Stress Response of Red Snapper (Lutjanus argentimaculatus) Exposed to Sublethal Concentrations of Crude Oil

Stress response indices including plasma cortisol. glucose, cholesterol, and total plasma proteins of red snapper (Lutjanus argentimaculatus) exposed to three different concentrations of water soluble fraction (WSF) of a crudc oil \Vere investigated. The experiment \Vas eonducted in a flow-through seawater system under tropical conditions and the concentrations of the toxicant \Vere assayed based on naphthalenes contents of WSF of crude oil as 0.107,0.052 and 0.028 ppm. Sublethal exposure to WSF of crude oil had a marked impact (P<0.05) on plasma cortisol, glucose, cholesterol and total plasma prote in. Dose-response relationships were obscrved in most of the affected parameters. The rcsults rcvcaled that, in the expcrimental tish both the primary and sccondary stress responses were activated following exposurc to diffcrcnt concentrations of the toxicant. The immunosuppressive effects of WSF of crude oil on tish following activation of stress rcsponscs arc discussed.