Stress responses and vibriosis induced by petroleum hydrocarbons in the penaeid shrimp Metapenaeus dobsoni (Miers)

Abstract

Experiments with juveniles and subadults of the penaeid shrimp Metapenaeus dobsoni (Miers) subjected to lethal and sublethal toxicity tests revealed that toxicity of the water accommodated 6action (WAF) of Bombay High Cmde were dose-, time-, size- and moult stage-dependant. 13-15% of shrimps (size 30- 35 mm) exposed to 1 ppm and 5-8% of shrimps exposed to 4 ppm beyond 18 days in a 30-days moulting pattern experiment developed symptoms of vibriosis. It is significant that the shrimps exposed to 8 ppm and those maintained under control conditions did not show any signs of vibriosis. A chitinoclastic Vibrio species was isolated from diseased individuals and Kochs Postulate was successfully proved. Chronic exposure of shrimps to low sublethal doses of petroleum hydrocarbons was found to render them susceptible to vibriosis.