Northeast Pacific flatfish management

In Collaboration with the Netherlands Institute for Sea Research USHAL

‘SEA ELSEVIER

Journal of Sea Research

OF

RRSRARCH

39 (1998) 167-181

Northeast Pacific flatfish management Robert J. Trumble * International Pacijic Halibut Commission, PO. Box 95009. Seattle. WA 98135. USA Received

20 December

1996; accepted

19 June 1997

Abstract

Exploitation of northeast Pacific flatfish effectively began in the late 1800s with the fishery for Pacific halibut. Harvest of other flatfish occurred on a limited, local basis until foreign fishing fleets came to the area in the late 1950s. When US and Canadian fishermen replaced the foreign fleets in the 1970s and 1980s. a conservation-based management system designed to control foreign fishing was applied to the domestic fleet. Flatfish stock assessment is based on scientific surveys, both trawl and longline, and on catch-age models. In Alaskan waters since 1989 and since 1996 in Canadian waters, mandatory observers collect data on species composition, discards of flatfish and other groundfish. and catch and discards of prohibited species. Fishermen pay observer costs. Most biomass and harvest occurs in the Bering Sea-Aleutian Islands area. Many northeast Pacific flatfish are near record-high abundance, an order of magnitude higher than 20 years ago. Exploitation rates based on F 3510or FO., generate acceptable biological catch of more than 1 million mt, but annual harvest reaches only 300,000 mt. Total groundfish harvest is limited by an optimum yield limit of 2 million mt in the Bering Sea-Aleutian Islands, where the acceptable biological catch is 3 million mt, and by limits on amounts of Pacific halibut and other prohibited species bycatch. Most flatfish are relatively low-value species, and fishermen chose to fish for more valuable species. A large, powerful fleet which developed under open access in the US saw fishing time decline and economic problems increase as catching capacity grew, while Canada stabilized its fleet with limited entry and catch restrictions for individual vessels. 0 1998 Elsevier Science B.V. All rights reserved. Keywords: flatfish; Pacific halibut; fishery management;

northeast Pacific Ocean

1. Introduction Groundfish

in the northeast

Pacific

Ocean

make

fishery harvests in the world, with approximately 2.42 million mt of removals in 1995. Of this quantity, flatfish species represent about 0.30 million mt, or 12%. The great majority of these harvests occur in the Bering Sea-Aleutian Islands (BSAI) region, where 1.83 million mt of groundfish and 0.23 million mt of flatfish are taken (Fig. 1). Even though a third of a million mt is a up one of the largest

* E-mail: [email protected] 1385-l 101/98/$19.00

0 1998 Elsevier Science B.V. All rights reserved

PII S13851101(97)00059-2

large harvest by world standards, the northeast Pacific flatfish harvest is far below its potential. In Alaskan waters, for example, the acceptable biological catch (ABC) for 1995 was about a million mt for the BSAI, and 0.3 million for the Gulf of Alaska (GOA), yet the total allowable catch (TAC), actual catch, and retained catch are successively smaller fractions (Fig. 2). Some flatfish species, particularly Pacific halibut (see Table 1 for common and scientific names of flatfish species), are fully exploited, but others are essentially unharvested. Reasons for the extreme range of exploitation lies in the history of developing the fisheries, management philoso-

R.J. Trumble/Joumal

of Sea Research 39 (1998) 167-181 Table I Common and scientific names for exploited North Pacific Ocean

ElMh~r GF 8Flaukh

Common

woe. 1904

GOh1905

SC, 1003

t3SAI. IS95

Area

Fig. 1.Flatfish and other ground&h Ocean.

catch in the northeast

Pacific

among users. This story may be unique in the world fisheries, often characterized by overharvest and resource crashes. However, many articles that review and evaluate the northeast Pacific flatfish fisheries and management practices occur mainly as unpublished documents with limited distribution.

phies

that

evolved,

and

conflicts

2. History Pacific halibut has the longest recorded history of flatfish exploitation in the eastern North Pacific. Pacific halibut were taken by aboriginal groups along the Pacific coast for centuries (Stewart, 1977; Bell, 1981; Trumble et al., 1993). Commercial fishing for Pacific halibut by non-natives began off the north coast of Washington state in 1888 using hook and line from sailing schooners with dories (Bell, 1981; Trumble et al., 1993). Trawling for groundfish species, which include flatfish, in the eastern North Pacific began in the mid 1870s off California. 1.2

# BSAI #GOA

f*:

iO,e

f

0.4

0.2

0

ABC

TAC

calch

Dl5card

“Saca Fig. 2. Utilization

of Alaskan

flatfish in 1995.

name

Alaska plaice Arrowtooth flounder Butter sole Dover sole English sole Flathead sole Greenland turbot Longhead dab Pacific sanddab Pacific halibut Petrale sole Rex sole Rock sole Starry flounder Yellowfin sole

Scientific

flatfish in the eastern

name

Atheresthes stomias Pleuronectes quadrituberculatus Pleuronectes isolepis Microstomus pacijicus Pleuronectes vet&is Hippoglossoides elassodon Reinhardtius hippoglossoides Pleuronectes proboscidea Citharichthvs sordidus Hippoglossus stenolepis Eopsetta jordani Errex zachirus Pleuronectes bilineatus Platichthys stellatus Pleuronectes asper

Initially, fishermen used two-boat paranzella trawls from sailboats (Alverson et al., 1964; Ketchen and Forrester, 1966), but these later gave way to steam some time after 1880. Trawling from steam-powered vessels spread to Oregon in 1884. Shortly after the turn of the century, the success of the Pacific halibut fishery with hook and line prompted several experiments for Pacific halibut with beam and otter trawl gear off the coasts of Washington and British Columbia (Alverson et al., 1964; Bell, 1981). The experiments achieved little success, and subsequent trawling turned to groundfish species. In 1918, a Canadian fishing magazine reported 1600 mt of flounder and 450 mt of ‘cod’ landed in Canadian ports (Alverson et al., 1964). Of the many flounder species of the west coast of the US and Canada, only the fishery for Pacific halibut grew substantially during the first four decades of the century. Flounder and other groundfish landings were restricted by market limitations. Shortly after the beginning of the Pacific halibut fishery, declining yields and belief that they were overharvesting the Pacific halibut resource, prompted fishermen to ask the US and Canada to regulate the fishery. The International Fisheries Commission (later renamed the International Pacific Halibut Commission (IPHC)) was formed in 1923 (McCaughran and Hoag, 1992), the oldest international fishery commission to which the US is a party, and the first

R.J. Trumble/Journal

of’Sea Research 39 (1998)

167-181

169

-. -. Halibut -Total

Fig. 3. Pacific halibut and total groundfish Ocean. 1954-1995.

Flatfish

catch. northeast

Pacific Year

Fig. 4. Foreign, joint venture. and domestic flatfish catch in the Bering Sea/Aleutian Islands. excluding Pacific halibut.

treaty Canada signed on her own behalf. As a result, Pacific halibut are managed separately from other groundtish. The Pacific halibut fishery dominated demersal fish landings prior to World War II. Post-war Pacific halibut landings in the 23,000-32,000 mt range generally equalled landings of groundfish (Fig. 3). Trawl fishing during the pre-war years in the eastern North Pacific occurred at fairly low levels, around 5000 mt in 1940, and consisting mainly of flounders (Alverson et al., 1964). Petrale sole and English sole predominated. Groundfish catch, consisting of about half flatfish, increased off Washington, Oregon, California (WOC) and British Columbia to about 32,000 mt in 1945. Vessels in the trawl fishery consisted of seiners, trollers, or longliners which used trawling as an off-season activity. Petrale sole was the first flatfish to experience overfishing (Ketchen and Forrester, 1966). Japanese nationals fished sporadically in waters off Alaska since the 1930s but major foreign fishing in the eastern north Pacific (California north to Alaska) did not start until the late 1950s and early 1960s (Alverson et al., 1964). Japan and the former-USSR dominated foreign fishing, but other Asian and Eastern Block nations participated. Foreign fleets comprised factory trawlers and motherships with catcher vessels because no on-shore processing facilities for groundfish existed. The domestic fishing industry at the time had no interest in groundfish. During the build-up of foreign fishing, especially off Alaska, flounders represented about two-thirds of the total catch. By 1964, decline in abundance of the flounder resource led the foreign fleets to target walleye pollock (Therugru

chalcogramma) (NPFMC. 1983). Flounder fishing by the foreign fleets off Alaska continued, but on a limited scale. By the mid 1970s the USSR fleet discontinued flounder fishing. Foreign fishing also developed off WOC and British Columbia during the 1960s but flounders were not an important component (French et al., 1981). Incidental catch by foreign fleets of species important to the domestic fishery led the US and Canadian governments to negotiate a series of harvest regulations, including bycatch restrictions, with foreign governments. Pacific halibut and Pacific salmon (Oncorhynchus spp.) were declared prohibited species for foreign fishermen, and were required to be discarded to the sea. Foreign vessels voluntarily carried US observers by the mid 1960s and Canadian observers by the 1970s. After passage of the Magnuson Fishery Conservation and Management Act (MFCMA) of 1976 and a Canadian proclamation in 1977 that extended fishery jurisdiction to 370.6 km (200 miles), foreign fishing gradually declined (Fig. 4). Joint venture fishing supplanted the foreign fleets. In 1991, domestic fishing consisting of catcher boats, motherships, and factory trawlers fully replaced joint venture fishing on the west coast of the US. The increased value of the domestic groundfish harvest led to competition between offshore processors and shore-side plants (NPFMC, 1991). Subsidies to develop the domestic fleet soon led to overcapitalized fleets and plants and shorter and shorter seasons. Competition among gears (trawl, hook-andline, and pots) and processors (onshore and offshore) led to allocations for the groundfish to specific user

170

R.J. Trumble/Journal

of Sea Reseurch 39 (1998) 167-181

groups. Ultimately, offshore processing was virtually excluded from the GOA area, while offshore processors remained active participants in the BSAI. Offshore processing occurs in WOC, but not for flatfish (PFMC, 1995). 3. Management regime Along the west coast of the US, domestic marine fisheries were traditionally managed by the individual states, with the exception of Pacific halibut which is managed by the IPHC in all waters (McCaughran, 1995). Passage of the MFCMA established regional councils to monitor both domestic and foreign fisheries and to prepare management plans for waters of the Exclusive Economic Zone (4.9-370.6 km (3-200 miles) (Witherell, 1995). The individual states retained authority for groundfish management within 4.9 km (3 miles). All plans must be reviewed and approved by the National Marine Fisheries Service (NFMS) and the Department of Commerce. NMFS administers and, in conjunction with the Coast Guard, enforces regulations. Two regional councils, the Pacific Fishery Management Council (PFMC) and the North Pacific Fishery Management Council (NPFMC), have responsibility for waters adjacent to WOC and Alaska, respectively (Figs. 5 and 6). The NPFMC implemented a groundfish fishery management plan for the GOA in 1978, and for the BSAI in 1982. The PFMC implemented a fishery management plan for groundfish in 1982. All three groundfish management plans have been amended numerous times to respond to changing biological, economic, or social conditions. The regional councils are also responsible for domestic allocation of Pacific halibut, within limitations placed by the Pacific halibut treaty and US legislation that enacts the treaty (McCaughran and Hoag, 1992). The MFMCA set national standards of ‘best scientific information available’ for decision making, defined criteria for determining harvest levels, and established a series of committees to prepare and review scientific assessments. ‘Management Teams’ with responsibilities for specific species and areas assemble and review the work of individual scientists, and recommend an ABC for species or species groups. Team recommendations are forwarded to a Scientific and Statistical Committee (SSC), com-

35"N

Fig. 5. Fishery conservation zone and management responsible for fishery management in waters adjacent ington, Oregon, and California.

160"E I

I

180 I

I

16o"W I

I

14ow I

I

agencies to Wash-

12o"w I 70"N

(Dept. Commerce;

NPFMC) 40”N

Fig. 6. Fishery conservation zone and management agencies responsible for fishery management in waters adjacent to Alaska.

R.J. Trumble/Journul ofSea Research 39 (1998) 167-181

171

4. Stock assessment and exploitation

4.1. Bottom trawl surveys

Fig. 7. Fishery conservation zone and management agencies responsible for fishery management in waters adjacent to western Canada.

posed of senior scientific advisors, and to an Advisory Panel (AP), composed of fishermen, processors, environmentalists, and other industry representatives, which make further reviews and recommendations to the relevant Council. The AP further advises the Council on TAC, which are quotas set for each fishery. The Councils make management decisions that are usually final, although forwarded to the US Secretary of Commerce for review of compliance with national standards. Policy and strategic planning for the Canadian groundfish fishery is the responsibility of the federal Department of Fisheries and Oceans (DFO) for territorial sea and extended jurisdiction waters (Fig. 7). As in the US, management of the Pacific halibut resource is conducted by the IPHC, and DFO is responsible for domestic legislation. The Canadian management system is similar to the US system, but with fewer layers. Management is carried out in consultation with various user groups. A Pacific Stock Assessment Review Committee (PSARC) assembles and peer reviews work by individual stock assessment scientists. PSARC recommendations on yield levels are forwarded to Pacific Region Groundfish Advisory Committees, composed of scientists, managers, and industry representatives, to develop final management plans (Leaman, 1993). The federal Minister of Fisheries approves management plans.

Assessment of demersal resources in the northeast Pacific began in the 1940s with US Fish and Wildlife trawl surveys of the Bering Sea to evaluate king crab (Paralithodes spp.) resources (Alverson et al., 1964). Standard commercial fishing gear provided a means for comparisons over time and area. Over the next 20 years, bottom trawl surveys known as ‘exploratory fishing’ expanded throughout the northeast Pacific from the Chukchi Sea to southern Oregon. These surveys emphasized distribution and relative abundance of fish and shellfish rather than absolute abundance. Bottom trawl survey continues to be a primary means of gathering abundance and biological data for flatfish and other groundfish in Alaskan and WOC waters (Table 2) (Wakabayashi et al., 1985; Dark and Wilkins, 1994). NMFS has conducted annual Bering Sea surveys on the eastern continental shelf since 1971. Every third year since 1979, triennial surveys cover the outer continental shelf and slope areas. The eastern Bering Sea consists of a smooth, flat shelf averaging 740 km wide, and is sampled without roller gear. The rough-bottomed 39 km wide slope is sampled with roller gear. Triennial surveys in WOC began in 1977 and the GOA in 1984. GOA has a narrow (5-100 km) continental shelf area with many rough, foul bottom areas difficult to trawl. WOC has a similarly narrow shelf. All surveys use standardized nets usually calibrated with comparison hauls. Herding and escapement of flatfish from the roller gear used on the rough bottoms of the GOA or WOC makes estimates of absolute abundance more difficult for flatfish than for round fish. Trawl surveys occur in the waters off British Columbia at 2- to 3-year intervals. Surveys originally targeting juvenile flatfish in the early 1980s developed into multi-species surveys by the mid 1980s. 4.2. Longline surveys for Pac$c

halibut

The IPHC conducts the only longline stock assessment surveys in the northeast Pacific for flatfish (Table 2). An NMFS longline survey targeted on

172

R.J. Trumble/Joumal

of Sea Research 39 (1998) 167-181

Pacific cod (Gadus macrocephalus) and sablefish (Anoplopoma jimbria) in the GOA and BSAI also obtains some information for deeper flatfish (>200 m). From 1966 to 1969, the IPHC carried out surveys over a wide area on the Pacific with a standard grid of closely spaced stations and widely spaced transects (Hoag et al., 1980). Sampling occurred during summer on the continental shelf where feeding Pacific halibut occur and when the commercial fishery occurred. Between 1976 and 1986, surveys occurred with modified grid pattern and more standardized techniques. The surveys terminated in 1986 because assessment data showed the same trends as commercial CPUE, but with higher variability, and were judged to have little stock assessment value. However, improved spatial distribution statistics (Pelletier and Parma, 1994) and changes in biological, especially growth, parameters led to a re-establishment of the surveys in 1993. A grid patterned that distributed stations evenly over the survey area replaced the widely spaced transects of previous surveys (Larsen and St-Pierre, 1994). 4.3. Population models During the 1960s early population models, such as yield per recruit, were used to evaluate flatfish resources (Ketchen and Fort-ester, 1966). By the late 1970s and early 1980s cohort analysis and virtual population analysis entered the flatfish assessment arena (Hoag and McNaughton, 1978), and evolved to generalized catch at age models (Foumier and Archibald, 1982; Deriso et al., 1985; Quinn et al., 1985) and synthesis models (Methot, 1991). The long history of Pacific halibut stock assessment (Sullivan and McCaughran, 1995) parallels methodologies for flatfish in the northeast Pacific. Biological and fishery data and age structures were collected from surveys and through at-sea or dockside observer programs. Fishermen pay for observer costs. In the WOC, GOA, and BSAI areas, stock synthesis modelling (Methot, 1991) is the standard technique for population assessment (Table 2) (PFMC, 1995; NPFMC, 1995a,b). However, biological data, especially ages, are not available for several species. In those cases, assessment scientists may apply biological values from similar species, or may use

results of trawl surveys to estimate absolute abundance. Landing records in Alaska are supplemented by observer data which are used to estimate total catch composition and discards. Catch records in WOC are landed catch, as observers are not available for estimating total catch. CPUE for many species is not suitable for stock assessment because the exploitation is too low. Canadian flatfish stock assessment (Fargo, 1995) uses the same suite of models as in the US for species with sufficient data. As in the US experience, adequate data are not always available. CPUE and catch history monitoring then provide information with which to adjust quotas (Table 2). Stock assessment activities mainly use landed catch rather than total catch as observer coverage only began in 1995. The IPHC uses the catch-age model CAGEAN (Deriso et al., 1985; Quinn et al., 1985) for estimating abundance (Table 2). The model uses estimates of all Pacific halibut removals: landed catch, bycatch mortality from other fisheries, recreational catch, dead-loss from the Pacific halibut fishery, discards of sublegal fish from the Pacific halibut fishery, and personal use (Fig. 8). In 1995, the IPHC staff recognized Pacific halibut growth declined by a factor of two over 20 years (Clark, 1996), which resulted in a retrospective pattern of underestimated biomass when applying CAGEAN methodology to past years (Parma, 1993). As a result, the IPHC changed to a catch-age-length model for 1996 assessments (Sullivan and Parma, 1996), which reduced retrospective differences and significantly increased biomass estimates.

Waaiaga sport

2%

Fig. 8. Sources of Pacific halibut removals,

199.5.

R.J. Trutnble/Journnl

4.4. Exploitation

of Sea Research 39 (1998) 167-181

(Clark, 1993) (Table 2). The NPFMC and the PFMC adopted an F3=,%exploitation in 1995, and an F~oc/ for 1997. An F35% or Fo., was used for Canadian flatfish species (Fargo, 1995), but now Fmed is the standard (J. Fargo, Canadian Department of Fisheries and Ocean, Nanaimo, BC. Canada, personal communication). Most of the fishery agencies define an overfishing definition, most commonly an F?o_~o~x (Table 2).

strategy

involved The earliest strategies for exploitation monitoring changes in CPUE, and adjusting harvest to keep CPUE within a chosen range. As population models became available, the IPHC determined that halibut abundance was far below optimum. The IPHC implemented a strategy of setting quotas as 75% of the Annual Surplus Production (Quinn et al., 1984), designed to rebuild abundance from historical low levels of the mid 1970s. Foreign and later domestic harvest of flatfish and other species also required exploitation strategies for these species. Recommended harvest limits were generally determined through application of an exploitation rate (total catch divided by exploitable biomass) to an estimated biomass. As management strategy evolved for the groundfish species, analysts often developed unique approaches for specific species or species groups in the various areas. Management agencies, however, desired a consistent approach and sought a standard methodology. Determination of appropriate exploitation rates was difficult, as required biological information usually lacked for most species. Clark (1991, 1993) determined that, for a wide variety of life-history parameters, maintaining spawning biomass at 2060% of the unfished level provides at least 75% of maximum sustainable yield, regardless of spawner recruit relationships. A fishing mortality that reduces spawning biomass per recruit to about 35% of the unfished level (F35%) achieves this goal (Clark, 1991). Variable recruitment, especially with high serial correlation, calls for a slightly lower target. F& Table 2 Stock assessment

and exploitation

3.5. Biomass and exploitation

for NE Pacific flattish

Stock assessment

Exploitation

WOC

Trawl surveys Stock synthesis Catch-at-age CPUE history Trawl surveys Stock synthesis Trawl surveys Stock synthesis Catch-at-age Longline surveys

None. average catch

GOA BSAl Pacific halibut All areas

strategy

Overfishing F 20%,

F35K Fo.

I , F?SU

trends

Most flatfish stocks are at very high levels, some at or near record abundance, and most are lightly exploited (Table 3). Of 24 hatfish species or species groups and areas assessed, only two are in a low or depressed state. Petrale sole. with the second longest history of exploitation off WAC and BC (after Pacific halibut) is at depressed levels off BC, but is above MSY and increasing in abundance off WOC. Greenland turbot, the only flatfish species other than Pacific halibut vulnerable to hook and line harvest, is depressed in BSAI waters. In both cases, harvest is constrained to incidental catch to protect the resource. Because of the long history of Pacific halibut under separate management, it is not considered as part of the groundfish species in any of the northeast Pacific Ocean fishery management jurisdictions. Pacific halibut abundance has undergone a series of increases and decreases since record keeping of the 1930s. Pacific halibut reached the lowest abundance level on record during the mid 1970s subsequently gained record high abundance during the late 1980s

Area

BC

173

. F,ncd

Constant exploitation Yield (30%)

‘High risk’

detinition

R.J. Trumble/Joumal

174 Table 3 Status of Aatfish resources Area/species/year

1. woe (1993) Petrale Arrowtooth English Dover Other flatfish Pacific halibut 2. BC (1993) Dover Petrale Rock sole English Pacific halibut 3. GOA (1995)’ Deep flats Rex Shallow flats Arrowtooth Flathead Pacific halibut 4. BSAI (1995)’ Yellowfin Greenland turbot Arrowtooth Rock sole Other flatfish Flathead Pacific halibut

of Sea Research 39 (1998) 167-181

in the eastern North Pacific Ocean a Biomass

Harvest

(mt)

(mt)

12,750

3,950

1,503 2,713 1,602 14.323 1,925 538

52,560

2,152 733 2.885 1,421 6,620

116,500 89,660 355.590 1,585,040 198,470 203,560 2,000,OOo 134,500 477,600 1,944,200 590.100 596,400 86,43 1

92,601

Target F

Biomass trend

Stock condition

0.107

0.275

0.017 0.077

0.121-0.150

Increasing Stable Increasing Stable

Above MSY Unknown Above MSY Low to average

0.14

20%

Exploitation

rate

0.13

20%

2,211 4,027 5.431 17,813 2,174 25,640

0.019 0.045 0.015 0.011 0.011 0.13

0.125 0.125

124,978 8,252 9,474 54,686 20,249 14,707 4,870

0.06 0.07 0.02 0.03 0.03 0.02 0.06

0.13 0.24 e 0.27 0.18

0.125 0.145 20%

0.16 20%

Above average Declining Declining Increasing Stable Stable

Average Very low Above average Average Above average

Stable Stable Stable Increasing Stable Declining

Unknown Unknown Unknown Very high Unknown Above average

Stable Stable Stable Stable Stable Stable Stable

Very high Low Very high Very high Very high Very high Above average

a All halibut data are from 1996. b Values vary from 0.213 to 0.594 for assumptions of M and Lsu. ’ Target F is Fuss. d Different rates for different species: 0.145, 0.147, 0.149. eTarget F is F0.m. f Different rates for different species: 0.17, 0.19.

and has currently declined to slightly below record levels (Sullivan and Parma, 1996). Pacific halibut is the only flatfish species targeted for full exploitation in all areas. The actual exploitation is somewhat less than intended because declining halibut growth rates caused the CAGEAN model to underestimate biomass. Dover sole is heavily exploited only in portions of WOC, but assessment does not occur for the whole region (Tumock et al., 1995). Biomass is below target levels in one portion, but above target in another region. Stock condition of arrowtooth flounder (Rickey, 1993) is unknown, as age data

and reliable estimates of absolute abundance are not available. Petrale sole (Tumock et al., 1993) and English sole (Sampson, 1993) are above target abundance levels and increasing, while catches are far below the F3.j~ level. Petrale sole exploitation rate reached about 11% in 1993, while exploitation of other species ranged from 3 to 8% (Table 3). Dover sole and English sole in the BC area are generally fully exploited, petrale sole is depressed, and rock sole is above average abundance (Fargo, personal communication). Lack of effort data during the intensively fished 1950s to 1970s and lack of age data preclude complete assessment for petrale sole,

R.J. Trumble/Joumal

of Sea Re.renrch 39 (1998) 167-181

175

1995; Wilderbuer and Walters, 1995; Walters and Wilderbuer, 1995), typified by rock sole (Fig. 10). Yellowfin sole recovered from an overfished status during foreign fishing following extended jurisdiction and control of the harvests. Population modelling shows that the abundance is far above MSY levels, as would be expected from low exploitation rates ranging from 2 to 7% (Table 3). Fig. 9. Abundance Alaska.

trends for arrowtooth

flounder

in the Gulf of

5. Major problems in flatfish management

5.1. Overcapitaliiation but CPUE has declined since 1987 and total catch is considerably below long-term harvest. Increasing recruitment of rock sole in the early 1990s has driven up abundance. Dover sole and English sole are at average abundance. The fisheries yields for most flatfish species have been well controlled because most are single-species fisheries, which has helped maintain stock productivity (Leaman, 1993). In the GOA area, the abundance of the dominant arrowtooth flounder population may be stabilising after years of increase (Fig. 9). All other llatfish stocks are considered to have stable abundance. Lack of an historical time series for age data for all flatfish species in the GOA precludes complete stock assessment for these species (Wilderbuer et al., 1995) so no estimates of MSY have been made. All species are probably at or above MSY levels (Wilderbuer et al., 1995), as they are exploited far below the target F~~o/c levels, with exploitation rates running between 1 and 4% (Table 3). BSAI flatfish species, with the exception of a very low Greenland turbot population (Ianelli et al., 1995), have apparently stabilized at very high abundance (Wilderbuer, 1995; Wilderbuer and Sample,

Fig. 10. Abundance Aleutian Islands.

trends

for rock sole in the Bering

Sea-

The first overcapitalized flatfish fishery in the northeast Pacific was that for Pacific halibut (Huppert, 1991). From its beginnings in the late 1880s Pacific halibut fishing occurred nearly year-around. Over the years, effort gradually increased and seasons shortened to several periods over 2-3 months (Bell, 1981). In the early 1980s however, rebuilding of the Pacific halibut resource from low levels coincided with major declines of the king crab resource and limited entry in the salmon fisheries, and effort shifted rapidly into the Pacific halibut fishery (Trumble et al., 1993). Canada addressed fleet size shortly after extending jurisdiction in 1977. License limitation for Pacific halibut vessels and for groundfish vessels eliminated those considered part time. The Canadian trawl fleet increased by about two-thirds after limited entry occurred, but less that would have occurred without limited entry. The trawl fleet obtained additional fishing opportunity as American fishermen who had previously fished in Canadian waters were excluded by extended jurisdiction. After limited entry, the Canadian halibut fleet fished two to three seasons per year for several days per season. A government-commissioned review of west coast fisheries (Pearse, 1981) recommended assigning individual transferable quotas to Pacific halibut fishermen, but the concept was abandoned in 1982. As fishing seasons compressed, the fleet reconsidered, and requested an individual quota system for Pacific halibut in 1988 (Tunis, personal communication). Begun in 1991, the Individual Vessel Quota (IVQ) system extended the Canadian halibut fishery to 9 months. Canadian fishermen received the IVQs free, but pay a per-pound fee to cover administrative costs.

176

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of Sea Research 39 (1998) 167-181

During the 1970s in the GOA, several hundred vessels fished about 40 days to harvest 12,000 mt of Pacific halibut, but by 1987, several thousand vessels fished two or three l-day seasons to harvest 30,000 mt (Trumble et al., 1993). Better navigation and doubling of the catch rates with circle hooks greatly increased effective effort. Virtually all Pacific halibut were frozen rather than marketed fresh, wastage in the halibut fishery from lost and abandoned gear reached 2,000 mt per year, sinkings and deaths increased as the fishery often occurred during storms, enforcement of seasons and areas was difficult, and maintaining the catch at or below the quotas during l-day fisheries required placing restrictions on the fleet to reduce efficiency. In 1995, federal authorities implemented an Individual Fishing Quota (IFQ) program for the Alaskan fishery. Alaska fishermen received the IFQs for free, and pay only for observers. A significant component of the fishing industry adamantly opposed IFQs. The Alaskan and Canadian fishery seasons co-occurred for 8 months per year, increased amounts of the product went into the fresh market, no lives were lost during halibut fishing in 1995, and many former opponents embraced the new system. With displacement of the foreign fleets in the late 198Os, the size of the domestic groundfish fleets in Alaskan waters increased rapidly under open access. The specter of overcapitalization from fleet growth was clearly identified as the domestic fleet grew (Huppert, 1991; Marasco and Aron, 1991), but the fleet and management authorities chose not to deal with fleet size. As a result, short seasons and smaller amounts of harvest for individual vessels and processors led to increasing competition, as one segment of the fleet pre-empted others (NPFMC, 1991). So far, the low exploitation of flatfish has precluded specific allocation among gears or processing sectors that has occurred for the Pacific cod and walleye pollock fisheries. The individual quota systems that worked so well for Pacific halibut in Alaska and BC are not available for Alaskan groundfish fisheries, as the US Congress placed a moratorium on development of individual quotas until the year 2000. To maximize the catch value during short openings, groundfish fishermen retain only the most valuable species. Flatfish, which typically have relatively low value, are often discarded to make room for more valuable species

FinD. I I. Retained and discarded Aleutian Islands, 1995.

flatfish

for the Bering

Sea-

(Fig. 2); even the targeted flatfish fisheries discard other flatfish and groundfish (Fig. 11). Canada significantly decreased trawl discarding in 1996 with the advent of observers by establishing trip limits for individual vessels that included discards as well as retained catch (Leaman, personal communication). 5.2. Bycatch effects NPFMC restrictions on foreign fisheries in the early 1980s reduced Pacific halibut bycatch mortality in 1985 to the lowest recent level (Fig. 12). Bycatch mortality increased as domestic groundfish fisheries, initially not subject to bycatch restrictions, replaced foreign and joint venture fisheries. As the fleets grew, over capitalization caused a race for fish which led to increased bycatch rates, even though higher harvest costs and higher bycatch resulted. As the fleets reached bycatch limits before they reached TAC, vessels started ‘racing for bycatch’, trying to catch as much groundfish as possible before a closure due to bycatch. 25

Fig. 12. Pacific 1995.

halibut

bycatch

mortality

from

1962 through

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Bycatch in the Alaskan groundfish fisheries is a lose-lose proposition for both the groundfish fisheries that cause bycatch mortality and the fisheries that target the species caught as bycatch. Bycatch limits for Pacific halibut, king and Tanner (Chionoec&es spp.) crab, salmon, and herring (Clupea harerzgus pallasi) often close various groundfish fisheries before the TAC is reached or force the fisheries to less productive areas. The NPFMC has implemented a labyrinth of regulations to control bycatch (Wilson and Weeks, 1996). However, thousands of metric tons and millions of dollars worth of groundfish go unharvested, and harvesting costs go up because of bycatch. The IPHC subtracts the amount of Pacific halibut bycatch mortality, on the order of 10,000 mt annually, from the coast-wide commercial Pacific halibut fishery quota, and lost growth of the largely sublegal Pacific halibut causes additional lost yield to the halibut fishery (Sullivan et al., 1994). Bycatch mortality represented 22% of the 1995 halibut total allowable catch, and was equal to 34% of the commercial harvest (Fig. 8). Both halibut and groundfish fisheries would benefit with more harvest and less costs from reductions in halibut bycatch mortality. Bycatch mortality has two components: the actual bycatch and the mortality rate of the discarded fish (discard mortality rate). In Alaskan and Canadian waters, bycatch mortality reductions are approached in two ways: (1) reduce the bycatch rate by decreasing the encounter rate between fishing gear and Pacific halibut or by increasing selectivity of the gear; (2) reduce the discard mortality rate of discarded Pacific halibut. In 1991, the NPFMC began a Vessel Incentive Program (VIP), designed to reduce bycatch rates, that established penalties for vessels that catch prohibited species at higher than a standard rate. Since then. only two cases have gone through the courts (Trumble and Leaman, 1996), and the effectiveness of the program is in doubt. The DFO started an individual Pacific halibut bycatch quota (IBQ) for trawlers in 1996, and preliminary data suggest that the 1996 Pacific halibut bycatch mortality will decline to less than one-third of the 1995 levels (Leaman, personal communication). Both bycatch rates and discard mortality rates for Pacific halibut decreased under the Canadian IBQ system. Trawlers

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for yellowfin sole in the Bering Sea, faced with closures from king crab bycatch, implemented a voluntary program of forwarding observer data daily to a private consultant who plotted bycatch rates and reported back to the fleet on hot spot areas to avoid (Gauvin et al., 1996). In 1995, the voluntary program reduced king crab bycatch to about 15% of the 1994 level for that fishery, but unfortunately, increased Pacific halibut bycatch by 50%. Hook and line fishermen for Pacific cod in the Bering Sea successfully reduced Pacific halibut discard mortality rates from 18-20% in the early 1990s to 11.5% in 1995 under a joint industry-agency program where observers reported weekly bycatch data to the IPHC and to an industry consultant. The consultant reported discard mortality rates back to individual vessels in-season (Smith, 1996) and the IPHC calculated a mid-year rate retroactively used for bycatch management calculations (Trumble, 1996). In general, the Alaskan systems have more effectively increased the amount of groundfish harvested under bycatch limits, than actually reducing the amount of Pacific halibut bycatch. Only the Canadian IBQ system has actually decreased the absolute amount of Pacific halibut bycatch. The NPFMC is scheduled to consider individual quotas for bycatch species in the groundfish fisheries during 1997 (Pautzke, personal communication). If successful, IBQs offer the best opportunity for actual bycatch reductions in Alaska, but US legal system restrictions will make implementation in Alaska more difficult and costly than in Canada. 6. Discussion Flatfish management in the northeast Pacific took two different paths to the conservative approach and low exploitation that characterises the dominant species. First, domestic fishermen requested joint management of the Pacific halibut shortly after the fishery began, and have occasionally supported quotas less than recommended by the IPHC. Second, scientific groundfish management, including flatfish, developed from efforts to control foreign fisheries when little domestic fishing occurred. Overharvest of yellowfin sole and other groundfish gave an impetus for conservative management. Pacific halibut has long been one of the most

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desired commercial species in the area, and growth in catching capacity made overharvest a virtual certainty in the absence of strict limits on the fishery. The US and Canadian governments formed the IPHC in response to requests from fishermen who expressed concern that overexploitation of Pacific halibut occurred early in the 20th century. Since its earliest days, the IPHC has enjoyed the support of the Pacific halibut fishing industry for conservative quotas. Groundfish species went largely unharvested during the first half of the century as fishermen, processors, and the marketplace focused on low-volume, high-value species such as halibut, salmon, crab and shrimp. Harvest of petrale sole off the coasts of Oregon, Washington, and British Columbia during the 1940s and 1950s caused depletion only in Canadian waters. Only when foreign fleets aggressively pursued groundfish in the Bering Sea and the Gulf of Alaska did major flatfish harvest occur. Depletion of the yellowfin sole resource in the Bering Sea during the 1970s and the subsequent shift to walleye pollock marked the end of high flatfish exploitation. Foreign fleets did not pursue flatfish off Washington, Oregon, and California or Canada. Bilateral and multilateral negotiations with the foreign fishing nations required scientific justification for conservation measures desired by the US or Canada. Extended jurisdiction by the two countries allowed for unilateral application of conservative management, as long as the measures could be scientifically supported. Essentially, no domestic fishing occurred at the time, so no constituency existed to plead for status quo. Controlling foreign harvest was politically accepted, perhaps even necessary. When joint venture supplanted foreign fleets, and domestic fleets supplanted joint venture, the conservation-based management structure applied to foreign fleets carried over to the domestic fleet. In most other parts of the world, foreign fleets had competed with domestic fleets which were willing and able to absorb harvest formerly taken by foreign fleets. Stock assessment and exploitation strategy evolved from analyses and policies unique for each species to consistent procedures for most species. Age structured models and scientific surveys are the basis for abundance estimates. Exploitation rates derived from an optimum fishing mortality con-

vert abundance to quotas. Although consistent stock assessment and exploitation policies occur for all species, the quality of implementation varies. Bottom trawl surveys, especially those using roller gear, do not effectively monitor absolute flatfish abundance because of escapement under the nets. Age, sex composition and maturity, and other biological information are not available for several species, so assessments must use values from similar species. Future assessment of more species is also vulnerable to uncertainties as budget reductions cut into data gathering and processing (Glock, personal communication; Leaman, personal communication). During the change from foreign to domestic fishing, flatfish stocks increased rapidly in abundance, some species by an order of magnitude. Low exploitation cannot fully account for the increases, as total flatfish harvest has changed little since the mid 1960s. Since the winter of 1976/77, consistently changed ocean and atmospheric conditions correlate with increased Pacific salmon production, and increased groundfish production in the northeast Pacific (Beamish, 1993). Such changes in physical and biological conditions, or regime shifts, appear over decadal scales (Francis and Hare, 1994; Hare and Francis, 1995). To date, most investigation of regime shifts has focused on Pacific salmon, but interest is increasing for groundfish, including flatfish. Declines in sea lion abundance also occurred during the most recent regime shift, but no causal link has been made. This area of research in the northeast Pacific is progressing rapidly, and has the potential to enhance understanding of the effects of fishing and environment on fish and mammal populations. Limitations on total harvest in the BSAI (OY much less than the sum of ABCs) and bycatch limits for prohibited species in the BSAI and GOA required that substantial amounts of groundfish go unharvested. Fishermen chose to forgo much of the potential flatfish harvest to achieve higher value from other species. Bycatch of halibut and other prohibited species often closes flatfish and other groundfish fisheries before they attain TACs. Overcapitalized fisheries consistent with open access fishing increased fishing pressure in Alaskan waters, and fishing seasons declined from all year to several weeks or months for many species. High levels of flatfish discards occur as fishermen try to

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fill the vessel with more valuable species during the often short window of availability. Most solutions to the problems of overcapitalization, such as requirements for increased retention and utilization under consideration at the NPFMC, address the symptoms rather than the cause. In Canada, license limitation followed by individual quotas brought reduced fleets, long seasons, improved safety, increased marketing of fresh fish, and increased profitability for several species including Pacific halibut. A new program of individual quotas for bycatch of Pacific halibut in Canada reduced bycatch mortality to less than a third of previous levels. Success of the Canadian program demonstrates the opportunity for improving flatfish fisheries management in the northeast Pacific.

Acknowledgements I especially thank Tom Wilderbuer and Jeff Fargo for helping me gather the widely dispersed material necessary for this review, and for their comments on a draft of the paper. Bruce Leaman and an anonymous reviewer also provided comments that improved the paper.

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