Influence of ectoparasites on hematological parameters of wild and cultured dusky grouper from Southeastern Brazil

Abstract

This study evaluated the occurrence of ectoparasites and its influence on the blood parameters of wild and cultured dusky grouper Epinephelus marginatus from Southeastern Brazil. Hematological and parasitological analyses were made on 147 groupers, obtained from wild (n = 73) and aquaculture origins (n = 74), during cold (n = 70) and hot (n= 77) seasons between July 2009 and June 2010. Two species of ectoparasites were identified: Pseudorhabdosynochus beverleyburtonae (Monogenea: Diplectanidae) on the gills and Neobenedenia melleni (Monogenea: Capsalidae) on the body surface of the fish. Positive and negative correlations between mean abundances of N. melleni and P. beverleyburtonae, respectively, with red blood cells were observed in fish from both origins during hot season. Positive correlations between mean abundances of P. beverleyburtonae and thrombocytes in fish from both origins and negative correlations between mean abundance of N. melleni in cultured fish and thrombocytes were observed during hot season. Also during hot season, positive correlations between total count of white blood cells and mean abundance of N. melleni in cultured fish were found. This study demonstrates that parasitism by N. melleni and P. beverleyburtonae had influence on hematological parameters of wild and cultured dusky grouper E. marginatus in Southeastern Brazil.