Search this Site
powered by Google
ISC Schedule of Meetings
  • Home
  • Working Groups
  • Albacore

Albacore Working Group

General Information

The Albacore Working Group (ALBWG) was established in 2005, but was preceded by the North Pacific Albacore Workshop which was established in 1974. The Working Group is made up of members from coastal states and fishing entities of the region and members from relevant intergovernmental fishery organizations.

The Albacore Working Group regularly assesses and analyses fishery and other relevant information to determine the status of the north Pacific stock of albacore tuna, and to develop scientific advice concerning conservation needs. The most recent stock assessment was completed in 2011.

Albacore (Thunnus alalunga) --- North Pacific

◊ Biological Profile

North Pacific albacore are highly migratory species and these movements are influenced by ocean conditions. Seasonal movements have been observed, especially among juvenile fish, which move into temperate waters of the eastern and western Pacific Ocean in the spring and early summer and return to the central Pacific Ocean in the late fall and winter. Adults tend to be distributed more widely than juveniles and migrate to lower latitudes to spawn.

  • Spawning season :
    March - September, peaks April - June
  • Spawning area :
    Subtropical waters between 10 and
    25 °N in central and western Pacific
  • Feeding area :
    Temperate waters north of 25°N
  • Life span : At least 15 years
  • Maturity : 50% age-5, 100% age-6
Distribution and spawning area of
albacore in the North Pacific Ocean.

◊ Fisheries for Albacore in the North Pacific Ocean

Extensive surface and longline fisheries harvest albacore in the North Pacific Ocean.Surface fisheries (troll and pole-and-line) capture smaller immature juvenile albacore and account for more than 60% of catch since 1952. Longline fisheries tend to catch mature fish and account for 30% of catch by weight since 1952. Other gears are also used and harvest about 8% of the total catch of North Pacific albacore.
Main fisheries landing albacore
by fishing gear and country.
alb_gear_list - Click to zoom up

The total catch has ranged between 37,000 to 127,000 metric tons (t) historically and for the 30 year period, 1981-2010 has averaged 72,429 t. During the last decade (2000-2009), fisheries in Japan accounted for 65% of the total annual harvest on average, followed by fisheries in the United States (16%), in Canada (7%), and in Chinese-Taipei (7%).

Annual landings of albacore from ISC members in the North Pacific Ocean, 1952-2011.

◊ Stock Status (From ISC13)

Although there is uncertainty in the absolute estimates of biomass (total and SSB) and fishing mortality, the stock status and conservation advice based on the FSSB-ATHL reference point are relatively insensitive to these uncertainties as trends in SSB and recruitment are robust to the different plausible assumptions tested. Estimates of F2006-2008 (current F) expressed as a ratio relative to several potential F-based reference points (FMAX, F0.1, FMED, F20-50%) are less than 1.0 and SSB is currently around the long-term median of the stock and is expected to fluctuate around the historical median SSB in the future assuming constant F2006-2008 and average historical recruitment. The ratio F2006-2008 /FSSB-ATHL is 0.71, which means current F is well below the fishing mortality that would lead SSB to fall below the SSB- ATHL threshold. Thus the stock in not experiencing overfishing and the stock is not in an overfished condition, (e.g., F20-50% < 1.0), although biomass-based reference points have not been established for this stock.

◊ Conservation Advice (From ISC13)

  1. The stock is considered to be healthy at average historical recruitment levels and fishing mortality (F2006-2008).
  2. Sustainability is not threatened by overfishing as the F2006-2008level (current F) is about 71% of FSSB-ATHL and the stock is expected to fluctuate around the long-term median SSB (~400,000 t) in the short- and long-term future.
  3. If future recruitment declines by about 25% below average historical recruitment levels, then the risk of SSB falling below the SSB-ATHL threshold with F2006-2008 levels increases to 54% indicating that the impact on the stock is unlikely to be sustainable.
  4. Increasing F beyond F2006-2008 levels (current F) will not result in proportional increases in yield as a result of the population dynamics of this stock.
  5. The current assessment results confirm that F has declined relative to the 2006 assessment, which is consistent with the intent of the previous (2006) WG recommendation.

Current Research Topics

The 2011 assessment of north Pacific albacore is based on the best available biology, fishery data, and modeling techniques at this time. Nevertheless, many research recommendations were identified during the assessment process that could improve the assessment model. These recommendations are categorized into following six priority areas:

  • Age and Growth Modeling
  • Spatial Patterns Analysis
  • CPUE Analysis
  • Maturity
  • Data Improvements
  • SS3 Model Improvements

Latest Stock Assessment

Click here to see the information.

Working Group Reports and Working Papers

Working Group Chair
Hidetada Kiyofuji