Composition and Diversity of Communities of Dactylogyrus spp. In Wild and Farmed Goldfish Carassius auratus.

Species composition and diversity of dactylogyrids were compared on gills of wild and cultured goldfish (silver crucian carp) Carassius auratus from 3 naturally populated lakes and 3 stocked aquaculture ponds in the Hubei province of China to examine the differences in the gill parasite community between these natural and farmed waters. Of the 7 Dactylogyrus spp. detected, all were found in lakes and 5 in ponds, with Dactylogyrus inexpectatus and Dactylogyrus anchoratus being absent from ponds. No significant correlation was found between the species richness and habitat area or host size, nor was there a significant difference in mean species richness between lakes (0.41-0.65) and ponds (0.30-0.76). Brillouin's diversity in lakes (0.049-0.067) was higher than that in ponds (0.024-0.046), but not significantly so. Although the diversity of parasite communities was higher in wild goldfish, higher mean abundance of some Dactylogyrus spp. was found in cultured goldfish. Based on Bray-Curtis similarity, it was difficult to differentiate parasite communities in lakes from those in ponds at the infracommunity level, whereas the 3 lakes and Guanqiao pond differed markedly from the remaining 2 ponds at the component community level. Although infracommunities differed among waterbodies, no effects of fish length or waterbody type were found on infracommunity or component community structure. Together, these results suggest that abundance and species richness of Dactylogyrus spp. on goldfish in lakes and farm ponds are influenced by habitat-specific environmental factors.