Community ecology of the metazoan parasites of the Atlantic thread herring, Opisthonema oglinum (Lesueur, 1818) (Actinopterygii: Clupeidae) from the Sepetiba Bay, Rio de Janeiro, Brazil

Abstract This study aimed to evaluate the parasitic fauna of Opisthonema oglinum (Lesueur, 1818) from Southeastern Brazil. Between September 2017 and March 2018, a total 100 specimens O. Sepetiba Bay, Rio de Janeiro, Brazil (22°54'S, 43°34'W) were examined. Ninety one parasitized by at least species metazoan with mean 5.84 ± 7.98 parasites/fish. Seven collected: 2 digeneans, monogeneans, copepods 1 nematode. The digenean Parahemiurus merus (Linton) was most abundant dominant species, representing 43% parasites collected. parasite richness positively correlated length hosts. Only Neobomolochus elongatus Cressey showed positive correlation between host's prevalence. diversity not length, but significant differences among males females observed. represents new host record for Caligus mutabilis Wilson, Hysterothylacium sp. Cribomazocraes travassosi Santos Kohn. copepod N. is recorded first time on Brazilian coast.