Understanding the Invasion Success of a Novel Predator: Burbot Life History and Trophic Interactions in Flaming Gorge Reservoir, WY-UT

Widespread biological invasions threaten the success of fisheries management plans and ecosystem health.  Illegally introduced populations of burbot have spread throughout Flaming Gorge Reservoir (FGR), WY-UT, and these novel invaders pose a threat to sport fishes and native fish ecosystems.  We assessed trophic interactions via food web analyses and burbot life history via acoustic telemetry to better understand the impacts of a rapid and expansive burbot invasion within FGR.  Crayfish consumption dominated burbot diets (80% occurrence); however, all size classes exhibited piscivory.  Bioenergetic and stable isotope analyses indicate high consumptive pressure on the prey base (e.g., crayfish, forage fish) and the strong potential for competition with the sport fishes of FGR (e.g., smallmouth bass, lake trout).  Many burbot moved up-reservoir during fall to spawn, and some of these migrations were extensive (65 km) and rapid (6.5 km/day).  Investigating the success of identified spawning locations will occur in spring (2013); highest larval densities are anticipated in the inflow region of the reservoir based on observed spawning migrations.  Furthermore, critical questions remain, such as the consumption of burbot by sport fishes in FGR, and the potential for burbot to expand further downstream and impact other ecosystems and their imperiled, desert river fishes.