Michigan Department of Natural Resources

The spawning behavior and early life history of lake trout has been a focus of research for several decades, in an effort to understand the failure of stocked lake trout to re-establish self-sustaining populations in the Great Lakes. Physical characteristics of spawning reefs have been described, but other cues that attract lake trout to spawning sites are not well understood. Attraction to physical reef characteristics alone (H1), to behavioral and/or pheromone cues from other spawners in fall (H2), or to fry ‘odors’ remaining in the substrate (H3) have all been hypothesized.

We question the specifics of the parasite-host interactions between sea lamprey and lake whitefish. The probability that an individual fish will survive an attack from a sea lamprey is a key component to sea lamprey damage assessments. Comprehensively studied for lake trout, survivability for whitefish is unclear with a single mark-recapture study from the 1960s providing data. Laboratory research has not been conducted to support or refute the results of the tagging study, which was completed when ecological conditions in the Great Lakes differed from those of today.

Lake whitefish support the most economically important commercial fishery on Lake Michigan. Genetic analyses have indicated that the lake whitefish population in Lake Michigan is comprised of at least six genetically distinct stocks, resulting in a mixed-stock commercial fishery. Growth, age structure, condition, fecundity, and age at maturation could vary among these genetic stocks. Consequently, responses to exploitation could vary among stocks, supporting the need for stock-specific management.

Fisheries managers attempt to produce the highest possible sustained benefits for people by actions that influence aquatic organisms, their environments, and their human users. Fisheries management decisions have consequences that extend beyond the participants in recreational and commercial fisheries. Within Michigan alone, licensed anglers contribute nearly $2 billion to the state economy.

Analysis of natural geochemical markers is a powerful, emerging approach for the study of natal origins and movement of animals. Our research will use otolith microchemistry to assign the rearing origin of Chinook salmon in Lake Huron. Our main hypothesis is that differences in elemental and isotopic concentrations among streams and hatcheries will be reflected in Chinook salmon otoliths.