"Research in Alaska"

The demersal shelf rockfish (DSR) complex (yelloweye, quillback, copper, rosethorn, canary, China, and tiger rockfish) is assessed on a biennial cycle, with a full stock assessment typically conducted in odd calendar years. Prior to 2010 yelloweye rockfish density was estimated using a manned submersible (Delta) and since 2012 density has been estimated using a remotely operated vehicle (ROV). No surveys were completed in 2010 or 2011. Yelloweye rockfish biomass is estimated as the product of density, mean fish weight, and area of rocky habitat for each management district. The recommended DSR acceptable biological catch (ABC) and overfishing level (OFL) for this year’s SAFE are based on the most recent yelloweye rockfish biomass estimates plus the Tier 6 calculation of the non-yelloweye rockfish DSR component. In addition, the results of a preliminary statistical age-structured assessment model, which incorporates submersible and ROV yelloweye rockfish density estimates, commercial, recreational, and subsistence fishery data, and International Pacific Halibut Commission (IPHC) survey data, are presented in Appendix A.

Squids are marine molluscs in the class Cephalopoda (Group Decapodiformes). They are streamlined animals with ten appendages (2 tentacles, 8 arms) extending from the head, and lateral fins extending from the rear of the mantle. Squids are active predators which swim by jet propulsion, reaching swimming speeds up to 40 km/hr, the fastest of any aquatic invertebrate. Squids also hold the record for largest size of any invertebrate (Barnes 1987).

The Gulf of Alaska deepwater flatfish complex (consisting of Dover sole, Greenland turbot, and deepsea sole) is assessed on a biennial stock assessment schedule to coincide with the availability of new survey data. For Gulf of Alaska deepwater flatfish, in alternate (even) years we present an executive summary to recommend harvest levels for the next two years.

Pacific cod (Gadus macrocephalus) is a transoceanic species, occurring at depths from shoreline to 500 m. The southern limit of the species’ distribution is about 34° N latitude, with a northern limit of about 63° N latitude. Pacific cod is distributed widely over Gulf of Alaska (GOA), as well as the eastern Bering Sea (EBS)  and  the  Aleutian  Islands  (AI)  area.  Tagging  studies  (e.g.,  Shimada  and  Kimura  1994)  have  demonstrated  significant  migration  both  within  and  between  the  EBS,  AI,  and  GOA.  Recent  research  indicates the existence of discrete stocks in the EBS and AI (Canino et al. 2005, Cunningham et al. 2009, Canino et al. 2010, Spies 2012). Pacific cod is not known to exhibit any special life history characteristics that would require it to be assessed or managed differently from other groundfish stocks in the GOA. The Pacific cod stock in the GOA is managed as one stock.

Arrowtooth flounder (Atheresthes stomias) are relatively large flatfish that range from central California to the eastern Bering Sea and are currently the most abundant  groundfish  species  in  the  Gulf  of  Alaska.  Arrowtooth flounder occur from central California to the Bering Sea, in waters from about 20m to 800m, although  catch  per  unit  effort  (CPUE)  from  survey  data  is  highest  between  100m  and  300m.  Spawningoccurs in deep water in the Gulf of Alaska and along the shelf break in the eastern Bering Sea. Migration patterns  are  not  well  known  for  arrowtooth  flounder;  however,  there  is  some  indication  that  arrowtooth  flounder move into deeper water as they grow, similar to other flatfish (Zimmerman and Goddard 1996).  Fisheries  data  off  Washington  suggest  that  larger  fish  may  migrate  to  deeper  water  in  winter  and  shallower water in summer (Rickey 1995). 

Multi-species statistical catch-at-age models (MSCAA) are an example of a class of multi-species ‘Models with Intermediate Complexity for Ecosystem assessments’, which have particular utility in addressing both strategic and tactical EBFM questions.

The yellowfin sole (Limanda aspera) is one of the most abundant flatfish species in the eastern Bering Sea (EBS) and currently is the target of the largest flatfish fishery in the world. They inhabit the EBS shelf and are considered one stock. Abundance in the Aleutian Islands region is negligible.

Greenland turbot have life history characteristics that complicate assessment surveys in the Eastern Bering Sea and Aleutian Islands region. There continues to be issues in rectifying inconsistencies between the NMFS Shelf surveys and NMFS Slope surveys.

The Bering Sea and Aleutian Islands (BSAI) skate complex is managed in aggregate, with a single set of harvest specifications applied to the entire complex. However, to generate the harvest recommendations the stock is divided into two units. Harvest recommendations for Alaska skate Bathyraja parmifera, the most abundant skate species in the BSAI, are made using the results of an age structured model and Tier 3. The remaining species (“other skates”) are managed under Tier 5 due to a lack of data. The Tier 3 and Tier 5 recommendations are combined to generate recommendations for the complex as a whole.

Shortraker rockfish (Sebastes borealis) are distributed along the continental slope in the north Pacific from Point Conception in southern California to Japan, and are commonly found between eastern Kamchatka and British Columbia (Love et al. 2002). As adults the species occurs in a narrow range of depths on the continental slope centered at ~350 m (Rooper 2008) often in areas of steep slope (Rooper and Martin 2012). Love et al. (2002) indicates the species is found at shallower depths during early life history. In bottom trawl survey data, the species is most common through the Aleutian Islands (AI) and northern Gulf of Alaska (GOA). In the Bering Sea they are found on the slope survey but not on the shelf survey.