A report on diversity and distribution of four non-indigenous red algae (Rhodophyceae) along the Tamil Nadu coast, Southeast coast of India

The present study was revealed that four Indian invasive seaweeds such as Acanthophora spicefera, Gracilaria salicornia, Kappaphycus alvarezii and Polysiphonia brodiei were recorded along the Tamil Nadu coast with 55 study sites from Palk Bay and Gulf of Mannar regions, Southeast coast of India. Maximum abundance of A. spicefera, G. salicornia, K. alvarezii and P. brodiei were recorded in Hare Island, Thondi coast, Thonithurai coast and Chinna muttam coast respectively. Highest species dominance (0.3) was recorded for G. salicornia during monsoon season and lowest dominance (0.05) was recorded for A. spicefera during post monsoon season. Species richness (D’) varied from 0.69-0.94 with minimum recorded was G. salicornia during monsoon season. Similarly, maximum species richness (D’) was recorded for A. spicefera during post monsoon season. Species diversity (H’) was ranged between 1.70 to 3.19 with the minimum was recorded for G. salicornia during monsoon season whereas maximum was recorded for P. brodiei during post monsoon season. The dendrogram results showed that three major clusters based on the abundance of species in the study sites. Further, the results revealed that Cluster 1 occupied by more species abundance at more stations and followed by Cluster 2 and Cluster 3.