The Great Lakes - St.Lawrence Research Inventory

We will develop highly sensitive, species-specific quantitative PCR-based assays to identify and discriminate different lamprey genera from water or other environmental samples (e.g., sediment) within the Great Lakes watershed. Environmental DNA (eDNA) has been used to detect other invasive freshwater species, and we hypothesize that there are sufficient differences in DNA sequences between sea and native lamprey species that they can be discriminated, and that DNA is resilient enough in the environment for detection.

RATIONALE: Diporeia declines in Lakes Huron, Michigan, Erie, and Ontario have been linked to dreissenid invasions. However, despite considerable research effort, we still do not know the causal mechanism. Continued co-existence of healthy population of Diporeia and dreissenids in smaller lakes like the New York Finger Lakes indicate that possible mechanisms linking Diporiea declines with dreissenid mussels may not operate outside the Great Lakes and dreissenids may simply not be the sole causal agent of the decline.

Fishes are probably the most important biological indicators of ecosystem health in the Great Lakes. Understanding changes in fish distributions over time and the processes responsible for these changes is essential to understanding and successfully managing Great Lakes aquatic ecosystems. A comprehensive standardized, georeferenced fish distribution database has been developed for the Great Lakes basin and its tributaries however these data are not yet available to the public via the web.

The Great Lakes once contained a diverse assemblage of ciscoes. Currently, the development of conservation and re-establishment plans is hampered by taxonomic uncertainty. Difficulties arise due a complex evolutionary history that likely included postglacial hybridization between glacial races, ongoing parallel ecological divergence, and later introgression across species groups.

Lake trout were the predominant fish predator in Lake Superior before stocks collapsed from fishery exploitation and sea lamprey predation. Stocks were restored through stocking, control of sea lampreys, and regulation of fisheries. In western Lake Superior, the Gull Island Shoal refuge, created in 1976 to prevent depletion of a remnant lake trout stock, enabled the stock to recover by providing recruitment to the entire Apostle Islands area. Fish refuges or aquatic protected areas are used as a management tool in other areas of the Great Lakes and growing in use worldwide.

INTRODUCTION:

RATIONALE:

RATIONALE: Lake Trout is one of only two native salmonines in Lake Ontario and has historically played a pivotal role in energy cycling in the offshore and exerting a stabilizing influence on the fish community. Overfishing and sea lamprey predation extirpated Lake Trout from Lake Ontario by the 1950s, and subsequent rehabilitation efforts through stocking remain plagued by poor survival and little evidence of natural reproduction. Current impediments to rehabilitation include changes in the quantity and quality of prey associated with on-going proliferation of non-indigenous species.