Investigations of Disease Factors Affecting Declines of Pacific Herring Populations in Prince William Sound Section III: The effects of oil and disease on various aspects of herring fitness Manuscripts Restoration Project 99162B Final Report

Pacific herring, Clupea pallasi, were exposed both acutely (96 h) and chronically (9 wk) to the water-soluble fraction (WSF) of North Slope crude oil. Initial mean total PAH concentrations were approximately 10, 40 and 100 μg/L. Biological availability was suggested by a significant induction of hepatic cytochrome P450 content, ethoxyresorufin O-deethylase and glutathione S-transferase activities. Acute exposure caused a transient organismal stress response. Chronic exposure resulted in prolonged ionoregulatory disturbance and an inability to mount a successful stress response. Acute and chronic exposure also affected the ability of herring to swim. The time courses and magnitudes of several key post-exercise parameters including plasma cortisol, lactate and muscle glycogen indicated that recovery from exhaustive exercise was also affected. Short-term exposure to WSF significantly affected respiratory burst activity (RBA) in macrophages and plasma lysozyme concentrations. With subchronic exposure, RBT activity continued to be affected. Fish in the high treatment group were less susceptible to the pathogen Vibrio anguillarum following acute hydrocarbon exposure; however, this group was the most susceptible by the end of the experiment. This study shows that hydrocarbon exposure can affect several physiological systems of herring at low ppb concentrations resulting in decreased performance and potentially, their fitness.