Cytochrome P4501A induction in oil-exposed pink salmon Oncorhynchus gorbuscha embryos predicts reduced survival potential

Cytochrome P4501A (CYP1A) induction in pink salmon Oncorhynchus gorbuscha embryos exposed to crude oil is linked to adverse effects at cellular, organism and population levels, and can be used to predict these responses. When combined with the results of an experiment designed to examine CYP1A induction during embryonic stages and growth after emergence, results from a series of experiments spanning 4 other brood years demonstrated that CYP1A induction is related to a variety of lethal and sublethal effects, including poorer marine survival, reduced growth and abnormalities. The lowest observed effective concentration of total polynuclear aromatic hydrocarbons (TPAH) in water that caused significant physiological responses, including reduced size 6 mo after exposure ended (<0.94 mu g l(-1)), was less than the lowest concentration that caused significant CYP1A induction (<3.7 mu g l(-1)). Thus, CYP1A induction is not only a biomarker, it can be considered a bioindicator; induction in early life stages implies long-term negative consequences for the individual and the population.