During the winter of 1970-71, thirteen species of warm-water fishes exhibited external symptoms of gas-bubble disease (mostly "pop-eye") in the discharge canal and cove of a steam generating station. Peak monthly incidences were 70.8, 33.3, and 23.5 percent for white bass, threadfin shad, and bluegill, respectively. Forty-nine percent of the bluegill in excess of 4 inches were afflicted, whereas only 4.4 percent of those under 4 inches exhibited symptoms. Among the bluegill, the right eye only symptoms were more prevalent than were the left eye only symptoms at the 97.5 percent confidence level. Dead fish, principally black crappie, observed in the discharge in February, 1971 did not exhibit external symptoms of gas-bubble disease. However, autopsies of dying black crappie revealed gas emboli in the larger vessels of the gill fragments.
