NOAA Technical Memorandum NMFS-NWFSC-51
Ecology of Marine Predatory
and Prey Fishes
off the Columbia River,
1998 and 1999
Robert L. Emmett, Paul J. Bentley, and Gregory K. Krutzikowsky*
Northwest Fisheries Science Center
U.S. DEPARTMENT OF COMMERCE Donald L. Evans, Secretary
National Oceanic and Atmospheric Administration
Scott B. Gudes, Acting Administrator
National Marine Fisheries Service
William T. Hogarth, Assistant Administrator for Fisheries
NOAA Technical MemorandumNMFS Series
The Northwest Fisheries Science Center of the Na tional Marine Fisheries Service, NOAA, uses the NOAA Technical Memorandum NMFS series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible due to time constraints. Documents published in this series may be referenced in the scientific and technical literature.
The NMFS-NWFSC Technical Memorandum series of the Northwest Fisheries Science Center continues the NMFS-F/NWC series established in 1970 by the Northwest & Alaska Fisheries Science Center, which has since been split into the Northwest Fisheries Science Center and the Alaska Fisheries Science Center. The NMFS-AFSC Technical Memorandum series is now being used by the Alaska Fisheries Science Center.
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This document should be cited as follows:
Emmett, R.L., P.J. Bentley, and G.K. Krutzikowsky.
2001. Ecology of marine predatory and prey fishes
off the Columbia River, 1998 and 1999. U.S. Dept.
Commer., NOAA Tech. Memo. NMFS-NWFSC-51,
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This HTML file represents the Introduction only; the rest of the document is available only in PDF format.
The National Marine Fisheries Service surface-trawled off the mouth of the Columbia River from April through July 1998 and 1999 to identify the pelagic fish community during the spring salmonid smolt migration period and to collect information on the feeding habits of predatory fishes. Preliminary results indicate that baitfish, primarily Pacifc sardine (Sardinops sagax) and Pacific herring (Clupea pallasi), numerically dominate this nearshore community. Important fish predators, Pacific hake (Merluccius productus), jack mackerel (Trachurus symmetricus), and chub mackerel (Scomber japonicus), are at times abundant. Initial food-habit studies have not identified direct predation on salmonids. However, potential indirect effects of the changing pelagic fish community associated with different oceanographic regimes on juvenile salmonids are presented.
Special thanks are due to Dan Parker, Captain of the FV Sea Eagle, for his willingness to work with us on these surveys. His encouragement and skill with fishing gear and equipment made this research possible. We also thank the crew of the FV Sea Eagle. Tim Hall and Ron Lowe made setting the trawl look easy and the cruises always interesting. Finally, thanks to Susan Hinton for providing logistical and moral support that enabled us to maintain intense ocean sampling schedules in 1998 and 1999.