Disease profiles differ between non-fished and fished populations of edible crab (Cancer pagurus) from a major commercial fishery

Abstract

Despite their significant contribution to global marine fisheries, relatively little information is available on the pathogen profile of commercially exploited decapod crustacean populations. Most of the information published relates to adult (fished) subpopulations, with almost nothing known about disease processes and mortality drivers in juveniles. The seasonal profile of pathogens in non-fished (prerecruit) and fished (recruit) subpopulations of Cancer pagurus, a major target fishery target in European waters, is investigated. Histopathology and ultrastructural assessment of tissues demonstrated a distinct pathogen profile in the two subpopulations, the apparent prevalence of specific pathogens varying with both season and life stage of the host. In some cases, highly prevalent pathogens in the prerecruit subpopulation were not observed in the recruit subpopulation. In this context, the discovery of a novel and highly prevalent haplosporidian-like parasite infecting the antennal gland and bladder of prerecruit life stages of C. pagurus is reported. Co-infections with pathogens described previously, such as Hematodinium sp. and C. pagurus bacilliform virus, were also observed. Disease assessments in the prerecruit subpopulation of commercial decapod fishery targets could perhaps be utilized to improve the estimation of cohort success and, therefore, forecasts of future recruitment to the fishery. © 2011 International Council for the Exploration of the Sea.