[Community ecology of the metazoan parasites of five Scombrid species (Perciformes: Scombridae), from the coastal zone of the State of Rio de Janeiro, Brazil].

From June 2001 to March 2004, 171 marine scombrid fishes (Perciformes: Scombridae) from the coastal zone of the State of Rio de Janeiro, Brazil (21-23 degrees S, 41-45 degrees W) were necropsied to study their community metazoan parasites: 46 Euthynnus alleteratus (Rafinesque, 1810); 15 Katsuwonus pelamis (Linnaeus, 1758); 30 Sarda sarda (Bloch, 1793) ; 43 Scomber scombrus Linnaeus, 1758 and 37 Scomberomorus brasiliensis Collette, Russo & Zavala-Camim, 1978. All specimens of E. alleteratus, K. pelamis and S. brasiliensis were parasitized by one or more metazoan species. In S. sarda and S. scombrus 96.7% and 60.4% of specimens were parasitized, respectively. Forty-four different metazoan parasites species were collected: 22 in E. alleteratus, 13 in K. pelamis, 14 in S. sarda, three in S. scombrus and 12 in S. brasiliensis. Euthynnus alleteratus is a new host record for 12 metazoan parasite species, K. pelamis and S. scombrus for one species each, S. sarda for eighth species and S. brasiliensis for five species. Nine parasites species were new geographical record. Fifteen species were common in at least two communities. The digeneans were the majority of the parasite specimens collected in E. alleteratus and S. brasiliensis with 85.7% and 72.5%, respectively. In K. pelamis and S. sarda the majority of the parasite specimens collected were cestodes and copepods, 64.5% and 62.9%, respectively. Only larval stages of nematodes were collected in S. scombrus. The parasite of 5 host species showed the typical aggregate pattern of distribution. Four cases of positive correlation and three cases of negative correlation between host's length and prevalence and parasite abundance were found. The parasite community of K. pelamis showed the higher values of the mean parasite species richness and diversity. Only in S. scombrus the abundance and parasite species richness were correlates with the host's length. Euthynnus alleteratus was the species with the higher number of ectoparasites (11), adult endoparasites (5) and larval stage of endoparasites (6). The infracommunities of larval stage of endoparasites showed correlation with the host's length and abundance, parasite species richness, diversity and numerical dominance.