Resource Ecology & Fisheries Management (REFM) Division
Status of Stocks & Multispecies Assessment Program
Groundfish Stock Assessments for 2012: Fishery Quota Recommendations
The stock assessment and fishery evaluation (SAFE) reports compiled this year included 47 sections for individual species groups or stocks. These reports provided the scientific basis for groundfish acceptable biological catches (ABC) and total catch recommendations and present analysis of the extensive data collected by NMFS-trained fishery observers and AFSC scientists aboard dedicated research surveys.
Observer data are used to estimate catch of target and prohibited species (e.g., salmon, crab, herring, and Pacific halibut) to ensure that fisheries do not exceed annually specified total allowable catches (TACs) or violate other fishery restrictions (such as time-area closures).
Results from the AFSC surveys, combined with observer data, are critical in conditioning statistical stock assessment models. Results from these models (and their estimates of uncertainty) are used to determine the status of individual species and make recommendations for future catch levels. This TAC-setting process involves annual presentations of these reports at a series of public meetings.
The reports present analyses on individual stocks and species groups and provide targets and limits—ABC and overfishing levels (OFL), respectively. The North Pacific Fishery Management Council's (NPFMC) groundfish plan teams review drafts of these reports in September and November meetings and make recommendations for ABC and OFL levels (one each for the Bering Sea and Aleutian Islands and Gulf of Alaska regions) for review by the NPFMC Scientific and Statistical Committee (SSC). The SSC then makes the final ABC recommendation to the Council and the Council's advisory panel of industry representatives makes TAC recommendations during the December NPFMC meeting. 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 tons) are met.
Importantly, the following rule applies for each federally managed groundfish stock (or stock complex) in a given year:
Catch < TAC < ABC < OFL
In practice, catch is often less than TAC and TAC is often less than ABC. The multispecies management system is therefore based on the premise that individual components be fished at safe sustainable levels and that overfishing is avoided.
The Midwater Assessment Conservation Engineering (MACE) program of the Center's RACE Division conducted a survey in summer 2011 covering part of the Gulf of Alaska. This survey represents a new initiative to use acoustic equipment along with trawls to survey this area during the summer. It is hoped that this survey can be used in future assessments as an index of abundance for groundfish species, in particular pollock.
The AFSC's Auke Bay Laboratories (ABL) Marine Ecology and Stock Assessment scientists again conducted the annual longline survey (see the ABL report in this issue), which is designed primarily for sablefish but also produces data used in Greenland turbot and some rockfish assessments. This survey covers the slope regions of the GOA along with segments of the Bering Sea and Aleutian Islands regions.
The Groundfish Assessment Program (RACE Division) also conducted bottom-trawl surveys that covered two areas during summer 2011: the EBS shelf area and the Gulf of Alaska. Groundfish bottom-trawl surveys for the Aleutian Islands are presently on a biennial cycle with the next one planned for summer 2012.
The Ecosystem Considerations chapter was updated with 7 new contributions and 44 others that were updated for Council consideration in setting catch limits and other recommendations for management. In 2011 a diverse team of scientists was convened for the Aleutian Islands ecosystem assessment developments. The team reviewed the state of knowledge and available data sets and recommended structuring ecosystem assessments by three ecoregions. A similar process is planned for a similar synthesis and report card for the Gulf of Alaska (GOA) region for summer 2012.
Fisheries for groundfish species during 2010 landed 1.52 million metric tons (t) valued at approximately $1.9 billion after primary processing (Economic Chapter). This 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 has declined since 2007 from previous years but totaled about 889,000 t and is up from 2009.
Many of the flatfish stocks (e.g., rock sole, Alaska plaice, and arrowtooth flounder) remain at high levels but catches are relatively low. Yellowfin sole abundance is high, but a larger fraction of the ABC is caught compared to other flatfish stocks in the eastern Bering Sea. Atka mackerel biomass is variable, but recent recruitment puts the stock at above-average levels. Rockfish species comprise 5%-8% of the groundfish complex biomass and have been generally increasing based on recent surveys.
Presently, projections of 2011 spawning biomass for the main groundfish stocks are estimated to be near or above their target stock size (Bmsy) for both the BSAI and GOA regions. The following pages present some assessment highlights by area and for selected species.