This chapter provides a brief overview of crustacean parasites that infect commercially important fish and shellfish. Crustaceans are a diverse group of arthropods, with over 60,000 species that are significant to the aquaculture and fisheries sector, including parasitic species affecting other crustaceans, mollusks, and fishes. This chapter focuses on parasitic caligid copepods (sea lice), cymothoid isopods, and pea crabs of high economic impacts on commercially important aquatic species. The biology of the parasites, their effects on their hosts, the epidemiology of the infections, and economic impacts of these groups are described. Chemical treatments and husbandry modifications as management options for a range of crustacean parasites are presented, which includes the use of cleaner fish to remove parasites, specially designed cages to reduce infestation of parasites, or moving farms to deeper waters. The utilization of crustacean parasites as marine pest controls is further discussed, with emphasis on either its potential benefits or the negative effects on native crab populations. Despite the continuous adverse impacts parasitic crustaceans have on aquaculture, the progressive understanding of their biology and ecology may eventually lead to mitigation, if not complete eradication, of the parasites.
The crustacean parasites Ellobiopsis Caullery, 1910 and Thalassomyces Niezabitowski, 1913 form a monophyletic divergent clade within the Alveolata
