This week EEB welcomes Dr. Tim Johnson, Great Lakes Research Scientist, Ontario Ministry of Natural Resources and Forestry:
Dynamics and Dilemmas within the Lake Ontario Salmonid Community
The fish community of Lake Ontario reflects a mix of native and introduced species that together support a multi-million dollar recreational fishery. Native top predators including lake trout and Atlantic salmon underwent dramatic population declines early in the past century and efforts are underway to rehabilitate these species. However, in the absence of abundant top predators, largely invasive prey fish populations rapidly expanded to nuisance levels. Binational management response included increasing stocking of several species of Pacific salmon which created economically important recreational fisheries. Is native species rehabilitation compatible with viable non-native salmonid fisheries? I combine analyses of fish production with ecological tracers and mass balance models to identify the mechanisms governing the intensity of interaction among the salmonid fishes of Lake Ontario. The talk will combine concepts of population dynamics, foraging theory, bioenergetics, and resource management to convey the complexity inherent in this productive ecosystem.
Tim Johnson is a Great Lakes Research Scientist with the Ontario Ministry of Natural Resources and Forestry, based at the Glenora Fisheries Station in eastern Lake Ontario. Tim holds a Ph.D. in Zoology with a minor in Limnology and Oceanography from the University of Wisconsin – Madison. Tim’s research focus is the structure and efficiency of aquatic food webs, including the effects of aquatic invasive species, climate change, and habitat alteration on growth and production of fishes and other aquatic organisms. Tim has co-authored over 70 peer-reviewed publications largely addressing ecological issues within the Great Lakes basin. Tim is a former president of the International Association for Great Lakes Research, an Associate Editor for the Journal of Great Lakes Research, and represents the Province’s interests on numerous bi-national boards and committees. Tim is adjunct professor in the Department of Biology, and is currently co-advising two MSc students with Shelley Arnott.
The EEB Seminars run weekly, on Thursdays, in the EEB Lounge of the BioSciences Complex, Room 4338, from 12:30-1:30pm. Light refreshments are served starting at 12:15.