NOAA Technical Memorandum NMFS-AFSC-83

Data Report:

National Marine Fisheries Service

Longline Surveys, 1991-96

by

T. L. Rutecki, M. F. Sigler, and H. H. Zenger Jr.

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Alaska Fisheries Science Center

November 1997
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:

Rutecki, T.L., M. F. Sigler, and H. H. Zenger Jr. 1997. Data report:

National Marine Fisheries Service longline surveys, 1991-96. U.S. Dep.

Commer., NOAA Tech. Memo. NMFS-AFSC-83, 64 p.

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

National Marine Fisheries Service, NOAA.
NOAA Technical Memorandum NMFS-AFSC-83

Data Report:

National Marine Fisheries Service

Longline Surveys, 1991-96

by

T. L. Rutecki1 M. F. Sigler1 and H. H. Zenger Jr2

1Auke Bay Laboratory

Alaska Fisheries Science Center

11305 Glacier Highway

Juneau, AK 99801-8626

2Resource Assessment and Conservation Engineering Division

Alaska Fisheries Science Center

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

Seattle, WA 98115-0070

U.S. DEPARTMENT OF COMMERCE

William M. Daley, Secretary

National Oceanic and Atmospheric Administration

D. James Baker, Under Secretary and Administrator

National Marine Fisheries Service

Rolland A. Schmitten, Assistant Administrator for Fisheries

November 1997
This document is available to the public through:

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iii

ABSTRACT

This report summarizes the results of the 1991-96 National Marine Fisheries

Service longline surveys of the Gulf of Alaska and eastern Aleutian Islands. Sablefish,

Anoplopoma fimbria, was the principal target species, although shortspine thornyhead,

Sebastolobus alascanus, rougheye rockfish, Sebastes aleutianus, and shortraker rockfish,

Sebastes borealis, populations appear to have been sampled adequately to derive

meaningful abundance indices. The survey area in the Gulf of Alaska extends from

Islands of Four Mountains (170°W long.) eastward to Dixon Entrance (133°25’W long.)

and covers the upper continental slope and selected gullies. Beginning in 1996, the

eastern Aleutian Islands were surveyed from Amchitka Pass (178°58’W long.) to the

western end of Umnak Island (170°12’W long.).

Sablefish abundance indices (relative population number, RPN) for the Gulf of

Alaska declined slightly from 1991 to 1996. The two large annual declines in 1992 and

1994 were followed by slight increases in 1993 and 1995. Sablefish relative biomass

(relative population weight, RPW) changes were similar to those for sablefish RPN in the

Gulf of Alaska. The length compositions for both sexes of sablefish increased from 1991

to 1996.

Gulfwide, shortspine thornyhead RPN and RPW increased during 1996 to the

highest number for any survey year, exceeding the previous high in 1992. For all years,

their length modes changed slightly.

Gulfwide, RPN and RPW for rougheye rockfish varied without a discernable trend

from 1991 to 1994, then increased substantially in 1995 and 1996. Their length modes

were generally 42-44 cm fork length (FL).

Shortraker rockfish RPN and RPW declined from 1991 to 1994 and then

increased in 1995 and 1996. Their length modes were generally 56-63 cm FL.
V

CONTENTS

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

MATERIALS AND METHODS ..................................... 1

Vessels and Gear .......................................... 1

Survey Area and Operations ................................... 2

Data Collection ........................................... 3

Other Biological Sampling .................................... 3

Analytical Methods ......................................... 4

RESULTS .................................................... 4

Sablefish ................................................ 4

Relative Abundance ................................... 4

Length Compositions .................................. 5

Shortspine Thornyhead ...................................... 5

Relative Abundance ................................... 5

Length Compositions .................................. 5

Rougheye Rockfish ......................................... 5

Relative Abundance ................................... 5

Length Compositions .................................. 5

Shortraker Rockfish ........................................ 6

Relative Abundance ................................... 6

Length Compositions .................................. 6

Greenland Turbot ........................................... 6

CITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

TABLES

Table 1 .--Area, number of stations, and year surveyed . . . . . . . . . . . . . . . . . . . . . . 11

Table 2.--Relative population number (RPN) and relative population weight (RPW)

of sablefish by area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 3.--Relative population number (RPN) and relative population weight (RPW)

of shortspine thornyhead by area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 4.--Relative population number (RPN) and relative population weight (RPW)

of rougheye rockfish by area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 5.--Relative population number (RPN) and relative population weight (RPW)

of shortraker rockfish by area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
vi

FIGURES

Figure 1 .--NMFS sablefish longline survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 2.--Average sablefish catch per skate by region in the Aleutian Islands for

the Japan-U.S. cooperative longline survey, 1983-94. . . . . . . . . . . . . . . . . . . 22

Figure 3.--Sablefish length frequencies weighted for relative population number . . . . 23

Figure 4.-Shortspine thornyhead length frequencies weighted by relative population

number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 

Figure 5.--Rougheye rockfish length frequencies weighted by relative population

number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Figure 6.--Shortraker rockfish length frequencies weighted by relative population

number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Figure 7.--Sablefish length frequencies weighted by relative population number for

the Northeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Figure 8.--Sablefish rockfish length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 61

Figure 9.--Shortspine thornyhead length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 61

Figure 10.--Shortspine thornyhead length frequencies weighted by relative

population number for the Southeastern Aleutian area, 1996. . . . . . . . . . . . . 62

Figure 11.--Rougheye rockfish length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 62

Figure 12.--Rougheye rockfish length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 62

Figure 13.--Shortraker rockfish length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 63

Figure 14.-Shortraker rockfish length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 63

Figure 15 .--Greenland turbot length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 63

Figure 16.--Greenland turbot length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996. . . . . . . . . . . . . . . . . . . . . 64
INTRODUCTION

From 1978 through 1994, Japan and the United States cooperatively conducted an

annual longline survey covering the upper continental slope of the Gulf of Alaska. In the

later years, the survey was expanded to the eastern Bering Sea and Aleutian Islands

region. The research supplied information needed to estimate the abundance of sablefish,

Anoplopomafimbria, and other groundfish species (Sasaki 1985, Sigler and Fujioka 1988).

Since 1987, the Alaska Fisheries Science Center, National Marine Fisheries Service

(NMFS), has conducted an independent annual longline survey designed to continue the

time series of data should Japan discontinue as a partner. Since the cooperative survey

was discontinued, the NMFS survey has been the primary method for assessing sablefish

and other groundfish species in Alaska. The cooperative survey covered the Gulf of

Alaska, eastern Bering Sea, and Aleutian Islands region, whereas the NMFS survey

covered only the Gulf of Alaska until 1996, when the survey was expanded to cover the

Aleutian Islands. Sampling of the eastern Bering Sea is planned for 1997.

The NMFS longline survey covers the same stations (Fig. 1) and season and uses

similar sampling gear as the cooperative longline survey. In addition, the NMFS longline

survey has expanded areal coverage from the upper continental slope to major deepwater

gullies on the continental shelf. The primary purpose of the NMFS longline survey is to

determine the relative annual abundance and length composition of sablefish, shortspine

thornyhead, Sebastolobus alascanus, rougheye rockfish, Sebastes aleutianus, and shortraker

rockfish, Sebastes borealis, in the Gulf of Alaska, Aleutian Islands, and eastern Bering

Sea; only these species will be discussed in this report. This report presents the 1991-96

survey results and updates the report on the 1987 (Sigler and Zenger 1989) and 1988-90

surveys (Zenger and Sigler 1992).

MATERIALS AND METHODS

Vessels and Gear

The chartered fishing vessel Ocean Prowler (47 m) was used for the 1991-93 and

1995 surveys, and the chartered fishing vessel Alaskan Leader (46 m) was used for the

1994 and 1996 surveys. As in the 1988-90 surveys, 16 km (8.6 nautical miles, nmi) of

groundline containing 7,200 hooks were set each day. The groundline consisted of 160

sections called skates, and each skate was 100 m (55 fathoms) long with 45 size 13/0

Mustad circle hooks spaced 2 m apart. The groundline was weighted with 3.2-kg lead

balls snapped onto the end of each skate. Each hook was hand baited with about 5.5 kg

of chopped squid, Illex illecebrosus, mantles per 100 hooks. The squid mantles were 15-

23 cm long. Each mantle was cut into 3 or 4 pieces, each about 4-6 cm long.
2

Survey Area and Operations

The survey area in the Gulf of Alaska extends from Islands of Four Mountains

(170°W long.) eastward to Dixon Entrance (133°25’W long.) and covers the upper

continental slope and selected gullies. The survey area in the eastern Aleutian Islands

extends from Amchitka Pass (178°58’W long.) to the western end of Umnak Island

(170°12’W long.). The western half of the Aleutian Islands region also was sampled

during the cooperative longline surveys from 1980 to 1994, but is not sampled in the

NMFS longline survey because of the low sablefish catch rate (Fig. 2).

Most stations were sampled at 200-1,000 m depths, but some at 150 m depths or

less. From 1988 through 1990, the survey period was 26 June to 12 September. From

1991 through 1994, the survey was shifted about 2 1/2 weeks later, to 13 July to 27

September, to avoid conflicts with the commercial sablefish fishery, which started 45 days

later in these years than it had in 1988-90. Implementation of the Individual Fishery

Quota (IFQ) system in the longline fishery for sablefish and Pacific halibut, Hippoglossus

stenolepis, started in 1995, and the survey was moved back to near the 1988-90 periods.

During 1996, the eastern Aleutian Islands were surveyed from 20 May to 4 June and the

Gulf of Alaska from 6 June to 18 August; the Gulf of Alaska was surveyed 16 days earlier

than in 1995 to avoid conflicts with the rockfish trawl fishery in the Kodiak Island and

west Yakutat areas.

The sampling gear was set from shallow to deep water and usually was retrieved in

the same order. Setting began about 0630 hours; retrieval began about 0930 hours and

was completed about 1900 hours. Soak time, defined as the time between last buoy

deployment and first buoy retrieval, ranged from 3 to 11 hours. This variation in soak

time has little effect on the survey index for sablefish (Sigler 1993).

Until 1995, 73 stations were sampled in the Gulf of Alaska: 45 along the upper

slope, 27 in gullies, and 1 on the continental shelf (Table l).1 Because of the low (2-4%

of total) relative number of sablefish there, two stations each in Alsek Strath and Iphigenia

Gully were discontinued in 1995 and the two Shumagin Gully stations in 1996. These

deletions allowed increased sampling in Amatuli Gully (six stations added in 1995)

because it has accounted for about 10-l5% of the total relative number of sablefish

(Fig. 3f) and because commercial fishing effort was concentrated in the eastern half of

Amatuli Gully, implying that sablefish density was higher there. Previously, only the

eastern half was sampled and, therefore, any spatial differences within the gully were not

measured. Hence, sampling was extended to the western half of Amatuli Gully as well as

to two nearby gullies. During 1996, 14 stations were sampled in the eastern Aleutian

Islands, whereas 17 stations had been sampled during the cooperative survey; the 3

stations were eliminated because of excessive gear loss.

1

The 45 stations on the upper continental slope correspond to station numbers 62-86, 88-102, and 104-108

of the Japan-U.S. cooperative longline survey (Sasaki and Yano 1990). Gully station 26 corresponds to station 87

of the cooperative longline survey. Shelf station 42 (station 103 of the cooperative longline survey) is on the

continental shelf off Baranof Island. The remaining 26 gully stations are additional to the original 47 stations of

the cooperative longline survey.
3

Data Collection

Catch data were recorded on a handheld electronic data logger. During gear

retrieval, a scientist recorded the species of each hooked fish, the condition of each

unoccupied hook (absent, broken, or tangled), and whether bait remained on the hook.

Time of day was recorded continuously from an internal clock, and depth was entered

when the first skate came aboard, at the beginning of each fifth skate, when crossing into

a new depth interval (0-100 m, 101-200 m, 201-300 m, 301-400 m, 401-600 m,

601-800 m, 801-1,000 m, or l,00l-1,200 m), and when the last skate came aboard.

Fish lengths were recorded using 4 bar-code-based measuring board and a bar-code

reader and data-storage device (Sigler 1994). Fish lengths were grouped by depth interval

for sablefish, Pacific cod, Gadus macrocephalus, grenadiers (Macrouridae), arrowtooth

flounder, Atheresthes stomias, rockfishes, Sebastes spp., and shortspine thornyhead.

Lengths of sablefish and Pacific cod also were recorded by sex. Pacific halibut were

counted and released at the rail without being measured. Catch and length frequency data

were transferred to a computer and electronic backup media twice a day. As in the

previous surveys, the conditions of the charter allowed the charter vessel to retain most of

the catch after the scientific data were recorded, except for prohibited species and those

retained as scientific specimens.

Other Biological Sampling

Otoliths were collected, individual lengths and weights recorded, and maturity

determined from a random sample of sablefish at each station starting in 1996.

Previously, biological sampling was conducted on the cooperative survey but not the

NMFS survey. The catch was sampled randomly, rather than stratified by length, because

the important variance of proportion-at-age estimates was examined from previous otolith

collections and found to be lower for random sampling, which is also true in general

(Kimura 1977). A random sample was taken as follows. The first hook of each skate was

examined at gear retrieval. If a sablefish occupied the hook, that fish was set aside for

other biological sampling. If no sablefish occupied the first hook, then no fish was set

aside from that skate. As catch rate varies with station, depth, etc., examining a fixed

fraction of the gear ensures that a fixed fraction of the sablefish catch is sampled. The

otolith sample was stratified by station and depth stratum (hereafter referred to as stratum).

As the selected fish came aboard, the fisherman at the rail separated the fish into tubs,

according to depth strata. Length, weight, and maturity were determined; both otoliths

were extracted and put in vials filled with 50% ethanol. Fork length and weight were

recorded as accurately as possible. Separate specimen forms were maintained for each

station and stratum.
4

Analytical Methods

The following is an overview; more detailed treatment of these analytical methods

may be found in Sigler and Zenger (1989). The number of fish caught per skate (catch

per unit effort [CPUE]) was calculated by species for each stratum sampled at a station.

Relative population number (RPN, an index of relative abundance in numbers) was

computed for each species (Quinn et al. 1982, Gulland 1983, Sasaki 1985) for strata from

201 to 1,000 m, but not for shallower waters because we considered that the shallower

depths were not sampled adequately to compute an RPN. The CPUE for each stationstratum was multiplied by the area of the stratum. Then the resulting products for all

stations within a stratum were averaged to obtain an RPN.

To examine the size distribution of the principal species, RPN-weighted length

frequencies were computed for depths 201-l,000 m, then multiplied by the sample length

frequencies. The resultant RPN length frequencies by station and stratum were averaged

within stratum to calculate a RPN length frequency by stratum. Finally, to assess relative

biomass, we computed relative population weights (RPWs) by using the size distributions

and length-weight equations.

Rougheye and shortraker rockfish were grouped together as catches were recorded

because they cannot be separated readily while the longline comes in. Length frequencies

were tallied separately, allowing estimation of RPN and RPW for each species.

The survey area includes most of the adult habitat of sablefish, rougheye and

shortraker rockfishes, and shortspine thornyhead and, therefore, samples the adult fraction

of their populations in the Gulf of Alaska and eastern Aleutian Islands. In contrast, large

portions of the habitat of adult Pacific cod, Pacific halibut, rockfish species other than

rougheye and shortraker rockfishes, grenadiers, and arrowtooth flounder are not included

in the survey area and, thus, the RPN does not reflect the total abundance of those species.

Consequently, the survey results for those species are not reported here.

RESULTS

Relative Abundance

Sablefish

Overall, sablefish numbers declined slightly from 1991 to 1996. The two large

annual declines in 1992 and 1994 were followed by slight increases in 1993 and 1995

(Table 2). The RPW also decreased from 1991 to 1996, but less than RPN because the

largest decreases in RPN were in gullies, where the fish are generally smaller than in the

upper slopes.
5

Length Compositions

The length compositions for each sex generally shifted toward larger fish from

1991 to 1996 (Figs. 3a-n). Few fish of either sex were less than 50 cm fork length (FL).

Generally, only one length mode was evident for each sex by area for all years. Length

modes were generally between 60 and 63 cm FL for males and between 67 and 70 cm FL

for females.

Relative Abundance

Shortspine Thornyhead

Total shortspine thornyhead RPN increased in 1996 to the highest number of any

survey year, exceeding the previous high in 1992 (Table 3). The RPN on slopes was

greater than in gullies. Shortspine thornyhead were more abundant in the central and

western gulf areas (Shumagin, Chirikof, and Kodiak) than in the eastern gulf areas

(Yakutat and Southeast) during all years, but none has ever been caught in Shumagin

Gully or Shelikof Trough in a survey. RPW paralleled RPN in all years.

Length Compositions

Shortspine thornyhead length modes changed slightly each year. Length modes

were generally between 36 and 44 cm FL (Figs. 4a-1). Usually only one length mode was

evident.

Relative Abundance

Rougheye Rockfish

RPN and RPW of rougheye rockfish varied without a discernable trend from 1991

to 1994. They increased substantially in 1995 and 1996; 1996 values were record highs

(Table 4).

In most years, rougheye rockfish RPN was highest in the Southeast area.

Length Compositions

Rougheye rockfish length modes were generally between 42 and 44 cm FL for all

years (Figs. 5a-f). Usually only one length mode was evident.
6

Relative Abundance

Shortraker Rockfish

Shortraker rockfish RPN and RPW declined in 1992 and 1994 and then increased

in 1993, 1995, and 1996 (Table 5). The RPN and RPW were always highest in the

Southeast area.

Length Compositions

Shortraker rockfish length modes were generally between 56 and 63 cm FL for all

years (Figs. 6a-f). Usually only one length mode was evident.

Aleutian Area

Inasmuch as this was the first year of sampling in the Aleutian area, length

compositions are merely shown (Figs. 7-16). Catches of Greenland turbot in the Gulf of

Alaska have been low. Now that sampling has expanded to the Aleutian Islands and

Bering Sea where catch rates are higher, they will be discussed in future reports.
7

CITATIONS

Gulland, J. A. 1983. Fish stock assessment: a manual of basic methods. John Wiley &

Sons, New York, 223 p.

Kimura, D. K. 1977. Statistical assessment of the age-length key. J. Fish. Res. Board

Can. 34:317-324.

Quinn, T. J., II, S. H. Hoag, and G. M. Southward. 1982. Comparison of two methods

of combining catch-per-unit-effort data from geographic regions. Can. J. Fish.

Aquat. Sci. 39:837-846.

Sasaki, T. 1985. Studies on the sablefish resources in the North Pacific Ocean. Far Seas

Fish. Res. Lab. Bull. 22, 108 p.

Sasaki, T., and K. Yano. 1990. Report on Japan-U.S. joint longline survey by Tomi

Maru No. 88 in the eastern Bering Sea, Aleutian region and Gulf of Alaska, 1988.

Fisheries Agency of Japan, National Research Institute of Far Seas Fisheries,

Shimizu, 424, Japan.

Sigler, M. F. 1993. Stock assessment and management of sablefish Anoplopoma fimbria

in the Gulf of Alaska. Ph.D. dissertation, University of Washington, Seattle, 190

p.

Sigler, M. F. 1994. An electronic measuring board with bar codes. Trans. Am. Fish. Soc.

123:115-117.

Sigler, M. F., and J. T. Fujioka. 1988. Evaluation of variability in sablefish, Anoplopoma

fimbria, abundance indices in the Gulf of Alaska using the bootstrap method. Fish.

Bull., U.S. 86:445452.

Sigler, M. F., and H. H. Zenger, Jr. 1989. Assessment of Gulf of Alaska sablefish and

other groundfish based on the domestic longline survey, 1987. U.S. Dep.

Commer., NOAA Tech Memo. NMFS F/NWC-169, 54 p.

Zenger H. H., Jr., and Sigler, M. F. 1992. Relative abundance of Gulf of Alaska

sablefish and other groundfish based on National Marine Fisheries Service longline

surveys, 1988-90. U.S. Dep. Commer., NOAA Tech Memo. NMFS F/NWC-216,

103 p.
TABLES
11

Table 1 .--Area, number of stations, and year surveyed (x) for the National Marine

Fisheries Service longline survey, 1991-96. Dash indicates no sampling.
12

Table 2.--Relative population number (RPN) and relative population weight (RPW) of

sablefish by area, 1991-96. Dash indicates no sampling.
13

Table 3.--Relative population number (RPN) and relative population weight (RPW) of

shortspine thornyhead by area, 1991-96. Dash indicates no sampling.
14

Table 4.--Relative population number (RPN) and relative population weight (RPW) of

rougheye rockfish by area, 1991-96. Dash indicates no sampling.
15

Table 5.--Relative population number (RPN) and relative population weight (RPW) of

shortraker rockfish by area, 1991-96. Dash indicates no sampling.
FIGURES
Figure 1 .--NMFS sablefish longline survey, Aleutian Island; stations.
Figure l.--Extended. NMFS sablefish longline survey, western Gulf of Alaska stations.
Figure l.--Extended. NMFS sablefish longline survey, eastern Gulf of Alaska stations.
Figure 2.--Average sablefish catch per skate by region in the Aleutian Islands for the Japan-U.S. cooperative longline

survey, 1983-94. 
Figure 3a.--Sablefish length frequencies weighted for relative population number for

the Shumagin slope by sex, 1991-96.
Figure 3b.--Sablefish length frequencies weighted for relative population number for

Shumagin Gully by sex, 1991-95.
Figure 3c.--Sablefish length frequencies weighted for relative population number for

the Chirikof slope by sex, 1991-96.
Figure 3d.--Sablefish length frequencies weighted for relative population number for

Shelikof Trough by sex, 1991-96.
Figure 3e.--Sablefish length frequencies weighted for relative population number for

the Kodiak slope by sex, 1991-96.
Figure 3f.--Sablefish length frequencies weighted for relative population number for

Amatuli Gully by sex, 1991-96.
Figure 3g.--Sablefish length frequencies weighted for relative population number for

the West Yakutat slope by sex, 1991-96.
Figure 3h.--Sablefish length frequencies weighted for relative population number for

the East Yakutat slope by sex, 1991-96.
Figure 3i.--Sablefish length frequencies weighted for relative population number for

the W-Grounds by sex, 1991-96.
Figure 3j.--Sablefish length frequencies weighted for relative population number for

Yakutat Valley by sex, 1991-96.
Figure 3k.--Sablefish length frequencies weighted for relative population number for

the Southeast slope by sex, 1991-96.
Figure 31.--Sablefish length frequencies weighted for relative population number for

Spencer Gully by sex, 1991-96.
Figure 3m.--Sablefish length frequencies weighted for relative population number for

Ommaney Trench by sex, 1991-96.
Figure 3n.--Sablefish length frequencies weighted for relative population number for

Dixon Entrance by sex, 1991-96.
Figure 4a.--Shortspine thornyhead length frequencies weighted by relative population

number for the Shumagin slope, 1991-96.
Figure 4b.--Shortspine thornyhead length frequencies weighted by relative population

number for the Chirikof slope, 1991-96.
Figure 4c.--Shortspine thornyhead length frequencies weighted by relative population

number for the Kodiak slope, 1991-96.
Figure 4d.--Shortspine thornyhead length frequencies weighted by relative population

number for Amatulli Gully, 1991-96.
Figure 4e.--Shortspine thornyhead length frequencies weighted by relative population

number for the West Yakutat slope, 1991-96.
Figure 4f.--Shortspine thornyhead length frequencies weighted by relative population

number for the East Yakutat slope, 1991-96.
Figure 4g.--Shortspine thornyhead length frequencies weighted by relative population

number for the W-Grounds. 1991-96.
Figure 4h.--Shortspine thornyhead length frequencies weighted by relative population

number for Yakutat Valley, 1991-96.
Figure 4i.--Shortspine thornyhead length frequencies weighted by relative population

number for the Southeast slope, 1991-96.
Figure 4j .--Shortspine thornyhead length frequencies weighted by relative population

number for Spencer Gully, 1991-96.
Figure 4k.--Shortspine thornyhead length frequencies weighted by relative population

number for Ommaney Trench, 1991-96.
Figure 4l.--Shortspine thornyhead length frequencies weighted by relative population

number for Dixon Entrance, 1991-96.
Figure 5a.--Rougheye rockfish length frequencies weighted by relative population

number for the Shumagin slope, 1991-96.
Figure Sb.--Rougheye rockfish length frequencies weighted by relative population

number for the Chirikof slope, 1991-96.
Figure Sc.--Rougheye rockfish length frequencies weighted by relative population

number for the Kodiak slope, 1991-96.
Figure 5d.--Rougheye rockfish length frequencies weighted by relative population

number for the West Yakutat slope, 1991-96.
Figure Se.--Rougheye rockfish length frequencies weighted by relative population

number for the East Yakutat slope, 91-96.
Figure 5f.--Rougheye rockfish length frequencies weighted by relative population

number for the Southeast slope, 1991-96.
Figure 6a.--Shortraker rockfish length frequencies weighted by relative population

number for the Shumagin slope, 1991-96.
56

Figure 6b.--Shortraker rockfish length frequencies weighted by relative population

number for the Chirikof slope, 1991-96.
Figure 6c.--Shortraker rockfish length frequencies weighted by relative population

number for the Kodiak slope. 1991-96.
Figure 6d.--Shortraker rockfish length frequencies weighted by relative population

number for the West Yakutat slope, 1991-96.
Figure 6e.--Shortraker rockfish length frequencies weighted by relative population

number for the East Yakutat slope, 1991-96.
Figure 6f.--Shortraker rockfish length frequencies weighted by relative population

number for the Southeast slope, 1991-96.
Figure 7.--Sablefish length frequencies weighted by relative population number for the

Northeastern Aleutian area, 1996.

Figure 8.--Sablefish rockfish length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996.

Figure 9.--Shortspine thornyhead length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996.
Figure l0.--Shortspine thornyhead length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996.

Figure 11 .--Rougheye rockfish length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996.

Figure 12.--Rougheye rockfish length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996.
Figure 13.--Shortraker rockfish length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996.

Figure 14.--Shortraker rockfish length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996.

Figure 15.--Greenland turbot length frequencies weighted by relative population

number for the Northeastern Aleutian area, 1996.
64

Figure 16.--Greenland turbot length frequencies weighted by relative population

number for the Southeastern Aleutian area, 1996.
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.

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MARTIN, M. H. 1997. Data report: 1996 Gulf of Alaska bottom trawl survey, 235 p. NTIS number

pending.

LAUTH, R. R. 1997. The 1996 Pacific West Coast upper continental slope trawl survey of groundfish

resources off Washington and Oregon: Estimates of distribution, abundance, and length composition,

156 p. NTIS No. PB97-208912.

LAUTH, R. R. 1997. The 1985 Pacific West Coast upper continental slope trawl survey of groundfish

resources off southern Oregon and northern California: Estimates of distribution, abundance, and length

composition, 110 p. NTIS No. PB97-208920.

LAUTH, R. R., M. E. WILKINS, and P. A. RAYMORE JR. 1997. Results of trawl surveys of groundfish

resources of the West Coast upper continental slope from 1989 to 1993, 342 p. NTIS No. PB97-208904.

HILL, P. S., D. P. DEMASTER, and R. J. SMALL. 1997. Alaska marine mammal stock assessments,

1996, 150 p. NTIS No. PB97-203277.

CHUMBLEY, K., J. SEASE, M. STRICK, and R. TOWELL. 1997. Field studies of Steller sea lions

(Eumetopias jubatus) at Marmot Island, Alaska, 1979 through 1994, 99 p. NTIS No. PB97-203376.

OSMEK, S., J. CALAMBOKIDIS, J. LAAKE, P. GEARIN, R. DELONG, J. SCORDINO, S. JEFFRIES, and

R. BROWN. 1997. Assessment of the status of harbor porpoise (Phocoena phocoena) in Oregon and

Washington waters, 46 p. NTIS No. PB97-198436.

WING, B. L., C. W. DERRAH, and V. M. O’CONNELL. 1997. Ichthyoplankton in the eastern Gulf of

Alaska, May 1990, 42 p. NTIS No. PB97-174379.

WILSON, C. D., and M. A. GUTTORMSEN. 1997. Echo integration-trawl survey of Pacific whiting,

Merluccius productus, off the west coasts of the United States and Canada during July-September 1995,

70 p. NTIS No. PB97-174387.

CELEWYCZ, A. G., and A. C. WERTHEIMER. 1997. Suitability of Dry Bay, southeastern Alaska, as

rearing habitat for juvenile salmon, 19 p. NTIS No. PB97-161343.

KINOSHITA, R. K., A. GREIG, D. COLPO, and J.M. TERRY. 1997. Economic status of the groundfish

fisheries off Alaska, 1995, 91 p. NTIS No. PB97-161269.

STRICK, J. M., L. W. FRITZ, and J. P. LEWIS. 1997. 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,

55 p. NTIS No. PB97-144026.

EBBERTS, B. D., and B. L. WING. 1997. Diversity and abundance of neustonic zooplankton in the north

Pacific subarctic frontal zone, 34 p. NTIS No. PB97-138218.

SINCLAIR, E.H. (editor). 1996. Fur seal investigations, 1994, 144 p. NTIS No. PB97-129456.

MERRICK, R. L., T. R. LOUGHLIN, and D. G. CALKINS. 1996. Hot branding: A technique for long-term

marking of pinnipeds, 21 p. NTIS No. PB97-124226.

LANG, G M., and P. A. LIVINGSTON. 1996. Food habits of key groundfish species in the eastern Bering

Sea slope region, 111 p, NTIS No. PB97-124010.