Herring are the most important food year-round for adult Chinook salmon in the Salish Sea.
Key Findings
A study by University of Victoria (UVic) and Pacific Salmon Foundation (PSF) scientists analyzed stomach contents of adult Chinook salmon in the Salish Sea.
Herring were found to be the most important food year-round throughout the region.
Anchovy were commonly found in stomachs near Howe Sound, while sand lance were important near Victoria and Sidney.
Seasonal differences were observed: salmon consumed more diverse prey in winter than summer.
In Sooke, crustaceans became more important in winter; lanternfish were more common in Campbell River and Victoria during winter.
Regional diet boundaries align with oceanographic features, such as freshwater inflow (anchovy near Fraser and Squamish rivers) and tidal mixing (lanternfish near Campbell River and Victoria).
Methodology
Stomachs were collected through the Adult Salmon Diet Program, a community science initiative involving recreational anglers.
Since 2017, over 250 anglers have submitted guts, with more than 7,000 salmon stomachs analyzed. This approach provides a cost-effective way to monitor salmon diet across regions and seasons.
Implications
The findings offer a baseline to monitor changes in salmon diet and the Salish Sea food chain due to climate change.
Information can support decisions such as designating protected areas.
Lead author Wesley Greentree (UVic PhD student) stated that the study provides fisheries scientists with a better understanding of regional food chain differences.