Community Ecology of Metazoan Parasites in Two Species of <I>Mystus</I> from River Godavari, Andhra Pradesh, India.

BACKGROUND AND OBJECTIVE

Fishes of the genus Mystus are the members of Bagridae family which occupy an important place in Godavari fishery. Two commonly available species, Mystus vittatus Bloch, 1800 and Mystus cavasius Hamilton, 1822 of River Godavari, Rajahmundry Andhra Pradesh serve as significant hosts for metazoa\n parasites. The present study was aimed to ascertain the population dynamics, community characteristics and the faunal similarity of the two bagridae fishes, Mystus vittatus (n = 116) and Mystus cavasius (n = 94) at both infra and component community level during the 2008-2009.

MATERIALS AND METHODS

Standard statistical analyses were conducted to study the parasitic communities of both the fishes. Jaccard's similarity coefficient was used to observe the faunal similarity of both the fishes. Various parameters such as Shannon-wiener index (H'), evenness (E) and Simpson's diversity indices were applied to the fully sampled metazoan infracommunities of both fishes. Mean-variance ratio described the distribution patterns of the parasites within the host. The correlation coefficient (R) explained the correlation between the standard length of host and parasitic abundance for all parasites. The Mann-Whitney U-test was applied to both the fishes to observe the influence of host sex on the overall parasitic abundance. Jaccard's interspecific association was used to find out the interspecific association between each pair of parasite species within a same host.

RESULTS

A total of nine metazoan parasites were obtained from both the fishes during the research study. The present investigation includes five species, i.e., Haplorchoides macrones, Bifurcohaptor indicus, Thaparocleidus tengra, Raosentis podderi and Raosentis thapari that are common to both the species. On the other hand, Metacercaria Isoparorchis hypselobagri, Raosentis godavarensis and Argulus striatus occurred specifically in Mystus vittatus and Lamproglena hospetensis occur exclusively from Mystus cavasius. There were no core and secondary species in the parasitic communities of both the fishes. Host length and rate of parasitisation showed very less correlation. There was no influence of sex on the parasitisation. Over-dispersed distribution is the generalized pattern of distribution of macroparasites and all the parasites showed over-dispersed distribution patterns except Argulus striatus, which displayed a random distribution pattern. The higher JI values indicate that there is very less competition among species as they occupy different niches within the same host.

CONCLUSION

Though, the faunal similarity of both the fishes was high but the parasitic communities of these fishes are less diverse, depauperate and non-interactive.