The Use of Fish Telemetry to Evaluate and Monitor Habitat Rehabilitaion and Enhancement Projects

It is widely accepted among fisheries managers that availability of suitable overwintering habitat is a limiting factor for Centrarchid species in the Upper Mississippi River (UMR).  Lock and Dam construction in the 1930’s greatly increased the total aquatic area of the UMR and provided deep backwater areas favorable for Centrarchid populations.  Since then sediment deposition in backwaters has reduced the quantity of deepwater lentic habitats.  As a result, multiple Habitat Rehabilitation and Enhancement Projects (HREPs) were implemented to mitigate the effects of backwater sedimentation by dredging, managing connectivity between backwater and channel areas, and installing control structures to introduce oxygen-rich channel water into backwaters areas during periods of hypoxia.  Information gained from fish telemetry research  in the design, monitoring, and assessment of HREPs.  Initial telemetry research documented habitat variables (e.g., temperature, dissolved oxygen, velocity, and depth) critical to overwintering Centrarchid habitat.  More recently, fish telemetry has been utilized to assess overwintering HREP function and to guide design modifications.  Current efforts are underway to establish quantitative measures of habitat utilization at individual backwaters to use in HREP evaluations and to assist in establishing habitat objectives for the UMR.