Seasonal population dynamics of parasitic copepods, Sinergasilus spp. on farmed fish in China

Seasonal population dynamics of parasitic copepods in the genus Sinergasilu s on fanned silver carp Hypophthalmichthys molitrix, farmed bighead carp Ar istichthys nobilis, and grass carp Ctenopharyngodon idellus were investigat ed in China. Changes in prevalence and abundance were seasonal with higher levels observed in summer. Reproduction of the copepods occurs from spring to early autumn as indicated by the higher ratio of gravid copepods. The fr equency distribution of Sinergasilus polycolpus and S. major in their host populations can be fitted well with negative binomial distribution. (C) 200 0 Elsevier Science B.V. All rights reserved.