Science & Data

Rock sole are demersal fish and can be found in shelf waters to 600 m (Allen and Smith, 1988). Two species of rock sole are known to occur in the north Pacific Ocean, northern rock sole (Lepidopsetta polyxystra) and southern rock sole (L. bilineata) (Orr and Matarese, 2000). Adults of the northern rock sole are found from Puget Sound through the Bering Sea and Aleutian Islands to the Kuril Islands, while the southern rock sole is known from the southeast Bering Sea to Baja California (Stark and Somerton, 2002). These species have an overlapping distribution in the Gulf of Alaska (Wilderbuer and Nichol, 2009). Rock sole are most abundant in the Kodiak and Shumagin areas. The northern rock sole spawns in midwinter and spring, and the southern rock sole spawns in summer (Stark and Somerton, 2002). Northern rock sole spawning occurred in areas where bottom temperatures averaged 3°C in January, and Southern rock sole spawning began in areas where bottom temperatures averaged 6°C in June (Stark and Somerton, 2002). Rock soles grow to approximately 60 cm and can live in excess of 20 years.

The National Standard Guidelines for Fishery Management Plans published by the National Marine Fisheries Service (NMFS) require that a stock assessment and fishery evaluation (SAFE) report be prepared and reviewed annually for each fishery management plan (FMP). The SAFE reports are intended to summarize the best available scientific information concerning the past, present, and possible future condition of the stocks and fisheries under federal management. The FMPs for the groundfish fisheries managed by the Council require that drafts of the SAFE reports be produced each year in time for the December North Pacific Fishery Management Council (Council) meetings.

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. We use a statistical age-structured model as the primary assessment tool for Gulf of Alaska northern rockfish stock which qualifies as a Tier 3 stock. For an off-cycle year, we do not re-run the assessment model, but do update the projection model with new catch information. This incorporates the most current catch information without re-estimating model parameters and biological reference points.

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Defining “forage species” can be a difficult task, as most fish species experience predation at some point in their life cycle. A forage fish designation is sometimes applied only to small, energy-rich, schooling fish like sardines and herring (e.g. Lenfest 2012), but in most ecosystems this is too limiting a description. Generally, forage species are those whose primary ecosystem role is as prey and that serve a critical link between lower and upper trophic levels.

Flathead sole (Hippoglossoides elassodon) are assessed on a biennial stock assessment schedule to coincide with the availability of new survey data. For Gulf of Alaska flathead sole in alternate (even) years we present an executive summary to recommend harvest levels for the next two years. GOA Flathead sole is managed in Tier 3a. The single species projection model was run using parameter values from the accepted 2013 accepted assessment model (McGilliard et al. 2013), together with updated catch information for 2013 - 2014, to predict stock status for flathead sole in 2015 and 2016 and to make ABC recommendations for those 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.

The demersal shelf rockfish (DSR) complex (yelloweye, quillback, copper, rosethorn, canary, China, and tiger rockfish) (Table 1) is assessed on a biennial cycle, with full stock assessments typically conducted in odd calendar years, however we are presenting a full stock assessment this year to coincide with new survey data and the development of a new model. Historically, the stock assessment was based on relative abundance estimates from a manned submersible (Delta), however as of 2010, the submersible was retired from use. No surveys were conducted in 2010 and 2011 while an alternate vehicle was sought. In 2012, we transitioned the survey from a submersible to a remote operated vehicle (ROV), and conducted stock assessment surveys in 2012 and 2013. In 2014, we planned to conduct a survey but had to cancel due to weather. The acceptable biological catch (ABC) and overfishing level (OFL) for this year’s SAFE (Table 2) are based on the most recent ROV and submersible density estimates of yelloweye rockfish in each management area using our historical methodology (Brylinsky et al. 2009). However, the results of a preliminary statistical age-structured model, which incorporates submersible and ROV yelloweye rockfish density estimates, commercial, sport, and subsistence fishery data, and International Pacific Halibut Commission (IPHC) survey data, are presented in Appendix B.

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.

Gulf of Alaska (GOA) Atka mackerel has been moved to a biennial stock assessment schedule to coincide with the availability of new survey data from the biennial trawl survey. A full assessment was presented in 2011, which included data from the 2011 GOA bottom trawl survey. On alternate (even) years we present an executive summary with updated catch, last year’s key assessment parameters, any significant new information available in the interim, and projections for this year. Although a survey was conducted in 2013, we only provided an expanded executive summary with updated catch and the 2013 survey information, due to the government shut-down in October 2013.