FY 1996

Contributions of FOCI research to forecasts of year-class strength of walleye pollock in Shelikof Strait, Alaska

Megrey, B.A., A.B. Hollowed, S.R. Hare, S.A. Macklin, and P.J. Stabeno

Fish. Oceanogr., 5(Suppl. 1), doi: 10.1111/j.1365-2419.1996.tb00092.x, 189–203 (1996)

NOAA's Fisheries Oceanography Coordinated Investigations (FOCI) contributes information to help forecast year-class strength of walleye pollock (Theragra chalcogramma) in the Gulf of Alaska. Quantitative estimates of recruitment are obtained from models of stock assessment and stock projection employing information supplied by FOCI. To generate its information, FOCI convenes specialists in marine biology, physical and fisheries oceanography, meteorology, and statistics to assemble and analyse relevant biological and physical time series with respect to recruitment and processes hypothesized to influence fish survival. Statistical methods encompass linear and nonlinear regression, stochastic simulation modelling, transfer function time series modelling, and tree-modelling regression. The current database consists of 31 years of data, and analyses have identified factors that affect ocean stratification and circulation during spring and summer of the fish's birth year as being important to recruitment. A conceptual model of the recruitment process serves as the framework for a recruitment forecast scheme. A stochastic mathematical simulation model of the conceptual model produces similarities between simulated and observed recruitment time series. FOCI has successfully forecast recruitment observed over the past several years.