Investigator: Dave Beauchamp (USGS)
Predation during early marine life stages can be a major source of juvenile salmon mortality; however, the impacts of fish predators are not well-understood. This research activity investigates the impacts of piscivorous resident Chinook on juvenile salmon. Researchers are characterizing monthly diet composition of resident chinook from May-September and creating bioenergetics models to determine the potential level of predation impact residents have on juvenile salmon. Additionally, this study explores whether increases in artificial light pollution in Puget Sound have increased predation risk for juvenile salmon. Predation impacts can intensify with increased light, as search and capture efficiency of visual predators improves. Potential juvenile salmon predators (marine mammals, birds, fish) all use vision to target prey; their efficacy may have increased since the 1980s as a result of artificial light pollution associated with accelerating urbanization in the Puget Sound area. Researchers are measuring the underwater light environment in Puget Sound and using these measurements to map predation risk for juvenile salmon.