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

Abstract

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 µg l -1 ), was less than the lowest concentration that caused significant CYP1A induction (< 3.7 µg 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.

A Perspective on the Toxicity of Petrogenic PAHs to Developing Fish Embryos Related to Environmental Chemistry

“…A series of papers have documented that exposure to dissolved polynuclear aromatic hydrocarbons (PAHs) from petrogenic sources such as crude oil are directly toxic to fish embryos at low µg/l aqueous concentrations (Marty et al 1997;Heintz et al 1999Heintz et al , 2000Carls et al 1999Carls et al , 2005Birtwell and McAllister 2002;Rhodes et al 2005;Farwell et al 2006). Early life stages are generally the most sensitive to toxicant insult, hence our studies have focused primarily on embryos.…”

Cytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20 years after the Exxon Valdez oil spill

“…Because CYP1A is strongly induced by a limited number of compounds, it can be a particularly useful biomarker, i.e., a measurable physiological response by an organism, for evaluating exposure to those chemicals. Although CYP1A induction does not necessarily indicate deleterious effects on individuals or populations [6], elevated CYP1A levels indicate exposure to inducing compounds and, hence, at least the potential for associated toxic consequences, including subtle effects that may be difficult to detect in nature [7]. Therefore, indicators of CYP1A have been part of many considerations of environmental effects of contamination, including those associated with the Exxon Valdez oil spill.…”

“…Indicators of induction of CYP1A have been used routinely to evaluate exposure to PAHs, PCBs, and dioxins in fish [5,[7][8][9]. Although such studies are less common for birds and mammals, indicators of CYP1A levels have been used successfully as biomarkers of exposure of these taxa to inducing compounds, including PAHs [10][11][12][13].…”

Ruptured yolk sacs and visceral fungi in emergent pink salmon alevins: histopathology and relation to marine survival

“…Differences among alevin length and weight were compared using ANOVA, followed by multiple t-tests to detect differences between group means. For the fish from Little Port Walter, a chi-squared 2 × 2 contingency table followed by Fisher's exact probability test was used for 2 comparisons: (1) the frequency of ruptured yolk sacs in control fish versus oil-exposed fish in 1999 (the present study); and (2) the frequency of ruptured yolk sacs among all fish in 1999 versus fish cultured under similar conditions and sampled for histopathology near the time of emergence at the Little Port Walter Facility in 1993 (n = 143, Marty et al 1997a) and 2000 (n = 160, Carls et al 2005).…”