Canada's lake trout lakes are a rare and valuable natural resource, both in ecological and economic terms. In Ontario alone, anglers spend an estimated 1.7 billion dollars on goods and services related to recreational fishing, with lake trout being the preferred species among many anglers. However, lake trout populations are increasingly threatened by multiple environmental stressors (e.g., over-exploitation, competition with introduced species, nutrient loading), with the added "threat-multiplier" of accelerated climate warming.
Concerns are growing that oxygen depletion is degrading habitat quality in the deep waters of many lake trout lakes. Moreover, recent investigations suggest that declines in deepwater oxygen concentrations may also be occurring in lakes that have not experienced increased nutrient inputs, or even in those where phosphorus inputs or lake nutrient concentrations have decreased over time. Exceptions to the increased nutrients; decreased deepwater oxygen paradigm is particularly worrying, as current approaches to resource management are prefaced on this major assumption.
The limitations of current management techniques are problematic in a multiple stressor world, particularly when climate change is affecting lake ice cover and thermal stratification, and consequently deepwater oxygen levels. It is clear that managers need a new toolset, one that includes predictive models able to forecast shifts in lake trout habitat while also improving our understanding of historical changes in lake trout habitat.
This project brings together university researchers and partners with diverse expertise (e.g., modellers, engineers, biologists, paleolimnologists) to develop and apply three distinct, yet complementary, techniques to accurately predict past, present, and future deepwater dissolved oxygen concentrations in lake trout lakes. We intend to provide managers with a scientifically-defensible approach for managing lake trout habitat, provide guidance on mitigation strategies, and ensuring sustainable management.