Research Article
M Srinivasa Rao, C Annapurn
Abstract
Diversity and Distribution of Benthic Polychaetes of Nizampatnam Bay, Bay of Bengal A study was carried out to observe the diversity and distribution of soft bottom macrobenthic polychaetes in Nizampatnam bay, Bay of Bengal. The aim of this study is to determine patterns of abundance, species richness and community structure along with the influence of environmental parameters on the diversity of polychaetes collected from the Nizampatnam Bay. Four cruises were conducted during 2006 to 2008 covering 20 stations along the Bay having a maximum depth of 40 m. Altogether 128 infaunal samples (van Veen grab 0.1 m2) were collected from the bay along with the hydrographical and sediment samples. Polychaete diversity indices S, N, d and H' were higher in the stations located nearer to the shoreline (15 m). Temporally post-monsoon seasons supported high polychaete diversity than pre-monsoon season. Multivariate analyses were used to define assemblages named after the most important (determining) taxon. Occurrence of Prionospio pinnata and Capitella capitata, the deposit feeders and indicators of organic pollution suggested that the stations that lie nearer the shore are organically rich. Canonical correspondence analysis (CCA) showed that depth, sediment organic matter and sediment mean size influenced polychaete distribution. Canonical correspondence analysis (CCA) showed that majority of polychaete species were deposit feeders and they preferred high organic carbon and clayey silt substratum.