Food Habits of the Salmon Smolts, Oncorhynchus tshawytscha and O. keta, from the Salcha River, Alaska

Abstract Stomach contents were examined from 454 chinook salmon smolts Oncorhynchus tshawytscha and 121 chum salmon smolts O. keta trapped in the Salcha River, Alaska, between 17 May and 8 June, 1973. Immature aquatic insects of the orders Diptera, Plecoptera, and Ephemeroptera predominated in the diet of both salmon species, although adult dipterans were frequently consumed by chum smolts. Chinook smolts, being larger fish, preyed more heavily upon plecopterans than did chum smolts. Chironomidae was the most important family of food organisms for both species. All other food items were relatively insignificant.