"North Pacific Groundfish Stock Assessments"

Squids in the Gulf of Alaska (GOA) are managed as a single stock complex comprising approximately 15 species. Harvest recommendations are based on an historical catch approach setting OFL equal to maximum historical catch during 1997 - 2007 and ABC equal to 0.75 * OFL. Gulf of Alaska squids are on a biennial stock assessment schedule, with full assessments due in odd years.

The Gulf of Alaska (GOA) skate complex is managed as three units. Big skates (Beringraja binoculata) and longnose skates (Raja rhina) each have separate harvest specifications, with acceptable biological catches (ABCs) specified for each GOA regulatory area (western, central, and eastern). A single gulfwide overfishing level (OFL) is specified for each stock. All remaining skate species are managed as an “Other Skates” complex with gulfwide harvest specifications. All GOA skates are managed under Tier 5, where OFL and ABC are based on survey biomass estimates and natural mortality rate.

The Stock Structure Working Group (SSWG) was formed in 2009 to develop a set of guidelines to assist stock assessment authors in providing recommendations on stock structure for Alaska stocks. The framework was presented at the September 2009 joint Groundfish Plan Team and a report was drafted shortly thereafter that included a template for presenting various scientific data for inferring stock structure. In November, 2010, the Gulf of Alaska Groundfish Plan Team (GOA GPT) discussed the advantages of having all stock assessment authors evaluate stock structure characteristics of specific stocks. Subsequently, the GOA GPT recommended that the shortraker rockfish template be completed for the November 2016 NPFMC Plan Team meeting. Shortraker rockfish, Sebastes borealis, is managed as a Tier 5 species with area-specific ABC and gulf-wide OFL recommendations. Included here is a summary of what is known regarding the population of shortraker rockfish in the GOA relevant to stock structure concerns along with an evaluation of the stock structure template, author recommendations, and potential management implications to be considered. The majority of this information is excerpted from the most recent full stock assessment and can be found in more detail there (Echave et al. 2015).

The shark complex (spiny dogfish, Pacific sleeper shark, salmon shark and other/unidentified sharks) in the Gulf of Alaska (GOA) is assessed on a biennial stock assessment schedule that coincides with the availability of new trawl survey biomass estimates. In alternate (even) years we present an executive summary to recommend harvest levels for the next two years. For detailed information regarding the assessment, please refer to the last full stock assessment.

Assessment for the shallow water flatfish complex has been moved to a biennial schedule to coincide with the expected receipt of new survey data. Usually, on alternate (even) years we will present an executive summary with last year’s key assessment parameters and projections for this year. A discussion at the September 2006 Groundfish Plan Team meetings concluded the following two important points for updating information in off-year assessments.

The Gulf of Alaska (GOA) sculpin complex is managed in Tier 5 and is assessed on a biennial basis to coincide with the biennial GOA groundfish trawl survey. These surveys occur in odd years, and for these years a full assessment of the sculpin stock complex is conducted.

Sablefish (Anoplopoma fimbria) inhabit the northeastern Pacific Ocean from northern Mexico to the Gulf of Alaska (GOA), westward to the Aleutian Islands (AI), and into the Bering Sea (BS) (Wolotira et al. 1993). Adult sablefish occur along the continental slope, shelf gullies, and in deep fjords, generally at depths greater than 200 m. Sablefish observed from a manned submersible were found on or within 1 m of the bottom (Krieger 1997). In contrast to the adult distribution, juvenile sablefish spend their first two to three years on the continental shelf of the GOA, and occasionally on the shelf of the southeast BS. The BS shelf is utilized significantly in some years and seldom used during other years (Shotwell et al. 2014). 

Rockfish are assessed on a biennial stock assessment schedule to coincide with the availability of new trawl survey data. For Gulf of Alaska rockfish in off-cycle (even) years, we present an executive summary to recommend harvest levels for the next two years.

Rex sole (Glyptocephalus zachirus) are assessed on a biennial stock assessment schedule to coincide with the availability of new survey data. For Gulf of Alaska rex sole in alternate (even) years we present an executive summary to recommend harvest levels for the next two years.

Rockfish are assessed on a biennial stock assessment schedule to coincide with the availability of new survey data. For Gulf of Alaska rockfish in alternate (even) years we present an executive summary to recommend harvest levels for the next two years. Please refer to last year’s full stock assessment report for further information regarding the assessment model (Hulson et al., 2015, A full stock assessment document with updated assessment and projection model results will be presented in next year’s SAFE report.