Parasites are found inside and on the outside of their hosts. These intimate associations have consequences for the host, which may subsequently affect the local environment. Because parasites are frequently either small or inconspicuous, parasite communities and the potential effects that parasites have on ecosystem interactions has been overlooked. In general, the parasites found in freshwater fishes has been understudied in parasitology research and recent records of parasites in particular locales is lacking. Centrarchids are a diverse group of freshwater fishes and host many parasites because they serve as intermediate and definitive hosts for different parasite lifecycles. Given this integral role in the freshwater and parasite communities, these interactions likely have broad ecological effects. Although Centrarchids in other areas have been sparsely studied for local parasites, the sites and habitat type have shown extensive variation. The objectives of this study were to 1) identify the intestinal helminth parasites from five species of Centrarchid fish from Indiana rivers and compare parasite diversity, prevalence, and intensity among fish host 2) relate those diversity, prevalence, and intensity numbers to fish host size, and 3) determine the prevalence and intensity of Neascus spp., the trematode that causes blackspot disease, across additional freshwater fish families.
Results/Conclusions
Overall, 12 taxa (three species of Nematoda, two species of Acanthocephala, five species of Trematoda, and two species of Cestoda) were collected from the intestines of five species of freshwater Centrachids. Parasite species diversity differed among host species; some hosts were infected by numerous parasite species, while other hosts were rarely infected. Trematodes maintained the greatest prevalence across fish hosts (25.21%), while the acanthocephalans had the lowest prevalence (10.08%) and intensity (3.67 ± 3.39). Nematodes were the only parasites found across all species of fish. However, nematode parasite species prevalence and intensity varied between fish species and individuals. Generally, larger fish hosted more parasites than smaller fish. Black spot disease varied in intensity across three of the five (Centrarchidae, Cyprinidae, and Percidae) families sampled, but Cyprinidae species had the greatest cysts intensities. This study reports the common adult parasites of fishes in Indiana and provides the basis for future investigations of the ecological effects of parasites. These data highlight the complexity and variation in assessing the trends between parasite communities and their hosts.