Epidermal condition in post‐spawned winter flounder, Pseudopleuronectes americanus (Walbaum), maintained in the laboratory and after exposure to crude petroleum

Skin samples were taken, during the post‐spawning period, from Pseudopleuronectes americanus maintained in both stationary and in running‐water systems, and after exposure to Venezuelan crude oil in each system. Comparisons with skin taken freshly from an inshore population revealed that dissociation of epidermal tissue, epidermal thinning and reduced epidermal melanophore frequency normally associated with the postspawning period were not so apparent after laboratory confinement and were even less pronounced after exposure to crude oil. In post‐spawned, laboratory maintained flounders, there was also correlation between epidermal thickness and the weight of the fish. Indications from the stationary system suggest that stress associated with environmental conditions may evoke mucigenesis in the superficial epidermal cells as distinct from the goblet cells.