Ultrasonic Telemetry Studies of Fish Activity Near the Nanticoke Thermal Generating Station

Nanticoke is a developing industrial centre on the north shore of Lake Erie on Long Point Bay. Ultrasonic telemetry studies were conducted in 1973–77 to determine the effects of Nanticoke Thermal Generating Station's warmwater discharge on movement patterns of smallmouth bass (Micropterus dolomieui), rock bass (Ambloplites rupestris), and yellow perch (Perca flavescens). A total of 74 fish were tracked in the station's effluent plume and at control locations. These fish were monitored continuously, recording position, distance between turns, swim speed and angle of course alteration, as well as various environmental parameters.An activity index was developed to measure the overall level of fish activity. The measured activity of all three species was significantly lower within the plume than outside of it. Water depth appeared to be the most important factor determining fish activity, followed by wave height, current speed, and temperature. Wave height, current speed, and temperature are directly affected by the thermal discharge. However, upon closer examination, the response to the plume appeared to have been principally rheotactic.No long-term residency in the plume was observed during this study or during concurrent mark-recapture studies.