Fig. 1. Map of Fraser River watershed and coastal British Columbia showing locations where fish were intercepted during migration. Samples were collected off the Queen Charlotte Islands (QCI), Port Renfrew (PR), Johnstone Strait (JS), and Georgia Strait (GS) in seawater. Sample locations within the Fraser River were Cottonwood (C), Whonnock (W), Hells Gate (HG), near Churn Creek (Cc), and on the Thompson River (T) near Ashcroft. Spawning sockeye from Harrison stock (H) were sampled from Weaver Creek; Late Shuswap stock (Sh) from the Adams River; Chilko stock (Ch) from the Chilko River; and Quesnel stock (Q) from the Horsefly River.