An Evaluation of Fish Assemblage Response to Restored Habitat Connectivity in a Large, Regulated River

The encroachment of robust cattail (Typha spp.) has limited the movement of fish throughout many extensive littoral areas of the St. Lawrence River leading to loss and decreased connectivity among wetland spawning habitats. To mitigate the effects, restoration projects have been implemented to reestablish connections between protected embayments as part of the St. Lawrence River Fish Habitat Conservation Strategy. The U.S. Fish and Wildlife Service excavated approximately 3,000 linear feet of channels through a cattail marsh in Blind Bay and another 800 linear feet at Club Island to reconnect embayments, create more suitable habitat and increase connectivity to promote movement of near-shore fishes. We collected baseline fish community, aquatic vegetation, dissolved oxygen, temperature and water level data prior to channel excavations to assess pre-restoration conditions. We will compare this dataset with the post-restoration conditions to evaluate the response of the fish community to this restoration. To evaluate the increased connectivity created by the excavated channels we will use remote PIT tag antenna arrays to monitor fish movement and usage throughout the marsh. The information from PIT tag monitoring will evaluate the efficacy of the excavated channels to increase connectivity between the protected embayments and will identify the frequency and duration of fish usage. The results of this study will inform managers to the efficacy of using excavated channels as a viable toolkit option to increase connectivity and enhance fish habitat in coastal wetlands.