Of California's 13 salmonid ESUs and DPSs, ten are listed by the ESA and one is a candidate for listing. Although freshwater habitat loss and degradation contribute to population declines, it is becoming apparent that ocean conditions play a major role in the interannual variability of salmon populations, especially during the first months after exiting freshwater. Climatic and oceanographic forcing, ranging from interdecadal ocean oscillations to more regional effects such as El Niño and La Niña, affect environmental conditions and marine productivity that influence salmon growth and survival. Effective management of salmonid stocks and their ecosystems requires greater knowledge of juvenile salmonids during marine residence. The need for basic biological data and the influences of environmental factors on survival and health have been identified as high priority research needs by the Pacific Fishery Management Council as well as the scientific community. To address these needs, we are conducting research on the ocean ecology of juvenile salmon off California. The goal is to determine interannual variability of juvenile salmon physiology and the influences of biotic and abiotic environmental factors through assessment of abundance, distribution, movement patterns, growth, feeding, and energy status.
Contact: SWFSC Fisheries Ecology Division, Salmon Ocean Ecology Team