Benthic polychaetes as good indicators of anthropogenic impact

Abstract

Seven stations were sampled within the Mormugao harbour area for benthos and environmental variables from September 2003 to July 2004. A total of 71 polychaete taxa were identified from the area. Polychaete abundance, biomass and species number was highest during post monsoon, mainly due to new recruitment. Pre monsoon is the most stable period for community development when, the fauna was dominated by opportunistic deposit feeding polychaete species. Average abundance ranged from 652-4096 ind m sup(-2) reported at channel and harbour station respectively. Harbour station was dominated by P. pinnata, Magelona sp., Tharyx sp. and Cossura sp. Univariate and multivariate analyses showed clear demarcation of outer harbour, inner harbour and channel stations. Correlation of physico-chemical and biotic parameters did not show a significant correlation. Dominance of opportunistic deposit feeding species and low polychaete diversity in the inner harbour indicate negative impact of harbour activities on the species composition