EFFECT OF PUMP SPEED ON INJURIES TO CHANNEL CATFISH (ICTALURUS-PUNCTATUS) DURING HARVEST WITH A TURBINE-PUMP

External injuries and serum activities of two enzymes were determined for market-size channel catfish (Ictalurus punctatus), moved from a po nd to a hauling truck by a turbine pump operated at different speeds. Compared with fish that were not passed through the pump, all pump spe eds caused an increase in the prevelance of split fins, but only the h igher operating speeds of the pump caused hemorrhage or marked erosion of the skin. Slight abrasions of the skin were most common after fish were pumped at the slowest or faster speeds. Activity of serum lactat e dehydrogenase increased in all fish harvested with the pump except f or fish pumped at the slowest speed tested Activity of serum aspartate aminotransferase increased only in fish harvested at one of the inter mediate speeds. Because the pump speed affects the severity of injury to fish, the optimum speed should be determined before a pump is used for commercial harvests.