Incidence of epibiosis has been studied in the deep-water portunid crab Bathynectes piperitus in the Benguela upwelling region. The serpulid polychaete Spirorbis cf. patagonicus, the hydroid Stegopoma plicatile and the stalked cirripede Poecilasma kaempferi were the commonest epizoitic species. Analysis revealed some biological and ecological features of the host population: the species does not have a terminal moult; both sexes show different moulting patterns; sexual maturity occurs at around 35 mm carapace length; there is asynchronous moulting among different sub-populations in different geographical areas; burying behaviour appears to be not very widespread.