Some investigations observed in cultured seabass (Dicentrarchus labrax L.) infested with Lernanthropus kroyeri and Nerocila orbignyi and exposed to cadmium pollution during different seasons at Dammaitte province

Abstract

This study was conducted to investigate the effect of crustaceans' copepoda and isopoda on cultured marine seabass (Dicentrarchus labrax L.) to cadmium pollution. A total of 400 adult infested fish collected seasonally from Damietta province were clinically examined for isolation and identification of infested parasites. Results obtained revealed some clinical pictures as bulging of opercula; sluggish movement; emaciation, severe erosion, and hemorrhages of gills; and mortality. The detected parasites were identified as copepoda (Lernanthropus kroyeri) and isopoda (Nerocila orbignyi). The morphological characteristics of Lernanthropus kroyeri van Beneden, 1851, and Nerocila orbignyi Guerin-Maneville, 1832, were studied by light microscopy. The total prevalence was 16%, and the summer displayed the highest seasonal prevalence. The relation between fish body weights and lengths and infestation rate was studied. Besides, the relation between heavy metal pollution and parasitic infestation was discussed. The present study concluded that there was inversely proportional relationship between cadmium concentration pollution in aquaculture and the prevalence of Lernanthropus kroyeri and Nerocila orbignyi infestation during European seabass summer and spring seasons, while infestation disappeared during autumn and winter seasons.