Physiological Stress in Channel Catfish, Ictalurus punctatus, Harvested by Lift Net, Vacuum Pump, or Turbine Pump

Abstract

Stress in freshwater fish results in an increase in serum cortisol and glucose and a decrease in serum electrolytes. These physiological indicators of stress were measured in fignerling and food-size channel catfish, "Ictalurus punctatus," before harvest, immediately after harvest, and for several days after the fish were harvested. Fingerlings were harvested in spring with either a turbine fish pump or a traditional boom-and-basket lift net. Food-size fish were harvested in winter, spring, and summer by a turbine fish pump, a vacuum fish pump, or a life net. Elctrolyte concentrations were very stable and did not show consistent effects of harvesting. Cortisol and glucose were the most sensitive to harvesting, and both increased during harvesting in all months tested. Recovery of the serum concentrations to pre-harvest levels was generally completed by the fifth day after harvest. Stress responses were similar among the different harvesting techniques, which suggests that the method of choice may be based on other factors, such as cost of available facilities.