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Status of Stocks & Multispecies Assessment Program

Groundfish Stock Assessments for 2016 

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The AFSC completed the set of stock assessments for the Gulf of Alaska (GOA) and Bering Sea and Aleutian Islands (BSAI) Stock Assessment and Fishery Evaluation (SAFE) reports for managing the 2016 fisheries. In summary, these reports present analysis of the extensive data collected by NMFS-trained fisheries 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.  AFSC survey data combined with  observer data are critical in conditioning the integrated statistical stock assessment models that serve to summarize trends and estimate stock productivity.  Results from these models (and their estimates of uncertainty) are used to determine the status of individual species and make recommendations for the upper limit allowed for future catch levels.  The TAC-setting process involves annual presentations of these reports at a series of public meetings coordinated by the North Pacific Fishery Management Council’s (NPFMC) staff.  These assessments were reviewed, compiled, and summarized by the Plan Teams for Council consideration in their 2016 and 2017 Alaska groundfish fisheries catch specification process.

In 2015 the key AFSC assessment surveys included:

  • Winter Gulf of Alaska Acoustic survey using the NOAA research vessel Oscar Dyson (specifically for pollock)
  • Summer Gulf of Alaska Acoustic survey using the Oscar Dyson (pollock and other species)
  • Summer bottom-trawl surveys in the eastern Bering Sea (EBS) shelf area (376 stations) and the Gulf of Alaska (~700+ stations)
  • Auke Bay Laboratory’s longline survey which extended over 96 days and completed about 160 stations

Figure 1.   Some stock specific trends based only on NMFS eastern Bering Sea shelf bottom trawl survey data.

Figure 2.   Some stock specific trends based only on NMFS Gulf of Alaska bottom trawl survey data.

Trends from the main bottom trawl survey in the eastern Bering Sea for selected stocks are shown in Figure 1, whereas results from the biennial NMFS survey in the Gulf of Alaska are shown in Figure 2. These figures show that pollock biomass in both regions are at above-average levels and that the majority of stocks (based on survey data alone) appear to be relatively stable.


Figure 3.   Catch relative to the catch at FMSY relative to the projected stock status (horizontal axis) of groundfish in the Bering Sea and Aleutian Islands.


Figure 4.   Catch relative to the catch at FMSY relative to the projected stock status (horizontal axis) of groundfish in the GOA.


The 2015 BSAI assessments presented in 25 chapters (13 of which were only partial updates since the most recent survey in the Aleutian Islands occurred in 2014) resulted in allowable biological catch (ABC)s that summed to 3.237 million metric tons (t) for 2016 representing an increase from the 2015 level 2.843 million t. Most of the BSAI groundfish stocks continue to be above target spawning biomass levels and below fishing mortality rates that are estimated to achieve maximum sustainable yield ,with only three stocks projected to be below BMSY in 2016: Greenland turbot, the blackspotted and rougheye rockfish complex, and sablefish (Fig. 3).

In the Gulf of Alaska, the completed 23 chapters resulted in ABCs that summed to 728,800 tons for 2016 compared to the 2015 level of 685,000 tons. The projected 2016 spawning biomass estimates were at or above the level expected to provide maximum sustained yield (MSY) in the long term for all stocks except sablefish (Fig. 4). This figure also indicates that the catches in 2015 were below levels associated with overfishing. For a number of the GOA stocks, e.g., rex sole, shortraker rockfish, other rockfish, demersal shelf rockfish, thornyhead rockfish, Atka mackerel, skates, sculpins, squid, octopus, and sharks, BMSY estimates are unavailable.

Other research reviewed at the November NPFMC groundfish Plan Team meetings included halibut discard mortality rate estimates, ecosystem considerations for all regions, and the Economic status.

For more information, please visit the AFSC's North Pacific Groundfish Stocks Assessments web page.


By Jim Ianelli


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