Diseases of the European edible crab (Cancer pagurus): a review

The edible crab (Cancer pagurus) supports an important fishery in European waters. The fishery is increasing in size and in relative importance as stocks of marine finfish decline. Despite its importance, though, studies on the pathogens and parasites of this crab species are relatively lacking compared with studies of commercially exploited finfish and molluscan hosts. Recent basic surveys of C. pagurus stocks from the English Channel carried out by the Cefas laboratory at Weymouth have identified a new viral infection (C. pagurus bacilliform virus, CpBV) in juvenile crabs, and several new species of protistan parasite (Hematodinium sp., Paramarteilia canceri, and Enterospora canceri) in the adult population. The histopathology and prevalence of each of these pathogens suggests that each can induce host mortality and, further, that specific pathogens are differentially prevalent in juvenile and adult cohorts from similar geographic locations and at different times of the year. In this review, these newly discovered pathogens are placed in context with previously described bacterial, fungal, protistan, and metazoan pathogens of C. pagurus, and the potential for these pathogens to impact on the health of individuals and populations within the English Channel fishery is discussed.