Characterization and Alleviation of Stress Associated with Hauling Largemouth Bass

Abstract

Stress and mortality associated with truck transport of largemouth bass Micropterus salmoides were characterized during and after simulated hauling periods of up to 30 hours at a density of 180 g fish/liter of water. Generally, “transported” fish had significantly elevated concentrations of plasma glucose and corticosteroids and decreased plasma chloride concentrations and osmolality. Significant mortality was associated with hauls of 24 and 30 hours (38% and 83–92%, respectively). Plasma characteristics returned to near-normal values 3–28 days after being hauled; recovery time generally was related to length of haul and associated mortality. Stress was reduced significantly and mortality was eliminated when fish were treated for diseases, held 72 hours without food before they were loaded, anesthetized before they were loaded, hauled at a cool temperature in physiological concentrations of salts with an antibiotic and a mild anesthetic, and allowed to recover in the same medium less the anesthetic. Received October 14, 1983 Accepted August 23, 1984