Skin lesions in captive lemon sharks Negaprion brevirostris (Carcharhinidae) associated with the monogenean Neodermophthirius harkemai price, 1963 (Microbothriidae)

Abstract

Microbothriid monogeneans commonly infect the skin and gills of wild and captive requiem sharks (Carcharhinidae). We studied clinical signs and treatments for a microbothriid infection in 4 captive lemon sharks Negaprion brevirostris (Poey) from a large public aquarium (Sea World) in Florida, USA. Three adult sharks were held in a large exhibit tank with a variety of other elasmobranchs and teleosts, and one immature shark was held in a separate exhibit tank that shared this water. In 1994, there began a series of outbreaks of infections by the microbothriid Neodermophthirius harkemai Price, 1963 (possibly with secondary bacterial involvement), on the skin of the sharks. The infections were characterised by the sharks rubbing against the rocks and walls of the aquarium, by a dark band of hemorrhage and heavy mucus production around the mouth, and by irregular grey patches with excess mucus production on the skin, particularly on the head. Oral and parenteral administration of praziquantel was not effective, and trichlorofon treatment of the whole system was only partly effective, as were freshwater baths. In contrast, success was achieved by removing the sharks to an isolated facility and treating the water with copper sulphate (0.25 ppm for 85 d); this removed the parasites, and the skin lesions were resolved. However, 2 mo after the recovered sharks were reintroduced into their original exhibit tank, the lesions on the skin and around the mouth recurred, strongly suggesting that a reservoir of parasites remained in the large exhibit tank, Novel aspects of microbothrid infection were the presence of N. harkemai as a serious pathogen on the skin, the dark band of hemorrhage around the sharks' mouths, and the successful use of copper sulfate to treat the infection.