Ecological drivers of juvenile coho salmon (Oncorhynchus kisutch) use of estuary habitat mosaics: exploring patterns across scales and estuaries

Estuaries can function as important nursery and stopover habitat for juvenile Pacific salmon, such as coho (Oncorhynchus kisutch), during their outmigration from their natal freshwaters to the ocean. However, knowledge gaps remain in understanding how particular estuarine environments and processes support these salmon. In this study, I investigated how juvenile coho abundance, growth, foraging performance, and diet were associated with various biotic and abiotic environmental parameters across nine estuaries in coastal British Columbia. I found that habitat type, temperature, and salinity were all significant predictors of coho abundance, growth, and foraging patterns; however, predictors differently influenced certain metrics. For example, warmer water temperatures were associated with lower abundances and increased growth, and increased salinity was associated with higher stomach fullness. This study underscores how different scales of biological responses provide complementary insights to understanding how estuary habitat mosaics provide nursery functions for salmon.