.___----

.....

30 40 fiO 

, LENGTH (CM)

1983

NUMBER (THOUSANDS)

1150-- SEXES COMBINED ------.____0_0_.____-.

100 0__-

60 

..

30 40 150 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

160 ----_.--------- SEXES COMBINED .."----------_0__0

100 

... 

30 40 50 80 0 70

LENGTH (CM)

235

1980

NUMBER (THOUSANDS)

SEXES COMBINED ---------------o1---..

...........

6 - __00______-_-_--_0_..

110 120 130 140 160 180

LENGTH (CM)

170 180 190

1983

NUMBER (THOUSANDS)

SEXES COMBINED 

0.15

._

100 110 120 130 140 160 160 170 180 180

LENGTH (CM)

1986

NUMBER (THOUSANDS)

--f SEXES COMBINED 

"0_---

110 120 130 140 160 180 170 180 190

LENGTH (CM)

Figure 154. Size composition of Pacif ic halibut in the Aleutian

Islands area during the U. -Japan 1980, 1983 , and

1986 groundfish surveys.
1980

NUMBER (THOUSANDS)

160 -

. 

- ."____h_"__.""-O".----_O..

SEXES COMIBNED 

120 ."-___0-_____.-.......--.-.-....--...--..---..--.

._..

30 40 60 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

160 h-h-_.____o_- ..--...-.-. --_0.- 0_0 

....

SEXES COMB~NED 

120 

...... 

.____"-0____.___0

. ------_._--_-0__"'0.___._.".----"_"-._0_"_..__0"."'_.

30 40 60 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

160 -

.......

---.--_0_.__...-..--...-.----

SEXES COMIBNED 

120

30 40 60 80 0 70

LENGTH (CM)

236

1980

NUMBER (THOUSANDS)

160 

.

r---.-.".-.....o_-..--..---...--.-------_

......

-__--0-....

SEXES COMIBNED I

120 ---"--"-----------.----..----.-"---.-...."'.---.0. -.__.0.--_-__0-----.---0"0.--.-.0-."-

............ .. ...

80 -----'-------..-_......_0_._.____-0____.------.-...0.--.-

.......

-..---...--___-_.0___"__-------.-.- 

... 

100

. I 

110 120 130 140 160 160

LENGTH (CM)

170 180 190

1983 180 NUMBER (THOUSANDS)

.. _.. 

-m. -- -... - __00_.._.0_._"._-0".--._."'..".".-

SEXES COMBINED 

120 -----.----------"-.O-------"O_-"'---"---_."_._h."_----_--'"--.---0-._-.0-..

....

80 ---.--- -------._____0______-- -_. - .0.. 

. 

.--...---.-- _0_.-

-"----.------"'.--_"0.0_"

110 120 130 140 160 180

LENGTH (CM)

170 180 190

1986

NUMBER (THOUSANDS)

180 

..

.-".-_-_-_0-

_.......

.____0-----.-_--------. -.

..... .... . . ....

120 SEXES COMIBNED I

_0___-

-_____0

1, . 7711111110 - 100 110 120 130 140 160 160

LENGTH (CM)

170 180 190

Figure 155. Size composition of Pacific halibut in the Southern

Bering Sea area during the U. S. -Japan 1980 , 1983 , and

1986 Aleutian Islands groundfish surveys.
237

Shortraker Rockfish

Distribution and Abundance

Shortraker rockfish Sebastes Borealis ) were found in a

discontinuous distribution throughout the Aleutian Islands area

and Southern Bering Sea primarily at depths greater than 300 m (Figs. 156-157). In the eastern Aleutians they occurred on the

north side of the chain from Seguam to Great si tkin Islands and

the Delarof Islands during all years. Shortraker rockfish were

found on the east side of Petrel bank in 1983 but there were

higher concentrations there in 1986. On the south side of the

Aleutian Islands chain they were found from Seguam to Great

sitkin Islands only during 1983 and 1986. In the western

Aleutian Islands areas , concentrations of higher abundance varied

from year to year and did not show a definitive pattern. In the

Southern Bering Sea area, they occurred in higher densities on Unalaska Island. the outer continental shelf off of Unalaska and Makushin Bays on

Biomass estimates of shortraker rockfish in the Aleutian

Islands area nearly doubled , from 12, 800 t in 1980 to 24 500 t in

1983 , and then stayed about the same at 24, 000 t in 1986 (Table

, Fig. 158). Population estimates increased from 5. 9 million

fish in 1980 to 15. 8 million in 1983 and 17. 6 million in 1986.

Increases occurred in all areas except the Northwest where the

biomass decreased 41%. During 1980 and 1983 over 80% of the

biomass was found in the 301-500 m depth interval , but in 1986,

50% occurred at 210-300 m and 48% at 301-500 

In the Southern Bering Sea area, the biomass estimates increased from 1, 000 t in 1980 to 13, 000 t in 1983, and then

decreased to 8 000 t in 1986. Population decreased from

3 million fish in 1983 , to 2. 2 million fish in 1968 (Fig. 159).

During all surveys the majority of the biomass was found in the

301-500 m depth interval.

In the Aleutian Islands area, the largest mean length and

the largest mean weight occurred during the 1986 and the 1980

surveys , respectively. In the Southern Bering Sea the largest

mean length and weight occurred in 1983 (Table 68, Figs.

160-161) .

Size Composition

In 1980 the size composition for shortraker rockfish in the

Aleutian Islands area was very non-descriptive (i. e., no size

group was dominant and no distinctive modes were visible) (Fig. 162). During 1983 , the size composition curve was bimodal with

the largest portion of the individuals in the 28-48 em size range

and a considerably smaller mode in the 52-62 em range. In 1986

the size composition curve was unimodal dominated by the 30-54 em

size range, and skewed slightly towards larger fish. The peak
PETREL BANK

1986CATCH IN KG/KM NO CATCH 1 - 1 . 000 

001-10. 000

10. 000' AMCHITKA I.

.....

PETREL BANK

1983

CATCH IN KG/KI1NO CATCH I - 1 . 000 

001-10. 000

10. 000'

1980

CATCH IN KG/KI1NO CATCH I - 1 . 000 

001-10. 000

10. 000'

PETREL BANK

~ST AlE~ TE B'NK

Figure 156. Distribution and relative abundance of shortraker rockfish in the Aleutian

Islands area during the -Japan 1980 , 1983 , and 1986 groundfish surveys.

;

,:
239

1986

CA TCH 1 N KG/KM

NO CATCH 1 - 1 . 000 

001-10, 000

10, 000:)

1983

CA TCH 1 N KG/KM

NO CATCH 

1 -1 , 000 

001-10, 000

10, 000:)

1980

CA TCH 1 N KG/KM

NO CATCH 

I - 1 , 000 

001-10, 000

10, 000:)

Figure 157.

1986

CA TCH IN KG/KM

NO CATCH 1 - 1 . 000 

001-10. 000 10, 000:) 

ULM PLATEAU

1983

CATCH IN KG/KM

NO CATCH 

1 -1 , 000 

001-10. 000

10, OOO~ 

ULM PLATEAU

1980

CA TCH 1 N KG/KM

NO CATCH 

1 -1 ,000 

001-10, 000 1 0, 000:) 4t!

BOWERS

BANK

000

IX)

BOWERS

BANK

Distribution and relative abundance of shortraker

rockfish in the Southern Bering Sea and Bowers Ridge

areas during the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.
240

Table 67. Estimates of biomass , biomass sampling error, and

population for shortraker rockfish based on the U.

Japan 1980, 1983, and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleuti an

Islands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1- 900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1- 900

1-100

101-200

201-300

301-500

501-900

1-900

1980

111

698

664

502

273

928

291

140

110

616

866

874

392

349

636

789

672

246

813

12. 797

294

619

1 , 020

Biomass (t)

1983

306

211

661

599

168

661

457

957

286

273

806

472

293

114

649

775

819

886

642

459

694

051

1 . 335

080

1986

979

655

697

275

651

963

889

067

814

890

757

037

827

527

155

682

361

981

624

23. 985

531

821

245

604

1980

57.

248.

122.

75.

480.

Sampl ing Error 

(%)

1983

71.7

90.

183.

339.

170.

0 1 215.

120.8 159.

114.5 170.

50.9 163.

87.9 54.

41.2 139.

185.

No sampl ing was conducted in this area-depth interval.

Fish not counted - Population not estimated.

308.

1986

499.

29.

96.

45.

158.

173.

99.

30.

263.

39.

188.

46.

39.

638.

200. 1

924.

124.

633.

758.

54.

927.

287.

268.

13.

24.

566.

99.

703.

21.

212.

28.

262.

59.

264.

978.

614.

917.

Populati on (1, 000s)

1980 1983

77.

28.

235.

935.

285.

11.

219.

151.

743.

126.

860.

153.

019.

880.

245 .

132.

24.

214.

245.

77.

21.

284.

341.6

084.

808.

81.

614.

587.

283.

1986

15.

18.

687.

703.

424.

133.

718.

514.

365.

505.

719.

226.

15.

483.

878.

377 .

. 185.

63.

248.

15.

168.

579.

879.

642.

1.1

52.

041.

84.

179.
241

THOUSANDS MILLIONS

30 

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION 

1980 1981 1982 1983 1984

YEAR S

1985 1986

Figure 158. Estimated biomass and population of shortraker

rockfish in the Aleutian Islands area during the

u. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.

1983 1984

YEARS

Figure 159. Estimated biomass and population of shortraker

rockfish in the Southern Bering Sea area during the

u. S. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.

THOUSANDS

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

1980 1981 1982

MILLIONS

1985 1988
242

Table 68. Estimates mean ca tch per unit effort length, and weight for shortraker rockf ish ba s ed the u. S. -Japan

1980 1983, and 1986 Aleutian Islands groundf ish

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 25. 17.

101-200 1.1 35. 1.08

201-300 48. 26. 19. 51. 48.

301-500 791. 849. 580. 54. 37. 43.

501-900 94. 172. 377. 35. 37. 38.

1-900 162. 345 . 0 204. 39. 36. 43. 1.38

Southeast 1-100

101-200

201-300 86. 189. 87. 44. 53. 62.

301-500 340. 009. 482. 41. 37. 41.

501-900 33. 233. 1 . 754. 1 38. 36.

1-900 115. 318. 657. 39. 38. 42. 1.08

Northwest 1-100

101-200

201-300 131. 28. 41.

301-500 403. 883. 481. 47. 50. 54.

501-900 137. 63. 626. 42. 41. 48.

1-900 348. 178. 304. 43. 48. 53.

Northeast 1-100

101-200

201-300 27. 13. 40.

301-500 837. 565. 839. 45. 58. 38.

501-900 66. 76. 167. 36. 42. 45. 1.21

1-900 186. 542. 215. 42. 57. 38. 1.61

Bowers 101-200

Ridge 201-300 65. 93. 67. 61.0

301-500 397. 405 . 953. 42. 54. 54.

501-900 10. 21. 51.

101-900 79. 75. 164. 42. 55. 54. 1.36

Aleuti an 1-100 17.

I s lands 101-200 35.

Total 201-300 66. 80. 35. 44. 54. 50.

301-500 765. 513. 877 . 43. 43. 44.

501-900 68. 95. 420. 38. 38. 44. 1.26 1.21

1-900 178. 320. 304. 40. 42. 44. 1.38

Southern 1-100 19.

Bering 101-200 O~O

Sea 201-300 293. 692. 529. 76. 10.

Total 301-500 486. 684. 360. 60. 54.

501-900 587. 1 107. 48.

1-900 80. 034. 601. 58. 54.

No sampl ing was conducted in this area-depth interval.

Fish not measured.

Fish not weighed.
Figure 160.

Figure 161.

60 

243

ALEUTIAN ISLANDS

.. MEAN LENGTH R1 MEAN WEIGHT

1980

80 

.... _. . . ...... .

----.--0 -...--

...... .......

0..--

.

_. -_-0'--0.._. - -- . .0"

___

1881 , 1982 1983 1984

YEARS

Mean length and weight of shortraker rockf ish in the

Aleutian Islands area during the U. -Japan 1980 1983, and 1986 groundfish surveys.

1985 1986

0__--- .--- 

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

_0"_.___'0- __0__.'0_"'____'_0___0'_--0.""-_. - ---'-. '0_._..-

40 -_0_____-""-'_0- '----0- - 

.0..

20 

___

_0 0._- 

_.

1983

YEARS

Mean length and weight of shortraker rockfish in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.

1880 1981 1982 1984

1985 1986
244

1980

LENGTH (CM'

NUMBER (MILLIONS)

1980

4---

0.8 

. 80 0 0.

NUMBER (MILLIONS'

1983

LENGTH (CM'

0.3

NUMBER (MilliONS'

1.2 -..----

1986

LENGTH (CM'

NUMBER (MIUIONS,

0.8--

. 0

SEXES COMBINED 

-___.__0_._"'___0"'__.

-_0--

___

-.. no. 

. . 

------- -h. .-_.

...__._._

m--____-O_----

30 40 

LENGTH (CM)

1983

SEXES COMBINED _._-_o_--_o__.o_---_.

_._._0_0__-

30 40 ISO

LENGTH (CM)

1986

SEXES COMBINED 

.............

30 40 

LENGTH (CM)

Figure 162. Size composition of shortraker rockfish in the

Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.
245

mode was shifted approximately 5 em larger than .in 1983, and

there was an increase in the number of fish in the 45-55 em

range, and a decrease in larger fish. During all three surveys

the stock appeared to be quite evenly split between males and

females.

There was considerable variation between the size

compos i tion curves in each of the areas dur ing the three survey

years (Figs. 163-166). In 1980 in the Southwest area the

majority of shortraker rockfish ranged from 30 to 50 em. There

was insufficient size data in the Southeast area to provide an

estimate of the size range for that year. In the Northwest area

the majority of the shortrakers were in the 47-61 em size range.

The Northeast area size composition curve was similar to the

Southwest with most fish ranging from 30-50 em.

During 1983 the size composition of the southern areas of

the Aleutian Islands , was similar in size range and mode with

most of the fish in the 28-48 em range. In the northern areas,

the mode of the size composition curve was considerably larger

with most fish ranging from 45 to 60 em in the Northwest and

44-68 em in the Northeast areas.

During 1986 In the Southwest area , most individuals were

from 30 to 45 em. Size composition curves In the Southeast,

Northwest and Northeast areas were similar, with most fish

ranging from 30 to 60 em, however, the Southeast and Northeast

had a larger percentage of fish in the 50-60 em range.

No size composition data were available for shortraker

rockfish in the Southern Bering Sea area from the 1980 survey. During 1983 and 1986 the majority of fish were in the 40-65 em

size range , however, during 1983 there were significantly more

larger specimens, in the 70-100 em size range (Fig. 167).

In 1983 the size composition curve for the Southern Bering

Sea showed no resemblance to the Northeast area of the Aleutian

Islands, the closest adjacent area surveyed , where most of the

stock was from 51-68 em. in length. In 1986 the size composition

of these two areas was similar but the Northeast area contained a

larger number of fish in the 30-40 em size range.

Shortraker rockfish otolith age reading and interpretation

techniques were not developed at the time of these surveys,

therefore no age data are available for this species.
1980

LENGTH (CM,

380 240 120 120 240 380

NUMBER (THOUSANDS'

1983

LENGTH (CM'

380 240 120 120 240

NUMBER (THOUSANDS'

360

1986

LENGTH (CM'

360 240 120 120 240

NUMBER (THOUSANDS'

380

246

1980

NUMBER (THOUSANDS)

900... SEXES COMBINED 

600...

300..

30 40 50 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

900...

..

_SEXES COMBINED 

600

300 .

30 40 50 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

900 -_u- .u.-.....-

SEXES COMBINED 

600 

300...

30 40 50 

LENGTH (CM)

Figure 163. Size composition of shortraker rockfish in the

Southwest area of the Aleutian Islands during the

-Japan 1980 , 1983 , and 1986 groundfish surveys.
1980

LENGTH (CM'

247

1980

NUMBER (THOUSANDS)

800

800----..0.._00_m___.

_.

SEXES COMBINED 

u.___..unn--_

__.

400 ---_0______-_. '--___0'_- "--'0_. 

MALE FEMALE I

200 

.

460 300 160 160 460

N UM BER (THOUSANDS'

300 30 40 

LENGTH (CM)

1983

LENGTH (CM'

MALE FEMALE

1983

NUMBER (THOUSANDS)

800

800 -0_"_0_ SEXES COMBINED 

.______oo.----.

400 '-_-_0"_'__-------_'_0'_-

460 300 160 160

NUMBER (THOUSANDS t

SOD 460

1986

LENGTH (CM' 

200 ---_-_-0-_'_"'--__0-"_0___0____-

30 40 

LENGTH (CM)

,

1986 800 NUMBER (THOUSANDS)

800 ---__"__"'0____.-1

SEXES COMBINED 

__o__.....u...

400 

.

MALE

.60 300 160 160

NUMBER (THOUSANDS'

300

200

460 30 40 

LENGTH (CM)

Figure 164. Size composition of shortraker rockfish in the

Southeast area of the Aleutian Islands during the

u. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
248

1980

LENGTH (CM'

MALE FEMALE

120 120

NUMBER (THOUSANDS'

1980

NUMBER (THOUSANDS)

240... SEXES COMBINED 

160

30 40 

LENGTH (CM)

1983 1983

LENGTH (CM'

NUMBER (THOUSANDS)

MALE FEMALE 240..... SEXES COMBINED 

160...

80..

....... ....................

120 80 40 40 

NUMBER (THOUSANDS'

120 30 40 

LENGTH (CM)

1986 1986

LENGTH (CM'

NUMBER (THOUSANDS)

MALE FEMALE 240...

............

_SEXES COMBINED 

120 80 40 40 

NUMBER (THOUSANDS'

120

160

80 ..

30 40 

LENGTH (CM)

Figure 165. Size composition of shortraker rockfish in the

Northwest area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
249

1980

LENGTH (CM'

MALE

180 120 120 180

NUMBER (THOUSANDS'

1980

NUMBER (THOUSANDS)

240 m SEXES COMBINED 

...

160",,-,-.

80 .

...........

30 40 

LENGTH (CM)

1983 1983

LENGTH (CM'

NUMBER (THOUSANDS)

MALE

240-

....

SEXES COMBINED 

....

180 120 60 60 120

NUMBER (THOUSANDS J

180

160.

.

80."

30 40 

LENGTH (CM)

1986 1986

LENGTH CCMJ 

NUMBER (THOUSANDS)

240.'. SEXES COMBINED 

160.....

180 120 60 80 120

NUMBER (THOUSANDS)

180

80-

30 40 

LENGTH (CM)

Figure 166. Size composition of shortraker rockfish in the

Northeast area of the Aleutian Islands during the

u. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
LENGTH (CM'

LENGTH (CM'

100

250

1983 1983

NUMBER (THOUSANDS)

200 ."--.-".-------"----.--.

SEXES COMBINED 

.......

160 ----

....

60.--.

100 

....

30 .0 60 

LENGTH (CM)

100 60 . 

NUMBER (THOUSANDS'

100

1986 1986

NUMBER (THOUSANDS)

MALE FEMALE 200

SEXES COMBINED

160

100 ..----

60 -.---

60 . 60

NUMBER (THOUSANDS'

100 30 .0 60 

LENGTH (CM)

Figure 167. Size composition of shortraker rockfish in the

Southern Bering Sea area during the U. -Japan 1983

and 1986 Aleutian Islands groundfish surveys.
251

Length-Weight Relationship

Length-weight data are available for shortraker rockfish

from all three surveys. Analysis of these data indicated nearly

identical agreement between the three years data (Fig. 168), and

provided the following estimates of the constants:

Weight (g) (1980) = . 0112 x Length (em) 3.108

We ight (g) ( 198 3 ) 

. 

009 6 x Length ( em) &1~

Weight (g) (1986) = . 0059 x Length (em) 3.268

1980 N. 139

SEXES COMBINED

-+- 1983 N. 335 --- 1986 N. 191

WEIGHT (g)

8000

.

4000.

2000

..

30 40 

LENGTH (em)

Figure 168. Length-weight relationships for shortraker rockfish

in the Aleutian Islands area during the U. s. -Japan

1980, 1983 , and 1986 groundfish surveys.
252

Shortspine Thornyhead

Distribution and Abundance

Shortspine thornyheads Sebastolobus alascanus ) were

distributed throughout the Aleutian Islands area primarily at

depths greater than 500 m (Figs. 169-170). Medium densities of

shortspine thornyheads were encountered in the Southwest area

during the 1980 survey, and north of Atka Island, southwest of

Semisopochnoi Island and on Bowers Ridge during the 1983 survey.

In 1986 medium densities were also found northwest of Seguam

Island, north of Atka Island , east of the Delarof Islands , on

both perimeters of Petrel Bank, north of Segula Island, on Tahoma

Reef, south of Buldir Island, west qf Agattu Island , north of

Attu Island and on Bowers Ridge.

The biomass estimate for the Aleutian Islands area decreased

26% from 19, 000 t in 1980 to 14, 000 t in 1983, then increased

160% to 23, 000 t in 1986 (Table 69, Fig. 171). Population

decreased from 41. 4 million fish in 1980 to 21. 9 million in 1983

then increased to 36. 6 million in 1986. Most of the decrease in

the 1983 biomass estimate occurred in the Southwest area. The

1986 increase was equally divided over all areas except the Southeast which remained unchanged. 

In the Southern Bering Sea area the biomass of shortspine

thornyheads remained relatively unchanged, going from 1, 000 t in

1980 to 1 400 t in 1983 , and back down to 900 t in 1986. Population went from 1. 1 million fish in 1980 to 2. 7 million in

1983 , and 1. 3 million in 1986 (Fig. 172).

In the Aleutian Islands the largest mean length and largest

mean weight occurred during the 1983 survey but in the Southern

Bering Sea area these parameters were both highest during the

1980 survey (Table 70, Figs. 173-174).

Size Composition

The size composition curves for shortspine thornyhead were

similar throughout all surveys in the Aleutian Islands area.

Size ranges were nearly identical and each size composition curve

had a normal distribution, the only difference being the height

of the curve which reflects abundance. The 1980 size composition

curve peaked at 28 em , slightly smaller than the 1983 curve which

peaked at 31-33 em , and the 1986 curve that peaked at 32-33 em

(Fig. 175).

Some variation was apparent between areas of the Aleutian Islands (Figs. 176-179). In 1980 the size composition curve in

the Southwest area peaked at 28 em. The size composition curve

in the Northwest area was skewed towards larger fish 38-47 em,

and the Northeast size composition curve peaked at 35 em.
...

,;:

PETREL BANK

AGATTU I.

1986

CATCH IN KG/KM

NO CATCH I - I . 000 

001-10. 000' .

10. 000' 

. 

PETREL BANK

1983CATCH IN KG/KM

NO CATCH 1-1 . 000 

001-10. 000

10. 000'

l\,)

1980

CATCH IN KG/KM NO CATCH 

1 -1 .000 

001-10. 000

10. 000'

PETREL BANK

STALEMATE BANK

:i~.

ADAK I.

000 M

Figure 169. Distribution and relative abundance of shortspine thornyhead n the Aleutian

Islands area during the U. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.
254

1"-

1986

CA T CH IN KG/

NO CATCH

1-1. 000

001-10. 000

1 O. OOO=-

1983

CA TCH IN KG/

NO CATCH

1-1. 000

001-10. 000

I O. OOO=-

.....

1980

CA TCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000

1 O. OOO=-

Figure 170.

BOWERS

BANK

1986

CA TCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000 10. ooo=- 

BOWERS

BANK

000

198~

CA TCH IN KG/KM

NO CATCH 

I -1 .000 

001-10. 000

10. OOO~ tt

IX)

BOWERS

BANK

1980

CA TCH IN KG/KH

NO CATCH 

1 -1 . 000 

001-10. 000

10. OOO~ tt

Distribution and relative abundance of shortspine

thornyhead in the Southern Bering Sea and Bowers

Ridge areas during the U. -Japan 1980 , 1983 , and

1986 Aleutian Islands groundfish surveys.
255

Table 69. Estimates of biomass , biomass sampling error, and

population for shortspine thornyhead based on the U. s. - Japan 1980, 1983 , and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleuti an

Islands

Total

Southern

Bering

Sea

Total

Depth em)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1980

367

497

628

888

419

141

100

138

381

149

987

183

995

1 . 970

3. 022

384

738

913

15. 041

135

970

1 . 079

Biomass (t)

1983

156

969

779

957

41'

130

739

913

1 . 712

1986

460

487

958

930

230

810

779

819

100

455

459

014

768

396

184

230

657

379

266

038

177

971

213

1980

102.

81.

52.

269.

66.

202.

58.

42.

80.

64.

485

389

926 101.

Sampl ing Error 

(%)

1983

34.

56.

43.

31.

54.

911.

112.

650.

39.

20.

16.

37.

no sampl ing was conducted in this area-depth interval.

Less than 0. 5 ton.

291

303

609

688

163

863

204

043

599

846

436

730

757

987

693

711

414

270.

124.

66.

21.

40.

23.

1986 1980

82.

210.

651.

458.

724.

438.

484.

17.

56.

193.

267.

49.

20.

212.

112.

046.

397.

13.

56.

277.

737.

50. 092.

28.

129.

856.

179.

165.

224.

679.

874.

11 . 027. 1

595.

400.

60.

094.

094.

Populati on (1 000s)

1983

51.

46.

263.

891.

310.

563.

76.

527.

437.

045.

22.

506.

897.

426.

062.

058.

132.

331.

397.

011.

740.

51.1

60.

696.

385.

715.

907.

12.

637.

092.

742.

1986

20.

638.

767.

236.

662.

163.

730.

714.

609.

205 .

666.

603.

476.

35.

125.

248.

412.

342.

460.

598.

400.

26.

384.

750.

400.

561.

74.

733.

465.

276.
ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION

. 1983 1984

YEARS

Figure 171. Estimated biomass and population of shortspine

thornyhead in- the Aleutian Islands area during the

-Japan 1980 , 1983, and 1986 groundfish surveys.

1983

YEARS

Estimated biomass and population of shortspine

thornyhead in the Southern Bering Sea area during the

u. S. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.

256

THOUSANDS

1980 1981 1982

THOUSANDS

SOUTHERN BERING SEA

.. 

B~OMASS (0 POPULATION

1980 1981 1982 1984

Figure 172.

MILLIONS

-- 24

1985 1986

MILLIONS

1985 1986
257

Table 70. Estimates mean catch per unit effort, length, and weight for shortspine thornyhead based the

Japan 1980 1983 and 1986 Aleutian Islands groundfish 

surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 17. 12. 32.

101-200 56. 33.

201-300 216. 67. 200. 36. 33. 35.

301-500 477. 284. 729. 31.7 31.8 32.

501-900 263. 537. 704. 38. 33. 30.

1-900 529. 223. 344. 35. 33. 31.

Southeast 1-100

101-200

201-300 18. 72. 40. 38.

301-500 15. 235. 258. 31. 37. 35.

501-900 28. 322. 275 . 1 32. 35. 30.

1-900 11. 122. 121. 32. 36. 31.

Northwest 1-100

101-200

201-300 131. 14. 93. 33. 35. 34.

301-500 45. 131. . 107. 35. 32. 37. ' 0.

501-900 698. 513. 770. 40. 42. 41.

1-900 304. 204. 471 . 37. 40. 40. 1.07

Northeast 1-100

101-200 42.

201-300 35. 41. 28.

301-500 43. 200. 234. 34. 34. 35.

501-900 166. 188. 387. 35. 35. 32.

1-900 66. 108. 179. 35. 35. 32.

Bowers 101-200

Ridge 201-300 46. 166. 188. 35. 34. 29.

301-500 621. 651 . 034. 29. 35. 27.

501-900 276. 224. 334. 33. 34. 33.

101-900 303. 277 . 416. 31. 34. 30.

Aleutian 1-100 32.

I s lands 101-200 24. 1.7 42. 33.

Total 201-300 72. 42. 101. 36. 34. 33.

301-500 217. 270. 599. 32. 34. 31.

501-900 565. 352. 505. 36. 35. 32.

1-900 266. 183. 294. 34. 35. 32.

Southern 1-100

Ber i ng 101-200

Sea 201-300 50. 51.4

Total 301-500 42. 544. 381. 35. 31.

501-900 426. 312. 170. 37. 33. 35.

1-900 85. 111. 73. 36. 32. 35.

No sampl ing was conducted in this area-depth interval.
258

ALEUTIAN ISLANDS 

.. MEAN LENGTH MEAN WEIGHT

.1983 1984

YEARS

Figure 173. Mean length and weight of shortspine thornyhead in

the Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.

1980 1981 1982 1985 1986

SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

1983 1984

YEARS

Figure 174. Mean length and weight of shortspine thornyhead in

the Southern Bering Sea area during the U. s. -Japan

1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.

1980 1981 1982 1985 1986
1980

LENGTH (CM'

MALE FEMALE

259

1980

NUMBER (MILLIONS)

..

- m _O_--_O-"--_n-_oo..__o_--------

SEXES COMBINED 7-"------

1.8

9 ..

8 --..-

1.8 

1.6

o~ 

NUMBER (MWONS'

8 ..

8 -

9 0

-_'0_____-

30 40 

LENGTH (CM)

1983

LENGTH (CM'

1983

NUMBER (MILLIONS)

----- ___m 

....

--___m.."__"------------'"

SEXES COMBINED 

--_____0______-

-_-_-0_-__-_----

30 40 

LENGTH (CM)

0 0.

NUMBER (MUlONe.

1986

NUMBER (MILLIONS)

SEXES COMBINED 

30 40 

LENGTH (CM)

1986

LENGTH (eM)

15 0 0.

NUMBER (MILLIONS'

Figure 175. Size composition of shortspine thornyhead in the

Aleutian Islands area during the u. S. -Japan 1980,

1983 , and 1986 groundfish surveys.
1980

LENGTH (CM'

fiO

,..

MALE FEMALE

0 0.

NUMBER CMIWONS)

1983

LENGTH fCM)

o.e 0.3 0.3 0.

NUMBER (MIWONSt

1986

LENGTH lcut

I .

0.3 0.3.

NUMBER CMIWONS'

260

1980

NUMBER (MILLIONS)

4------___ SEXES COMBINED 

1.8

30 40 

LENGTH (CM)

1983

NUMBER (MILLIONS)

SEXES COMBINED

1.8

0.8

30 40 fiO

LENGTH (eM)

1986

NUMBER (MILLIONS)

SEXES COMBINED

1.8

0.15

30 

LENGTH (CM)

Figure 176. Size composition of shortspine thornyhead in the

Southwest area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
261

1980 1980

LENGTH (CM,

NUMBER (THOUSANDS)

MALE FEMALE

460---'------"'----'- SEXES COMBINED "--._0___"_"'-'-'-'

300 --..--'...--..------.-----.-.--...-

.....,...

160 ---

.........,........,...................

210 140 70 70 140

NUMBER (THOUSANDS'

210 30 

LENGTH (CM)

1983 1983

LENGTH (CM'

MALE FEMALE

460

-SEXES COMBINED 

...................

NUMBER (THOUSANDS)

210

300 

160

....

140 70 70 140

NUMBER (THOUSANDS)

210 30 

LENGTH (CM)

1986

LENGTH (CU)

210 140 140 210

1986

NUMBER (THOUSANDS)

460 

......

SEXES COMBINED 

......

300 

.....,.......____,,,,,,,,,,.. .,....,.

NUMBER (THOUSANDS'

30 

LENGTH (CM)

Figure 177. Size composition of shortspine thornyhead in the

Southeast area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
I .

1980

LENGTH (CM)

262

1980

NUMBER (THOUSANDS)

800

SEXES COMBINED

800 ""'----.-_.____n_._..--.--..--------.-

MALE FEMALE

400

........

150

4&0 300 1fiO 1150 300

NUMBER (THOUSANDS'

450

200

1983

LENGTH (CM)

30 

LENGTH (CM)

MALE L\\\\') FEMALE

1983

NUMBER (THOUSANDS)

800

800

SEXES COMBINED 

_

400

200

150

4&0 300 110 1fiO 300

NUMBER (THOUSANDS)

4150 30 

LENGTH (CM)

1986

LENGTH (CM)

4&0 300 110 110 300

NUMBER (THOUSANDS'

4&0

1986

NUMBER (THOUSANDS)

800

800

400

200

30 

LENGTH (CM)

Figure 178. Size composition of shortspine thornyhead in the

Northwest area of the Aleutian Islands during the

u. S. -Japan 1980 , 1983 , and 1986 groundfish surveys.
263

1980

LENGTH (CM'

MALE

1980

NUMBER (THOUSANDS)

360 

...

SEXES COMBINED 

240

120 ..

210 140 70 70 140

NUMBER (THOUSANDS'

210 30 

LENGTH (CM)

1983

LENGTH (CM'

MALE

1983

NUMBER (THOUSANDS)

360."...-.....

SEXES COMBINED 

240

12O...-u.-.-.."".

210 140 70 70 140

NUMBER CTHOUSANDSl

210 30 

LENGTH (CM)

1986 1986

LENGTH (CM'

NUMBER (THOUSANDS)

360... SEXES COMBINED 

120 .

240 

MALE FEMALE

210 140 70 70 140

NUMBER (THOUSANDS'

210 30 

LENGTH (CM)

Figure 179. Size composition of shortspine thornyhead in the

Northeast area of the Aleutian Islands during the

u. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
264

A similar situation was noted in 1983 , although the

Southwest size composi tion curve was much flatter. The Southeast , and Northeast size composition curves peaked in the

low 30 em range. As in 1983, the size curve in the Northwest

area was skewed toward larger fish peaking at 41-42 em.

In 1986 the size curve in the Southwest area peaked in the

high 30 em range and the Southeast curve in the low 30 ems. The

size composition in the Northwest area also peaked in the high

30 ems. The Northeast area size composition curve peaked in the

low 30 ems similar to the Southeast curve but there were more

fish greater than 50 em in length. 

In the Southern Bering Sea area the size composition curves

were different each year (Fig. 180). In 1980 the size

composition database was small , however, the available data

indicates that most of the fish were in the 31-36 em size range,

peaking at 34 em. During the 1983 survey most fish were in the

24-37 em range , peaking at 31 em. In 1986 the size composition

curve was skewed towards larger fish , peaking at 38 em, with most

of the fish in the 32-41 em range.

Techniques and criteria for ageing shortspine thornyheads

have not been developed at the Alaska Fisheries Science Center,

therefore no age data is available at this time. otolith

collections were made throughout these surveys so age data may

become available in the future.
1980

LENGTH (CM)

MALE FEMALE

265

1980

NUMBER (THOUSANDS)

380 

SEXES COMBINED 

..

180 120 80 80 120

NUMBER (THOUSANDS'

180

2 40 -------.----..---...---

.................

20 30 

LENGTH (CM)

1983

LENGTH (CM'

MALE FEMALE

1983

NUMBER (THOUSANDS)

380 

..

SEXES COMBINED 

.

240

120 --

20 30 

LENGTH (CM)

180 110 80 80 120

NUMBER (THOUSANDS'

180

1986

NUMBER (THOUSANDS)

380 .

SEXES COMBINED 

1986

LENGTH CCM'

MALE FEMALE

240 --

1 20 ."_h_"...".

'---'__-m"--.

__..

20 30 

LENGTH (CM)

180 120 80 80 120

NUMBER (THOUSANDS'

180

Figure 180. Size composition of shortspine thornyhead in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.
266

Length-Weight Relationship

Weight at length data are available from only the 1983 and

1986 surveys and are very similar for the two years, with the

fish being slightly heavier for a given length in 1983 (Fig. 181). Length-weight relationships for the two years are:

Weight (g) (1983) = . 0050 x Length (em) 3.270

Weight (g) (1986) = . 0040 x Length (em) 3.315

SEXES COMBINED

-+- 1983 N. 316 --+- 1986 N. 384

WEIGHT (g)

6000

4000

._.

2000

30 

LENGTH (em)

Figure 181. Length-weight relationships for shortspine thornyhead

in the Aleutian Islands area during 1983 and 1986

groundf ish surveys.
267

Rock Sole

Distribution and Abundance

Rock sole Pleuronectes bilineata) were distributed

throughout the Aleutian Islands area and the Southern Bering Sea

primarily at depths less than 200 m (Figs. 182-183). Rock sole

were never encountered in high densities , however, medium-density

concentrations were found in the Southern Bering Sea, and on both

sides of the Aleutian Islands chain as far west as Kiska Island

during all three years. During the 1986 survey, medium densities

of rock sole were encountered around Attu and Agattu Islands and

on Petrel Bank.

The surveys for the Aleutian Islands area indicated a

continuing modest increase in the rock sole stock (Table 71, Fig. 184). The biomass estimate for rock sole in the Aleutian Islands

area totaled 12 000 in 1980, increased to 15, 000 t in 1983, and

was 19, 000 t in 1986. Population estimates went from

42. 0 million fish in 1980 to 44. 0 million in 1983, and

60. 7 million in 1986. Most of the rock sole biomass was located

in the Northeast and Southwest areas , those with the widest

continental shelf. The increase in 1983 was observed in all

areas except the Northeast area which decreased 38%. In 1986 the

biomass estimate increased in all four areas of the Aleutian Islands.

In the Southern Bering Sea the biomass estimate of rock sole

decreased substantially from 16 000 t in 1980 to 4 000 t in 1983,

then increased to 6 000 t in 1986. The population estimate also

decreased substantially from 52. 2 million fish in 1980 to

6 million in 1983, then increased to 14. 3 million in 1986 (Fig.

185) .

Mean lengths and weights were largest during the 1983 survey

in the Aleutian Islands area. In the Southern Bering Sea, mean

length and weight were greatest during the 1980 and 1983 surveys, respectively (Table 72, Figs. 186-187).

Size and Age Composition

Size composition curves for rock sole in the Aleutian

Islands were similar during all three surveys (Fig. 188). All

curves were unimodal ranging from approximately 20 to 40 em. In

1980 the size composition curve peaked at 26-29 em and consisted

of equal numbers of males and females. There were . 13 year

classes of which 6 , the 1970-75 year classes, contributed over

75% to the stock (Fig. 189).

In 1983 the size composition curve peaked at 29 em, but was

skewed to the smaller fish. There was a slight increase in the

larger fish, 33-40 em in length, and an occurrence of fish in the

40-45 em range which were not evident in the 1980 size

composition. The stock was dominated by females.
,

~ST 'LEM' TE B'",

1986

CATCH IN KG/KM

NO CATCH 

1-1 .000 

001-10. 000 .

10. 000:- 

PETREL BANK AMCHI TKA 

 

_._

....

PETREL BANK

1983

CATCH IN KG/KM

NO CATCH

1-1. 000

001-10. 000

10. 000:-

L...--

AMCHITKA I.

~ST 'LEMATE BANK

PETREl BANK

1980

CATCH IN KG/KM NO CATCH I - I . 000 

001-10. 000

10. 000:-

Figure 182. Distribution and relative abundance of rock sole in the Aleutian Islands area

during the U. -Japan 1980 , 1983 , and 1986 Aleutian Islands groundfish surveys.
269

1986

CATCH IN KG/

NO CATCH

1-1. 000

001-10. 000

10. OOO~

1983

CATCH IN KG/

NO CATCH

1-1. 000

001-10. 000

10. OOO~

1980

CA TCH 1 N KG/KM

NO CATCH I -1 . 000 

001-10. 000

1 O. OOO~

Figure 183.

1986

CATCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 . 10. OOO~ 

1983

CA TCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 I A. OOO~ 

1980

CA TCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 1 O. OOO~ 

BOWERS

BANK

000

CI)

BOWERS

BANK

Distribution and relative abundance of rock sole in the Southern Bering Sea and Bowers Ridge areas

during the U. S. -Japan 1980 , 1983 , and 1986 Aleutian

Islands groundf ish surveys.
270

Table 71. Estimates of biomass, biomass sampling error, and

population for rock sole based on the U. -Japan 1980 1983, and 1986 Aleutian Islands .groundfish surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleutian

Islands

Total

Southern

Ber i ng

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1980

399

630

351

419

1 . 251

218

479

106

647

208

983

032

1 . 607

482

136

278

537

135

259

177

159

127

359

287

789

Biomass (t)

1983

560

. 158

813

535

305

109

340

821

628

068

857

553

986

842

343

104

275

479

181

353

175

188

878

1 , 109

025

1986

028

351

661

051

610

1 . 396

116

123

1 . 077

155

753

369

354

1 . 702

228

800

112

842

417

136

330

493

376

030

067

119

128

344

1980

Sampl ing Error 

(%)

52.

41.0

108.

20.

35.

59.

194.

113.

21.

64.

1983

493.

43.

42.

20.

0 1 270.

691 .

23.

44.

195.

222.

No samp~ ing was conducted in this area-depth interval.

31.

51.9

15.

40.

130.

19.

32.

1986

50.

951.9

893.

936.

24.

806.

42.

699.

425.

124.

367.

726.

315.

92.

57. 501.

34.

12. 272.

097.

924.

291.

586.

591.7

415.

601.

408.

017.

371.

837.

209.

Population (1 000s)

1980

828.

368.

847.

28.

073.

977 .

487.

824.

143.

432.

533.

928.

614.

076.

994.

452.

748.

231.

427.

332.

243.

035.

404.

016.

086.

418.

68.

572.

1983 1986

841.

519.

769.

17.

147.

471.

341.

374.

190.

329.

821.

598.

735.

484.

386.

709.

638.

181.5

916.

028.

400.

380.

937.

747.

988.

911.

217.

237.

354.
271

THOUSANDS MILLIONS

60 

...

ALEUTIAN ISLANDS 

.. 

BIOMASS (t) POPULATION

._......

. 60

4 0 ---..-- . 40

....

1983

YEARS

Figure 184. Estimated biomass and population of rock sole in the

Aleutian Islands area during the U. -Japan 1980, 1983, and 1986 groundfish surveys.

1980 1981 1982 1984 1985 1986

THOUSANDS

....

MILLIONS

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

12 

.............. ,,,,,

"-""m"""""'--"""'"--"-."",,,,, 

.........

........-m"."."."."_m_mm 

1983

YEARS

Figure 185. Estimated biomass and population of rock sole in the

Southern Bering Sea area during the U. s. -Japan 1980,

1983, and 1986 Aleutian Islands groundfish surveys.

1980 1981 1982 1984 1985 1986
272

Table 72. Estimates mean catch per unit effort length, and weight for rock sole based the u. S . -Japan 1980,

1983, and 1986 Aleutian Islands groundf ish surveys.

Mean CPUE (kg/k~) Mean Length (em) Mean Wei ght (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 174. 871 . 804. 27. 29.

101-200 555. 483. 513. 28. 30. 28.

201-300 152. 354. 287. 30. 33. 31.

301-500 30.

501-900

1-900 204. 294. 306. 28. 30. 28.

Southeast 1-100 193. 230. 29.

101-200 382. 339. 426. 29. 34. 29.

201-300 69. 107. 353. 34. 34. 34.

301-500 21.

501-900

1-900 132. 130. 207. 30. 33. 29.

Northwest 1-100 70. 266. 456. 26. 32.

101-200 352. 787. 1 439. 30. 32. 30.

201-300 194. 800. 703. 33. 35. 34.

301-500 166. 38.

501-900

1-900 88. 278. 262. 29. 33. 31.

Northeast 1-100 1 368. 845 . 2 887. 27. 23. 25.

101-200 411. 471. 826. 30. 33. 29.

201-300 197. 140. 327. 33. 33. 34.

301-500 39. 30. 34. 37. 34. 35.

501-900

1-900 294. 191. 329. 29. 28. 27.

Bowers 101-200 12. 17.

Ridge 201-300

301-500

501-900

101-900

Aleuti an 1-100 589. 556. 600. 27. 27. 25.

Islands 101-200 458. 491. 548. 29. 32. 28.

Total 201-300 123. 231. 326. 33. 34. 33.

301-500 13. 12. 36. 38. 34. 35.

501-900

1-900 169. 199. 245 . 29. 30. 28.

Southern 1-100 2 516. 597. 836. 30. 30. 28.

Ber i ng 101-200 1 026. 339. 631. 34. 31.2 31.

Sea 201-300 287. 37. 119. 36.

ota l 301-500 11.8 100.

501-900

1-900 1 249. 318. 501. 32. 30. 28.

No sampl ing was conducted in this area-depth interval.
273

50 

.

ALEUTIAN ISLANDS

.. MEAN LENGTH MEAN WEIGHT

40 

.. .......... ,.............................. .,..............................,..................... .... ............................. .............................

0.4

30 '.""-.'--""."'-

............................,...........

1980 1981 1982

Figure 186.

1983

YEARS

Mean length and weight of rock sole in the Aleutian

Islands area during the U. S. -Japan 1980 , 1983 , and

1986 groundfish surveys.

1984 1985 1986

SOUTHERN BERING SEA 

.. .... .... ...

50 .-.-..".................. ' 0.

.

.. MEAN LENGTH MEAN WEIGHT

40 .'.--"'-""""'--"

..........................

.. 0.48

10 

.. ............... ... ................ .... ............. .

30 

.

20 

..... ...................... . ...................

. 0.

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 187. Mean length and weight of rock sole in the Southern

Bering Sea area during the u. S. -Japan 1980 , 1983 , and

1986 Aleutian Islands groundfish surveys.
1980

LENGTH (CM)

274

1980

NUMBER (MILLIONS)

6-----.......-.....-........_.....

SEXES COMBINED 

.__..._.........:.....................

4 ...--....-..

................................................

MALE

20 

LENGTH (CM) NUMBER (MILUONS).

1983

NUMBER (MILLIONS)

.....................

SEXES COMBINED 

1..

...........,,........ ..........

1983

LENGTH (CM)

0 .

_MALE

2 '-----..-..-.

NUMBER (MfWONS)

1986

LENGTH (CM)

20 

LENGTH (CM)

1986

NUMBER (MILLIONS)

8 ------.--....----

SEXES COMBINED 

..

4 ---.....-

MALE

2 " _-m

0 1

NUMBER (MILLIONS) 20 

LENGTH (CM)

Figure 188. Size composition of rock sole in the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986

groundf ish surveys.
275

PERCENT

1-900 m

1980

20 .

10 12 14 16 18 

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

"..._n. 

.._

1-900 m

1983

.,..

10 .

10 12 14 -16 18 20

AGE (YEARS)

ALEUTIAN ISLANDS

PERCENT

1-900 m

1986

t----...--

10 12 14 16 18 

AGE (YEARS)

ALEUTIAN ISLANDS

Figure 189. Age composition of rock sole in the Aleutian Islands

area during the U. S. -Japan 1980 , 1983, and 1986

groundf ish surveys.
276

Fourteen year classes contributed to the rock sole stock

with the 1975-78 year classes contributing approximately 54%.

The 1971-74 year classes were still major contributors in 1983.

The 1974 year class which made up nearly 16% of the stock in 1980

was still contributing about 8% of the stock in 1983. In 1983,

the 1971 to 1973 year classes added another 16% to the stock.

In 1986, the size composition curve was again skewed toward smaller fish , peaking at 28 cm. There was a stronger showing of

19-25 cm fish and there were more intermediate (ie., 26-33 cm in

length) sized fish. The sex ratio still favored the females.

Eighteen year classes contributed to the age composition with the

1977-1979 and 1981 year classes contributing approximately 45% of

the total stock. The 1977 year class was again dominant in 1983

contributing 15% of the stock. The 1975 and 1976 year classes

which contributed about 14% of the stock in 1983 continued to

contribute 7-8% in 1986. The 1971-1974 year classes which

dominated during the 1980 survey, were still viable as 12-15 year-olds , contributing nearly 15% of the stock collectively.

Size composition curves for each of the areas of the

Aleutian Islands are shown in Figs. 190-192. In 1980 the

Southwest and Southeast size composition curves had similar

ranges of 20-38 cm. The Southwest area peaked at 26-28 cm, and

the Southeast area peaked at 29-30 cm. The sex ratio in the

Southwest area favored males but the ratio in the Southeast area

favored females. The size composition curve in the Northeast

area was considerably different, ranging from 15 to 40 cm, with a

. mode at 17-22 cm , and a fairly equal distribution from 28 to 

cm. The sex ratio in the Northeast area also favored females.

No data was available for the Northwest area.

During the 1983 survey fish of the same size range were

found in the Southeast and Southwest areas and their size

composition curves peaked near 30 cm, however, the Southeast area

held a higher percentage of larger fish (ie. , 33-39 cm) in length.

The size composition curve for the Northeast area covered the

size range of 11-47 cm. The principle mode was skewed toward the

smaller fish, peaking at 25 cm, and there were fish larger than

40 cm which were not present in the other areas. In all three

areas the females outnumbered the males.

In 1986 there was greater similarity in the size composition

curves of all three areas. All curves were unimodal with similar size ranges. The curves peaked at 27-28 cm in the Southwest

area , 28-29 cm in the Southeast area, and 28 cm in the Northeast area. During the 1986 survey the sex ratio in the Southwest area

was nearly equal , but in the other two areas strongly favored

females.

In the Southern Bering Sea rock sole size ranges were

similar for each survey. In 1980 , the size composition curve was

strong and unimodal , with most of the fish in the 23-32 cm size

range. There were about as many males as females (Fig. 193). 

1983, the size composition curve was extremely weak and flat
277

1980 1980

LENGTH (CM)

NUMBER (MILLIONS)

MALE FEMALE

.

SEXES COMBINED 

3-" ...n..._....-------.---.....-.."...--

............. .

0 0.8 1.

NUMBER (MILLIONS) 20 

LENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

3 ----

1 '--nNUMBER (MIWONS) 20 

LENGTH (CM)

1986 1986

NUMBER (MILLIONS)

MALE FEMALE

SEXES COMBINED 

___.__

1 ..

0 0.6 . 1.

NUMBER (MILLIONS)

1.8 20 

LENGTH (CM)

Figure 190. Size composition of rock sole in the Southwest area

of the Aleutian Islands during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.
1980

LENGTH (CMt

MALE FEMALE

4t50 300 160 160

NUMBER (THOUSANDS)

300

1983

LENGTH (CM)

MALE FEMALE

4t50 300 160 150

N UMBER (THOUSANDS)

300

1986

LENGTH (CM)

4t50 300 1t50 160

NUMBER (THOUSANDS)

300

278

1980

NUMBER (THOUSANDS)

760...--n_n._.__ SEXES COMBINED 

_..__..._.__......_...._

600 """""'-----"""

,, 

"""--"'-'-""""""""'-""""'_'n....""""",--"

460

260 . "'-'-' -'-""""""-""-...__.....n...............--.....---...

20 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

760 ......

............

SEXES COMBINED 

.....................

600 

.. ...

260 

460 20 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

760- SEXES COMBINED 

_.._

600,"""--""-"--- 

............... ...

"_"n_-

460 20 

LENGTH (CM)

Figure 191. Size composition of rock sole in the Southeast area

of the Aleutian Islands during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.
1980

LENGTH (CM)

NUMBER (MIWONS)

1983

LENGTH (CM)

004 004

NUMBER (MIWONS) 

, 

LENGTH (CM)

1986

004 004

NUMBER (MILLIONS)

279

1980

NUMBER (MILLIONS)

SEXES COMBINED 

1.8 ..

2 .

6 ..

20 

LENGTH (CM)

1983

NUMBER (MILLIONS)

204 

SEXES COMBINED 

8 ..

6 m

20 

LENGTH (CM)

1986

NUMBER (MILLIONS)

4 ..

SEXES COMBINED 

8 m

2 .

6 """"'

20 

LENGTH (CM)

Figure 192. Size composition of rock sole in the Northeast area

of the Aleutian Islands during the U. -Japan 1980

1983 , and 1986 groundfish surveys.
280

1980 1980

LENGTH (CM)

6 ..

NUMBER (MILLIONS)

SEXES COMBINED 

....................................

5,,-,

3 .

0 0.8 1.

NUMBER (MILLIONS)

20 

LENGTH (CM)

1983 1983

LENGTH (CM)

_MALE FEMALE

NUMBER (MILLIONS)

8 .... SEXES COMBINED 

...... .........

3 --

......

8 0. 1.8

NUMBER (MILLIONS) 20 

LENGTH (CM)

1986 1986

LENGTH (CM)

NUMBER (MILLIONS)

SEXES 'COMBINED r--

......

3 ..._~---_......__...__..__.._---_....__...._... ._.. 

.

6 ..

NUMBER (MILLIONS)

20 I I

LENGTH (CM)

Figure 193. Size composition of rock sole in the Southern Bering

Sea area during the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundf ish surveys.
281

with a slight mode ~t 27 cm , and there were more females than

males. In 1986 , the size composition curve continued to be weak

and flat with more females , however a small mode was present

peaking at 33 cm.

Mean Length-at-Age and Growth

Mean length-at-age data revealed some maj or differences

during the three surveys (Table 73). During the 1980 survey

there was a rapid rate of growth increasing from 14. 7 cm at

age 3 to 39. 3 cm at age 13. In 1983, fish less than 9-years-old

were larger at a given age than in 1980, but at ages older than

9 years they were smaller. By age 13, they had attained a mean

length of only 36. 1 cm. The situation in 1986 was similar in

that 3-7 year-old fish were slightly larger than the same age

groups in 1980 but slightly smaller than those in 1983. After

age 7 the mean length-at-age increased very slowly and by age 

was 'only 31. 6 cm , considerably smaller than the 1980 and 1983

surveys.

Table 73. Mean length (rom) at age for rock sole sampled during the U. S. -Japan 1980 1983 , and 1986 Aleutian Islands

groundf ish surveys.

1980 1983 1986

Age M+F M+F M+F

170 170

148 147 147 194 194 185 150 168

196 199 199 228 238 232 213 223 218

221 226 223 245 261 252 246 235 241

252 272 262 262 299 284 261 276 269

270 285 279 276 323 307 266 300 283

291 310 303 293 344 324 282 310 296

303 341 331 305 355 331 280 322 303

318 363 354 311 371 345 277 326 300

332 382 370 318 382 360 285 334 312

341 386 377 326 384 356 285 330 317

354 406 393 341 383 361 294 335 316

360 428 418 341 345 340 288 352 338

283 367 342

380 440 410 392 393 335 361 357
282

Estimates of the yearly growth increments of rock sole are

shown in Table 74. These data indicate a decline in the average

yearly growth rate from 4. 7 cm between age 3 and 4, to 1. 4 cm

between age 8 and 

Table 74. Estimates of yearly incremental growth (cm) of rocksole

based on the U. -Japan 1980, 1983 , and 1986 Aleutian

Islands groundf ish surveys.

Year

Age 1980 1983 1986 Average

3-4

4-5

5-6

6-7

7-8

8-9

Length-at-age data were fitted to the von Bertalanffy growth

equation to obtain estimates of to, 4NF, and K (Table 75).

Table 75. Estimated von Bertalanffy growth curve Parameters for

rock sole sampled during the U. s. -Japan 1980 1983, and

1986 Aleutian Islands groundfish surveys.

Range von Bertalanffy

Growth Parameters

Age Length

Area-Year Sex (Years) (cm) Lmr

Aleutian I s lands

1980 3-16 12-38 39. 173 222

3-16 11-44 51. 120 188

M+F 3-16 11-44 50. 119 071

1983 3-16 17-41 39. 118 -3. 068

4-14 23-44 40. 257 862

M+F 3-16 17-44 38. 230 O. 119

1986 2-17 17-35 29. 373 129

3-21 12-43 36. 243 286

M+F 2-21 12-43 35. 190 -1. 196
283

Length-Weiqht Relationship

Length-weight data were collected during the 1983 and 1986

surveys and showed very good agreement between the 2 years (Fig. 194). In 1986 the specimens over 30 cm were slightly heavier for

a given size than during 1983. These analysis provided the

following estimates of the constants: 

156 Weight (g) (1983) = . 0063 x Length(cm)

Weight (g) (1986) = . 0057 x Length(cm) 192

SEXES COMBINED

-+- 1983 N. 719 --- 1986 N. 832

WEIGHT (g)

900

600 

..

300

20 

LENGTH (em)

Figure 194. Length-weight relationships for rock sole in the

Aleutian Islands area based on the U. S. -Japan 1983

and 1986 Aleutian Islands groundfish surveys.
284

Skates

Because of the difficulties faced by u. S. and Japanese

scientists in identifying skates to the species level, all skates

have been combined into a single species complex for discussion in this report. Seven species from two genera were identified aboard the u. s. vessels during the 1980 survey. The major

species and the percentage of the biomass which they represented

during the 1980 survey are: Bathyraja rosispinis 32%, B. aleutica

27%, B. kincaidii 20%, Raja binoculata 9% and R. stellulata 7%.

Two other species B. abyssicola and B. trachura contributed the remaining 5%.

Distribution and Abundance

Skates were uniformly distributed throughout the Aleutian

Islands area and the Southern Bering Sea primarily at depths

deeper than 100 m (Figs. 195-196). Dense concentrations of

skates were encountered in the western Aleutian Islands area from

Attu to Amchitka Islands and in the Southern Bering Sea area

north of Unalaska Island. A relatively similar distribution

pattern for skates was found in the Southwest and Northwest areas

during all three surveys and in the Southeast and Northeast areas

during 1980 and 1983. During 1986 high densities of skates were

encountered from Amukta to Seguam Passes and also near Petrel

Bank.

Biomass estimates for skates in the Aleutian Islands area

increased from 10 000 t in 1980 to 16, 000 t in 1983, and 19, 000 t in 1986. The population went from 1. 6 million fish in 1980, to

5 million in 1983, and 7. 0 millon in 1986 (Table 76, Fig. 197).

Skates were more abundant in the eastern Aleutian Islands and

fairly uniformly distributed throughout all depth intervals

greater than 100 m. However , during all three surveys the

300-500 m depth interval contained the largest percentage of the

total biomass.

In the Southern Bering Sea area the biomass increased from

000 t in 1980 to 3, 000 t in 1983 before decreasing to 1, 000 t

in 1986 (Table 76, Fig. 198).

Size and age composition data were not available from these

surveys.
1986

CATCH IN KG/KM

NO CATCH I - 1 . 000 

001-10. 000

10. 000-

PETREL BANK

~ST ALEHATE BANK

(

C""

=C..c;;....

..

~STALEHATE BANK

(

)

\. 

1983

CATCH IN KG/KMNO CATCH I - I . 000 

001-10. 000

10. 000-

PETREL BANK

OATA NOT USEO

FOR ANALYSIS t\)

PETREL BANK

1980

CATCH IN KG/KM

NO CATCH 

I -I .000 

001-10. 000

10. 000-

Figure 195. Distribution and relative abundance of skates in the Aleutian Islands area

during the U. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
286

1986

CA TCH IN KG/KM

NO CATCH 

+ I 1 - I . 000 

001-10. 000 10. OOO=- 

1983

CATCH IN KG/KM

NO CATCH 

1 -I . 000 

001-10. 000

I O. OOO=-

1980

CA TCH IN KG/KM

NO CATCH I - I . 000 

001-10. 000

10. OOO=-

Figure 196.

1986

CATCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 . 10. ODD=- 

1983

CA TCH IN KG/KM

NO CATCH I -1 . 000 

001-10. 000 10. aDO=- 

1980 

CA TCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000

I O. OOO=- .

CJ)

BOWERS

BANK

CJ)

I. 000

(:)

CJ)

BOWERS

BANK

Distribution and relative abundance of skates in the

Southern Ber ing Sea and Bowers Ridge areas dur ing the u. s. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.
287

Table 76. Estimates of' biomass, biomass sampling error, and population for skates based on the U. s. -Japan 1980

1983, and 1986 Aleutian Islands groundf ish surveys.

Biomass (t) Sampl ing Error (%) Population (1 000s)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100 433 64. 33.

101-200 357 193 357 126. 231. 463.

201-300 326 735 515 29. 139. 209.

301-500 234 613 323 53. 98. 93.

501-900 148 856 219 84. 220.

1-900 065 830 424 72. 57. 90. 209. 709. 020.

Southeast 1-100 14.

101-200 724 469 373 286. 132. 86.

201-300 627 036 867 138. 270. 353.

301-500 194 1 , 278 996 14. 676. 280.

501-900 456 574 369 224. 120.

1-900 001 357 611 88. 71. 79. 439. 303. 855.

Northwest 1-100 30.

101-200 219 361 237. 94.

201-300 244 375 306 29. 64. 135.

301-500 568 722 924 335. 348. 479.

501-900 918 033 520 335. 251.

1-900 785 364 125 46. 45. 28. 365. 994. 991.

Northeast 1-100 20.

101-200 106 942 053 203. 219.

201-300 510 690 1 , 769 76. 116. 447.

301-500 123 848 772 19. 661. 770.

501-900 130 1 , 627 1 , 394 466. 308. 340.

1-900 888 157 988 79. 36. 35. 566. 310.

Bowers 101-200 161

Ridge 201-300 102 225 18. 35.

301-500 128 22. 33.

510-900 271 371 830 162. 274.

101-900 383 554 344 106. 339. 79. 266. 351.

Aleuti an 1-100 498 945 . 126. 92. 78.

Is lands 101-200 242 851 305 78. 34. 84. 416. 803. 873.

Total 201-300 761 938 682 57. 46. 47. 274. 605. 180.

301-500 177 514 143 108. 52. 66. 423. 805. 656.

501-900 923 461 332 84. 37. 38. 466. 216. 207.

1-900 122 262 492 33. 20. 30. 580. 522. 6~993.

Southern 1-100 154 254 24. 46.

Ber i ng 101-200 100 284 159. 34.

Sea 201- 300 206 17.

Total 301-500 473 855 154 85. 65.

501-900 307 121 511 55. 326.

1-900 173 175 244 27. 797. 96. 24. 318. 479.

No sampl ing was conducted in this area-depth interval.
THOUSANDS

288.

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION

1983

YEARS

Estimated biomass and population of skates,

Aleutian Islands area during the U. S. -Japan

1983 ~ and 1986 groundfish surveys.

6 -

1980 1981

Figure 197.

. THOUSANDS

1982 1984

MilliONS

- 6

- 4

- 2

1985 1986

in the

1980

THOUSANDS

720

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

600

1982 1983 1984

YEAR S

Figure 198. Estimated biomass and population of skates, in the

Southern Bering Sea area during the U. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.

_. .

6 -

..........

1980 1981

.. 480

. 360

.... ....

.. 240

120

1985 1986
289

Flathead Sole

Distribution and Abundance

Flathead sole Hippoglossoides elassodon) were found in the

Aleutian Islands area in very small quantities. This species was

encountered around Agattu Island , on the south side of Kiska and

Amchi tka Islands , and on both sides of Atka and Amlia Islands at

depths less than 200 m (Figs. 199-200).

The biomass estimate for flathead sole in the Aleutian Islands totaled 2, 000 t in 1980, decreased to 600 t in 1983 and then jumped to 5, 800 t in 1986 (Table 77 , Fig. 201). Over 75% of

the total biomass was found in the Southwest and Northeast areas.

An identical pattern was evident in the Southern Bering Sea

where the biomass estimate decreased from 1 900 t, in 1980 to

700 t in 1983 before increasing to 4 000 t in 1986 (Table 77

Fig. 202).

Size Composition

Flathead sole in the Aleutian Islands ranged in length from

13 to 41 cm during the 1980 and 1983 surveys. Size composition

curves were extremely flat , consisting of only a few individuals

in any size category (Fig. 203). In 1980 the sex ratio favored

males , in 1983 , the numbers of males and females were nearly equal. In 1986 , the size composition curve was unimodal and

skewed toward fish in the 25-31 cm size range.

No similarity was found between size composition curves of

flathead sole in the Southern Bering Sea (Fig. 204). In 1980

flathead sole ranged in size from 22 to 42 cm with most of the

fish in the 26-33 cm range. In 1983 the stock consisted mainly

of fish from 29 to 48 cm and the size curve had two weak modes at

33-37 and 39-46 cm. During the 1986 survey the size composition

curve of flathead sole was stronger and bimodal with a primary

mode of larger fish at 31-44 and a secondary mode of smaller fish

21-30 cm in length.

Because of low abundance , otolith collections were not

adequate to define the age composition of the flathead sole

stocks in the Aleutian Islands area and therefore no age data are

available for this species.
PETREL BANK

1986

CATCH IN KG/KM NO CATCH 1 - 1 . 000 

001-10. 000

1 O. 000 ~ AMCHITKA 1.

1983

CATCH IN KG/KMNO CATCH , - I . 000 

00'-10. 000

10. 000~

PETREl BANK

~~STALEMATE BANK

Q,-+ cd::..

l\)

AMCHITKA 1.

PETREL BANK

1980

CATCH IN KG/KM NO CATCH 

1 -1 .000 

001-10. 000 .

10. 000~

Figure 199. Distribution and relative abundance of flathead sole in the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
291

000 M

1986

CA TCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000

10. 000=-

1983

CA TCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000

10. OOO=-

1980

CA TCH IN KG/KM

NO CATCH

1-1. 000

00l-10. 000

10. OOO=-

Figure 200.

BOWERS

BANK

1986 

CA TCH IN KG/KM

NO CATCH 

1 -1 . 000 

00l-10. 000 .

10. 000=- 

BOWERS

BANK

1 . 000

1983

CATCH IN KG/KM

NO CATCH 

I -1 .000 

001-10. 000

1 O. OOO=- 

(:)

BOWERS

BANK

1980

CA TCH IN KG/KM

NO CATCH 

1 -1 .000 

001-10. 000 10. OOO=- 

Distribution and relative abundance of flathead sole

in the Southern Bering Sea and Bowers Ridge areas

during the U. -Japan 1980 , 1983 , and 1986 Aleutian

Islands groundfish surveys.
292

Table 77. Estimates of biomass , biomass sampling error, and

population for flathead sole based on the U. s. -Japan

1980, 1983 , and 1986 Aleutian Islands groundfish

surveys.

Area

Southwest

Southeast

Northwest

Northeast

Bowers

Ridge

Aleuti an

Islands

Total

Southern

Bering

Sea

Total

Depth (m)

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1980

244

597

101

963

258

980

538

190

966

612

977

246

1 , 871

Biomass (t)

115

194

378

510

294

294

1983

169

171

371

1986

852

211

336

409

Sampl ing Error 

(%)

1980

64. 631.

150

166

660

1 , 320

142

136

145. 250.

178

384

631

120

232

318

694

1 , 542

595

607

836

334

003

971

701

, 009

144. 127. 1

125.

136

136 0 1 270.

0 1 204.

82.2 57.

53.9 103.

100.5 372.

0 207.

42.2 404.

68. 132.

No sampl ing was conducted in this area-depth interval.

1983 1986

45.

152.

113.

89. 105.

430.

82.

64.

91.8

157.

099.

44.

57.

1980

265.

662.

896.

85.

909.

317.

317.

876.

64.

184.

125.

840.

840.

265.

538.

118.

269.

192.

676.

910.

298.

885.

Populat i on (1 , OOOs)

1983

476.

529.

61.4

28.

102.

13.

14.

30.

160.

65.

256.

910.

28.

14.

10.

964.

506.

613.

162.

22.

38.

344.

372.

700.

610.

46.

731.1

1986

510.

344.

344.

30.

229.

14.

21.

176.

216.

222.

616.

204.

180.

178.

93.

63.

720.

246.

246.

891.9

747.

006.

123.

63.

833.

500.

865.

064.

232.

662.
293

THOUSANDS MilliONS

ALEUTIAN ISLANDS

.. 

BIOMSSS (t) POPULATION " 27

1983

YEARS

Estimated biomass and population of flathead sole in

the Aleutian Islands area during the U. -Japan 1980

1983 , and 1986 groundfish surveys.

1980 1981 1982 1984

Figure 201.

THOUSANDS

1985 1986

MilliONS

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

1983

YEARS

Estimated biomass and population of flathead sole in

the Southern Bering Sea area during the U. S. -Jqpan

1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.

1980 1981 1982 1984

Figure 202.

1985 1988
294

1980 1980

LENGTH (CM)

NUMBER (MILLIONS)

MALE FEMALE

........ . ...............

SEXES COMBINED 

1.8

,,,,,

0 0.

NUMBER (MILUONS) LENGTH (CM)

1983 1983

LENGTH (CM)

MALE FEMALE

6 ...-..---.....-..-

.............................................

SEXES COMBINED I

...........................................

1.8

.............. 

0 0.

NUMBER (MIWONS)

.. 

. I . 

. . .. . .

10 20 

LENGTH (CM)

1986 1986

LENGTH (CM)

_..

SEXES COMBINED 

NUMBER (MILUONS)

7 ----

8,,-

9 ""

LENGTH (CM)

Figure 203. Size composition of flathead sole in the Aleutian

Islands area during the U. -Japan 1980 , 1983 , and

1986 groundfish surveys.
1983

LENGTH (CM)

800 400 200 200 400

NUMBER (THOUSANDS)

1980

LENGTH (CMt

MALE FEMALE

600 400 200 200

NUMBER (THOUSANDS)

1986

LENGTH (CM)

600 400 200 200 400

NUMBER (THOUSANDS)

295

1980

NUMBER (Thousands)

800

SEXES COMIBNED 

600 

400 

200 

400 600 20 

LENGTH (CM)

1983

NUMBER (Thousands)

800 

600 

400

200 

600

SEXES COMBINED 

20 

LENGTH (CM)

1986

NUMBER (Thousands)

800 ..

600

400

200..

600

SEXES COMIBNED 

20 

LENGTH (CM)

Figure 204. Size composition of flathead sole in the Southern

Bering Sea area during the U. S. -Japan 1980 , 1983 , and

1986 Aleutian Islands groundfish surveys.
296

Rex Sole

Distribution and Abundance

Rex sole Errex zachirus ) occurred at very low abundances

throughout the Aleutian Islands area and Southern Bering Sea at

depths primarily from 201-500 m (Fig. 205-206). They were most

frequently encountered in the western Aleutian Islands; around

Kiska , Amchi tka and Agattu Islands and in the eastern Aleutian

Islands north of Atka and Amlia Islands. In the Southern Bering

Sea they were found north of Unalaska Island.

The biomass estimate for rex sole in the Aleutian Islands

increased from 600 t in 1980 to 1 800 t in 1983 , and 3, 000 t in 1986 (Table 78, Fig. 207). In the Southern Bering Sea area

biomass increased from 1 200 t in 1980 to 4 400 t in 1983 and then decreased to 2, 500 t in 1986 (Table 78, Fig. 208).

Size Composition

The 1980 size composition curve for rex sole in the Aleutian

Islands was weak and bimodal (Fig. 209). There were more males

in the 29-33 cm size range and more females in the 42-44 cm range. In 1983 there was a stronger mode of fish from 40-50 cm

consisting of more females than males. In 1986 there was a

considerably stronger curve with a principle mode at 34-48 cm

which again consisted of nearly equal numbers of males and

females.

In the Southern Bering Sea area, the 1980 size composition

curve consisted primarily of fish in the 20-35 cm size range (Fig. 210). In 1983 and 1986 these fish ranged from 36-47 cm in length.

No age data is available for rex sole because of the small

number of otoliths collected.
PETREL BANK

DATA NOT USED

FOR ANALYS 1 S

1986

CATCH IN KG/KMNO CATCH I - I . 000 

001-10. 000

10. OOO~

PETREL BANK

1983

CATCH IN KG/KMNO CATCH I - I . 000 

001-10. 000 .

10. OOO~

(\)...J

AMCHITKA I.

1980

CATCH IN KG/KHNO CATCH 1 - I . 000 

001-10. 000

10. OOO~

PETREL BANK

~STALEHATE BANK

Figure 205. Distribution and relative abundance of rex sole in the Aleutian Islands area

during the U. -Japan 1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.
.298

1986

CATCH 1 N KG/KM

NO CATCH 1 -1 . 000 

001-10. 000

1 O. OOO~

1983

CA TCH IN KG/KM

NO CATCH 1-1 . 000 

001-10. 000

1 O. 000:-

1980

CA TCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000

1 O. ooo~

Figure 206.

1986

CA TCH IN KG/KM

NO CATCH 

1 -1 . 000 

001-10. 000

1 O. OOO~ 

BOWERS

BANK

000

1983

CATCH IN KG/KM

NO CATCH 

I -1 .000 

001-10. 000

10.000~ .

BOWERS

BANK

1980

CATCH IN KG/KM

NO CATCH 

1 -I .000

001-10. 000 . 10. OOO~ 

Distribution and relative abundance of rex sole in

the Southern Bering Sea and Bowers Ridge areas during

the u. S. -Japan 1980, 1983, and 1986 Aleutian Islands

groundf ish surveys.
299

Table 78. Estimates of biomass , biomass sampling error, and

population for rex sole based on the U. -Japan 1980,

1983 , and 1986 Aleutian Islands groundfish surveys.

Area

Southwest

Southeas t

Northwest

Northeast

Bowers

Ridge

Aleuti an

Is lands

Total

Southern

Bering

Sea

Total

Depth (m) 1980

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

101-200

201-300

301-500

510-900

101-900

1-100

101-200

201-300

301-500

501-900

1-900

1-100

101-200

201-300

301-500

501-900

1-900

206

422

286

214

222

Biomass (t)

205

108

129

131

191

213

574

351

236

760

418

1 , 765

1983 1986 1980

55.

102.

244

458

727 199.

Sampl ing Error 

(%)

1983

99.

38.

94.

97.

94.

80.

51.

43.

136.

36.

No sampl ing was conducted in this area-depth interval.

246.

419

182

252

562

442

314

200

640

249

352

518

409

184

111

113

240

305

368

134

178

348

174

399

639

226

320

602

166

211

037

789

476

112

459

127.

293.

77.

49.

79.

90.

35.

72.

585 .

245 . 1

274.

68.

68.

29.

203. 1

31.

487. 1

1986 1980

190.

96.

190.

57. 477.

41.

57.

92.

191.

71.

61.8

47.

109.

52.

142.

52.

147.

342.

409.

64.

474.

373.

678.

542.

594.

540.

675.

210.

426.

Population (1 000s)

1983

741.

269.

87.

140.

237.

11.

152.

474.

38.

676.

41.9

61.9

432.

17.

553.

34.

67.

320.

128.

550.

24.

102.

63.

190.

853.

653.

377 .

324.

208.

75.

849.

312.

723.

913.

879.

1986

985.

724.

401 .

111.

97.

236.

153.

487.

12.

26.

517.

860.

12.

428.

75.

74.

439.

1064.

657.

285.

241.

531.8

89.

183.

203.

721.

16.

217.

193.

656.

954.

954.

38.

797.
THOUSANDS

300

MilliONS

ALEUTIAN ISLANDS

3 ""

...... .......................... .. 

BIOMASS (t) POPULATION . 6

2 -"""-"-"""'-""""""""""""""

........................ .................................... .... ....................................................................... ................. ... ........................

1980 1981

.. 4

1982 1983

YEARS

1984 1985 1986

Figure 207. Estimated biomass and population of rex sole in the

Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys.

THOUSANDS

1 2 

...................................

MilliONS

..... 

SOUTHERN BERING SEA

.. 

BIOMASS (t) POPULATION

..................................... ..............................

1983

YEARS

Figure 208. Estimated biomass and population of rex sole in the

Southern Bering Sea area during the U. -Japan 1980,

1983 , and 1986 Aleutian Islands groundfish surveys.

........... ........ .

1980 1981

_

. 9

... .................

1982 1984 1985 1986
301

1980 1980

LENGTH (CMJ

NUMBER (THOUSANDS)

MALE FEMALE 600'--""--"'---""

SEXES COMBINED 

..........

400

,,,,,,,...

200 -.....-..--....--..---..-

.....

300 200 100 100

NUMBER (THOUSANDS)

200 300 20 

LENGTH (CM)

1983 1983

LENGTH (CM)

NUMBER (THOUSANDS)

MALE FEMALE

300

600--""'- SEXES COMBINED r--

....

400,---"

200 

..

200 100 100

NUMBER (THOUSANDS)

200 300 20 

LENGTH (CM)

1986 1986

LENGTH (CM)

NUMBER (THOUSANDS)

MALE FEMALE 600 "'-'-"""'-"--' SEXES COMBINED 

.

400 -'-'-'-'-"---"'----

300 200 100 100 200

NUMBER (THOUSANDS)

300

200

,,

20 

LENGTH (CM)

Figure 209. Size composition of rex sole in the Aleutian Islands

area during the U. S. -Japan 1980 , 1983 , and 1986

groundf ish surveys.
1980

LENGTH (CM)

800 400 200 200

NUMBER (THOUSANDS)

1983

LENGTH (CM)

MALE FEMALE

800 400 200 200

NUMBER CTHOUSANDS)

1986

LENGTH (CM)

800 400 200 200 400

NUMBER (THOUSANDS)

302

1980

NUMBER (THOUSANDS)

1200 .

SEXES COMIBNED 

900 ....

.......

600

300 ..

400 600 20 30 

LENGTH (CM)

1983

NUMBER (THOUSANDS)

1200 .

SEXES COMBINED 

900 

600 ...

300 ...

400 600 20 30 

LENGTH (CM)

1986

NUMBER (THOUSANDS)

1200 .

900...

800

300

600

- SEXES ~OMI ~~ED 

20 30 

LENGTH (CM)

Figure 210. Size composition of rex sole in the Southern Bering

Sea area during the U. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.
303

Length-Weight Relationship

Length-weight data were collected only during the 1986

survey and provided the following relationship (Fig. 211):

Weight (g) (1986) = . 0018 x (Length (cm) 3.387

SEXES COMBINED

--- 1986 N. 133

WEIGHT (g)

900

600

300

20 

LENGTH (em)

Figure 211. Length-weight relationships for rex sole in the

Aleutian Islands area during the U. S. -Japan 1986

groundf ish survey.
304

Dover Sole

Distribution and Abundance

Dover sole Microstomus pacificus ) were encountered at low

abundances primarily at depths greater than 500 m throughout the

Aleutian Islands area and Southern Bering Sea (Figs. 212-213).

The biomass estimate for Dover sole in the Aleutian Islands

increased from 344 t in 1980 to 369 t in 1983 and 1, 000 t in 1986

(Table 79 , Fig. 214-215). In the Southern Bering Sea area the

biomass decreased from 190 t in 1980 to 55 t in 1986.
PETREL BANK

1986CATCH IN KG/KM

NO CATCH 1 - 1 . 000 

001-10. 000

10. OOO~

AMCHI TKA I.

PETREL BANK

1983CATCH IN KG/KMNO CATCH

1-1. 000

001-10. 000

10. OOO~

000 M

AMCHITKA I.

1980

CATCH IN KG/KMNO CATCH 1 - 1 . 000 

OOI-IO. OOO

10. OOO~

PETREL BANK

~STALEMATE BANK

AMCHITKA I.

Figure 212. Distribution and relative abundance of Dover sole in the Aleutian Islands area

during the U. -Japan 1980, 1983 , and 1986 groundfish surveys.
306

......

1986

CATCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000

I O. OOO~

......

1983

CATCH IN KG/

NO CATCH

I-I. 000

001-10. 000

I O. OOO~

......

1980

CA T CH IN KG/KH

NO CATCH I -1 . 000 

1 . 00 1 -I O. 000

I O. OOO~

Figure 213.

1986

CA TCH IN KG/KM

NO CATCH I -I . 000 

001-10. 000 I O. OOO~ 

(XI

BOWERS

BANK

1983

CATCH IN KG/KM

NO CATCH I -1 . 000 

001-10. 000 . I O. OOO~ 

1980

CA TCH IN KG/KM

NO CATCH 

I -I .000 

001-10. 000 .

I O. OOO~ 

(XI

BOWERS

BANK

Distribution and relative abundance of Dover sole in

the Southern Bering Sea and Bowers Ridge areas during the U. S. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf i sh surveys.
307

Table 79. Estimates biomass, biomass sampling error, and population for Dover sole based the u. s. -Japan 1980,

1983, and 1986 Aleutian Islands groundf ish surveys.

Biomass (t) Sampl ing Error 

(%)

Population (1 000s)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100

101-200

201-300

301-500 10.

501-900 169 99. 13. 27.

1-900 184 169. 173. 086. 99. 14. 38.

Southeast 1-100

101-200

201-300 13.

301-500 11.

501-900 116 99. 46.

1-900 127 122 52. 232. 37. 111. 71.

Northwest 1-100

101-200

201-300

301-500

501-900 38.

1-900 153. 155. 110. 46.

Northeast 1-100

101-200

201- 300

301-500 11. 28.

501-900 166 713 145. 480.

1-900 191 747 178. 90. 163. 157. 509.

Bowers 101-200

Ridge 201-300

301-500 23. 50.

510-900

101-900 198. 267. 23. 50.

Aleuti an 1-100

Islands 101-200 226.

ota l 201-300 44. 219. 207. 15.

301-500 135 232. 161. 125 . 45. 108.

501-900 264 306 889 826. 89. 137. 99. 264. 593.

1-900 344 369 047 637. 72. 118. 103. 313. 716.

Southern 1-100 20.

Bering 101-200 29.

Sea 201-300 11.

Total 301-500 80. 15. 23.

501-900 75.

1-900 190 117 228. 203. 899. 80. 152. 31.

No sampl ing was conducted in this area-depth interval.
308

THOUSANDS THOUSANDS

800

.. , ..... .... 

600

 ..

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION

...........................

. 400

200

1982 1983 1984

YEARS

Figure 214. Estimated biomass and population of Dover sole in the

Aleutian Islands area during the U. -Japan 1980

1983 , and 1986 groundfish surveys.

1980 1981 1985 1986

240

THOUSANDS

240

60 

...

SOUTHERN BERING SEA

.. 

180 BIOMASS (t) POPULATION 180

120 

....

120

... ....... 

1980 1981 1982 1983 1984

YEARS

1985 1986

Figure 215. Estimated biomass and population of Dover sole in the

Southern Bering Sea area during the U. -Japan 1980,

1983 , and 1986 Aleutian Islands groundfish surveys.
309

Giant Grenadier

Although giant grenadier Albatrossia pectoralis ) are not

being used commercially, a discussion of this species is included

because of the tremendous biomass of this species which is

available in the Aleutian Islands area.

Distribution and Abundance

Giant grenadier were found throughout the Aleutian Islands

area including Bowers Ridge and the Southern Bering Sea areas.

The highest abundance was found along the north side of the

Aleutian Islands chain and in each successive survey the number

of high density encounters increased (Figs. 216-217).

Concentrations were found from the Islands of Four Mountains to

Atka Island and around the Delarof Islands in the eastern Aleutians. In the western Aleutians high densities occurred in

the deep water basin which lies between Segula Island and Petrel

Bank, and on Bowers Ridge.

The biomass estimate for giant grenadier in the Aleutian

Islands increased modestly from 313 000 t in 1980 to 350 000 t in

1983, then nearly doubled to 601, 000 t in 1986 (Table 80, Fig. 218). The Population estimate went from 110. 5 million fish in

1980, to 114. 0 million in 1983 , and 150. 3 million in 1986. In

1983 increases occurred in the Southwest, Southeast, and

Northwest areas while decreases were indicated in the Northeast

and Bowers Ridge areas. In 1986, biomass increases were noted in

all areas of the Aleutian Islands with the largest increases

occurring in the Northwest and Northeast areas.

Biomass estimates in the Southern Bering Sea area were

extremely low ranging from 600 t in 1980 to 1, 800 t in 1983

(Table 80 , Fig. 219).

Stock mean length and weight measurements were erratic

(Table 81 , Figs. 220-221). In the Aleutian Islands area the

largest mean length occurred during 1980 the year of the lowest

mean weight, and the largest mean weight occurred in 1986 , the

year of the smallest mean length.

Size Composition

As giant grenadier are very susceptible to losing the

posterior portions of their caudal fin during the rigors of being

sampled with otter trawls , total length measurements are of little value. The length measurement used for this species was

from the anterior tip of the snout to the leading edge of the

anus.
PETREl BANK

1986

CATCH IN KG/KM NO CATCH I -I . 000 

001-10. 000 .

10, 000" AMCHI TKA 

PETREl BANK

I 1983

CATCH IN KG/KMNO CATCH I -I . 000 

001-10. 000 .

10. 000" AMCHI TKA I.

.

1980

CA TCH IN KG/KM

NO CATCH I - I . 000 

001-10. 000 .

10. 000"

PETREl BANK

~S"LEH' TE B~.

Figure 216. Distribution and relative abundance of giant grenadier in the Aleutian Islands

area during the U. s. -Japan 1980 , 1983 , and 1986 groundfish surveys.
311

5'.

1 . 000 M

1986

CATCH IN KG/

NO CATCH

1-1. 000

001-10. 000

10. 000)0

1983

CA TCH IN KG/KM

NO CATCH

1-1. 000

001-10. 000

I O. 000)0

1980

CATCH IN KG/KM

NO CATCH I - I . 000 

001-10. 000

10. 000)0

Figure 217. Distribution and

grenadier in the

areas dur ing the Aleutian Islands

relative abundance of giant

Southern Bering Sea and Bowers Ridge

u. S. -Japan 1980 , 1983 , and 1986

groundf ish surveys.

BOWERS

BANK

1986

CATCH IN KG/KM

NO CATCH 

I - 1 . 000 

001-10. 000 .

10. 000)0 

BOWERS

BANK

1983

CA TCH IN KG/KM

NO CATCH I -1 . 000 

001-10. 000 .

10.000)0 

BOWERS

BANK

1980

CATCH IN KG/KM

NO CATCH I -1 . 000 

001-10. 000

1 0.000)0 
312

Table 80. Estimates biomass biomass sampling error, and population for giant grenadier based on the U. S. -Japan

1980, 1983, and 1986 Aleutian Islands groundf ish

surveys.

Biomass (t) Sampl ing Error 

(%)

Populati on (1 000s)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100

101-200

201-300

301-500 170 116 233 251. 506. 40.

501-900 243 189 098 646. 080. 557.

1-900 413 305 331 713. 78. 110. 897. 586. 598.

Southeast 1-100

101-200

201-300

301-500 572 721 230. 903.

501-900 044 772 237 305. 910. 18, 380.

1-900 079 344 958 629. 179. 739. 305. 140. 283.

Northwest 1-100

101-200

201-300

301-500 592 011 729 162. 367. 737.

501-900 779 154 176 248 445 248. 590. 864.

1-900 83, 371 156 187 252 174 54. 43. 90. 410. 958. 601.

Northeast 1-100

101-200

201-300

301-500 390 328 732 78. 633. 767.

501-900 060 033 133 846 079. 392. 909.

1-900 450 361 142 578 216. 82. 124. 158. 927. 677.

Bowers 101-200

Ridge 201-300

301-500 599 765 217 518. 638. 39.

501-900 568 576 398 213. 12, 776. 22, 080.

101-900 167 341 615 77. 34. 54. 731. 350. 120.

Aleuti an 1-100

Islands 101-200

Total 201-300

301-500 786 792 632 752. 117. 115. 010. 272. 488.

501-900 308 694 322 746 584 024 58. 34. 53. 109 493. 108 689. 146, 791.

1-900 313 480 349 538 600 656 57. 30. 51. 110 504. 113 961. 150 280.

Southern 1-100

Bering 101-200

Sea 201-300

Total 301-500

501-900 549 1 , 766 927 337. 827. 670.

1- 900 551 766 927 943. 151. 792. 337. 827. 670.

No sampl ing was conducted in this area-depth interval.
THOUSANDS

800

313

MilliONS

200

600

ALEUTIAN ISLANDS

.. 

BIOMASS (t) POPULATION - 150

1983 1984 YEARS 

Estimated biomass and population of giant grenadier

in the Aleutian Islands area during the U. S. -Japan 1980, 1983, and 1986 groundfish surveys.

400

200

1980 1981

Figure 218.

THOUSANDS

100

198. 1985 1986

MilliONS

SOUTHERN BERING SEA

.. 

BIOMASS (T) POPULATION

1983

YEARS

Estimated biomass and population of giant grenadier

in the Southern Bering Sea area during the U. S. -Japan

1980 , 1983 , and 1986 Aleutian Islands groundfish

surveys.

1980 1981

Figure 219.

1982 1984 1985 1886
314

Table 81. Estimates mean catch per unit effort, length, and weight for giant grenadier (Albatrossia pectoralis)

based the u. S . -Japan 1980, 1983, and 1986 Aleutian Islands groundf ish surveys.

Mean CPUE (kg/km Mean Length (cm) Mean Weight (kg)

Area Depth (m) 1980 1983 1986 1980 1983 1986 1980 1983 1986

Southwest 1-100

101-200

201-300

301-500 343. 620. 68. 29. 30.

501-900 156. 281. 116. 28. 27. 22.

1- 900 410. 085. 489. 28. 27. 23.

Southeast 1-100

101-200

201-300

301-500 13. 456. 185. 30. 30.

501-900 771. 589. 942. 30. 25. 25.

1-900 688. 888. 315. 30. 26. 25.

Northwest 1-100

101-200

201-300

301-500 267. 907. 683. 32. 32. 27.

501-900 18, 437. 339. 336. 30. 27. 25.

1-900 504. 237. 758. 31. 27. 25.

Northeast 1-100

101-200

201-300

301-500 113. , 717. 660. 32. 35. 30.

501-900 354. 447. 655. 30. 29. 25.

1-900 434. 232. 042. 30. 30. 25.

Bowers 101-200

Ridge 201-300

301-500 622. 472. 135. 32. 33.

501-900 298. 013. 605. 26. 24. 25.

101-900 068. 641. 690. 26. 25. 25.

Aleuti an 1-100

I s lands 101-200

Total 201-300

301-500 357. 941.6 218. 32. 32. 31.

501-900 605. 670. 118. 29. 26. 25.

1-900 370. 579. 620. 29. 27. 25.

Southern 1-100

Ber i ng 101-200

Sea 201-300

Total 301-500

501-900 241. 776. 407. 24. 19.

1-900 43. 139. 73. 24. 19.

No sampl i ng was conducted in th i s area-depth i nterva l.
315

. ALEUTIAN ISLANDS

4 O .......-.........._..m"....."

.. MEAN LENGTH MEAN WEIGHT

30 

.... ..... ....................................

10 

....

1980 1981 1982 1984 1985 1986

:,.

Figure 220.

1983

YEARS

Mean length and weight of giant grenadier in the

Aleutian Islands area during the U. S. -Japan 1980

1983 , and 1986 groundfish surveys. 

40 . SOUTHERN BERING SEA

.. MEAN LENGTH MEAN WEIGHT

30 

.............

20 

.......

1983

YEARS

Figure 221. Mean length and weight of giant grenadier in the

Southern Bering Sea area during the U. S. -Japan 1980

1983 , and 1986 Aleutian Islands groundfish surveys.

1980 1981 1982 1984 1985 1986
LENGTH (CM)

LENGTH (CM)

LENGTH (eM)

316

1980 1980

NUMBER (MILLIONS)

....

SEXES COMBINED 

_..._.._..__..__._._._..

16 .

12.

8 -..

....,,.......... ,,,,,

20 " I" I I 30 

LENGTH (CM)

MALE FEMALE

NUMBER (MIWONS)

1983 1983

NUMBER (MILLIONS)

SEXES COMBINED 

! . _..._.

20 

LENGTH (CM)

MALE FEMALE

1986 1986

NUMBER (MILLIONS)

SEXES COMBINED 

20 

LENGTH (CM)

NUMBER (MILUONS)

Figure 222. Size composition of giant grenadier in the Aleutian

Islands area during the u. s. -Japan 1980 , 1983 , and

1986 groundfish surveys.

MALE FEMALE

NUMBER (MILLIONS)
317

size composition curves of Giant grenadier in the Aleutian

Islands area were uni-modal with most fish ranging from 16 to

39 cm in length (Fig. 222). In 1980 the size composition curve

was skewed slightly toward larger fish. There was a strong

single mode of females from 20 to 31 cm , and a much weaker mode

of males from 14 to 25 cm.

In 1983 the size curve was normally shaped with a strong

female mode ranging from 19 to 35 cm and a considerably weaker

male mode ranging from 19 to 27 cm.

In 1986 the size composition curve was skewed towards larger

as in 1980 , and was again influenced by an extremely strong

of females ranging from 20 to 37 cm, and an extremely weak

of males ranging from 20 to 30 cm.

Giant grenadier were characterized by strong sexual

dimorphism and an extremely unequal sex ratio.

In the Southern Bering Sea , the 1980 size composition curve

mode of male giant grenadiers occurred at approximately the same

size range as in the Aleutian Islands area (Fig. 223). However

the female mode covered a much smaller range of 14-24 cm. 

1983 the males and females ranged from 20-26 and 20-28 cm

respectively. No length data were available for 1986 from the

Southern Bering Sea.

fish

mode

mode

1980

LENGTH (CM)

120

1980

NUMBER (THOUSANDS)

200

160 

..

--...J SEXES COMBINED 

100

..

NUMBER (THOUSANDS)

120 20 

LENGTH (CM)

1983

LENGTH (CM)

MALE

120

NUMBER (THOUSANDS)

1983

NUMBER (THOUSANDS)

200

160--,-,-", 

-sEXES COMBINED 

._.........................

100 

.................................... .......................................

120 20 

LENGTH (CM)

Figure 223. Size composition of giant grenadier in the Southern

Bering Sea area during the U. S. -Japan 1980 and 1983

Aleutian Islands groundf ish surveys.
318

Length-Weight Relationship

Length-weight data are only available for 1986 and provided

the following relationship (Fig. 224):

Weight (g) (1986) = . 5868 x Length(cm) 6o6

SEXES COMBINED

1986 N. 156

WEIGHT (g)

9000

6000

3000

LENGTH (em)

Figure 224. Length-weight relationship for giant grenadier in the

Aleutian Islands area during the U. -Japan 1986 groundfish survey.
319

Red Squid

The reader is cautioned that squid resources are not

adequately sampled by trawls. For this reason biomass tables are

not presented in this report, and other data may not reflect true population parameters. Data on red squid Berryteuthis magister

from the 1980 survey are not presented due to a squid

identification problem that year.

Distribution and Abundance

Red squid were found throughout the Aleutian Islands area

and the Southern Bering Sea primarily at depths from 201-300 m (Figs. 225-226). In 1983 and 1986, high-density concentrations

were found on Stalemate Bank, and in 1986 another high-density

area was found on the east side of Petrel Bank. Smaller

concentrations were located south of Amchitka Island in 1983 and

1986 , and north of Amlia Island, and around Petrel Bank in 1986.

Size Composition

In 1983 and 1986 the size composition curves of red squid,

were very similar (Fig. 227). Mantle lengths ranged from

14-45 cm and size composi tion curves had normal distributions,

peaking at 27 cm both years but considerably stronger in 1986 due

to higher catch rates. The vast majority of the stock was in the

21-32 cm size range during both surveys with a few larger squid,

40-45 cm in length , found in 1986.
PETREL BANK

AGATTU I.

1986CATCH IN KG/KMNO CATCH 

I -1 .000 

001-10. 000

I 0 . OOO~ AHCHI TKA I.

~STALEHATE BANK ~I~.

,;.

PETREL BANK

1983

CATCH IN KG/KM NO CATCH I -1 . 000 

001-10. 000

10. OOO~

Figure 225. Distribution and relative abundance of red squid in the Aleutian Islands area

during the U. S. -Japan 1983 and 1986 groundfish surveys.

fIV
321

1986

CA TCH IN KG/KM

NO CATCH 

1 - 1 . 000 

Oal-10. 000

10. OOO~ 

1983

CA TCH KG/KM

NO CATCH

1-1. 000

001-10. 000

10. OOO~ 

Figure 226.

1986

CA T CH IN KG/KM

NO CATCH 

1 -I . 000 

001-10. 000 10. OOO~ 

1983

CATCH IN KG/KM

NO CATCH I -I . 000 

001-lO. 000 10. OOO=- 

BOWERS

BANK

\:)

BOWERS

BANK

000

Distribution and relative abundance of red squid in

the Southern Bering Sea and Bowers Ridge areas during

the U. -Japan 1983 and 1986 Aleutian Islands

groundf ish surveys.
322

1983

NUMBER (MILLIONS)

5-'----"-'-"' SEXES COMBINED 

-_n__...

20 

LENGTH (CM)

1986

NUMBER (MILLIONS)

3 .

...

20 

LENGTH (CM)

..

SEXES COMBINED

...

Figure 227. Size composition of red squid in the Aleutian Islands

area during the U. S. -Japan 1983 and 1986 groundfish

surveys.
323

Len th-Wei ht Relationshi

In 1986 mantle length-weight data obtained for red squid provided the following relationship 

(Fig. 228):

Weight (g) (1986) = . 1470 x (Length (cm) 2.528

SEXES COMBINED

---- 1986 N. 131

WEIGHT (g)

300

........... .....

900

600

LENGTH (em)

Figure 228. Length-weight relationship for red squid in the

Aleutian Islands area during the 

groundfish u. s. -Japan 1986 survey.

325

CITATIONS

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explorations in the northeastern Pacific Ocean--An

evaluation of exploratory fishing methods and

analytical approaches to stock size and yield

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Bakkala, R. G. , K. Wakabayashi, and T. M. Sample. 1985. Results

of the demersal trawl surveys. Bakkala , R. G., and Wakabayashi (editors). Resul ts of Cooperative U. S. -Japan

groundfish investigations in the Bering Sea during MayAugust 1979. Int. North Pac. Fish. Comm. Bull. 44:39-191.

Bakkala, R. G., M. S. Alton , and D. K. Kimura. 1987.

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Region in 1986. p. 67-81. U. S. Dep. Commer., NOAA Tech.

Memo. NMFS F /NWC-117.

Brown, E. S. 1986. Preliminary results of the 1984 U. -Japan cooperati ve bottom trawl survey of the central and western

Gulf of Alaska. Major R. L. (editor), Condition of

groundfish resources of the Gulf of Alaska region as

assessed in 1985. p. 259-296. U. S. Dep. Commer., NOAA Tech.

Memo. NMFS F/NWC-106.

Cochran, W. G. 1977. Sampling Techniques. 3rd ed. Wiley Series

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Wiley & Sons. N. Y., N. Y. 428 p.

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Oceanography of the Bering Sea. p. 3-37. Inst. Mar. Sci.

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Oceanography of the northern North Pacific Ocean. p. 13-29.

Idemi tsu Shoten, Tokyo.

Forrester, C. R., A. J. Beardsley, and Y. Takahashi. 1978. Groundfish, shrimp, and herring fisheries in the Bering Sea

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1970. Int. North Pac. Fish. Comm. Bull. 37:1-147.
326

Forrester, C. R., R. G. Bakkala, K. Okada, and J. E. smith. 1983. Groundfish , shrimp and herring fisheries in the Bering Sea

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1976. Int. north Pac. Fish. Comm. Bull. 41:1-100.

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Estuaries and enclosed seas , p. 337-373. Elsevier. N. Y., Y. 500 p.

Hughes, S. E. 1976. System for sampling large trawl catches

of research vessels. J. Fish. Res. Board Can. 33:833-839.

Ito, D. H. 1987.

W. Balsiger

the eastern

p. 117-138.

117.

Pacific ocean perch. R. G. Bakkala and 

editors), Condition of groundf ish resources of

Bering Sea and Aleutian Islands region in 1986,

U. S. Dep. Commer., NOAA Tech. Memo. NMFS F /NWCKoyama, T. 1974. Study on the stern trawl. Bull. Tokai Reg.

Fish. Lab. 77: 181-247. ,(In Japanese with English abstract).

Reed, R. K., and J. D. Schumacher , 1986. Physical oceanography of

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Environment and Biological Resources, D. W. Hood and S. 

Zimmerman (editors), p 57-75. NOAA and Minerals Management

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American Fisheries Society, Spec. Publ. 20. 183 

Ronholt , L. L. , K. Wakayabashi , and T. K. Wilderbuer, Hirotsune

Yamaguchi and Keisuke Okada. 1986. Groundfish resources of

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Sasaki, T. 1985. Studies on the sablefish resources in the North Pacific ocean. Far Seas Fish. Res. Lab. , Japan, Bull:22:1-

108.

Sasaki, T. , and T. Yoshimura. 1987. Past progress and present

condition of the Japanese pollock fishery in the Aleutian Basin. (Document no. 3189 submitted to the Annual Meeting of

the INPFC, Vancouver , Canada , October, 1987.

) p. 

1-9.

Fishery Agency of Japan.
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Thompson, G. G. , and A. M. Shimada. 1987. Pacific cod. Bakkala, R. G. (editor), Condition of groundfish resources

of the eastern Bering Sea and Aleutian Islands Region in

1987. p. 33-49. U. S. Dep. Commer., NOAA Tech. Memo. NMFS

/NWC-139.

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

growth (Inquiries on growth laws. II). Hum. BioI.

10: 181-213.

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

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

, and K. Wakabayashi (editors). Resul ts of Cooperative

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

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

44: 7-29.

Wakabayashi, K., and K. Teshima. 1986. Wingspread measurements

of trawl net using net monitor transducer. Unpubl.

Manuscr., 15 p. Far Seas Fisheries Research Lab., Fish.

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Wilderbuer, T. K. , K. Wakabayashi, L. L. Ronholt, and 

Yamaguchi. 1985. Survey Report: Coopera ti ve U. S. -Japan

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Commer., NOAA Tech. Memo. NMFS F /NWC-9 3. 356 p.

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Pub 1 . 7. 7 7 p.


329

APPENDIX A

INDICES OF ABUNDANCE

331

INDICES OF ABUNDANCE

since 1979 the Japan Fisheries Agency and the National

Marine Fisheries Service have conducted cooperative longline

surveys for sablefish and other deepwater species throughout the

Aleutian Islands area, Bering Sea and Gulf of Alaska (Sasaki 1985). Data from these surveys have been extremely useful in

managing the sablef ish resource but have not been as widely used

for other species. Index of abundance data or Relative

Population Weights (RPWs) from the longline surveys were

calculated to compare with Mean Catch Per unit Effort (CPUEs)

from the three trawl surveys. This section compares these two

indices for selected species.

Sablef ish

The indices of abundance from the longline and otter trawl

surveys in the Aleutian Islands area show remarkable agreement for sablefish. However, the longline index (RPW), peaked ~n 1985

and decreased slightly in 1986 and 1987 while the otter trawl index (CPUE), was still increasing in 1986 (Fig. A-1).

Pacif ic cod

The indices of abundance for Pacific cod also showed

extremely good agreement increasing each year from a low in 1980

to a peak in 1986 (Fig. A-2). The longline index (RPW),

indicated a decline in 1987.

Arrowtooth flounder

Al though the agreement between the indices of abundance for

arrowtooth flounder was not as good as that reported for

sablefish and Pacific cod , similarities do exist (Fig. A-3). The

longline index fluctuated from 1979 to 1986 showing a slight

downward trend before increasing substantially in 1987. The

otter trawl index remained relatively unchanged from 1980 to 1983

but increased substantially in 1986 , suggesting a greater change

than the longline index.

Greenland turbot

The general trend in indices of abundance for Greenland

turbot showed good agreement, however the longline results

fluctuated more because of the annual data points (Fig. A-4).

The otter trawl index indicated a low abundance in 1980 with

increasing abundance in 1983 and 1986, but the longline index

showed a large decrease from 1979 to 1981 with increases in 1982

and 1983 followed by a slight decreases in 1984-1986 before

increasing slightly in 1987.
332

RPW (THOUSANDS) CPUE (kg/km*km) 

2000

Longllne -A- Otter trawl 

60 .....

..............._........ .. ,

-"""_'.'..n

.... ...................................... ................

1500

4 0 ---"'-'--"-"...-..._...__n.

......_......................... ..............................................

1000

20 

....................... ... ...... ..... ........................... ... 

500

1983

YEAR,S

Figure A-1. Indices of abundance for sablefish during the U. s.

Japan cooperative Aleutian Islands longline surveys

of 1979-87 , and the U. S. -Japan 1980, 1983, and 1986

Aleutian Islands groundfish surveys.

1978 1881 1986 1987

RPW (THOUSANDS)

200

CPUE (kg/k m*k 

2500

160 

...... ........................................................... ........... ...............................................................

2000

1 20 ...........

................. ...............

1500

.. . ............... ..................................................

1000

1983

YEARS

Figure A-2. Indices of abundance for Pacif ic cod during the U. s. -

Japan cooperative Aleutian Islands longline surveys

of 1979-87 , and the U. S. -Japan 1980 , 1983 , and 1986

Aleutian Islands groundfish surveys.

Longline -b- Otter trawl 

...

1979

........ 

500

1981\ 1985 1987
333

RPW (THOUSANDS) CPUE (kg/km*km)

2500

,,

Long!ine

-A- Otter trawl 

2000

,,.......... ....................................... 

1500 ..-..........---..-..------.........n-""""--"""""""-"","""

1000

................. ............................................................ ............................... .... .........................................

500

1981 1983

YEARS

1979 1985 1987

Figure A-3. Indices of abundance for arrowtooth flounder during

the U. s. -Japan cooperative Aleutian Islands longline

surveys of 1979-1987 , and the U. -Japan 1980 , 1983

and 1986 Aleutian Islands groundfish surveys.

RPW (THOUSANDS) CPUE (kg/km*km) 1600

1 0 .---...-..

..... .......................................... 

Longllne -A- Otter trawl 

...................................... ..... ......

15 

....................................................................................... .....................................................

1200

800

... ........... .... .................... 

400

1881 1983

YEARS

1985 1987 1979

Figure A-4. Indices of abundance for Greenland turbot during the

U. s. -Japan cooperative Aleutian Islands longline

surveys of 1979-87 , and the U. s. -Japan 1980 , 1983

and 1986 Aleutian Islands groundfish surveys.
334

Shortspine thornyhead

The comparison between the indices for shortspine thornyhead

showed contradictory trends. The longline index increased

substantially from 1979 to 1980 before fluctuating around a very

slight decreasing trend from 1981-1987. The otter trawl index

has fluctuated around a slightly increasing trend (Fig. A-S).

Rougheye and shortraker rockf ish

The indices for rougheye and shortraker rockf ish, were

similar to shortspine thornyhead in that there was a fluctuation

around a slightly decreasing trend for the longline survey and a

slightly increasing trend for the otter trawl index (Fig. A-6).

Giant grenadier

Indices of abundance for giant grenadier showed some

agreement for comparable years, however , the longline index

because of its yearly data points shows more fluctuations (Fig. A-7). After increasing from 1979 to 1980 and decreasing from

1981 to 1982 the index increased nearly every year until 1987.

The otter trawl index indicated no change from 1980 to 1983 and

then increased substantially from 1983 to 1986.
335

RPW (THOUSANDS) CPUE (kg/km*km)

600

...................................................................................................... ............

450

300

1. 

.............................._...

L._...

_.......................

.........-..............--.-.--.-...-..--..-................-......."n',"""""."""'"

Longline --A-- Otter trawl 

1978 1881 1883

YEARS

1986 1887

Figure A-5. Indices of abundance for shortspine thornyhead during

the u. s. -Japan cooperative Aleutian Islands longline

surveys of 1979-87 , and the U. s. -Japan 1980 , 1983

and 1986 Aleutian Islands groundfish surveys.

RPW (THOUSANDS) CPUE (kg/km*km)

1600

1 5 

"m....

.,,, ........ .....

....u

1200

.................. ............................................................................. .............................................................. ............. .... .......................... ........ ........................

. 400

Longllne -b- Otter trawl 

1978

Figure A-6.

1M3

YEARS

Indices of abundance for rockfish , primarily rougheye and shortraker , dur ing the U. s. -Japan coopera ti ve

Aleutian Islands longline surveys of 1979-87 , and the

U. s. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.

1St81 1986 1987
336

RPW CPUE (kg/km*km)

160

1 20 

..,,, .............. .................................... ........... .................... ......... ,, ...... ........................... 

40 

.......................................................................................................... ........................................................._.........................

Langline -b- Otter trawl 

1983

YEARS

Figure A-7. Indices of abundance for giant grenadier during the

u. s. -Japan cooperative Aleutian Islands longline

surveys of 1979-87 , and the U. S. -Japan 1980 , 1983

and 1986 Aleutian Islands groundfish surveys.

1979 1981 1985 1987

337

APPENDIX B

WATER TEMPERATURES

339

Water temperatures

The number of water temperature measurements taken with

expendable bathythermograph temperature probes (XBTs) are 

summarized in Table B-1. The overall annual mean surface water

temperature was 6. 30 C in 1980 , rose to 7. 40 C in 1983 then decreased to 6. 90 C in 1986. Following a similar pattern mean

bottom temperatures increased from 4. 30 C in 1980 to 5. 30 C in

1983 and then decreased slightly to 4. 60 C in 1986 (Table B-2).

In general the south side of the Aleutian Islands chain had

slightly warmer surface temperatures than the north side during

all survey years. However in 1986 the mean surface temperature

on Bowers Ridge was 10. 3 0 C , much warmer than recorded in the other surveys. This is probably a result of survey timing. 

1986, Bowers Ridge was surveyed in August, instead of late

September-October as in earlier years. While somewhat unusual in

that area , it is possible for the surface water temperatures to

become that warm if there is period of clear sunny calm weather.

Mean bottom temperatures at depths to 100 meters were 4. 7OC

in 1980, 5. 7 in 1983, and 5. 2 in 1986. Bottom temperatures

gradually decreased with depth, to a low of 3. 40 for depths

between 500 and 900 meters in 1983 and 1986.

Locations of stations used in the temperature analysis are

shown in Figs. B-1 to B-4.

Table B-1. Number of surface to bottom water temperature profile

observations taken during the U. -Japan 1980, 1983,

and 1986 Aleutian Islands groundfish surveys.

Vessels Year

No. of

Survey

Stations

No. of XBT

Temperature

Prof iles

Stations

Sampled

(% )

Ocean Harvester

Hal f Moon Bay

Hatsue Maru No. 62

Miller Freeman

Cha man

Daito Maru No. 

Let s 

Ginr u Maru No.

1980

1980

1980

1983

1983

1983

1986

1986

145

220

129

312

111

210

180

52.

76.

87.

88.

95.

50.

36.

a Expendable bathythermograph.
340

Table B-2. Mean surface and bottom temperatures taken during the

u. S. -Japan 1980, 1983, and 1986 Aleutian Islands

groundf ish surveys.

Surface

Temperatures

1980 1983 1986

Mean No. Mean No. Mean No.

Area Temp. Cbs. Temp. Cbs. Temp. Cbs.

of Aleutians 161 159

of Aleutians 129 154 193

Bowers Ridge 10.

Ber ing Sea

Annual Mean 283 389 425

Bottom

Temperatures

1980 1983 1986

Mean No.

Area Temp. Cbs.

of Aleutians

of Aleutians

Bowers Ridge

Bering Sea

Mean No.

Temp. Cbs.

153

125

Mean No.

Temp. Cbs.

1980 1983 1986

Depth Mean No. Mean No. Mean No. Strata (m) Temp. Cbs. Temp. Cbs. Temp. Cbs.

1-100

101-200 122

201-300

301-500

501-900

Annual Mean 176 338 190
~STALEMATE BANK

PETREL 8ANK

AMCH! TKA

t 986 SURF ACE TEMPERATURES

PETREL BANK

t-A

1983 SURF ACE TEMPERATURES

~STALEMATE BANK

PETREL BANK

ANCH! TKA I.

19BO SURFACE TEMPERATURES

Figure B-1. Locations where surface temperatures were taken in the Aleutian Islands area

during the U. -Japan 1980 , 1983 , and 1986 groundfish surveys.
PETREL BANK

AGATTU I.

1986 BOTTOM TEMPERATURES

PETREL BANK

l\J

1983 BOT TOM TEMPERATURES

AI1CHITKA I.

PETREL BANK

AGATTU I.

1980 BOT TOI1 TEMPERATURES

AI1CHITKA I.

Figure B-2. Locations where bottom temperatures were taken in the Aleutian Islands area

during the U. -Japan 1980 , 1983 , and 1986 groundfish surveys.
rt" rt" t't I'i P"P"O

c:: en rt"

p,. 0

...,.

ti) en s:: 0

...,.. 

rt"::;$

fJ) I P" fJ) P"~CDfJ) ttj ::;$ P" s:: D1 

I'i ::;$ tP 

CD CD

CD 

...,. fJ)

fJ)

.... 

00~ o~ 

ti)

en D1CD 0D1 CD

D1 rt"

.... 

P, S D1 ttj

tP CD P, 0 CD rt"

11 ~ 00 fJ) 11 0'\ 

...,.::0 rn

...,. ::;$

I-'p,~CD rt" 

D1 I'i rt"

CD D1

D1 ?;'fJ) CD rn 

::;$

I-' P,D1 ~ 

...,.

::;$ 11 P, 1-'.

rn 

::;$ ..., .

::0rrI

J 70

::0

rrI

rrI

rrI

rrI::0

::0

rrI

c.I::0

rrI

J 70

c.I::0

rrI

rrI

rrI

ITI::0::0

ITI

::0

ITI

170

(J\

::0ITI

rrI

rrIrrI::0C!:::0

ITI
344

Figure B-4.

1986 BOTTOM TEMPERATURES

(:)

tc'

1983 BOTTOM TEMPERATURES

1980 BOTTOM TEMPERATURES

Locations where bottom temperatures were taken in the

Southern Bering Sea and Bowers Ridge areas during the

u. s. -Japan 1980 , 1983 , and 1986 Aleutian Islands

groundf ish surveys.

345

APPENDIX C

SPECIES INVENTORY

347

Table C-1. Species recorded during the U. S-Japan 1980 , 1983,

1986 Aleutian Islands groundfish surveys. 

and

Taxon

Engl ish

CORman name

Japanese

Standard name

FISH

Pet romyzont i dae

Lam etra tridentate

Lanpreys

Paci fi c lamprey

Mackerel sharks

Salmon shark

Yufutsuyatsune

Lannidae

Lamna di tro i s Nezuni zame

Squa l i dae

Somn i sus ac i ficus

ua l us acanth i as

Dogfish sharks

Pacific sleeper shark

Spi ny dogf i sh

Ondenzame

Aburatsunozame

Rajidae

Bath ra asp.

Bath a ab ssi cola

Bath ra a a l eut i 

Bath ra a kincaidi

Bath a l indber

Bath a maculata

Bath a minis inosa

Bath armifera

Bath a rosis inis

Bath ra a t rachura

Bath a vi olacea

Ra ia sp.

Raja binoculata

Raja stellulata

Skates

Skate unident.

Ch i h i rokasube

Arasukakasube

Deepsea skate

Aleutian skate

Sandpaper skate

Conmander skate

Wh i tebl etched skate

Wh i tebrow skate

Alaska skate

Flathead skate

Roughtail skate

Okhotsk skate

Skate unident.

Big skate

Starry skate

Komandorukasube

Montsuk i kasube

Subesubekasube

Ki tatsunokasube

Yasudakasube

Ki tanokasube

Kohosh i kasube

Clupeidae

elu es allasi

Herrings

Pacific herring N i sh i n

Salmonidae

Oncorh nchus orbuscha

Oncorh nchus keta

Oncorh nchus nerka

Oncorh nchus tshaw tscha

Sa lman and trout

Pink salmon

Chum salmon

Sockeye sa lmon

Chinook salmon

Karafutomasu

Sake

Beni zake

Masunosuke

Osmeridae

Ma II otus vi II osus

Thal ichth acificus

Smel ts

Capel in

Eulachon

Bathylagidae

Bath us sp.

Bath us mi lleri

Bath us acificus

Leuro l ossus schmi dt i

Deepsea smel 

Deepsea smelt unident.

Robust blacksmel t

Pacific blacksmel 

Northern smoothtongue

asesoko i wash i

Opi sthoproct i dae

Macro inna microstoma

Spookf i shes

Barreleye Demenigisu

Gonostomatidae

clothone accl inidens

clothone atrari a

ightfishes

Benttooth bristlemouth

Black bristlemouth

Senonihadaka

Onihadaka

Malacosteidae

Chaul iodontidae

Chaul i odus macouni

Loosejaws

Vi perf i shes

Pacific viperfish Hi gash i hours i eso

Alepocephal idae

acal ifornia erimoensis

Sl ickheads

Ukeguch i i wash i

a - Scientific and CORman names of fish agree with Robins 1991.

Scientific and CORman names of crustaceans agree with Williams 1989.

Year

80 83 86
348

Table C-1. (continued)

Taxon

Engl ish

CORman name

Sears i i dae

ami chth abei

TLbeshoulders

Shinning tubeshoulder

Paralepidae

Parale is atlantica

Barracudi nas

Northern duckbi II barracudina

Alepisauridae

Ale isaurus ferox

Lancetf i shes

Longnose lancetfish

Scopelarchidae

Benthalbella dentate

Pearleyes

Northern pearleye

Myctoph i dae

D i a hus theta

Lam ctus sp.

Lam ctus ordani

Lam ctus re s lis

Proto cto hum thom soni

Stenobrach i us l euco sarus

Stenobrach ius nannoch i r

Lanternf i shes

Ca l i forni a headl i ghtf i sh

Lampf i sh uni dent.

Brokenl ine lampfish

Pinpoint lampfish

Northern flashl ightfish

Northern l ampf i sh

Garnet lampfish

Oneirodidae

Oneirodes thom soni

Dreamers

Mod dae

Antimora microle

Laemonema lon

Moras

Pacific flatnose

Gadidae

Gadus macroce halus

Thera ra chalco ranma

Codf i shes

Pacific cod

Walleye pollock

Zoarcidae

Bothrocara brunneum

cenchel s sp.

coda us sp.

coda us endemoscotus

codes brevi 

codes di a terus

codes a l ear i s

codes soldatovi

Puzanovi a rubra

Eelpouts

Twol ine eelpout

Eelpout unident.

Eelpout unident.

Deepwater eelpout

Shortfin eel pout

Black ee l pout

Wattled eelpout

Macrour i dae

Albatrossia ectoral is

Cor haenoides acrole

Cor haenoides cinereus

Cor haenoides fi l ifera

Grenadi ers

Giant grenadier

Pacific grenadier

Popeye

Sconeeresoc i dae

Cololabis saira

Sauries

Pac if i c saury

Melaqilaidae

Melam haes lu ubris

Poromi t ra crass i ce

Bigscale

Hi ghsnout bi gsca l e

Crested bigscale

Tri chodontidae

Trichodon trichodon

Sandt i shes

Pacific sandfish

Bathymaster i dae

Bath aster caerul eofasci stUB

Bath aster s natus

Ron ui lug ordani

Ronqui ls

. Alaskan ronquil

Searcher

Northern ronqui l

Japanese

Standard name

Haname i wash i

suns r i demeeso

Todohadaka

Mamehadaka

M i kadohadaka

Koh i rehadaka

Sekk i hadaka

Kanadadara

Itch i k i dare

Madara

Suketodara

Yawagenge

Hakusengaj i

Sokogaj i

Akagenge

Munedara

Ibarahige

Karafutosokodara

Honkabutouo

Kabutouo

Ezohatahata

Madaramedamauo

Sokomedamauo

80 83 86

Year
349

Table C-1. (continued)

Taxon

Eng li sh

CORman name

Stichaeidae

ozoi chth s mar orius

Lum enella lon i rostri s

Prieklebaeks

Pearly prickleback

Longsnout prickleback

Anarh i chadi dae

Anarhichas oriental is

"ol ffishes

Bering wol ffishes

Cryptaeanthodi dae

tacanthodes anteus

"rymouths

Giant wrymouth

lapror i dae

rora s i l enus

Prowfishes

P rowf i sh

Anmodyt i dae

Anmo tes hexa terus

Sand lances

Pacific sand lance

I eostei dae

Icosteus aeni maticus

Ragfishes

Ragf i sh

Seorpaeni dae

Sebastes aleutianus

Sebastes alutus

Sebastes babcocki

Sebastes bores lis

Sebastes ci l latus

Sebastes crameri

Sebastes melano

Sebastes stinus

Sebastes rori 

Sebastes o l i ni s

Sebastes ruberrimus

Sebastes veri e atus

Sebastes zacentrus

Sebastolobus alascanus

Sebastolobus al tivel is

Sebastolobus macrochir

Seorpi oof i shes

Rougheye rockfish

Pacific ocean perch

Redbanded rockfish

Short raker rockf i sh

Dusky rockf i sh

Darkblotched rockfish

Black rockfish

Blue rockfish

Red stripe rockfish

Northern rockf i 

Yelloweye rockfi sh

Harlequin rockfish

Sharpch i n rockf i sh

Shortspi ne thornyhead

Longspi ne thornyhead

Broadbanded thornyhead

Mop l opomat i dae

Ano oma fimbria

Sablefishes

Sablefish

Hexagranmi dae

Hexa rammos deca ranmus

Hexa ranmos la oce halus

Pleuro ranmus mono ter ius

Greenl ings

Kelp greenl ing

Rock greenl ing

Atka mackerel

Cott i dae

Artedi ell us sp.

Artediellus acificus

Das cottus set 

Eno s diceraus

Eno s lucasi

Eur en r i nus

nocanthus aleatus

nocanthus isti II i

nocanthus tri cus i s

Hemi le idotus hemi idotus

Hemi le idotus ordani

Hemi le idotus i l io

Hemi l e i dotus s i nasus

Hemi le idotus lepus

Hemitri terus bel ini

Icelus cavifrons

Icelus canal iculatus

Ice l us scut i 

Icelus s ini

Seulpins

Sculpin unident.

Pacific hookear sculpin

Spinyhead sculpin

Antlered sculpin

Leister sculpin

Smoothcheek sculpin

Armorhead sculpin

Threaded sculpin

Arctic staghorn sculpin

Red Irish lord

Yellow I ri sh lord

Butterfly sculpin

Brown Irish lord

Longfin Irish lord

Bigmouth sculpin

Pit-head sculpin

Porehead sculpin

Thorny sculpin

Japanese

Standard name

Nezuniginpo

Bouzuginpo

Ki tal kanago

I rezuni konnyakuaj i

Aramenuke

Arasukamenuke

Akash i mamenuke

Hi reguromenuke

Nagamenuke

Yotsuj imamenuke

Aomenuke

Ki tanomenuke

Arasukaakazoi

Madaraakauo

Agomenuke

Arasukak i ch i j i

Hi renagaki chi j i

K i ch i j 

Gindara

Arasuka- ainame

Ki tanohokke

Ganko

Oni kaj i ka

Yagi shi ri kaj i ka

Ch i kamekaj i ka

Sh iberi atsumagurokaj i ka

Honyokosuj i kaj i ka

Nameyokosuj i kaj i ka

Kemush i kaj i kamodoki

Koorimatsukaj ika

Koori kaj i ka

80 83 86

Year
Table C-1. (continued)

Taxon

Icelus uncinal is

Jordani a zono

tocottus armatus

Ma l acocottus sp.

Malacocottus kincaidi

Malacocottus zonurus

oxoce ha l us sp.

oxoce ha l us o l acanthoce ha l us

Nautichth s oculofasciatus

chrolutes aradoxus

r i scus ano l us

Tri s forficata

Tri s macellus

Tri el i

Tri s sce ti cus

Agonidae

ido horoides bartoni

Bath onus ni innis

onus uadri corni s

Podothecus aci enserinus

Sarri tor frenatus

Sarr i tor l e torh nchus

Cyclopteri dae

toc clus ventricosus

Care roctus bowers i anus

Care roctus candi dug

Care roctus colletti

Care roctus c selurus

Care roctus furcellus

Care roctus i lberti

Care roctus melanurus

Care roctus cnosoma

Care roctus rastrinus

stall ichth s c clos i lug

Elassodiscus sp.

lassodi scus caudatus

E l assod i scus t remebundus

Eumi crotremus andri ashevi

Eumi crotremus orbi s

Lethot remus rout i cus

aris sp.

L i aris denn

Nectol i aris ela icus

Parali aris sp.

Paral i aris dact losus

Rhinol i aris sp.

P leur-onect i dae

Atheresthes evermanni

Atheresthes stomi 

Cl idoderma as errimum

Embass i chth s bath bi us

rrex zach i rug

Hi l ossa ides e l assodon

lossus stenole

Mi crostomus aci fi cus

Platichth s stellatus

Pleuronectes asper

Pleuronectes bi l ineatus

Pleuronectes isole

Pleuronectes vetulus

Reinhardt i us hi lossoi des

350

Eng li sh

Coll1Tlon name

Longfin sculpin

Pacific staghorn sculpin

Sculpin unident.

Blackfin sculpin

Sculpin unident.

Great sculpin

Sai l fin sculpin

Spineless sculpin

Scissortai l sculpin

Roughspine sculpin

Ribbed sculpin

Spectacled sculpin

Poacher-s

Aleutian all igatorfish

Blackfin poacher

Fourhorn poacher

Sturgeon poacher

Sawback poacher

Longnose poacher

Snai l fishes

Smooth lumpsucker

Blacktai l snai l fish

Blotched snai l fish

Snai l fi sh unident.

Humpback sna i l fish

Pimpled lumpsucker

Pacific spiny lumpsucker

Lumpsucker

Lumpsucker uni dent.

Marbl ed sna i l fish

Tadpole snai l fi sh

Lumpsucker uni dent.

Red snai l fish

Snai l fi sh unident.

Righteye flounder-s

Kamchatka flounder

Arrowtooth flounder

Roughscale flounder

Deepsea sole

Rex sole

Flathead sole

Pacific hat ibut

Dover sole

Starry flounder

Yellowfin sole

Rock sole

Butter so l e

Engl ish sole

Greenland hat ibut

Japanese

Standard name

Himekoorikaj ika

Montsukikajika

Kobush i kaj i ka

Togekaj i ka

Futamatakaj i ka

Hokkyokukaj i ka

Ni r-amikaj ika

Tatetokubi r-e

Sokotokubi re

Ki tanotokubi re

Yasetengutokubi re

Tengutokubi re

Hoteiuo

Arasukabikunin

Aibikunin

Ogurokonnyakuuo

Konnyakuuo

Sakebikunin

Zeni gatasui shouo

Fuura i kusauo

I bodango

Kitadangouo

Kokuteni nk i uo

Aburagarei

Arasukaaburagarei

Samegarei

Shimofurigarei

Hi renaganameta

Umagarei

Ohyo

Koganega re i

Shumushugarei

Karasugarei

80 83 86

Year
351

Table C-1. (continued)

Year

Taxon

Engl ish

CORman name

Japanese

Standard name 80 83 86

SQUID

Onychoteuth i dae

Moroteuthis robustus Giant squid Nyudouika

Red squid Dosuika

Boreopacific senate squid Takoi ka

Mako senate squi d Makkoutako i ka

Kuj akui ka

Gonatidae

Berryteuthis magister

GonatoDs i s borea lis

GonatoDs is makko

Cranchi idae

Taonius Davo

OCTOPUSES

Octopodidae

Octopus sp.

Octopus dofleini

Octopuses

Octopus unident.

North Pacific giant octopus M i zudako

Opi sthoteuth i dae

SCALLOPS

Pectinidae

Ch l amvs sp.

Chlamvs islandica

Pecten caurinus

Scallops

Scallop unident.

Weathervane sca II op

SHRIMP

Pandal idae

PandaloDsis aleutica

PandaloDsis ample

PandaloDsis dispel'

Pandalus boreal is

Pandalus Qoniurus

Pandalus hYDSinotus

Pandalus tridens

Pandal id shrinp

Aleutian bigeye

Deepwater bi geye

Sidestripe shrimp

Northern shrimp

Humpy shrimp

Coonstriped shrimp

Yellowleg pandal id

Sh i maakaebi

Hokkokuakaebi

Beni suj i ebe

CRAB

ithodidae

ithodes ae uis ina

Lithodes couesi

Para l i thodes camtschat i ca

Paral ithodes lat

ithodid crabs

Golden king crab

Scarlet king crab

Red king crab

Blue king crab

Ibaraganimodoki

Ki taibaragani

Tarabagani

Aburagani

Majidae

Ch i onoecetes hybr i 

Chionoecetes an ulatus

Ch i onoecetes ba i rdi

Ch i onoecetes o i l i 0

Ch i onoecetes tanneri

Spi del' crabs

Hybrid Tanner crab

Triangle Tanner crab

Tanner crab

Snow crab

Grooved Tanner crab

ogezuuwa i gan i

Zuwa i san i

Cancridae

Cancer ma ister

Cancer crabs

Dungeness crab

Atelecycl idae

Erimacrus isenbecki i

Hai I' crabs

Hai I' crab Kegani

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. 

AFSC30 LORENZ, J. M. 1994. Distribution and habitat of adult salmon in the Situk River, Alaska: Potential

impacts of flooding from Russell Fiord, 27 p. NTIS No. PB94-151859.

29 IGNELL, S. E., L. J. SIMON, and M. L. DAHLBERG. 1994. Estimation of salmonid bycatch in the

1989 Japanese squid driftnet fishery, 45 p. NTIS No. PB94-152105.

28 MORTENSEN, D. G., and H. SAVIKKO. 1993. Effects of water temperature on growth of juvenile

pink salmon (Oncorhynchus gorbuscha), 12 p. NTIS No. PB94-145349.

27 LOW, L-L. (coordinator). 1994. Status of living marine resources off Alaska, 1993, 110 p. NTIS No.

PB94-149846.

26 LOW, L-L. (coordinator). 1993. Status of living marine resources off the Pacific coast of the United

States for 1993, 90 p. NTIS No. PB94-133733.

25 KINOSHITA, R. K., A. GREIG, J. D. HASTIE, and J. M. TERRY. 1993. Economic status of the

groundfish fisheries off Alaska, 1992, 102 p. PB94-142759.

24 SINCLAIR, E. H. (editor) 1993. Fur seal investigations, 1991, 142 p. NTIS No. PB94-118171. 

23 PARKS, N. B., F. R. SHAW, and R. L HENRY. 1993. Results of a 1988 trawl survey of groundfish

resources of the upper continental slope off Oregon, 164 p. NTIS No. PB94-118163.

22 YANG, M-S. 1993. Food habits of the commercially important groundfishes in the Gulf of Alaska

in 1990, 150 p. NTIS No. PB94-112463.

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

fishery products, 1992, 52 p. NTIS No. PB93-226652.

20 REEVES, J. E. 1993. Use of lower minimum size limits to reduce discards in the Bristol Bay red

king crab (Paralithodes camtschaticus) fishery, 16 p. NTIS No. PB93-228187.

19 SYRJALA, S. E. 1993. Species-specific stratification and the estimate of groundfish biomass in

the Eastern Bering Sea, 20 p. PB94-103215.

18 PELLA, J., M. HOFFMAN, S. HOFFMAN, M. MASUDA, S. NELSON, and L. TALLEY. 1993. Adult

sockeye and pink salmon tagging experiments for separating stocks in northern British Columbia and

southern Southeast Alaska, 1982-1985, 134 p. NTIS No. PB93-226660.

17 SEASE, J. L., J. P. LEWIS, D. C. MCALLISTER, R. L. MERRICK, and S. M. MELLO. 1993. 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 1992, 57 p. NTIS No. PB93-226025. 

16 FISCUS, C. F. 1993. Catalogue of cephalopods at the National Marine Mammal Laboratory, 183 p. NTIS

No. PB93-226678.