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Incidence and prevalence of D iplectanum aequans and its influence on the fitness of juvenile sea bass ( D icentrarchus labrax ) in the B lack S ea
Author(s) -
Ogut Hamdi,
Uzun Ecren
Publication year - 2014
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.12015
Subject(s) - dicentrarchus , sea bass , biology , juvenile , fishery , black sea , brackish water , bass (fish) , zoology , ecology , fish <actinopterygii> , salinity , oceanography , geology
Abstract High rates of unexplained mortalities (up to 70%) are anticipated in the cultured juvenile sea bass ( D icentrarchus labrax ) in farms in the eastern B lack S ea at least for the last 8 years. D iplectanum aequans, often blamed for the observed mortalities, is the only prevalent parasite impacting the health of sea bass in the brackish water of the B lack S ea. To investigate the seasonal fluctuation of D . aequans prevalence, mean intensities and the potential effects of D . aequans on the fitness of sea bass, eight cages from one farm (Farm A) and four cages at another distinct site (Farm B) were surveyed monthly from May to October of 2008. Six hundred and sixty‐one juvenile sea bass from Farm A and 236 from Farm B were individually examined for the presence and intensity of the parasite. The prevalence of D . aequans in cultured sea bass (96.3 ± 11.11; Mean ± SD) ranged from 66.7% to 100% in June, the beginning of 6‐month growing season. The mean intensity was 6.08 ± 2.19, significantly higher than that (2.74 ± 0.87; P < 0.05) in December ( P < 0.05), the end of the growing season. Fish with low fitness had significantly higher number of parasite than the fish with higher fitness ( P < 0.005). Although D . aequans negatively influenced host's condition factor, the impact was not enough to lead mortalities in the cultured sea bass in the B lack S ea.