Chromatophoromas and chromatophore hyperplasia in Pacific rockfish (Sebastes spp.).

Pacific rockfish from Cordell Bank, off central California (United States), were collected and histologically examined from 1985 to 1990. Hyperplastic and neoplastic cutaneous lesions, involving dermal chromatophores, were observed in five species; yellowtail rockfish (Sebastes flavidus), bocaccio (S. paucispinis), olive rockfish (S. serranoides), widow rockfish (S. entomelas), and chilipepper rockfish (S. goodei). Yearly prevalences were highest in S. paucispinis (29-38%). Prevalence was initially low in S. flavidus, but increased more than 3-fold from 1985 (7.5%) to 1990 (25%). The majority of lesions were black, but white, yellow, orange, red, and mixed-color variants were also seen. Lesions were found in skin, fins, lips, gingiva, tongue, urogenital papilla, conjunctiva, and cornea of the eye. Flat lesions were consistent with melanophore (black), xanthophore (yellow or orange), and erythrophore (red) hyperplasia. Neoplastic lesions included melanophoromas, amelanotic melanophoromas, xanthophoromas, erythrophoromas, and mixed chromatophoromas. Although etiology has not been determined, interest is currently focused on potential exposure to chemical and radioactive carcinogens from the Farallon Island Radioactive Waste Dump, 30 km to the south.