Controversy over Connectivity: Resolving Tensions Between Restoration of Migratory Native Fishes and Control of Invasive Fishes

Dam removals in the Laurentian Great Lakes are revealing tensions between the use of dams to control the impacts of aquatic invasive species and the removal of dams to enhance connectivity and the production of native fishes. Controversy surrounding dams used to control the Sea Lamprey (Petromyzon marinus), an invasive species in the Great Lakes, demonstrates the ecological and economic importance of the tensions. I hypothesize the tensions arise from three phenomena. First, the long-term success of the Sea Lamprey control program can cause local managers and stakeholders to underestimate the need for Sea Lamprey control. Second, ignoring uncertainty in the success of dam removals can cause local managers and stakeholders to overestimate the benefits of restoring connectivity. Third, the mosaic management structure in the Great Lakes, combined with how benefits and costs of dam removals are distributed among management agencies, can facilitate the adoption a free rider tactic, where local managers and stakeholders pursue the benefits expected from restoring connectivity while placing the added cost of invasive species control on neighbouring jurisdictions and partner agencies. Decision tools are needed to improve the understanding and communication of these phenomena and ensure that connectivity decisions are balanced and scientifically defensible.