Parasite Life-history Determines the Relationship between Anthropogenic Change and Parasite Community Structure

Parasites may be indicators of salt marsh health because of their dependence on multiple host organisms to complete their life cycle and potential sensitivity to environmental contaminants. Our objectives were to survey the community composition of parasites within salt marshes, and determine whether complex life cycle parasites are indicators of salt marsh ecosystem health. We used the parasite community of Fundulus heteroclitus, a common inhabitant of salt marshes in Georgia, as a focal species. Six salt marsh sites along coastal Georgia, U.S.A. (St. Marys, Shellman Bluff, Skidaway Island, Tybee Island, and St. Marys) were selected using impervious surface as a proxy for anthropogenic disturbance. Percent impervious surface within a 250 m buffer from the collection site ranged from 5% (Skidaway Island) to 66% (Tybee Island). 630 fish were necropsied: 72% of fish were infected with parasites, and included 8 parasite taxa with a range of life-histories including tapeworms, nematodes, and digeneans that have multi-host life cycles, and monogeneans, crustaceans, and branchiurans that have single-host life-cycles. Parasite infracommunity species richness differed among sites (