Marine Fisheries Review 2002: Vol 64 Iss 4

65 Pages·2002·22.7 MB·English

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Marine Fisheries
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W. L. Hobart, Editor
J. A. Strader, Managing Editor
On the cover:
A northern rockfish,
Sebastes polyspinus, in
the Aleutian Islands,
photographed from a sub-
mersible. NMFS photo-
graph by Robert Stone,
AFSC Auke Bay Laboratory.
Articles 64(4), 2002
The Northern Rockfish, Sebastes polyspinus, in
Alaska: Commercial Fishery, Distribution, and Biology David M. Clausen and Jonathan Heifetz
Measuring Fishing Capacity and Utilization with Roaald G. Felthoven, Terry Hiatt,
Commonly Available Data: An Application to Alaska Fisheries and Joseph M. Terry
Characteristics of Shark Bycatch Observed on Pelagic Lawrence R. Beerkircher, Enric Cortés,
Longlines off the Southeastern United States, 1992-2000 and Mahmood Shivji
Spatial and Temporal Distribution of Sea Turtles
in the Western North Atlantic and the U.S. Gulf of
Mexico from Marine Fishery Statistics Survey (MRFSS) Joanne Braun-McNeill and Sheryan P. Epperly
Index
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The Northern Rockfish, Sebastes polyspinis, in Alaska:
Commercial Fishery, Distribution, and Biology
DAVID M. CLAUSEN and JONATHAN HEIFETZ
Introduction indicate that northern rockfish is the Bering Sea. The only biological study to
second most abundant rockfish species deal exclusively with northern rockfish
The northern rockfish, Sebastes poly- there, surpassed only by Pacific ocean is that of Westrheim and Tsuyuki (1971).
spinis, is one of the most abundant and perch, S. alutus (Harrison, 1993; Ronholt Their report presented information on
commercially valuable members of its et al., 1994; Stark and Clausen, 1995; many aspects of northern rockfish biol-
genus in Alaska waters. As implied by Martin and Clausen, 1995; Martin, 1997). ogy, including taxonomy, distribution and
its common name, this fish has one of Amongst all species caught in three sur- abundance, size composition, age and
the most northerly distributions among veys of each region that were conducted growth, and size at maturity. Although
the 60+ species of Sebastes in the North in the 1990's, northern rockfish ranked this study still provides valuable informa-
Pacific Ocean. It ranges from extreme tenth in average biomass in the Gulf tion, much of it now has to be considered
northern British Columbia around the of Alaska, and fourth in the Aleutian somewhat outdated. The distribution
northern Pacific Rim to eastern Kam- Islands.* Since 1990, northern rockfish and abundance data came from research
chatka and the northern Kurile Islands has supported a valuable domestic trawl
and also north into the eastern Bering Sea fishery in Alaska; for the Gulf of Alaska
(Allen and Smith, 1988; Orlov!), but is region alone, gross wholesale value of 'Orlov, Alexie, Russian Federal Research Insti-
common only in Alaska waters. this fishery was estimated at $3.5 mil- tute of Fisheries and Oceanography (VNIRO),
17 Krasnoselskaya, Moscow, 107140, Russia.
Bottom trawl surveys of the Gulf of lion in 1995 and $1.2 million in 1999 Personal commun., May 2000.
Alaska and Aleutian Islands regions (Bibb’). Based on data in the “RACEBASE” database,
Despite this ecological and commer- the trawl survey database maintained by the
NMFS, NOAA, Alaska Fisheries Science Cen-
cial importance, little has been published
ter’s Resource Assessment and Conservation
The authors are with the Auke Bay Labora- on the biology of northern rockfish or its Engineering (RACE) Division, February 2000.
tory, Alaska Fisheries Science Center, National fishery. The species was first described ’Bibb, Sally, Sustainable Fisheries Division,
Marine Fisheries Service, NOAA, 11305 Glacier by Taranetz and Moisev (Taranetz, 1933) NOAA, Natl. Mar. Fish. Serv., Alaska Regional
Hwy., Juneau, AK 99801-8626. Corresponding Office, Juneau, AK. Personal commun., April
author: dave.cla@ unosaae. gnov . based on a specimen from the eastern 1997 and June 2000.
ABSTRACT— The northern rockfish, Se- in the Atka mackerel fishery. In both cial abundance in the surveys. The surveys
bastes polyspinis, is the second most abun- regions, most of the catch was taken from also found two areas of abundance that
dant rockfish in Alaska, and it supports a a number of relatively small and discrete were not evident in the fishery data. Rela-
valuable trawl fishery. Little information is fishing grounds at depths of 75-150 m in tively few juvenile northern rockfish were
available, however, on either the biology of the Gulf of Alaska and 75-175 m in the caught in any of the surveys, but those
this species or its commercial fishery. To Aleutian Islands. These grounds, especially taken in the Guolf Aflas ka tended to occur
provide a synopsis of information on north- in the Gulf of Alaska, are on shallow rises more inshore and at shallower depths than
ern rockfish in Alaska, this study examined or banks located on the outer continental adults. Individual size of northern rock-
data for this species from commercial fish- shelf, and often are surrounded by deeper fish was substantially larger in the Gulfo f
ery observations in 1990-98 and from fish- water. Five fishing grounds were identi- Alaska than in the Aleutian Islands accord-
ery-independent trawl surveys in 1980-99. fied in the Guloff Alaska, and eleven in the ing to both fishery and survey data. Analy-
Nearly all the commercial catch came from Aleutian Islands. One fishing ground in the sis of age data from each region supports
bottom trawling, mostly by large factory- Gulf of Alaska, the “Snakehead” south of this, as Gulf of Alaska fish were found to
trawlers, although smaller shore-based Kodiak Island, accounted for 46% of the grow significantly faster and reach a larger
trawlers in recent years took an increasing total northern rockfish catch in this region. maximum length than those in the Aleutian
portion of the catch in the Guolf Alfask a. Analysis of the survey data generally Islands. Sex ratio in the Guolf Aflas ka was
Most of the northern rockfish catch in revealed similar patterns of geographic nearly 50:50, but females predominated in
the Gulf of Alaska was taken by a directed distribution as those seen in the fishery, the Aleutian Islands by a ratio of 57:43. In
fishery, whereas that of the Aleutian Islands although some of the commercial fishing both regions, size of females was signifi-
predominantly came as discarded bycatch grounds did not stand out as areas of spe- cantly larger than males.
64(4)
trawling conducted in the Guolf Aflas ka
over 30 years ago, and the age results are
based on surface readings of otoliths, a
technique which is now thought to sub-
stantially underage rockfish.
More recent information on northern
rockfish can be gleaned from trawl survey
data reports such as those referenced in
the second paragraph of this section, or
from annual stock assessment documents
for rockfish (e.g. Heifetz et al., 1999).
Also, a population dynamics modeling
analysis of northern rockfish in the Gulf
of Alaska has been completed to quantita-
tively assess stock condition of these fish,
and this study presents some data on the
fishery and on survey results (Courtney et
al., 1999). In addition, a limited amount Figure 1.—The three major fishery management regions that are discussed in this
of food habits information is available for report: Gulf of Alaska, Aleutian Islands, and eastern Bering Sea.
northern rockfish in the Gulf of Alaska
and Aleutian Islands (Yang, 1993, 1996). First, we use the fishery data to de- catches by Soviet and Japanese bottom
Most recently, a small and preliminary scribe the commercial fishery and to trawlers (Balsiger et al., 1985), and for-
genetics study of northern rockfish was present information on the distribution eign catches of rockfish continued until
conducted to determine if any stock struc- and biology of northern rockfish. Then, 1987. Most of the fishery was for Pacific
ture for this species was readily apparent we analyze the survey data to present ocean perch, Sebastes alutus, and mas-
(Gharrett et al.+). Except for the Courtney alternative information on the distribu- sive fishing effort targeting this species in
et al. (1999) and Gharrett et al.4 studies, tion and biology of northern rockfish the 1960's caused a precipitous decline in
however, none of these recent reports and to provide a comparison with the its abundance throughout Alaska waters
focuses completely on northern rockfish, results from the fishery data. As part of that has been well documented (Ito*). To
and none discusses the biology of this the survey analysis, we also present age what extent the foreign rockfish fishery
species in any detail. and growth information for northern was also taking northern rockfish, and
This report provides an updated rockfish. whether there was directed fishing for this
synopsis of available information on This report focuses particularly on species, is unknown for the years through
northern rockfish and is based on two northern rockfish in the Gulf of Alaska 1976, as there are no available summaries
major data sources: |) data collected and the Aleutian Islands regions (Fig. 1). of northern rockfish catches over this
from the commercial fishery in the Although the species is also found on the period. Foreign catches of all rockfish
years 1990-98 by the National Marine outer continental shelf and slope of the were often reported simply as “Pacific
Fisheries Service (NMFS), Alaska Fish- eastern Bering Sea, its abundance there ocean perch” (Murai et al., 1981), with
eries Science Center’s (AFSC) fisheries has been very low in trawl surveys (Ito no attempt to differentiate species. In
Observer Program and contained on the et al., 1999), and commercial catches of other instances, Pacific ocean perch were
Program’s “NORPAC” database, and 2) northern rockfish in this region have been separated out, but all other Sebastes were
data from various bottom trawl surveys much less than in the other two regions. assigned the category of “other rockfish,”
conducted between 1980 and i999 by the Consequently, for northern rockfish in the and there is still no way to determine the
AFSC’s Resource Assessment and Con- eastern Bering Sea, only fishery data will catch of northern rockfish.
servation Engineering (RACE) Division be presented in this report, and these data With the advent of a substantial NMFS
and contained on their “RACEBASE” will be analyzed in less detail than those observer program aboard foreign fishing
database. for the Gulf of Alaska and Aleutian Is- vessels in 1977, enough information on
lands. The three regions also correspond species composition of rockfish catches
4Gharrett, A. J., A. K. Gray, S. Lyons, D. Clau- to major fishery management regions for was collected so that estimates of the
sen, and J. Heifetz. 2003. A preliminary study of
Federal waters off Alaska. northern rockfish foreign catch can be
population structure in Alaskan northern rock-
fish, Sebastes polyspinis, based on microsatellite
and mtDNA variation. /n A. J. Gharrett (Editor), Commercial Fisheries
Population structure of rougheye, shortraker, and ‘Ito, D. H. 1982. A cohort analysis of Pacific
northern rockfish based on analysis of mitochon- Foreign Fishery ocean perch stocks from the Gulf of Alaska and
drial DNA variation and microsatellites: comple- Bering Sea regions. NOAA, Alaska Fish. Sci.
tion, p. 1-16. Juneau Center, School of Fisheries Directed fishing for rockfish in Alaska Cent., Natl. Mar. Fish. Serv., Bldg. 4, 7600 Sand
and Ocean Sciences, University of Alaska Fair- Point Way N.E., Seattle, WA 98115. NWAFC
banks, 11120 Glacier Hwy., Juneau, AK 99801. waters began in 1960 with the first Processed Rep. 82-15, 157 p.
Marine Fisheries Review
made for 1977-87 (Tables 1-3). The rela- Table 1.— Commercial catch of northern rockfish in the Gulf of Alaska, 1977-99.':2
tively large catch estimates for 1977-78 Catch (t)
in the Aleutian Islands and 1982-83
Year Foreign Joint venture Domestic Total
in the Gulf of Alaska are an indication
that at least some directed fishing prob- 1977 622 622
1978 553 553
ably occurred in those years. Except for 1979 666 669
reporting the foreign catches in Tables 1980 809 809
1981 1,469 1,469
1-3, however, we have decided to omit 1982 3,914 3,914
the foreign fishery observer data from 1983 2,705 3,616
1984 489 N.a.4 N.a
our analyses and to focus instead on the 1985 Tr. N.a N.a
more recent domestic fishery. 1986 | Nia N.a
1987 N.a N.a
Joint Venture Fishery 1988 N.a N.a
1989 N.a N.a
A new era in Alaska commercial 1990 1,697 1,697
1991 4,528 4,528
fishing began in 1976 with the passage 1992 7,770 7,770
of the Magnuson Fishery Conservation 1993 4,825 4,825
1994 5,968 5,968
and Management Act, later renamed the 1995 5,634 5,634
Magnuson-Stevens Fishery Conserva- 1996 3,386 3,386
1997 2,947 2,947
tion and Management Act (MSFCMA; 1998 3,051 3,051
Anonymous, 1996). This Act gave 1999 ooooocococcoc°oc;”;o”ooo:o ocoococoo;:;>5, 397 5,397
the United States jurisdiction over all ' Catches for 1977-92 are estimates based on extrapolation Alaska Fisheries Center, Nati. Mar. Fish. Serv., NOAA,
groundfish resources within 200 nautical of catch composition data from the foreign and domestic 2725 Montlake Bivd. E., Seattle, WA 98112
miles (n.mi.) of its shoreline, and set in oDbastear vSeoru rpcreosg rams. o1f9 84U:. S.B erobgseerr,vJ e.r, J. saWamlpll, inagnd oRf. Nfeolrseoingn Jr.a n1d9 85j.o inStu-mvemnaturrye
place regulatory policies that eventually 1977: Wall, J., R. French, R. Nelson Jr., and D. Hennick. fisheries in the northeast Pacific Ocean and eastern Bering
resulted in domestic fishermen replacing i1n9 7t8h.e DGautlaf offr oAml atshkea , ob1s9e7r7v.a ti(oDnosc uomfe nftor eisgunb mfiitstheidn g tfol etethse Sofe at,h e 19I8n4t.e rn(atDioocnualm enNto rths ubPmaictitfeicd Ftios htehrei esa nnCuoalm mimseseitoinn,g
the foreign fishermen. The Act also creat- International North Pacific Fisheries Commission by the Tokyo, Japan, October 1985.) Northwest and Alaska
U.S. National Section.) Northwest and Alaska Fisheries Fisheries Center, Natl. Mar. Fish. Serv., NOAA, Building 4
ed the North Pacific Fishery Management Center, Natl. Mar. Fish. Serv., NOAA, 2725 Montlake Bivd 7600 Sand Point Way N. E., Seattle, WA 98115
Council (NPFMC) as an advisory body E., Seattle, WA 98112 1985: Berger, J., J.W all, and R. Nelson Jr. 1987. Summary
to develop and implement management O1b97s8e:r vaWtailoln, s J.,o f R.f oreFirgenn chf,i shianngd flRe.e tsN elisn ont he Jr. Gul1f9 79o f fofi shUe.rSi.e s obisn ertvheer nsoarmtphelaisntg oPfa ciffoirce igOnc eaannd jaonidnt evaesntteurrne
plans for Alaska groundfish. Alaska, 1978. (Document submitted to the International Bering Sea, 1985. U.S. Dep. Commer., NOAA Tech
North Pacific Fisheries Commission by the U.S. National Memo. NMFS F/NWC-112, 169 p
As an interim step in the transition Section.) Northwest and Alaska Fisheries Center, Natl 1986: Berger, J., R. Nelson Jr., J. Wall, H. Weikart, and
from foreign to domestic fishing, joint Mar. Fish. Serv., NOAA, 2725 Montlake Bivd. E., Seattle, B. Maier. 1988. Summary of U.S. observer sampling of
venture fisheries developed in the early WA 98112 foreign and joint venture fisheries in the northeast Pacific
1979: Wall, J., R. French, and R. Nelson Jr. 1980 Ocean and eastern Bering Sea, 1986. U.S. Dep. Commer.,
1980’s in which U.S. fishing boats caught Observations of foreign fishing fleets in the Guif of Alaska, NOAA Tech. Memo. NMFS F/NWC-128, 167 p.
and delivered fish to foreign processing t1h9e7 9. Int(eDrnoactuimoneanlt Nsourbtmhi ttPeadc ifitco tFhies hearnineusa l Commemeitsisnigo n,o f o1b98s7e:r veBre rgsear,m plJi.,n ga ndo f Hf. orWeeiigkna rta.n d 19j8o8i.n t Sveunmtmuarer y fisohf erUi.eSs
vessels (Megrey and Wespestad, 1990). Anchorage, Alaska, September 1980.) Northwest and in the northeast Pacific Ocean and eastern Bering Sea,
Although joint venture catches were 2Al7a2s5k aM onFtilshaekrei esB ivdC.e ntE.e,r ,S eaNtattll.e , MWaAr. 9F8i1sh1.2 Serv., NOAA, N19W8C7.- 14U8.S,. D1e41p . p.C ommer., NOAA Tech. Memo. NMFS F.
sizeable for some species, they were 1980: Wall, J., R. French, and R. Nelson Jr. 1981 1988: Berger, J., and H. Weikart. 1989. Summary of U.S
relatively modest for northern rockfish O1b98s0e.r va(tDioocnsu meonf tf oresiugbnm iftitsehdin g tfol eetthse ina nthneu aGlu lfm eoef tAilnags kao,f observer sampling of foreign and joint venture fisheries
in the northeast Pacific Ocean and eastern Bering Sea,
(Tables 1-3). By 1990, both the foreign the International North Pacific Fisheries Commission, 1988. U.S. Dep. Commer., NOAA Tech. Memo. NMFS F/
Vancouver, B. C., Canada, September 1981.) Northwest
and the joint venture fisheries for rockfish and Alaska Fisheries Center, Natl. Mar. Fish. Serv., NOAA, NWC-172, 118 p
in Alaska had ended. 2725 Montlake Bivd. E., Seattle, WA 98112 1989: Heifetz, J., J. N. lanelli, D. M. Clausen, and J. T.
1981: Wall, J., R. Nelson Jr., and J. Berger. 1982 Fujioka. 1999. Slope rockfish. In Stock assessment and
Observations of foreign fishing fleets in the Gulf of Alaska, fishery evaluation report for the groundfish resources
Domestic Fishery 1981. (Document submitted to the annual meeting of of the Gulf of Alaska, p. 309-360. North Pacific Fishery
the International North Pacific Fisheries Commission, Management Council, 605 W 4'" Ave, Suite 306, Anchor-
Vancouver, B. C., Canada, October 1982.) Northwest and age, AK 99501
Management History and Alaska Fisheries Center, Natl. Mar. Fish. Serv., NOAA, 1990-91: Data on file at National Marine Fisheries
Catch Statistics 21798225: MoNnetllsaokne, BiRv.d,. JEr.,, SJe.a ttWlael,l , WAa n9d 811J.2 Berger. 1983 9Se9r8v0i2c e,a ndA lDasokmae stRiecg ioOnb,s erPv.eOr. PBrooxg ra2m1,6 68N,a tiJonuanle auM,a riAneK
Since passage of the MSFCMA, Summary of U.S. observer sampling of foreign and Fisheries Service, Alaska Fisheries Science Center,
joint-venture fisheries in the northeast Pacific Ocean REFM Division, 7600 Sand Point Way N. E., Seattle, WA
northern rockfish have been assigned to and eastern Bering Sea, 1982. (Document submitted 98115
various management groupings (Table 4). to the annual meeting of the International North Pacific 1992-98: Heifetz, J., J. N. lanelli, D. M.C lausen, and J. T.
Fisheries Commission, Anchorage, Alaska, October Fujioka. 1999. Slope rockfish. In Stock assessment and
Until the early 1990's, they were always 1983.) Northwest and Alaska Fisheries Center, Natl. Mar. fishery evaluation report for the groundfish resources
managed as part of a “complex” or Fish. Serv., NOAA, 2725 Montlake Bivd. E., Seattle, WA of the Gulf of Alaska, p. 309-360. North Pacific Fishery
98112 Management Council, 605 W 4" Ave, Suite 306,
assemblage of rockfish species. Pre- 1983: Berger, J., J. Wall, and R. Nelson Jr. 1984. Summary Anchorage, AK 99501
sumably, the original reason for this of U.S. observer sampling of foreign and joint-venture 1999: Data on file at National Marine Fisheries Service,
fisheries in the northeast Pacific Ocean and eastern Bering Alaska Region, P.O. Box 21668, Juneau, AK 99802
assemblage management was because it Sea, 1983. (Document submitted to the annual meeting
was thought to be too difficult for fisher- oVfa ntchoeu vIenrt,e rnBa.tCi.o,n alC anNaodrat,h OPacctiofbice r Fi1s9h8e4r.i)e s NoCrotmhmwiesssti oann,d 34 TNr..a .= =t rancoet available
men to accurately identify the individual complex or assemblage in each region.® Islands that the grouping is effectively
rockfish species, which are superficially Consequently, fishermen and processors northern rockfish alone). Likewise,
similar in appearance. Also, many species were only required to report catches as northern rockfish were separated as a
were believed to sometimes co-occur in “Pacific Ocean Perch Complex,” “Slope distinct management entity in the Gulf
catches, which would make sorting to Rockfish Assemblage,” etc., without of Alaska in 1993 (Heifetz et al., 1993).
species a time consuming process. regard to which exact species in the In the eastern Bering Sea, however,
Each year, the NPFMC assigned a assemblage they were actually taking. northern rockfish in the years 1993-99
single level of acceptable biological The assemblage approach as applied to continued to be managed as part of the
catch (ABC) and fishing quota (since northern rockfish management had a de “Other Red Rockfish Assemblage” (Ito
1988 the quota has been called “total facto ending in the Aleutian Islands in et al., 1999) .
allowable catch” (TAC)) for the entire 1992, when the “Sharpchin/Northern” A completely domestic fishery for
management subgroup was established in rockfishes, in which U.S. vessels both
this region (Ito and Ianelli, 1994; sharp- caught and processed the fish, began in
chin rockfish are so rare in the Aleutian the Gulf of Alaska and eastern Bering
Table 2.—Commercial catch of northern rockfish in the Sea in 1984, and in the Aleutian Islands
Aleutian Isiands, 1977-99.'2 in 1985 (Tables 1-3). Catches of northern
Catch (t) ®In actual practice, the ABC and quota for the rockfish in this fishery, however, cannot
Gulf of Alaska were further subdivided into three
be determined for years before 1990.
Joint manaargeas:e Wesmterne, Cnentrtal, and Eastern.
Year Foreign venture Domestic Total During these years, northern rockfish
were part of either the Pacific Ocean
1977 5,311 0 5,311
1978 3,782 0 3,782 Perch Complex or the Slope Rockfish
1979 997 0 997 Table 3.— Commercial catch of northern rockfish in the Assemblage, so directly reported catch
11998810 317348 00 317440 eastern Bering Sea, 1977-99.' statistics for individual species are
1982 193 0 193 Catch (t) unavailable. This was not a problem
1983 28 0 28
1984 12 0 185 Joint in the foreign or joint venture fisheries
1985 Tr N.a.4 N.a Year Foreign venture Domestic Total because U.S. observers aboard foreign
1986 = N.a N.a 1977 322 322 vessels collected species composition
11998878 NN..aa NN..aa 11997789 111296 111296 data that could be used to estimate the
1989 N.a N.a 1980 58 69 catch of northern rockfish. Unfortunately,
1990 1,273 1,273 1981 31 31 a comparable observer program for
1991 251 251 1982 68
1992 1,041 1,041 1983 10 domestic vessels was not implemented
1993 4,486 4,486 1984 19
1994 4,667 4,667 1985
1995 3,873 3,873 1986
1996 6,708 6,708 1987 Table 4.— Management groupings’ that northern rock-
1997 1,997 1,997 1988 fish were assigned to in the Gulf of Alaska, Aleutian
1998 3,675 3,675 1989 Islands, and eastern Bering Sea, 1979-99.
1999 oooooocooooooo5co,2o5o5c qoccocoo9 5o,2 55 11999910 612830 Region and year Management grouping
' Catches for 1977-91 are estimates based on extrapolation 1992 328
of catch composition data from the foreign and domestic 1993 959 Gulf of Alaska
observer programs. Catches for 1992-99 may include 1994 47 1979-87 Pacific ocean perch complex
very small amounts of sharpchin rockfish 1995 287 1988-90 Slope rockfish assemblage
2 Data sources 1996 116 1991-92 Other slope rockfish
(B1Ee9dr7ii7tn-org8) 6,: S eCaoI ntod,ai ntDdi. onHA. l eou1f9t 8ig8ar.no unOIdtsfhlieasrnhd sr orcrekesfgoiisuhor.nc esiin n oR1f.9 8tG7h.,e Bepa.a ksk1tae3lr9an— 111999999879 ooooococoooooocooooo11o14c5854o o Oco°Ocn;aon 1 45 Ale11u99ti97a39n-- 999I0s lands NPaocritfhiec rno ceraonck fipsehr ch complex
146. U.S. Dep. Commer., NOAA Tech. Memo. NMFS F/ 1991-99 Sharpchin/northern
NWC-139 ' Catches for 1977-91 are estimates based on extrapolation Eastern Bering Sea
of catch composition data from the foreign and domestic 1979-90 Pacific ocean perch complex
s1e9e8 7-T-a8b8l:e B1e).r ger and Weikart (1988, 1989; for references, ovebrsye rvsmearl l parmogoruanmtss. ofC asthcahrepsc hinfo r roc1k9f9i2sh- 99 may include 1991-99 Other red rockfish
1989: Guttormsen, M., R. Narita, and J. Berger. 1990 Data sources: ' Definition of management groupings
Summary of U.S. observer sampling of foreign and joint
venture fisheries in the northeast Pacific Ocean and 1977-86: Ito (1988; see Table 2 for reference) Pacific ocean perch complex: Pacific ocean perch, Sebas-
eastern Bering Sea, 1989. U.S. Dep. Commer., NOAA 1987-88: Berger and Weikert (1988, 1989; see Table 1 for tes alutus; northern rockfish, S. polyspinis; rougheye rock-
Tech. Memo. NMFS F/NWC- 189, 84 p. references). fish, S. aleutianus, shortraker rockfish, S. borealis; and
sharpchin rockfish, S. zacentrus.
1990-91: Data on file at National Marine Fisheries 1989: Guttormsen et al. (1990; see Table 2 for reference)
9FSRei9Ers8Fvh0ieM2cr ei,ea Dsni dvAi lsSaiDeosornkmv,aie cse7t,6Ri 0ec0g i AoOlSnba,ass nekdra Pv OeP.ro F iinsPtBhr oeoxrWg iareyas2 m1,6N 6.S 8cN,Eia .te,in JocSuneeana ltet aluCeMe,,a n rtieWAnrAKe, 9SF1ei99rs98vh00ie-2cr9 ei1,e:a s n dA lDSaDeasortkmvaaei cset,oRi nec g iAfOolinblae,ss ekraaPv t. eOr.F N iastPBhiroeooxrng iarelas 2 m1,6M 6Sa8cNr,iai tenineJoc unean leF aiusCMh,eaen rrtiieAnereKs, ohSbraclereovlpaieensq puiripnoniec srk,cf rihos achnk cdfoi amssph1s,l3e e mxmbS,i.l n aoprgvl aeur:ssi peegrTcaehitdeeus tssr;f ii vopefes isSlrpevoebeccarkigsferitesseyh s, .i n r Sot.ch kepf rioPsrahic,gi efriS,c.
98115 REFM Division, 7600 Sand Point Way N. E., Seattle, WA Other slope rockfish: Northern, sharpchin, redstripe, har-
1992-99: Data on file at National Marine Fisheries 98115 lequin, and silvergrey rockfish and 13 minor Sebastes sp.
Service, Alaska Region, P.O. Box 21668, Juneau, AK 1992-99: Data on file at National Marine Fisheries Northern rockfish: Northern rockfish only.
99802 Service, Alaska Region, P.O. Box 21668, Juneau, AK Sharpchin/northern: Sharpchin and northern rockfish.
3 Tr. = trace 99802 Other red rockfish: Northern, rougheye, shortraker, and
4 N.a. = not available 3 N.a. = not available sharpchin rockfish
Marine Fisheries Review
until 1990, which left a gap in the catch result of this more restrictive manage- curred if both targeted and bycatch fish-
estimates for the domestic fishery from ment policy, the rockfish fleet redirected ing for northern rockfish were allowed
1984 to 1989. The domestic trawl fishery more of its effort to northern rockfish, and and, in combination, were to cause the
for rockfish developed rapidly over these catches for the species greatly increased TAC for this species to be exceeded.
years, especially in the Gulf of Alaska, in both 1991 and 1992. The high catches Annual domestic catches of northern
where the reported catch of the Pacific of northern rockfish in these two years rockfish in the eastern Bering Sea have
ocean perch complex/slope rockfish as- raised concern among fishery assessment consistently been much less than those
semblage increased from 119 metric tons scientists that fishermen were selectively in the Gulf of Alaska or Aleutian Islands
(t) in 1984 to 19,002 t in 1989 (Heifetz overharvesting this species within the (Table 3). Catches were highest in the
et al., 1999). Presumably, some northern “Other Slope Rockfish” management years 1991-93, when targeted fishing was
rockfish were taken, but most of the catch subgroup (Gulf of Alaska Groundfish allowed during some periods. After 1993,
by the domestic fishery in this period is Plan Team, 1992). Consequently, in catches for the “Other Red Rockfish”
believed to be Pacific ocean perch, short- 1993 the NPFMC implemented another assemblage (of which northern rockfish
raker rockfish, Sebastes borealis; and change in rockfish management policy was a member), were usually limited to
rougheye rockfish, Sebastes aleutianus. by separating out northern rockfish as bycatch only. TAC’s for this assemblage
These latter three species have tradition- its own distinct management subgroup in were also quite small after 1993, which
ally been more valuable than northern the Guolf Aflask a. The NPFMC assigned restricted the catches even further.
rockfish on a price-per-pound basis, and northern rockfish its own ABC and TAC,
there is evidence that some domestic fish- and since 1993, the restrictions imposed Targeted vs. Bycatch Fishing
in the Guolf Aflas ka
ermen were selectively harvesting them by this quota have resulted in the catches
and Aleutian Islands
rather than northern rockfish (Heifetz and listed in Table 1. To ensure the TAC was
Clausen, 1990). not exceeded, and to limit bycatch of Our analysis of -he observer data indi-
With the start of an observer program other species, catches in 1996-98 were cates that in the Gulf of Alaska, the ma-
on U.S. groundfish vessels in 1990 further reduced due to in-season manage- jority of northern rockfish catch has been
(NPFMC, 1989a, 1989b), detailed infor- ment actions by NMFS, which closed the taken by vessels specifically targeting this
mation on domestic catches of rockfish fishery early. species, whereas in the Aleutian Islands
in Alaska finally became available. In In the Aleutian Islands, annual domes- it has been taken mostly as bycatch in
the Gulf of Alaska, catches of northern tic catches of northern rockfish increased other fisheries. As mentioned, manage-
rockfish increased sharply from 1,697 t at a slower rate than those in the Gulf ment regulations since 1997 have limited
in 1990 to 7,770 t in 1992, and dimin- of Alaska (Table 2). Although northern the Aleutians fishery to bycatch only, but
ished somewhat in the years following rockfish in the Aleutian Islands were even before 1997, most of the catch was
(Table 1). This catch trend can be related separated from the Pacific ocean perch taken as bycatch. Because the observer
to management actions of the NPFMC complex in 1991 and assigned their own database does not contain information on
and NMFS during this period. In 1990, ABC and TAC, catches that year totaled the intended target species for each haul,
northern rockfish were in the Slope Rock- only 251 t. A large increase in catches we used procedures described in Ackley
fish Assemblage, along with Pacific ocean was finally seen in 1993, when nearly and Heifetz (2001) to determine the prob-
perch, shortraker and rougheye rockfish, 4,500 t were taken, and catches have able target species. In these procedures,
and other species (Table 4). Fishermen remained relatively large in the years the predominant species by weight in a
were free to catch any of these species thereafter. In 1994—96, catches were lim- haul was usually determined to be the
within the Slope Rockfish quota. Given ited by mid-season closures for targeted target. The results showed that for the
the comparatively low market value of fishing to ensure that the TAC was not overall period 1990-98, an estimated
northern rockfish, fishing was apparently exceeded. Since 1997, NMFS has prohib- 81.8% of the northern rockfish catch
directed toward the three other species in ited targeted fishing for northern rockfish in the Gulf of Alaska came from hauls
the assemblage mentioned above. The in the Aleutian Islands, and northern that targeted this species, whereas only
result was a relatively moderate catch of rockfish have been taken only as bycatch 20.6% of the northern rockfish catch in
northern rockfish that year. In 1991, how- in other fisheries. This bycatch-only fish- the Aleutian Islands came from targeted
ever, the NPFMC separated Pacific ocean ery was deemed necessary to prevent the fishing (Table 5).
perch, shortraker rockfish, and rougheye closure of other more valuable fisheries Most of this large bycatch of northern
rockfish from the rest of the Slope Rock- in the Aleutian Islands, such as those for rockfish in the Aleutian Islands has been
fish Assemblage and assigned individual Atka mackerel and Pacific ocean perch taken in the trawl fishery for Atka mack-
ABC’s and TAC’s for these three spe- (Smoker’). Such closures may have oc- erel, Pleurogrammus monopterygius.
cies (Heifetz and Clausen, 1992). These For 1990-98, our targeting analysis indi-
ABC’s and TAC’s were considerably less cated that 68.8% of the northern rockfish
than the values in previous years, when 7Smoker, Andrew, Sustainable Fisheries Divi- catch in the Aleutian Islands came from
a single ABC and TAC was set for all sion, NOAA, Natl. Mar. Fish. Serv., Alaska hauls that were actually targeting Atka
Regional Office, Juneau, AK. Personal commun.,
Slope Rockfish species combined. As a April 2003. mackerel (Table 6). Except for 1990, the
Table 5.—Estimated percent of northern rockfish com- Tabie 7.—Summary of information on the commercial fishery for northern rockfish in the Gulf of Alaska and Aleu-
mercial catch in the Gulf of Alaska and Aleutian Islands tian Islands, 1990-99."
that came from targeted fishing for northern ifieh :
1990-98, based on data in the National Marine Fisher- % caught % caught Mean
ies Service, Alaska Fisheries Science Center Observer Region Catch % by factory by shore- No. vessels duration of
Program database. and year (t) discarded trawlers based trawlers in fishery? tow (min)*
Year Gulf of Alaska Aleutian Islands Gulf of Alaska
1990 1,697 N.aé N.a. 12 124
1990 47.1 26.2 1991 4,528 N.a. N.a. 21 68
1991 91.3 20.0 1992 7,770 N.a. 28 119
1992 82.8 5.9 1993 4,825 5,760 5,760 26.5 21 151
1993 81.3 13.2 1994 5,968 5,760 5,760 17.7 21 116
1994 92.3 15.3 1995 5,634 5,270 5,270 12.7 24 127
1995 89.9 22.3 1996 3,343 5,270 5,270 16.5 30 113
1996 74.1 35.3 1997 2,947 5,000 5,000 28.0 22 156
1997 68.8 11.5 1998 3,051 5,000 5,000 22 94
1998 53.8 18.9 1999 5,397 4,990 4,990 N.a.
All years comb 81.8 20.6 Aleutian Islands
1990 1,273 N.a. a. 10
1991 251 3,440 3,440 N.a. a. 2
Table 6.— Estimated percent of northern rockfish com- 1992 1,041 5,670 5,670 N.a. a. 11
mercial catch in the Aleutian Islands taken as bycatch 1993 4,486 5,670 5,100 100.0 d 17
in the Atka mackerel targeted fishery, 1990-98, based 1994 4,667 5,670 5,670 100.0 4 11
on data in the National Marine Fisheries Service, 1995 3,873 5,670 5,103 100.0 h 14
Alaska Fisheries Science Center Observer Program 1996 6,708 5,810 5,229 100.0 : 11
database. 1997 1,997 4,360 4,360 100.0 . 4
1998 3,675 4,230 4,230 100.0 8
Year Percent 1999 5,255 4,230 4,230 90.1 100.0 ; N.a.
1990 31.0 ' Data sources: For catch, percent discarded, percent caught by factory trawlers, and percent caught by shore-based
1991 66.4 trawlers: National Marine Fisheries Service, Alaska Region, P. O. Box 21688, Juneau, AK 99802-1668. For ABC and TAC:
1992 75.9 North Pacific Fishery Management Council, 605 W. 4th. Avenue, Suite 306, Anchorage, AK 99501-2252. For number of
1993 78.2 vessels in fishery and mean duration of tow: Observer Program database, National Marine Fisheries Service, Alaska
1994 75.8 Fisheries Science Center, REFM Division, 7600 Sand Point Way N. E., Seattle, WA 98115.
1995 68.4 2 Acceptable biological catch (ABC) and total allowable catch (TAC) are not listed for 1990-92 in the Gulf of Alaska and for
1996 57.7 1990 in the Aleutian Islands because northern rockfish were not in their own management category these years.
1997 79.7 3 Number of vessels that had at least one haul in the observer database for which northern rockfish was determined to be
1998 TAT the target species.
All years comb 68.8 4 Time between brake-set and haulback (generally equivalent to time on bottom) for hauls in which northern rockfish was
determined to be the target species.
5 N.a. = data not available
majority of the northern rockfish catch in 6 Tr. = trace
the Aleutians has consistently been taken
as bycatch in the Atka mackerel targeted gards to northern rockfish. The fishery Northern rockfish in the Gulf of Alaska
fishery. In reality, the actual percentage data may be more an indication of how are generally caught with bottom trawls
of northern rockfish caught in the Atka the Atka mackerel fishery operates rather identical to those used in the Pacific
mackerel fishery was likely even higher than what a true directed fishery for ocean perch fishery. Many of these nets
than the data in Table 6 indicate. For northern rockfish would show. are equipped with so-called “tire gear,”
example, there were many incidences in which automobile tires are attached
in the observer database where a vessel Description of the Fishery to the footrope of the net to facilitate
made a series of hauls in the same in the Guolf Aflas ka towing over rough substrates. The fish
general location, and all but one or two and Aleutian Islands are headed, gutted, and frozen on board,
caught predominantly Atka mackerel. The domestic rockfish fishery in and then exported to markets in Asia,
In these exceptions, northern rockfish Alaska was pioneered by factory-trawler primarily Japan and South Korea. The
often comprised a dominant percentage vessels that catch and process fish at sea, Japanese market, in particular, esteems
of the catch, and in our targeting analysis, and these catcher-processors have gen- fish that are red in color; because northern
these hauls were identified as targeting erally dominated the northern rockfish rockfish tend to have less red coloration
northern rockfish. In such cases, however, fishery in the Gulf of Alaska (Table 7). than Pacific ocean perch, they are corre-
the vessel was more likely directing its The majority of these vessels are about spondingly lower in value and are gener-
efforts toward Atka mackerel, but had 150-250 ft in length, and carry a crew ally marketed as a low-cost substitute for
unintentionally encountered a large catch of about 30-40, including processors.® Pacific ocean perch.
of northern rockfish. Northern rockfish have also been
Because of the bycatch nature of the ‘This description of the factory-trawler fishery caught by shore-based trawlers in the
northern rockfish catch in the Aleutian was based on interviews in August 1997 with the Guolf Aflas ka since 1993 (Table 7). This
following individuals: Andrew Smoker, Sustain-
Islands, the reader is cautioned that much able Fisheries Division, NOAA, Natl. Mar. Fish. fishery remained relatively small until
of the information in this report from Serv., Alaska Regional Office, Juneau, AK; Eric 1996, when it expanded substantially
commercial fishery data in the Aleutian Hollis, Fishing Company of Alaska, Seattle, WA; and took nearly 31% of the Gulfwide
Laurie Bowen, Tyson Seafood, Seattle, WA; and
Islands may be somewhat biased in re- Tim Meintz, Cascade Fishing, Seattle, WA. catch. The shore-based vessels are much
Marine Fisheries Review
smaller than the factory-trawlers and Discard Rates for Northern Rockfish In some years, the northern rockfish
range in length from about 70-120 ft; fishery extended into August until it
crew size is roughly 3—5 (Blackburn’). The amount of the northern rockfish was closed, which explains the catches
The fish are caught and retained on catch discarded and not retained for pro- seen for this month in Figure 2. In other
board in tanks of refrigerated seawater cessing has differed markedly between instances, directed fishing was closed
for as long as 3 days, after which they are the Gulf of Alaska and Aleutian Islands in July or August before the TAC was
delivered to shore-side plants in the port (Table 7). In the Gulf of Alaska, annual achieved. The rockfish trawl fishery was
of Kodiak for processing and freezing. discard rates have been relatively low, then opened again in October to allow the
Because of the economic advantages of ranging from 26.5% in 1993 to only remainder of the quota to be filled, which
operating close to port, virtually all the 11.1% in 1999. In contrast, annual dis- accounts for the relatively large catches
shore-based catches have come from cards of northern rockfish in the Aleutian seen in this month. In the Aleutian Is-
waters around Kodiak Island. Islands have been consistently very high, lands, the monthly distribution of north-
The annual number of vessels in the with several years showing discard rates ern rockfish catches is chiefly related to
Gulf of Alaska that our analysis deter- of around 90%. This difference can be the timing of the Atka mackerel fishery,
mined to have targeted northern rockfish explained by a combination of two fac- in which the majority of northern rockfish
has ranged from 12 to 30 (Table 7). The tors: 1) because northern rockfish in the are caught. Due to NMFS regulations, the
actual number of vessels in the fishery Aleutian Islands are mostly caught as Atka mackerel fishery in recent years has
after 1995 is probably underestimated bycatch in the Atka mackerel fishery, mostly occurred in the spring, resulting
in Table 7, however, because the smaller catcher-processors in this fishery are not in a large bycatch of northern rockfish
shore-based vessels that entered the fish- set up for processing northern rockfish, during March, April, and May.
ery during these years had a lower level of and 2) northern rockfish in the Aleutian This seasonal pattern of the fishery,
observer coverage than the larger factory Islands appear to be much smaller in size especially in the Gulf of Alaska, needs to
trawlers.'° Consequently, some of these than those in the Gulf of Alaska (data be kept in mind when considering some
smaller vessels likely were not listed in supporting this observation are presented of the results presented in this paper. For
the observer database each year. Mean later in this report). These small fish are example, examination of the depth dis-
duration of an individual tow in the Gulf of lower market value; consequently, tribution of northern rockfish in the Gulf
of Alaska that targeted northern rockfish there is less economic incentive for fish- based on fishery data will emphasize the
has usually been about 2 hours on bottom ermen to retain them. summer distribution of the fish because
(Table 7). Duration of individual tows, this is when most of the data have been
Seasonality of Fishery
however, has been quite variable, and has collected.
ranged from 2 to 570 min. The distribution of the northern rock-
In the Aleutian Islands, the number fish catch by month for both the Gulf of Catch by Gear Type
of vessels determined to be targeting Alaska and Aleutian Islands is shown in and On-bottom vs.
Off-bottom Catches
northern rockfish has been fewer than in Figure 2 for the years 1990-98 combined.
the Gulf of Alaska, and has ranged from The seasonal distribution of catches has According to the observer database,
2 to 17 in the years 1990-98 (Table 7). been very different in each region. In the bottom trawls have accounted for over
As discussed, some of these vessels in Gulf of Alaska, the majority of the catch 99% of the northern rockfish catch in
reality may have been attempting to has been taken in July, with a secondary both the Gulf of Alaska and Aleutian
catch Atka mackerel rather than northern peak in October. In the Aleutian Islands, Islands (Table 8). A very small amount
rockfish. The lower number of vessels in however, most of the catch has come in has been taken by pelagic trawls. Bottom
the Aleutian Islands is due in part to the the spring, although sizeable catches are trawls can be defined as nets specifically
near absence of any shore-based fishing also seen in other months. These seasonal designed to handle the rigors of towing
in this region. Most of the vessels in the catch patterns are largely determined by over the bottom, with weighty “doors”
Atka mackerel fishery have a history fishery opening and closing regulations to sink and spread the net, and heavy
of also participating in Gulf of Alaska enacted by NMFS. In the Guolf Alfask a, footropes and webbing. In contrast, pe-
and Aleutian Islands rockfish fisheries, the directed rockfish trawl fishery during lagic trawls are designed for off-bottom
so the previous description of rockfish these years has traditionally opened towing with lighter doors, footropes, and
factory-trawlers applies equally to these on | July, which accounts for the large webbing, and they usually have a much
vessels. catches during this month. Rockfish larger vertical and horizontal spread at
trawlers usually direct their efforts first the mouth for capturing pelagic schools
toward Pacific ocean perch because of of fish. It should be noted, however,
its higher value relative to other rockfish that bottom trawls are sometimes fished
9Blackburn, Chris, Alaska Groundfish Data Bank,
Kodiak, AK. Personal commun., May 1997. species; after the TAC for Pacific ocean off bottom; likewise, skilled fishermen
'ONPFMC regulations require only 30% of the perch has been reached and NMFS closes can fish pelagic trawls very near orj ust
vessels less than 125 ft to have an observer on directed fishing for this species, trawlers touching the bottom, especially where
board, whereas all vessels over 125 ft must have
an observer. then switch and target northern rockfish. the substrate is smooth.
Gulf of Alaska and Aleutian Islands,
however, the frequency and percentage
of catches of northern rockfish in the
eastern Bering Sea coming from pelagic
trawls has been much higher. This can be
explained by the large amount of pelagic
Gulf of Alaska
trawling for walleye pollock in the Bering
Sea in which small amounts of northern
rockfish may be taken as bycatch.
In both the Gulf of Alaska and Aleu-
tian Islands, about 90% of the northern
rockfish catch has been taken on bottom
(Fig. 3). Furthermore, for the portion
of the catch taken off bottom, there ap-
pears to be a trend toward larger catches
as hauls are made increasingly close
to bottom. For example, in the Gulf of
Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. Alaska, most (71%) of the off-bottom
catch has been taken within the first 10
m of the bottom. These data suggest that
adult northern rockfish are mostly demer-
sal in nature, and that there may be little
pelagic component to their distribution, at
least during those times of the year when
the commercial fishery has operated.
Also, it should be noted that some of the
occierPnfaeaeo tgcrmcihcmho ee nnr tc iaAll eutian Islands
vessels that fish for northern rockfish in
the Gulf of Alaska have successfully used
pelagic trawls for capturing off-bottom
aggregations of rockfish, in particular
Pacific ocean perch. The fact that they
have not chosen to do this for northern
rockfish is a further indication that north-
ern rockfish are mostly bottom-oriented
in their distribution.
~ ~ — ARETE Depth Distribution of the Catch
Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec.
Observer data were analyzed to deter-
Figure 2.— Distribution by month of the northern rockfish commercial catch in the
mine the depth distribution of commer-
Guolf Aflas ka and Aleutian Islands, 1990-98, based on data collected by the NMFS
Alaska Fisheries Science Center Observer Program. cial hauls that caught northern rockfish in
the Gulf of Alaska and Aleutian Islands.
Results showed most of the northern
Catches of northern rockfish in pots preferences of northern rockfish. Food rockfish catch in both regions was taken
or on longlines have been very low studies of northern rockfish in both the from a relatively narrow depth range
(Table 8). Although in the Aleutian Gulf of Alaska and Aleutian Islands (Fig. 4). In the Guolf Alfask a, about 70%
Islands this species has been taken rela- indicate that the fish feed predominantly of the catch came from depths between
tively often on longlines (over 3,400 ob- on plankton, especially euphausiids and 75 and 125 m, with the 75—100 m stra-
served longline hauls have shown catches copepods (Yang, 1993; 1996). Therefore, tum showing the highest catches. In the
of northern rockfish), longline catches it is likely that northern rockfish are not Aleutian Islands, catches were distributed
amount to only 0.5% of the total for this attracted to baited gear such as pots or slightly deeper, with about 65% taken
region. In the Gulf of Alaska, catches longlines. at depths 100-150 m, and the 100-125
of these fish on longlines are much less In the eastern Bering Sea, bottom stratum showing the highest catches.
frequent, and longlines account for only trawls have also been the predominant In both regions, the depth distribution
a trace of the region’s total catch of this gear for catching northern rockfish, with was not symmetrical; catches abruptly
species. These low catches in pots or on an estimated 92% of the catch coming dropped to near zero at depths less than
longlines can be explained by the diet from bottom trawls. Compared to the 50 m, but gradually tapered off at depths
Marine Fisheries Review