Tolerance of selected fish species to atmospheric gas supersaturation

Several fish species were collected in SE Washington, acclimated to 2O deg C and 100 to 150% gas supersaturation, and exposed to high-gas-content waters (100 to 140% supersaturation) at 20 deg C under standard acute bioassay conditions. The flsh were monitored to determine death time and necropsied to determine the cause of death. The species exhibited a differential tolerance to high gas levels with smallmouth bass more tolerant and salmonids less tolerant. Nearly all fish that died during the test exhibited signs of gas bubble disease, ranging from massive heart embolism to mild subepidermal emphysema. These signs were related to exposure time and to gas supersaturation levels. Gas concentrations were monitored by molecular sieve gas chromatography. (auth