Differences in hydrocarbon uptake and mixed function oxidase activity between juvenile and spawning adult coho salmon ( Oncorhynchus kisutch) exposed to Cook Inlet crude oil

Abstract

1. 1. Coho salmon smolts accumulated up to 30 times more hydrocarbon in selected tissues than did coho salmon jacks when exposed to water-soluble fraction of Cook Inlet crude oil. 2. 2. Aryl hydrocarbon hydroxylase (AHH) activity continued to increase during 12 days of exposure in coho smolts, in contrast to jacks in which AHH activity peaked at 2 days and remained elevated during 20 days of exposure. 3. 3. Cytochrome P-450 concentrations peaked in 48 hr and returned to control levels in exposed smolts. In exposed and control jacks, cytochrome P-450 decreased during the 20 day experimental period. Concentrations of P-450 were significantly greater, however, in exposed jacks than in control jacks. 4. 4. Aryl hydrocarbon hydroxylase (AHH) activity and cytochrome P-450 concentrations were greater in non-exposed coho smolts and jacks than in non-exposed pre-spawning adults. 5. 5. Coho jacks were not as responsive as coho smolts in terms of P-450 induction, however, they were more responsive than anticipated for a fish in a terminal life stage.