The primary effects on embryonic fish exposed to crude oil - II. A case study of Spotted perch and olive flounder

Abstract

The Hebei Spirit oil spill occurred on 7th December 2007 and was recorded as one of the largest tanker spills of recent years (ITOPF, 2008). Many marine species were found dead on rocky shores and beaches and more than 8,571 ha of land-based fish aquaculture facilities were directly affected by the crude oil. Hatching success rate in rockfish and flatfish declined to lower than 50% in local field for artificial seedling production immediately after the spill that there was continuing controversy about the impacts of residual oil (NFRDI, 2009). To clarify the effects of spilled oil on resident fish development, spotted perch (Lateolabrax maculates) and olive flounder (Paralichthys olivaceus) embryos were exposed to oiled gravel effluent of Iranian Heavy Crude Oil (IHCO) for 48 hr. After 24 hr, several complex effects, including the edema and tail fin mutant were observed in olive flounder embryos exposed to IHCO. The distribution of CYP1A in embryo was assessed by immunofluorescence. CYP1A immunofluorescence activity was high significantly in the endothelium of head, epidermis and endocardium and a significant induction in CYP1A mRNA was observed in both of embryos after the oil exposure. Our results confirm that fish embryos exposed to the IHCO may disrupt the cardiac function and shape of fish tail fin during development, which is highly relevant for fitness and survival.