Abundance and movement patterns of fish accessing a reconnected Lake Erie coastal wetland: Insights from high-resolution sonar data

Abstract

Coastal wetlands of the Laurentian Great Lakes are complex ecosystems that provide essential biological services, including providing habitat for a suite of fish species. As restoration efforts for these coastal wetlands increase, the need to characterize how well restored areas support the life histories of wetland, riverine, and lake fish species grows. Most traditional survey methods (e.g., 24hr trap netting, visual surveys) are implemented over periods of time that make it difficult to describe short-term fluxes in fish activity, especially in waters with limited access or high turbidity. To address this gap, we used acoustic sonar technology to evaluate fish movement in a recently reconnected coastal wetland on the southern shore of western Lake Erie. Data collected over four years (2011-2014) indicate that the 10 ha wetland is continuously utilized by millions of fish, with discernible fluctuations in usage patterns observed on both daily and annual scales. These insights add to our understanding of how fish assemblages respond to restored access to coastal wetland habitats and can inform management decisions that may impact fish access (e.g., conduct management activities during periods of reduced fish utilization). Additional study of short-term fish movements using high-resolution sonar and other technologies will reveal patterns that may enhance the effectiveness of restoration and management efforts in Great Lakes coastal wetlands.