Hepatic lesions in English sole (Parophrys vetulus) from Commencement Bay,Washington (USA)

Prevalences of idiopathic hepatic lesions in English sole (Parophrys vetulus) were evaluated at 15 transects in Commencement Bay, Washington (a chemically contaminated embayment), and at two transects in Carr Inlet. Washington (a relatively uncontaminated reference embayment). The lesions considered were neoplasms (tumors), foci of cellular alteration (putative preneoplasms), megalocytic hepatosis and nuclear pleomorphism.Prevalences of one or more of the four lesions at 10 (67%) of the Commencement Bay transects were significantly higher (P ≤ 0·05) than the prevalence observed in Carr Inlet. Prevalences of neoplasms and foci of cellular alteration were correlated positively (P ≤ 0·05) with fish age, but none of the four lesions exhibited a relationship with fish sex. A significant concordance (P ≤ 0·005) was found among the spatial distributions of the four lesions, suggesting that all were induced by similar stimuli. Length-at-age did not differ significantly (P > 0·05) between fish with and without hepatic lesions, indicating that fish growth did not appear to be influenced by the presence of the lesions. The spatial patterns of lesion prevalences observed in this study were similar to those found at similar locations in a precious study 3–5 years earlier, suggesting that these patterns are persistent.