Shifts in Steelhead life histories associated with fish community change in Black Bay, Lake Superior

Session: Restoration and Management of Great Lakes Fishes (1)

Kyle Stratton, Lakehead University, [email protected]
Erin Dunlop, ON Ministry of Natural Resources, Trent University, [email protected]
Jon George, Ministry of Natural Resources (retired), [email protected]
Fischer Friedrich, Ontario Ministry of Natural Resources and Forestry, [email protected]
Michael Rennie, Lakehead University, [email protected]

Abstract

Steelhead have been present in the Great Lakes since their introduction in the late 1800’s.  Localized adaptations have allowed for each population to thrive, given the natural conditions with which they are presented.  We compared local adaptations from Steelhead in three of Lake Superior’s North Shore tributaries and evaluated how life history strategies have changed in a population that has experienced significant ecological changes to better understand why certain life histories strategies are selected for given a particular set of ecological conditions.  Steelhead were angled, sampled and released during their annual spawning migration on the McIntyre River, Portage Creek, and the Jackpine River over multiple spawning seasons. The McIntyre and Jackpine River life histories were consistent over time, with 2-year smolts the most common strategy. In Portage Creek, observed life histories shifted from 1-year to 2-year old smolts, approximately 5 years after the population showed signs of decline. Though the dominant life history of Portage Creek Steelhead is now similar to other North Shore Steelhead populations, population size remains low. We hypothesize that this shift towards older/larger smolts is in response to changes in the Black Bay fish community, and may represent the first step in the recovery of this population.