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Recruitment Processes: Forage Fish Ecology Subproject

plankton collection gearThe Ecosystems and Fisheries-Oceanography Coordinated Investigations Program (Eco-FOCI) in NOAA initiated a two-part field study in the western Gulf of Alaska (GOA) during 2000-03. The study was designed to examine geographic and seasonal effects on forage fish productivity in the western Gulf of Alaska (see station maps).

Small pelagic fishes in coastal ecosystems consume zooplankton and, in turn, are consumed by fishes, birds, and mammals. sorting anchovy trawlThis is one way that trophic energy is transferred up the food web to commercial fisheries and protected marine mammals. Because zooplankton are advected by ocean currents, hydrographic features can concentrate zooplankton and affect their availability to zooplanktivores. Consequently, hydrographic features can affect fish production. In addition to spatial variability, seasonal cycles in zooplankton production affect fish production. Learning more about these processes contributes to our understanding of the mechanisms that force ecosystem dynamics.

Small pelagic fish imagePart I of the study focused on specific hydrographic features hypothesized to affect forage fishes by enhancing prey availability. Such effects may explain why forage species are abundant in the western GOA despite a lack of extensive upwelling. The forage fishes of interest were walleye pollock (Theragra chalcogramma) juveniles, capelin (Mallotus villosus), and eulachon (Thaleichthys pacificus). Part II of the study provided a seasonal perspective by focussing on juvenile pollock before, during, and after the north temperate winter over a larger part of the western GOA. The response variables examined included body size, condition (length-specific weight and caloric density), and diet.

The final report can be found at

Recent Publications, Poster Presentations, Reports & Activities

  • MAZUR, M.M., M.T. WILSON, A.B. DOUGHERTY, A. Buchheister and D.A. Beauchamp. 2007. Temperature and prey quality effects on growth of juvenile walleye pollock Theragra chalcogramma (Pallas): a spatially explicit bioenergetics approach. J. Fish Biol., 70, 816836.
  • WILSON, M.T., C.M. JUMP and J.T. DUFFY-ANDERSON. 2006. Comparative analysis of the feeding ecology of two pelagic forage fishes: capelin (Mallotus villosus) and walleye pollock (Theragra chalcogramma). Mar. Ecol.-Prog. Ser., 317, 245258.
  • BUCHHEISTER, A. and M.T. WILSON. 2005. Shrinkage correction and length conversion equations for Theragra chalcogramma, Mallotus villosus, and Thaleichthys pacificus. Journal of Fish Biology 67:541-548.
  • WILSON, M.T., A.L. BROWN and K.L. MIER. 2005. Geographic variation among age-0 walleye pollock (Theragra chalcogramma): evidence of mesoscale variation in nursery quality? Fishery Bulletin, Vol. 103, No. 1, pp. 207-218 (January 2005).
  • BRODEUR, R.D., M.T. WILSON, L. CIANNELLI, M.J. DOYLE and J.M. NAPP. 2002. Interannual and regional variability in distribution and ecology of juvenile pollock and their prey in fronal structures of the Bering Sea. Deep-Sea Research, Part II: Topical Studies in Oceanography, Vol. 49, Issue 26, pp. 6,051-6,067 (December 2002).

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