Mortalities associated with the handling and transporting (hauling) of fishes have long been a problem. Tolerance to these stressors varies greatly among species (Davis and Parker 1979; Tomasso et al. 1980; Wydoski and Wedenmeyer 1976). In most fishes, however, handling and hauling losses are caused by two major factors - activation of latent infections as a result of increased endocrine activity (cf. Wedemeyer 1970), and osmoregulatory dysfunctions due to blood electrolyte disturbances (Lewis 1971; Wydoski and Wedemeyer 1976).

Basic physiological information on the stress caused by current hatchery practices is helpful in developing new and improved techniques to increase survival. In view of the present fishery management requirements for stocking smallmouth bas (Micropterus dolomieu), baseline information on the physiological effects of handling and hauling hatchery-reared fish is needed to serve as the foundation for improving transport methods. Shell (1959) summarized several physiological characteristics of smallmouth bass, but little information on their physiological tolerance to stress exists. The present study was designed to determine the physiological effects of handling and short-term hauling in small mouth bass. Plasma chloride, sodium, potassium, and glucose dynamics were monitored in indicate the severity of the resulting stress and the recovery time needed.