|Document Type:||Journal Article|
|Title:||Interrelationships between juvenile salmonids and nonsalmonid fish in the Columbia River estuary|
|Author:||George T. McCabe, William D. Muir, Robert L. Emmett, Joseph T. Durkin|
Interrelationships between juvenile salmonids—coho salmon, Oncorhynchus kisutch; chinook salmon, O. tshawytscha; and steelhead, Salmo gairdneri—and nonsalmonid fish were studied in the Columbia River estuary during 1980. Nonsalmonid species were numerically dominant in pelagic and intertidal areas of the lower estuary. In pelagic and intertidal areas of the upper estuary, juvenile salmonids, particularly subyearling chinook salmon were proportionally important Nonsalmonid species commonly associated with juvenile subyearling chinook salmon included American shad Alosa sapidissima, Pacific herring Clupea harengus pallasi, northern anchovy Engraulis mordax, surf smelt Hypomesus pretiosus, longfin smelt Spirinchus thaleichthys, peamouth Mylocheilus caurinus, threespine stickleback Gasterosteus aculeatus, shiner perch Cymatogaster aggregata, Pacific staghorn sculpin Leptocottus armatus, and starry flounder Platichthys stellatus. Commonly associated species were generally defined only in reference to subyearling chinook salmon because, of all the juvenile salmonids, subyearling chinook salmon were clearly the most abundant and available in sizable numbers for the longest time. Predation on juvenile salmonids by non· salmonids and other juvenile salmonids was insignificant Significant diet overlap occurred among subyearling and yearling chinook salmon, coho salmon, and steelhead during the spring. American shad, threespine stickleback, and starry flounder had significant diet overlaps with juvenile salmonids.