2005 Volume 40 Issue 2 Pages 63-66
A practical method to distinguish two pathogenic monogeneans of fish, Neobenedenia girellae and Benedenia seriolae, is described.N. girellae and B. seriolae were obtained from experimentally infected olive flounder Paralichthys olivaceus and yellowtail Seriola quinqueradiata, respectively, by freshwater bathing and fixed in 10% formalin. The two species were found to have a different shape at the anterior end in the midline of the body and are clearly distinguishable by this difference. Using this method, the ratio of these two parasite species was monitored in greater amberjack Seriola dumerili cultured in net cages at Amami-Oshima Island for one year. A seasonal shift of abundance between the two species was observed.