Spatiotemporal analysis in brown seaweed diversity and abundance at selected coastal locations on the Southern coast of Tamil Nadu, India: A way forward for conservation and sustainable utilization

Tamil Nadu and its southern coast are well-known for seaweed diversity and abundant resources in India. Brown seaweeds are primary habitat producers in reef environments. The objective of this study was to assess the spatiotemporal variation in diversity and abundance of brown seaweed species along the intertidal region at selected coastal locations on the southern coast of Tamil Nadu, India. The sampling was performed monthly at six coastal locations, namely Hare Island (HI), Tuticorin Harbour (TH), Chinna Muttom (CM), Arockiapuram (AP), Vedhalai (VD), and Mandapam (MP), along the intertidal region during low tides between January 2021 and December 2021. A total of 36 brown seaweed species were identified at six locations, namely Sargassum (9 species), followed by Padina (5 species), Turbinaria (3 species), Dictyota (3 species) and 16 species each of others. In the context of different locations, the highest species diversity was observed at HI (35) and the lowest at CM (21) during the study period. The highest abundance was recorded at CM (19.80 kg wt m−2), while the lowest was reported at AP (9.51 kg wt m−2). Sargassum and Turbinaria exhibited the highest prevalence across all the locations. Among different seasons, the maximum species diversity was recorded during PoMoN (26), whereas the minimum species diversity was recorded during PrMoN (11). Similarly, the highest abundance was seen during PoMoN, whereas the lowest abundance was reported during PrMoN. These findings offer crucial foundational data for the preservation and exploitation of brown seaweeds.