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Status of Stocks & Multispecies Assessment Program

Groundfish Stock Assessments for 2009: Fishery Quota Recommendations

Figure 1, see caption
Figure 1.  Click image to enlarge.


Figure 2, see caption
Figure 2.  Click image to enlarge.


Figure 3, see caption
Figure 3.  Click image to enlarge.
 
 

The Alaska groundfish management system is based on extensive data available from the AFSC's North Pacific Groundfish Observer Program and dedicated research cruises. Catch of target and prohibited species (e.g., Pacific salmon, crab, herring, and Pacific halibut) are estimated at sea or in processing plants to provide real-time information to ensure that fisheries do not exceed total allowable catches (TACs) or violate other fishery restrictions, such as time-area closures.

Dedicated research cruises coupled with observer data make it possible to build detailed population dynamics models. Results from these modeling activities are used to determine the status of individual species and make recommendations for future catch levels.

Establishing TACs involves annual evaluation of the best available scientific information through a series of documents and public meetings. The first step begins with the preparation of stock assessment and fishery evaluation (SAFE) reports. These reports contain analyses summarizing the information about the individual stocks and species groups, and include acceptable biological catch (ABC) and overfishing level (OFL) recommendations for future years.

The authors of these reports (generally NMFS scientists) present their findings to the North Pacific Fishery Management Council's (NPFMC) groundfish plan teams in September and November. At these meetings, the reports are reviewed, and recommendations for ABC levels are compiled into two SAFE report volumes (one each for the Bering Sea/Aleutian Islands (BSAI) and Gulf of Alaska (GOA) regions), along with Plan Team recommendations for ABC.

The compiled reports are then submitted to the NPFMC Scientific and Statistical Committee (SSC) for further review. The SSC makes the final ABC recommendation to the Council, and the Council's Advisory Panel of industry representatives makes TAC recommendations.

Finally, the recommended TAC levels are adjusted (for some species) by the Council to ensure that other constraints (e.g., limiting the sum of all TACs in the Bering Sea and Aleutian Islands to be less than 2 million metric tons (t)) are met. The following rule applies for all federally managed groundfish species in a given year:

Catch < TAC < ABC < OFL

In practice, catch is often much less than TAC, and TAC is often much less than ABC. The multispecies management system is, therefore, based on the premise that no individual components are overfished or below stock sizes that are considered detrimental to the ecosystem. The most recent stock assessments can be obtained on the AFSC website at http://www.afsc.noaa.gov/refm/stocks/assessments.htm.

The Midwater Assessment Conservation Engineering (MACE) Program of the Center's RACE Division conducted two major surveys in 2008: the winter echo-integration trawl survey in the Shelikof Strait and nearby areas and the entire shelf region of the eastern Bering Sea (EBS) (with extensions into the Russian exclusive economic zone (EEZ)) to assess the summer abundance of walleye pollock and other species.

Scientists from the AFSC's Auke Bay Laboratories (ABL) conducted the annual longline survey, which is designed primarily for sablefish but also produces data used in the Greenland turbot and some rockfish assessments. This survey covers the slope regions of the GOA along with segments of the BSAI regions.

The groundfish assessment group also conducted the standard summer-trawl survey for the EBS shelf area and a separate EBS slope-region survey. Groundfish bottom-trawl surveys for the GOA are presently on a biennial cycle with the next one planned for summer 2009.

The Ecosystem Considerations chapter was updated, and the 236 page document details an overall picture of the ecosystem status with the following highlights:

  • No groundfish stocks are overfished or approaching an overfished condition
  • No systematic decline in the amount of large fish from 1982 to 2006 was identified in community size spectrum analysis of the EBS
  • Recent exploitation rates on biological guilds are within one standard deviation of long-term mean levels
  • Discards and discard rates are below those prior to 1998
  • Five new closures were implemented in 2008 as part of protection for essential fish habitat, which encompass a large part of the northern Bering Sea (almost 50% of the U.S. EEZ off Alaska is now closed to bottom trawling)
  • Despite warming trends throughout the Arctic, Bering Sea climate will remain controlled by large multi-annual natural variability
  • In the Bering Sea, there is a return to below average groundfish recruitment from 2004

Presently, projections of 2009 spawning biomass for the main groundfish stocks are estimated to be near or above their target stock size (Bmsy), while the 2008 catch levels were below Fmsy levels for both the BSAI and GOA regions (Figs. 1 and 2).

Fisheries for these groundfish species during 2007 landed 1.9 million t valued at approximately $2.0 billion after primary processing. This harvest represents nearly half of the weight of all commercial fish species landed in the United States. The bulk of the landings are from eastern Bering Sea pollock, which declined in 2008 from previous years but totaled about 1.0 million t.

Many of the flatfish stocks (e.g., rock sole, Alaska plaice, and arrowtooth flounder) are at high levels, but catches remain relatively low. Yellowfin sole abundance is high, but a larger fraction of the ABC is caught compared to other flatfish stocks in the EBS.

Atka mackerel abundance biomass is variable, but apparently strong incoming year classes have the stock at above-average levels (Fig. 3). Rockfish species comprise 5%-8% of the groundfish complex biomass and are generally increasing based on recent surveys.

On the following three pages are summaries of stock assessment results by area (Gulf of Alaska and Bering Sea/Aleutian Islands) and species or species group.
 

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