Resource Assessment & Conservation Engineering (RACE) Division

Fisheries Oceanography Coordinated Investigations (FOCI) Program

Recruitment Processes

The Recruitment Processes Program had a successful spring field season staging cruises in the eastern Bering Sea and Gulf of Alaska. In early May, program scientists worked in the vicinity of Unimak Island on the NOAA Ship Miller Freeman surveying the vertical and horizontal distributions of larval walleye pollock and Alaska plaice. Scientists are working to understand variations in the transport of these larvae from the spawning grounds to nursery areas. The research is being conducted as part of NOAA’s North Pacific Climate Regimes and Ecosystem Productivity Program, in collaboration with NOAA’s Pacific Marine Environmental Laboratory (PMEL). The PMEL has constructed a numerical model of depth-specific currents for the area.

The modeled currents and sampled vertical distributions of fish larvae will help us to better understand how changes in climate may affect the transport of larval fish towards or away from favorable nursery areas. Scientists also released several satellite-tracked drifters to validate PMEL’s model of currents. Also of note on this cruise was the observation of an organic film covering the sea surface at over half the stations sampled. The film is thought to be soybean oil from the grounded freighter, Selendang Ayu.

Recruitment Processes scientists also conducted a biophysical survey of the eastern Bering Sea from the Alaska Peninsula to the ice edge in the vicinity of St. Lawrence Island. Again, working in collaboration with PMEL on the Climate Regimes and Ecosystem Productivity Project, scientists sampled water properties, nutrient chemistry, and plankton abundances on four transects across the continental shelf and one transect along the 70-m isobath to the ice edge. This cruise, conducted on the University of Washington research vessel Thomas G. Thompson, also obtained samples within the seasonal sea ice.

The extent of seasonal sea ice in the southeast Bering Sea has changed over the last several decades, and NOAA scientists are studying how sea ice contributes to the structure and function of the eastern Bering Sea shelf ecosystem. This knowledge will better prepare NOAA scientists to forecast changes in the ecosystem due to fluctuations in climate.

The Program also completed its annual survey for late larval walleye pollock in the Gulf of Alaska, sampling stations between Unimak Pass and the northern end of Kodiak Island. These data are used by NOAA’s Ecosystems & Fisheries Oceanography Coordinated Investigations Program (Eco-FOCI) to make its annual pollock recruitment forecast.

By Jeff Napp

AFSC Quarterly Research Reports April-June 2005