The Great Lakes - St.Lawrence Research Inventory

Previous attempts to rehabilitate Great Lakes coregonines (Coregonus spp.) have been unsuccessful due to the reliance on fry and stocking on top of existing populations that made evaluations difficult. After the demise of cisco and deepwater coregonines during 1940-50, non-native alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), replaced native species as forage of top predators. A basin-wide decline of both rainbow smelt and alewive has generated broad inter-lake, international interest and urgency in re-establishing species such as cisco (C. artedii), bloater (C.

RATIONALE: In a recent study we found that the timing of reproductive maturation in siscowet populations in southern Lake Superior was synchronized within populations east and west of the Keweenaw Peninsula, and occurred from August to October as observed in an adjacent lean lake trout population (Goetz et al., 2011). However, historical and more recent accounts strongly suggest that siscowets and possibly humpers, reproduce at other times of the year in other locations, particularly areas surrounding Isle Royale.

The Red Flags Analysis (RFA) is an annual procedure to help monitor and communicate the progress of chinook salmon stocking policies in Lake Michigan. It was developed by the Salmonid Working Group (SWG) under the Lake Michigan Technical Committee (LMTC). A critical review of the analysis was conducted in 2011 (Clark 2012 - Michigan State University, Quantitative Fisheries Center Technical Report T2012-01). It concluded that the procedure had a number of analytical and structural problems that should be fixed. The review gave eight specific recommendations for fixing and updating RFA.

Restoration of self-sustaining lake trout populations in the Great Lakes has been slow, except in Lake Superior and local populations in Lake Huron. Potential reasons may be related to the inability of hatchery-reared lake trout to select appropriate spawning habitat where eggs can successfully incubate and hatch.

The proposed research seeks to better understand downstream migration (i.e., outmigration) of newly metamorphosed sea lamprey larvae (transformers) to inform development of new trapping methods for control of this invasive species in the Great Lakes. Our current understanding of behavior during outmigration is limited to studies focused on when migration occurs seasonally (Applegate 1950, Applegate and Brynildson 1952, Applegate 1960). Little information is available describing diel or spatial movement patterns of sea lamprey transformers.

The muskellunge (Esox masquinongy) is a native Great Lakes apex predatory fish that has experienced declines and extirpations in many areas resulting in numerous restoration efforts. Despite localized understanding of genetic diversity in some locations, a broader understanding of genetic differences among most major Great Lakes spawning aggregates is lacking. Historic and ongoing stocking of Great Lakes and non-Great Lakes strain muskellunge poses a threat to the genetic integrity of remnant populations.

Lake-wide adult sea lamprey abundance estimates are a key metric of sea lamprey control program success reported to stakeholders and resource managers. Lake-wide sea lamprey abundance is estimated from a combination of stream-specific mark-recapture estimates, trap catches adjusted for capture efficiency, and model-based estimates based on stream drainage area and treatment history. Lake-wide adult sea lamprey abundance estimates are sensitive to mark-recapture estimates on large rivers, because a small proportion of large rivers are trappable within each Great Lake.

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.