MEPS 480:245-261 (2013)  -  DOI:

Predicting fish recruitment from juvenile abundance and environmental indices

Leif Christian Stige1,*, Mary E. Hunsicker2, Kevin M. Bailey3, Natalia A. Yaragina4, George L. Hunt Jr5

1Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, Oslo 0316, Norway
2College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
3Alaska Fisheries Science Center, Seattle, Washington 98115, USA
4Polar Research Institute of Marine Fisheries and Oceanography, Murmansk 183038, Russia
5School of Aquatic and Fishery Science, University of Washington, Seattle, Washington 98195, USA

ABSTRACT: Prediction of year-class strength is a critical challenge for fisheries managers. Theoretically, predictions of recruitment should be better when they are based on estimates of cohort size taken close to the age of recruitment and may improve if the effects of environmental factors that influence pre-recruit mortality are accounted for. In practice, measurement error and difficulties in establishing robust recruitment–environment relationships complicate the picture. For 5 fish stocks of 4 species in 3 ecosystems, we examined the usefulness of indices of juvenile abundance relative to larval abundance for predicting recruitment. Further, we examined whether the use of environmental covariates improved predictions. For 2 of 4 stocks with sufficient data (1 stock did not have larval data), juvenile abundance was a better predictor of recruitment compared to larval indices. For the 2 other stocks, we found that juvenile indices were not superior to larval indices, possibly because of error in the measurement of juvenile abundance. In all 5 of these stocks, regression analysis showed that inclusion of environmental correlates contributed significantly to explaining recruitment variation compared to models based on juvenile indices alone. Further, cross validation showed that forecasts of future recruitment were either improved or qualitatively unchanged by including environmental correlates. This was despite apparent nonstationarity in the recruitment–environment relationships; most of the environmental variables and pre-recruit abundance indices were significantly correlated with recruitment for only parts of the studied period. Such complex responses to environmental changes are difficult to anticipate, yet the environmental information should not be ignored altogether.

KEY WORDS: Fish recruitment · Environmental covariates · Predicting recruitment · Gulf of Alaska walleye pollock · Bering Sea walleye pollock · Barents Sea capelin · Northeast Arctic cod · Northeast Arctic haddock

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Cite this article as: Stige LC, Hunsicker ME, Bailey KM, Yaragina NA, Hunt GL Jr (2013) Predicting fish recruitment from juvenile abundance and environmental indices. Mar Ecol Prog Ser 480:245-261.

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