Dietary analyses of Atlantic salmon Salmo salar post‐smolt stomachs collected from 2001 to 2005 in Penobscot Bay, Maine, U.S.A., have yielded insights into the feeding ecology of early marine phase post‐smolts from different rearing origins. Most stomachs contained
only one or two prey types, suggesting active prey selection. Post‐smolts that lived in the river longer (i.e. from naturally reared and parr‐stocked origins) were smaller and consumed more fishes than invertebrates compared to larger post‐smolts that emigrated
immediately post‐stocking (i.e. from smolt‐stocked origins). Naturally reared S. salar consumed c. 84% fishes and 16% crustaceans and parr‐stocked S. salar consumed 64% fishes and 34% crustaceans. Stocked smolts consumed 48% fishes and 40% crustaceans.
Differences in the type and quantity of consumed prey may be indicative of behavioural differences among rearing origins that influence post‐smolt survival.