Automated fish respiratory monitoring system for stream acidification episode assessment

Summary

Physiological and behavioral responses of fish have been measured in the laboratory as a means of detecting dose-dependent stress resulting from acidification. Providing validation of cause/effect responses from fish subjected to increasing stream acidification by evaluating surface water quality data in light of site-specific derived biological values would be an important complement to monitoring programs. In meeting this goal, we designed and tested an automated biosensing monitor for measuring fish ventilatory (breathing) rates in response to natural and experimental changes in water quality characteristics affected by acidification. Utilizing floating dock facilities and a stream-side mobile laboratory, fish breathing rate detectors were interfaced to a minicomputer for continuously generating physiological response data simultaneously with chemical/physical information. Following a series of simulated acid rainfall hydrographic episodes, rainbow trout, Salmo gairdneri Rich, and bluegill sunfish, Lepomis macrochirus RAF. showed pronounced initial changes in breathing rates after several hours exposure to peak pH shifts from 7.2 to 4.5.