INFLUENCE OF FINE SEDIMENTS ON INTRA- AND INTERSPECIFIC COMPETITION IN SALMONIDS
Competition among fluvial salmonids may involve aggressive interactions over profitable foraging locations, but changes in habitat such as aggradation of fine streambed sediments can alter food availability. Changes in food availability can alter the value of a site and cause foraging modes to shift. In 2017 we conducted snorkel surveys to observe behavioral interactions among Brook Trout (Salvelinus fontinalis), Rainbow Trout (Oncorhynchus mykiss) and Coho Salmon (Oncorhynchus kisutch) in sandy and less sandy sites within the heavily sediment aggraded Salmon Trout River, Marquette County, Michigan. During snorkel surveys of mid-channel habitats, 5 fish were observed across 3 sites including juvenile Coho Salmon chasing smaller Rainbow Trout and Coho Salmon. Foraging forays were observed at 3 sites with drift foraging being the most common method of prey capture. Observations of woody debris microhabitats revealed higher fish densities than mid-channel habitats but were not observed for foraging behaviors or interactions. Moving forward, we will pair snorkel surveys with underwater videography of mid-channel and woody debris microhabitats pre and post sediment removals to assess competition and detect foraging mode shifts.
Bradley Wells (Primary Presenter/Author), Michigan Technological University, firstname.lastname@example.org;
Casey Huckins (Co-Presenter/Co-Author), Michigan Technological University, email@example.com;