Estudo de ocorrência de ectoparasitas de Oreochromis mossambicus na lagoa Chúali, Manhiça

Abstract

In this work, the occurrence, prevalence, average intensity and location of monogenetic parasites in O. mossambicus in Lagoa Chúali are presented. Two types of ectoparasites were identified namely Cichlidogyrus spp and Dactylogyrus spp with mean prevalence and intensity of 89%, 11.7 and 7.8%, 1.2 respectively. Ectoparasitic copepods showed an average prevalence and intensity of zero. Cichlidogyrus spp, the most prevalent ectoparasite, preferred to be located on the right side ( X2=11.8, p<0.001,df 1) of the gills, with dominance in the first and second gill arches (the two external arches) X2 =101.26, p<0.001 df 3 n=64 and in the median and posterior part of the arch (X2 =22.7 , p<0.001 d.f. =2 , n=64). Of the analyzed fish, the increase in weight and the increase in length show a slight tendency towards an increase in the infection rate. But with a significance level of p>0.05, both for length and weight. The aquatic environment of Lagoa Chúali during the sampling period was characterized by pH=7.5, oxygen content 6 mg/1, salinity 9.5ppt, and turbidity 50cm (TRADUÇÃO NOSSA)