Conceptual Foundations for Fish Habitat Restoration in the Great Lakes Connecting Channels

The goal of this presentation is to present for wider review a conceptual model for fish habitat restoration in the Great Lakes connecting channels, the waterways that drain the individual Great Lakes.  Some of the largest runs of potadromous fish species in the Great Lakes historically occurred in the Great Lakes connecting channels (herein, GLCCs), but these have declined dramatically or ceased altogether.  These declines co-occurred with significant alterations to the GLCCs in the form of navigational dredging, dam construction, shoreline hardening, and filling of wetlands, which suggested that loss and/or destruction of spawning and nursery habitat contributed to declines in several ecologically and commercially valuable species such as lake sturgeon (Acipenser fulvescens), lake white fish (Coregonus clupeaformis), cisco (C. artedii), and walleye (Sander vitreus).  The GLCCs currently are a focal point for fish habitat restoration activities as the current administration makes restoration and protection of the Great Lakes one of its top environmental priorities.  Unfortunately, many recently-completed and ongoing fish habitat restoration efforts within the GLCCs lack a clearly articulated scientific basis that explains how individual projects (or project components) are connected, that highlights critical assumptions and that prioritizes future actions and information needs.  Long-term effectiveness also is a concern given uncertainty as to whether restored habitats leverage natural habitat-forming processes.  The conceptual framework described in the presentation was developed from first principles related to environmental variability and fish life history and attempts to place fish habitat restoration within the context of landscape-scale processes and population biology.  I then apply the model to the Detroit-St. Clair system to show how a clear conceptual foundation might help guide fish habit restoration and restoration research in this system.