Oral Presentation Society for Freshwater Science 2026 Annual Meeting

Juvenile coho salmon shift foraging tactics across current velocities and prey densities (136122)

Tyson B. Hallbert 1 , Sarah M. Yarnell 1 , Robert A. Lusardi 1
  1. Center for Watershed Sciences, University of California, Davis, Davis, CA, United States

Stream ecosystems are often described as mosaics of microhabitats that together promote both species and life history diversity. Habitat degradation in streams often reduces complexity by removing critical habitat features that may promote behavioral diversity and resource partitioning in aquatic taxa. For salmonid fishes, complex habitat allows individuals to distribute themselves across suitable areas and thereby exploit the array of resources present in stream ecosystems. Here, we are studying whether instream habitat conditions created by beaver dam analog restoration promote diversity of foraging tactics used by coho salmon (Oncorhynchus kisutch). Using underwater videography to observe fish foraging behavior, we are examining habitat thresholds that promote behavioral shifts in foraging tactics. To pair with behavioral observations, we are collecting measures of food abundance for salmon to examine if habitat conditions in restored areas influence the availability and production of invertebrate prey. This study will aid in identifying how the addition of critical habitat features influences resource availability and behavioral diversity in juvenile salmon.