Community ecology of the metazoan parasites of white sea catfish, Netuma barba (Osteichthyes: Ariidae), from the coastal zone of the state of Rio de Janeiro, Brazil

Abstract

Between March 2000 and April 2001, 63 specimens of N. barba from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23 degrees 0' S, 44 degrees 19' W), Brazil, were necropsied to study their infracommunities of metazoan parasites. Fifteen species of metazoan parasites were collected: 2 digeneans, 1 monogenean, 2 cestodes, 1 acantocephalan, 2 nematodes, 6 copepods, and 1 hirudinean. Ninety-six percent of the catfishes were parasitized by at least one metazoan parasite species. A total of 646 individual parasites was collected, with mean of 10.3 +/- 16.6 parasites/fish. The copepods were 37.5% of the total parasite specimens collected. Lepeophtheirus monacanthus was the most dominant species and the only species with abundance positively correlated with the host total length. Host sex did not influence parasite prevalence or mean abundance of any species. The mean diversity in the infracommunities of N. barba was H = 0.130 +/- 0.115 with no correlation with host's total length and without differences in relation to sex of the host. One pair of endoparasites (Dinosoma clupeola and Pseudoacanthostomum floridensis) showed positive association and covariation between their abundances and prevalences. The parasite community of N. barba from Rio de Janeiro can be defined as a complex of species with low prevalence and abundance and with scarcity of interspecific associations. However, because of both the presence of assemblages of sympatric ariid species as well as the spawning behavior characteristic of these fishes, additional comparative studies of the parasite component communities of ariids are necessaries to elucidate this pattern.

Structure of the parasite infracommunity of Sciades proops from the Japaratuba River Estuary, Sergipe, Brazil

“…weight and length influenced only the prevalence and mean abundance. Tavares and Luque (2004) did not observe a correlation between the total length of the host and frequency of nematode parasites, in contrast with the results of the present study. Koya and Mohandas (1982) observed that, in general, the frequency of nematodes is higher among juveniles, although intensity is higher among older fish; this finding also differs from the results of this study, in which larger size was negatively correlated with the intensity of infection.…”

“…This finding supports the hypothesis that many hosts harbor few parasites and few hosts harbor many parasites (Anderson and Gordon, 1982). All the N. barba parasites found by Tavares and Luque (2004) showed the typical pattern of aggregate distribution similar to S. proops. The spatial distribution of Ergasilus sp.…”

“…In the work of Tavares and Luque (2004), none of the species of parasites found in N. barba demonstrated an effect of host sex on abundance and prevalence. The observed abundance was similar to the present study, but the total prevalence (considering all species of parasites) differed: in this study we found a significant difference between males (47.62%) and females (30.15%).…”

“…was found in S. proops. Tavares and Luque (2004) found that copepods are the main components of the parasite community of adult N. barba, and suggested that a sample containing only adult individuals can influence the observed abundance and prevalence of these ectoparasites compared to other endoparasites. In the present study, Ergasilus sp.…”

“…In their study of the structure of the parasitic fauna of the white catfish Netuma barba (Ariidae), a demersal fish that occurs in marine and estuarine environments and seeks the mouths of rivers and lagoon areas at spawning time, Tavares and Luque (2004) found that Copepoda was the most abundant taxon, representing 37.5% of total parasites collected. Similarly, in S. proops, the prevalence of the same taxon was 77.8%.…”