Loose habitat affiliations and divergent winter distributions in round goby population of Thunder Bay, Lake Huron

Session: 29. - Preliminary Results from the 2017 CSMI Intensive Field Year on Lake Huron

Peter Esselman, U.S. Geological Survey, [email protected]
Darryl Hondorp, U.S. Geological Survey-Great Lakes Science Center, [email protected]
Todd Wills, Michigan Dept. of Natural Resources, [email protected]
Meredith Nevers, U.S. Geological Survey - Great Lakes Science Center, [email protected]
Murulee Byappanahalli, U.S. Geological Survey, Great Lakes Science Center, [email protected]

Themes
Aquatic Invasive and Nuisance Species in the Great Lakes

Abstract

Round goby have become an important prey item for a variety of predator fishes, and also have caused negative consequences for native species.  Despite their growing importance to valuable fisheries, their annual distributions remain poorly understood and their habitat associations in the open waters of Lake Huron remain unsubstantiated.  We employed yankee trawls, beam trawls, tripod mounted cameras, and environmental DNA to document the seasonal distributions and habitat affiliations of round goby along a depth gradient in Thunder Bay, Lake Huron.  We hypothesized that goby abundances would be greatest in deep water habitats in late winter, and shallow habitats in summer.  We also hypothesized that round goby biomass density would be greatest in rocky habitats.  Neither of our hypotheses were strongly supported by our data.  Contrary to results from Lake Ontario, round goby were not captured in warmer deeper waters during winter, nor was their eDNA detected at greater depths.  Instead, eDNA results suggested that round goby were present in shallow water habitats during winter.  We found a weak but non-significant association with rocky habitats.  High variation around estimates of biomass density in different habitats may have resulted from low sampling efficiency of the gear types used.