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.

Reference throughout this document to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA.

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,
108 p.

Most NOAA Technical Memorandums NMFS-NWFSC are
available on-line at the Northwest Fisheries Science Center
web site (http://www.nwfsc.noaa.gov)

Copies are also available from:

National Technical Information Service
U.S. Department of Commerce
5285 Port Royal Road
Springfield, VA 22161
phone orders (1-800-553-6847)
e-mail orders (orders@ntis.fedworld.gov)

This HTML file represents the Introduction only; the rest of the document is available only in PDF format.

EXECUTIVE SUMMARY

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.