BIOMARKERS OF HYDROCARBON EXPOSURE AND SUBLETHAL EFFECTS IN EMBIOTOCID FISHES FROM A NATURAL PETROLEUM SEEP IN THE SANTA-BARBARA CHANNEL

Several markers of hydrocarbon exposure and sublethal effects were mea sured in rainbow surfperch Hypsurus caryi and rubberlip surfperch Rach ochilus toxodes from a shallow natural petroleum seep and from referen ce areas in the Santa Barbara Channel. Hydrocarbon exposure was assess ed by an HPLC-based analysis of fluorescing compounds in the bile. Com pounds fluorescing at wavelengths of naphthalene were significantly el evated in bile of rainbow surfperch (similar to 3x), but not rubberlip surfperch, from the seep. Compounds fluorescing at wavelengths of phe nanthrene were significantly elevated in bile of both species (similar to 2x to 3x) relative to those from the comparison areas. Content of cytochrome 4501A (CYP1A) in hepatic microsomes of both species from th e petroleum seep was significantly greater than in individuals from th e reference areas (similar to 10x in rainbow surfperch and similar to 2x in rubberlip surfperch). Immunohistochemical analysis also showed g reater content of CYP1A in both species from the petroleum seep. The C YP1A content of gill epithelia in particular was greatly different bet ween fish from the seep and reference areas. A variety of histopatholo gical lesions were documented in gills, livers and kidneys of both spe cies. Total lesion scores were not different between the two groups of rubberlip surfperch. However, in the rainbow surfperch total lesion s cores from petroleum seep fish were approximately twice as high in gil ls and one and one-half times as high in liver as those from the compa rison area. In the latter species liver lesions were relatively mild, but in gills relatively severe lesions occurred, including cartilage d ysplasia, abnormal branching and fusion of lamellae, various sorts of inflammation, aneurysms, and epithelial hyperplasia. Such interspecifi c differences in hydrocarbon exposure and response are consistent with the greater reliance on benthic feeding and more limited movements of the rainbow surfperch. It is suggested that cartilage displaysia and abnormal branching of gill filaments and lamellae are biological marke rs for xenobiotic compounds that induce CYP1A.