Title : Correlation between water quality and Amyloodinium ocellatum parasitic infestation in European seabass (Dicentrarchus labrax)
Amyloodinium ocellatum is one of the most important ectoparasitic protozoa infecting marine species especially during early life stages (fries and fingerlings). Whether the environmental parameters and water quality affecting the occurrence of Amyloodinium infestation is worth to be investigated as a tool for proper control strategies. The present study was carried out on 768 cultured European seabass fries that were collected during the period from April 2017 to April 2018 . The collected samples subjected to full clinical, parasitological and histopathological examination studies. The results revealed a heavy infestation with Amyloodinium ocellatum causing severe hyperplasia in the affected gill epithelia with fusion of the secondary gill lamella and moderate hyperplasia in the skin with desquamation of the covering epithelium. Interaction between the environmental stressors and Amyloodinium ocellatum infestation showed that pH and salinity were positively correlated with Amyloodiniosis. In conclusion, the severity of infestation by A. ocellatum is evaluated by interaction of this pathogenic parasite with variable environmental stressors. In conclusion, infestations of European seabass by A. ocellatum can be avoided if defined patterns of quarantine, biosecurity and disinfection protocols are kept in mariculture facilities.