Occurrence of Neobenedenia melleni (Monogenea: Capsalidae) in dusky grouper, Epinephelus marginatus (Lowe, 1834), farmed in floating cages

Abstract

The precocious diagnosis of pathologies in aquaculture is constituted in a vital need for the success of the  cultivations. The monogeneans capsalids are considered parasites opportunists and constituted in one barrier for  the expansion of cultivations of marine fish. Outbreaks of infestation of  Benedenia or  Neobenedenia sp. can cause  massal mortalities generating enormous damages in the cultivations. After sixty days of cultivation, dusky groupers  Epinephelus marginatus (Lowe, 1834), with medium weight of 473,9 ± 109,5 g, cultivated in a floating cage of 8,0 m 3 ,  in Ubatuba/SP, presented refusal of the feeding and symptoms as the darkening of the body, erratic swimming, opacity of  the eyes, exoftalmia and hemorrhages in several areas of the body. After analyses of the fishes was identified the occurrence  of  Neobenedenia melleni in all groupers of this floating cage. After five days of the detection of the symptoms this  clinical picture became worse, resulting, in the affected fishes, in lesions in the eyeball, blindness and extensive bacterial  infections, following by mortality of 80% of the fishes.