Comparison of polychaete diversity and distribution along the south Tamilnadu coast (Lat. 8.08[formula omitted] to 10.79[formula omitted]N), India

Abstract

In the present study, an attempt was made to investigate the diversity and distribution of polychaetes at four different stations (Lat. 8.08∘ & Long. 77.57∘, Lat. 8.48∘ & Long. 78.11∘, Lat. 9.28∘ & Long. 79.03∘ and Lat. 10.79∘ & Long. 79.85∘) in three different seasons (Post monsoon, Summer and Monsoon) along the south Tamilnadu coast, India for a period of one year (January to December 2015). In toto, 2911 individual polychaetes belonging to 35 families, 65 genera and 107 species were recorded in the surficial sediment samples of selected sampling stations. The polychaete species diversity H’ (2.594 to 3.347), species richness d’ (3.593 to 7.285), species evenness J’ (0.914 to 0.988) and Simpson’s dominance λ (0.039 to 0.078) showed notable variation during the study period. The maximum (1276 ind.) number of individuals was observed during summer season and minimum (704 ind.) during monsoon season. Analysis of polychaete diversity at different depths (0, 10 and 30 m) through Univariate measures such as Shannon–Weiner diversity and Margalef’s richness inferred that, the abundance of benthic polychaetes was remarkably higher at 30 m depth. The cluster analysis showed 74.42% similarity during summer and post monsoon seasons at 30 m depth. During the study period, Capitella capitata and Paraprionospio pinnata were the most dominant species recorded in all the sampling stations, thereby indicating that the selected sampling points were rich in organic matter.