Dermal nematodosis in commercially captured rockfish (Sebastes spp) from coastal British Columbia, Canada

Members of an Ahousaht First Nations community of Vancouver Island, Canada have developed a market for wild-caught species of indigenous rockfish (Sebastes spp.). The fish, which are caught by hook and line, are transported live to fish markets in Vancouver. Recently, market place downgrading of the fish has occurred due to a syndrome referred to as "black-mould", characterized by linear black disfigurations, and erosions, of the skin. Samples from 14 wild-caught rockfish were examined to determine the cause. On the basis of sub-gross and histological examination, the black-mould syndrome was attributed to intraepithelial deposition of eggs from a trichuroid nematode of the genus Huffmanela, coupled with an inflammatory response. The eggs observed in the tissues of the rockfish differed in size and morphology from those described for other species of Huffmanela. This is the first report of Huffmanela spp. infection in rockfish, probably due to a previously undescribed species.