FRESH WATER BATH IN CONTROL NEOBEDENIA MELLENI (MONOGENEA: CAPSALIDAE) IN COMMON SNOOK CENTROPOMUS UNDECIMALLIS: A CASE REPORT

Abstract

Neobenedenia melleni, Capsalidae family Monogenea, is an ectoparasite of marine fish often found in fish cultivation. Infestation outbreaks by these parasites constitute serious problem in the cultivation of tropical marine fish (PAPERNA et al., 1984; KOESHARYANI et al., 1999), and some measures to control infestations are being developed. The Freshwater bath is a preventative measure that can be used to minimize the impact on marine fish ectoparasites. In this sense the present work aimed to evaluate the effect of treatment with fresh water in eliminating Neobenenedenia melleni, common snook (Centropomus undecimalis) bred in captivity. One hundred and twenty fish were randomly selected six cages arranged in Itapocoroy the Frame Inlet in Penha, Santa Catarina distributed in tanks of 1000 liters in the Mariculture Laboratory of Experimental Center of the University of Vale do Itajaí to experiment with food frequency. Initially biometrics was performed in which the fish had about 29,02 g weight and total length of 16,28 cm. The average water temperature was 27 ° C, dissolved oxygen of 8.0 mg/l, 36 ppt salinity and pH 7.0. After 10 days of experiment it was observed that the fish had refused food and clinical signs such as erratic swimming, opacity of the eye, injury to the eyeball and bleeding in various areas of the body. With a mortality rate of 15 fish infestation by monogenoidea it was detected. From this, the fish were subjected to treatment with fresh water bath neutralized with sodium thiosulphate , which resulted in a 100 % survival rate.