Effects of Recovery Water Salinity on Secondary Stress Responses of Hybrid Striped Bass Fingerlings

Abstract

Fed and fasted (for 3d) fingerling hybrid striped bass, female white bass Morone chrysops × male striped bass M. saxatilis, raised in freshwater were subjected to an acute handling stress in groups of six, Fish were then allowed to recover in salt water of 5, 10, or 15%o. Severity of the stress response was quantitated by measuring whole-body glucose, glycogen and lactic acid and blood osmolality. Measurements were taken at rest, immediately after the stress, and at 0.5, 1, 6, 12, 24, and 48 h poststress. Feeding state and salinity of the recovery water had effects on the stress response. The glucose response was greater in fed fish, The lactate response in fed and fasted fish was similar in all salinity recovery treatments, The glycogen response was dominated by feeding state: salinity of the recovery water did not have a significant effect. None of the fasted groups regained resting glycogen levels within 48 h, but all the fed groups did. Blood osmolality was not affected greatly, but fish gained electrolytes in all three salinity groups, Resting osmolality levels were higher in fasted fish, Overall, fish, either fed or fasted, in the 5%o saline water recovery treatments had the more moderate responses, and prestress feeding permitted more rapid recovery of glycogen.