The inability to identify natal origins (i.e., individual rivers and hatcheries) of adult Pacific salmon in the ocean has impeded our understanding of their ocean ecology and the management of mixed‐stock fisheries. Strontium isotope ( 87 Sr : 86 Sr) ratios recorded in otoliths of fall‐run Chinook salmon ( Oncorhynchus tshawytscha ) from all major natural and hatchery spawning sites in the California Central Valley can be used...

We assessed growth in subyearling chinook salmon ( Oncorhynchus tshawytscha ) during the 1998 El Niño and 1999 La Niña in the Gulf of the Farallones, a region of the continental shelf off central California seaward of the Golden Gate and the southernmost ocean entry point for the species in North America. Juvenile salmon demonstrated greater growth during this strong El Niño, when water temperature anomalies of more than +3°C...