"Fish Stocks"

Catch, abundance, and biology data feed into mathematical models that represent the factors causing changes in harvested fish stocks.

A biological fish stock is a group of fish of the same species that live in the same geographic area and mix enough to breed with each other when mature.

The Southeast Coastal Monitoring project (SECM) is a component of the NOAA Auke Bay Laboratories salmon research program which has sampled juvenile salmon and associated biophysical parameters in northern Southeast Alaska (SEAK) since 1997 utilizing the NOAA Ship John N. Cobb and chartered trawl vessels. Sampling juveniles as they migrate to the Gulf of Alaska, after high-mortality periods of freshwater incubation and early marine residency, provides information on year-class strength that can be used with associated environmental data to forecast abundance of the fish when they return as adults. Data from these annual surveys have been used to develop models that predicted SEAK pink salmon harvests within 16% of actual harvests for 2004, 2005, 2007, 2008, and 2009. However, this forecast accuracy was not achieved in 2006, when pink salmon harvest was well below both the SECM forecast based on juvenile salmon abundance and the Alaska Department of Fish and Game (ADF&G) forecast based on previous pink salmon harvest time series. Despite this overestimate, the 2006 SECM forecast accurately identified a decline in average pink salmon harvest. The ADF&G is now incorporating the SECM juvenile data into their annual harvest time series forecast.

On August 28, 2010, the Alaska Fisheries Science Center (AFSC) completed the thirty second annual longline survey of Alaska sablefish (Anoplopoma fimbria) and other groundfish resources of the upper continental slope (Figure 1). This survey was designed to continue the time series (1979-94) of the Gulf of Alaska portion of the Japan-U.S. cooperative longline survey that was discontinued after 1994. The National Marine Fisheries Service (NMFS) has surveyed the Gulf of Alaska annually since 1987, the eastern Aleutian Islands biennially since 1996, and the eastern Bering Sea biennially since 1997. The Gulf of Alaska and eastern Aleutian Islands were sampled in 2010.

The Southeast Alaska Coastal Monitoring (SECM) project has been sampling juvenile salmon (Oncorhynchus spp.) and associated environmental parameters in northern Southeast Alaska (SEAK) since 1997 to better understand effects of environmental change on salmon production. A pragmatic application of this effort is to forecast the abundance of adult salmon returns in subsequent years. Since 2004, juvenile peak salmon catch per unit effort (CPUE) from SECM, modified by other environmental parameters as appropriate, has been used to forecast harvest of adult pink salmon (O. gorbuscha) in SEAK. The forecast of 16.1 million fish for 2008 was within 2% of the actual harvest of 15.9 million fish. This represents the fourth forecast over the period 2004-2008 which was within 11% of the actual harvest. In 2006, however, the harvest was substantially different from the forecast. Although a simple CPUE model did indicate a downturn in harvest for 2006, the forecast was nonetheless 200% higher than the actual 2006 harvest. These results show that the CPUE information has great utility for forecasting year class strength of SEAK pink salmon, but additional environmental data are needed to avoid “misses” such as the 2006 return. Since 2007, the forecast model was developed using stepwise multiple regression, jackknife hindcast analysis, and bootstrap confidence intervals. A four-parameter model was selected as the “best” forecast model for 2009. Juvenile pink salmon CPUE in northern SEAK accounted for 82% of the variability in annual harvest of SEAK pink salmon over the 1997-2008 time period. The amount of variability explained was improved to 99% when the May 20-m integrated sea water temperatures and mixed-layer depths (from the SECM strait habitat) and the El Niño Southern Oscillation (ENSO) Index were included in the four-parameter multiple regression model. The 2009 forecast from the four-parameter model, using data collected in 2008, is 44.4 million fish, with an 80% bootstrap confidence interval of 37-52 million fish. Juvenile pink salmon peak CPUE collected in southern SEAK from 2005-2007 was highly correlated (r = 0.99) with the peak CPUE from northern SEAK in those years, and was not correlated (r < 0.01) with the residuals from the forecast model. Because the pattern of juvenile abundance was similar for the two areas, no additional variation in the harvest was explained by including the southern region data. However, that time series includes only three years of data; more years may provide additional information on regional variation in pink salmon year-class strength, especially for years when the two areas have distinctly different environmental conditions.

On August 28, 2009, the Alaska Fisheries Science Center (AFSC) completed the thirty-first annual longline survey of Alaska sablefish (Anoplopoma fimbria) and other groundfish resources of the upper continental slope (Figure 1). This survey was designed to continue the time series (1979-94) of the Gulf of Alaska portion of the Japan-U.S. cooperative longline survey that was discontinued after 1994. The National Marine Fisheries Service (NMFS) has surveyed the Gulf of Alaska annually since 1987, the eastern Aleutian Islands biennially since 1996, and the eastern Bering Sea biennially since 1997. The Gulf of Alaska and eastern Bering Sea were sampled in 2009.

The annual stock assessment and fishery evaluation (SAFE) report is a requirement of the North Pacific Fishery Management Council's Fishery Management Plan for Bering Sea/Aleutian Islands King and Tanner Crabs (FMP), and a federal requirement [50 CFR Section 602.12(e)]. The SAFE report summarizes the current biological and economic status of fisheries, total allowable catch (TAC) or Guideline Harvest Level (GHL), and analytical information used for management decisions. Additional information on Bering Sea/Aleutian Islands (BSAI) king and Tanner crab is available on the NMFS web page at http://www.fakr.noaa.gov and the Alaska Department of Fish and Game (ADF&G) Westward Region Shellfish web page at: http://www.cf.adfg.state.ak.us/region4/shellfsh/shelhom4.php.

On September 1, 2008, the Alaska Fisheries Science Center (AFSC) completed the thirtieth annual longline survey of Alaska sablefish (Anoplopoma fimbria) resources of the upper continental slope (Figure 1). This survey was designed to continue the time series (1979-94) of the Gulf of Alaska portion of the Japan-U.S. cooperative longline survey that was discontinued after 1994. The National Marine Fisheries Service (NMFS) has surveyed the Gulf of Alaska annually since 1987, the eastern Aleutian Islands biennially since 1996, and the eastern Bering Sea biennially since 1997. The Gulf of Alaska and eastern Aleutian Islands were sampled in 2008.

NAO 216-6, Environmental Review Procedures, requires all proposed agency actions to be reviewed with respect to potential impacts on the human environment. This memorandum summarizes the determination that this Proposed Rule to revise pollock trip limit regulations in the Gulf of Alaska (GOA) qualifies to be categorically excluded from further National Environmental Policy Act (NEPA) review.

Research with Otoliths.