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Status of Stocks & Multispecies Assessment Program

Groundfish Stock Assessments (pg. 2)

Research Reports
Oct-Nov-Dec 2013
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Figure 3.   Relative change in the biomass estimates derived from Gulf of Alaska trawl survey data between 2011 and 2013. Click to enlarge.

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

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Figure 5.   Relative change in the biomass estimates derived from eastern Bering Sea shelf trawl survey data between 2012 and 2013. Click to enlarge.

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Figure 6.   Catch relative to the catch at FMSY relative to the projected stock status (horizontal axis) of groundfish in the Bering Sea and Aleutian Islands. Click to enlarge.

In the GOA, several groundfish stocks indicated substantial increases in biomass relative to previous years, largely due to indications from 2013 survey data (Fig. 3). Overall, the ABCs increased by 8% (+44,755 t) compared with last year.

The biggest source for this change was driven by the 45% increase in ABC for GOA pollock (53,930 t). Indications for this stock were positive based on the winter acoustic-trawl survey (the Shelikof Strait biomass estimate is 2.7 times the biomass estimate for 2012 and is the largest biomass estimate from this survey since 1985).  Additionally, the 2013 NMFS bottom trawl survey biomass estimate is the highest in the time series and is up by 43% relative to the 2011 survey estimate. 

In comparison, the Pacific cod ABC increased by 7,700 t (10%) and deepwater flatfish by 8,300 t. Offsetting these increases were reductions in sablefish ABC (by 450 t compared to the 2013 value) and the remaining flatfish stock ABCs dropped by about 27,300 t (mostly due to the 7% reduction in (arrowtooth flounder). Nearly all rockfish stocks or stock complexes increased (combined 12%) with the largest increase from Pacific ocean perch at 2,897 t (+18%) compared to the 2013 ABC.

Relative to reference points, with the exception of sablefish, GOA stocks are above target stock size (Fig. 4).  The target biomass levels for deep-water flatfish (excluding Dover sole), shallow-water flatfish (excluding northern and southern rock sole), rex sole, shortraker rockfish, other rockfish (formerly other slope rockfish), demersal shelf rockfish, thornyhead rockfish, Atka mackerel, skates, sculpins, squid, octopus, and sharks are unknown.

New survey data used within the assessments were only available for the EBS shelf region comprising 365 trawl survey stations. These data suggest general increases in the conditions of several key stocks (e.g., pollock, yellowfin sole, and Greenland turbot; Fig. 5). For the region, the assessment analyses presented in the SAFE report resulted in ABCs for 2014 that sum to about 2.57 million t, down from the 2013 totals (2.64 million t). 

The largest component is EBS pollock ABC (1.369 million t for 2014 compared to 1.375 million t in 2013).  The 2014 Pacific cod ABC (combined EBS and Aleutian Islands ABCs) is 270 thousand t compared to 307 t in 2013 (a drop of 12%). Atka mackerel biomass estimates increased from the 2012 assessment and the 2014 ABC accordingly increased by about 22%. Combined BSAI flatfish ABCs dropped by 4% (29 thousand 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.  Presently four stocks are projected to be below BMSY in 2014: Aleutian Islands pollock, Greenland turbot, the rougheye and blackspotted rockfish (REBS) complex, and sablefish (Fig. 6). Relative to last year’s analysis, the REBS complex dropped because the SSC accepted that a recent strong year class should be folded into the proxy that is used for BMSY which increased the target (denominator of horizontal axis in Fig. 6). (continued)


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