| Summary: | The Forage Fish Diet Overlap component of the Alaska Predator Ecosystem Experiment (APEX) investigated the trophic interactions of forage fish prey of seabird populations which were impacted during the Exxon Valdez oil spill. We analyzed more than 5000 specimens of 14 forage species, and zooplankton and epibenthic prey samples from Prince William Sound (PWS), 1994-96. Forage fish were collected monthly in western PWS with purse seines in 1994 and in three regions of PWS (southwestern, central and northeastern) with a mid-water trawl in 1995 (summer and autumn) and with a beach seine in 1996 (summer). The species examined were mainly young-of-the-year (YOY) and age 1 walleye pollock (Theragra chalcogramma), Pacific herring (Clupeu pallasi), Pacific sandlance (Ammodytes hexapterus), pink salmon (Oncorhynchus gorbuscha), chum salmon (O. keta), sockeye salmon (O. nerka), Pacific cod (Gadus macrocephalus), Pacific tomcod (Microgadus proximus), prowfish (Zaprora silenus), northern smoothtongue (Leuroglossus schmidti), eulachon (Thaleichthys pacificus), capelin (Mallotus villosus), threespine stickleback (Gasterosteus aculeatus), and Pacific sandfish (Trichodon trichodon). We compared seasonal size, diet composition and diet overlap between species from May-November, 1994; described the diets, prey fields and prey selection of juvenile pollock and herring in summer and autumn, 1995 and of juvenile herring, sandlance and pink salmon in summer, 1996; examined for prey shifts and feeding declines when the 1995-96 fish occurred in multi-species aggregations (sympatrically) compared to when they occurred in single species aggregations (allopatrically) to test for competition; and compared diet composition interannually for several species in July of the three years. Publications: Purcell, J. E. and M. V. Sturdevant. 2001. Prey selection and dietary overlap among zooplanktivorous jellyfish and juvenile fishes in Prince William Sound, Alaska. Marine Ecology Progress Series 210:67-83. Sturdevant, M. V., T. M. Willette, S. C. Jewett, E. Debevec, L. B. Hulbert, and A. L. J. Brase. 1999. Forage fish diet overlap, 1994-1996. Exxon Valdez Oil Spill Restoration Project Final Report. Restoration Project 97163C, 3 chapters: 103 pages+ figures and tables. EVOS Trustee Council, Anchorage, AK. Available at: http://www.arlis.org/ Sturdevant, M. V., T. M. Willette, S. C. Jewett, E. Debevec, L. B. Hulbert, and A. L. J. Brase. 1999. Diet composition, diet overlap, and size of 14 species of forage fish collected monthly in Prince William Sound, Alaska, 1994-1996. Pgs. 10-37 (Chapter 1) in M. V. Sturdevant et al. (ed.). Forage fish diet overlap, 1994-1996. Exxon Valdez Oil Spill Restoration Project Final Report, Restoration Project 97163C, 103 pages+ figures and tables. EVOS Trustee Council, Anchorage, AK. Available at: http://www.arlis.org/ Sturdevant, M. V., A. L. J. Brase, and L. B. Hulbert. 1999. Feeding, prey fields, and potential competition of young-of-the-year walleye pollock (Theragra chalcogramma) and Pacific herring (Clupea pallasi) in Prince William Sound, Alaska in summer and autumn. Pgs. 38-71 (Chapter 2) in M. V. Sturdevant et al. (ed.). Forage fish diet overlap, 1994-1996. Exxon Valdez Oil Spill Restoration Project Final Report, Restoration Project 97163C, 103 pages+ figures and tables. EVOS Trustee Council, Anchorage, AK. Available at: http://www.arlis.org/ Sturdevant, M. V. B., A.L.J./ Brase, and L. B. Hulbert. 1999. Diet overlap, prey selection, and potential food competition among allopatric and sympatric forage fish species in Prince William Sound, 1996. Pgs. 72-100 (Chapter 3) in M. V. Sturdevant et al. (ed.). Forage fish diet overlap, 1994-1996. Exxon Valdez Oil Spill Restoration Project Final Report, Restoration Project 97163C, 103 pages+ figures and tables. EVOS Trustee Council, Anchorage, AK. Available at: http://www.arlis.org/ Sturdevant, M. V. 2001. Summer zooplankton abundance and composition estimates from 20-m vertical hauls in Prince William Sound, Alaska, using three net meshes. Alaska Fishery Research Bulletin 8:96-106. Sturdevant, M. V., A. L. J. Brase, and L. B. Hulbert. 2001. Feeding habits, prey fields, and potential competition of young-of-the-year walleye pollock (Theragra chalcogramma) and Pacific herring (Clupea pallasi) in Prince William Sound, Alaska, 1994-1995. Fishery Bulletin 99:482-501.
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