Freshwater Colloquium: Assessing the Basis for Heritable Phenotypic Variation in Lake Charr Ecomorphs of Lake Superior
The School of Freshwater Sciences’ Freshwater Colloquium creates a platform for students, faculty and scientists to discuss their research and emergent issues related to freshwater resources. Presentations are open to the public.
All events will take place on Mondays from 3:30-4:20 p.m. in-person in the GLRF Ballroom.
The School of Freshwater Sciences Great Lakes Research Facility, is located at 600 E. Greenfield Ave.
Resource polymorphisms are common among charr (Salvelinus) ecomorphs. In North America, there are lake charr (Salvelinus namaycush) ecomorphs exhibiting variations in morphology, physiology and behavior. Many of these occur in deep lake ecosystems (e.g., Lake Superior, Great Bear and Slave Lakes) where depth provides a variety of habitats varying in temperature, pressure, and forage composition. Which phenotypic variations are heritable or result from environmental plasticity is a fundamental question for understanding the sympatric evolution of these ecomorphs and may have profound impacts on their resiliency to habitat change in the future. In Lake Superior, there have been four reported ecomorphs; leans, siscowets, redfins and humpers. However, based on observations particularly in complex bathymetric habitats (e.g., Isle Royale, Stannard Rock, Klondike Reef), there are certainly more ecomorphs that have yet to be described. So far, ecomorphs (particularly leans and siscowets) can be differentiated based on morphometry, growth, habitat, incidence of skip spawning, pyloric caeca, and to a lesser extent diet. They also exhibit physiological differences in the amount of lipid and glycogen stored in the muscle and liver as well as in the effects of lamprey wounding. This talk will synthesize efforts that have been made to delineate which of these phenotypes have a genetic basis and to what extent. It relies heavily on the results of a 15-year, multi-generational common garden rearing experiment of lean and siscowet lake charr. Rick Goetz is currently a Professor Emeritus in the School of Freshwater Sciences at the University of Wisconsin-Milwaukee and an Affiliate Professor in the School of Aquatic and Fishery Sciences at the University of Washington. From 2011-2021 he was a research physiologist heading the Program on Aquaculture and Marine Fish and Shellfish Biology at the Manchester Research Station (Seattle-NOAA Northwest Fisheries Science Center), studying biological questions pivotal to the sustainability of natural marine fish and shellfish populations as well as the artificial propagation of marine fish for aquaculture. Prior to coming to Seattle, he was a Professor in the School of Freshwater Sciences at the University of Wisconsin-Milwaukee (2004-2011), Director of the Program on Scientific Aquaculture at the Marine Biological Lab in Woods Hole, Massachusetts (2000-2004), and a Professor in the Department of Biological Sciences at the University of Notre Dame (1977-2000). In the past he has conducted research on reproduction, growth and innate immunity in fish and for the past two decades has been investigating the basis of phenotypic differentiation and speciation in lake trout.