First assessment of the metazoan parasite community of the Argentine menhaden Brevoortia pectinata (Jenyns, 1842) (Clupeiformes: Alosidae) off Rio de Janeiro, southeastern Brazil

Brevoortia pectinata is important for the fish industry and crucial for the ecology of South Atlantic marine environments. Despite this importance, the structure of the parasite community of B. pectinata has never been investigated. We evaluated for the first time the parasite community structure from a population of B. pectinata, off the State of Rio de Janeiro, Brazil, and the factors influencing it. One hundred fish were bought from local fisherman at Sepetiba Bay (22°57'44"S; 43°52'28"W). Detailed parasitological examination revealed that all fish were parasitized by at least one parasite. We found 14 parasite taxa: 3 monogeneans, 4 copepods, 1 isopod, 3 digenetics and 3 nematode larvae. Presence of both adult and larvae indicated that B. pectinata occupies an intermediate trophic level, acting as definitive and intermediate / paratenic host. The community had low diversity and was dominated by the monogeneans Mazocraeoides georgei and Kuhnia sp., whereas the endoparasites were less prevalent and abundant. Fish schools and host specificity seem to be important for ectoparasite infestation, and host diet influenced the infection by trophic-transmitted endoparasites. Fish sex and body length exerted weak influence in the parasite community structure, which was depauperate and non-interactive.