Indian Journal of Geo Marine Sciences Vol. 48 (04), April 2019, pp. 416-422 Macroalgae as indicator species for shore platform zones of Dwarka, Gujarat, India Dimpal Sanghvi 1* , Nandini Ray Chaudhury 2 , & B. K. Jain 1 1 Department of Botany, M.G. Science Institute, Navarangpura, Ahmedabad, Gujarat, India 2 Space Applications Centre (SAC), Indian Space Research Organization (ISRO), Ahmedabad, Gujarat, India [E-mail: dimpalsanghvi@gmail.com] Received 08 September 2017; Revised 09 January 2018 Dwarka coast of Gujarat state in India has a stable shore platform. A study was carried out to identify indicator species among the sampled macroalgae to understand their spatial preferences on the shore platform zones. For this study, the shore platform was divided into three sections in north-south direction: Northern, central, and southern sections. These sections were further divided into three microzones in west-to-east direction based on their local geomorphology and tidal inundation characteristics for more detailed study. These microhabitat zones are: Cliff Base Zone (CBZ), Intertidal Mixed Zone (IMZ) and Subtidal Zone (STZ). To identify indicator species for each microzone, the shore platform was surveyed based on systematic random sampling for two years (April 2013 to April 2015). Line intercept transects and GPS-tagged photo quadrates were carried out from land to seaward as part of the sampling procedure. Indicator species were identified on the basis of a decision-rule when a single species belonged to only one microhabitat zone in all the three sections. Total 97 species of seaweeds were recorded in the shore platform of Dwarka. Out of these, 27 belonged to chlorophyta, 21 to phaeophyta and 49 to rhodophyta. Out of all these species, rhodophyta was found as the dominant group in the shore platform. Out of 97 species, only 12 species were identified as indicator species. Out of these, only one species was from phaeophyta group and eleven from rhodophyta group. This study shows indicator species of the microhabitat zones of the shore platform, with rhodophyta sp. as the prominent macroalgae group. Indicator species can act as proxy indicators of the microhabitats created by the local geomorphology and tidal regime on the shore platform. [Keywords: Macroalgae; Microhabitat; Indicator species; Shore platform; Dwarka] Introduction Macroalgae are generally found in shallow coastal waters. They grow in the shallow, intertidal and even deep sea areas up to 180 m depth and also in estuaries and back waters on the solid substrate, such as rock, dead corals, pebbles, shells, and other plant materials 1 . They belong to mainly three groups: chlorophyceae (green algae), phaeophyceae (brown algae) and rhodophyceae (red algae). They are abundant on hard substrates like shore platform, coral reef, pebbles, etc. Macroalgae are primary producers and provide habitat for near shore benthic communities. They play a significant role in the benthic food web. Macroalgae are key space occupier on rocky shores and interact with other organisms and hence play a key role in overall coastal biodiversity. They are found on shore platform in the intertidal zones as giant underwater forest. Macroalgae grow abundantly along the Indian coastline particularly in rocky shore regions:- e.g. rich macroalgal beds occur around Visakhapatnam in the east coast; Mahabalipuram, Gulf of Mannar, Tiruchendur and Tuticorin in Tamil Nadu and Kerala in the south; Veraval and Gulf of Kachchh in the west coast; Andaman and Nicobar Islands, and Lakshadweep. They are also found in abundant around the coastal locations of Mumbai, Ratnagiri, Goa, Karwar, Varkala, Vizhinjam, and Pulicat in Tamil Nadu in the west and southern coast of India and Chilika in Orissa in the east coast 2 . Macroalgae constitute one of the commercially important renewable marine living resources 3 . They are used as food, fodder, fertilizer and also as a source of raw materials for industry, production of medicines, cosmetics and other items. The floristic variation in macroalgal communities are controlled by several, environmental factors, including season, habitat, topography, duration of tidal exposure, tidal amplitude, and biotic factors (algal turf, grazing, high concentration of limpets and many others) 4 . Many scientists have worked on the seasonal variation of macroalgae in Indian waters 5,6,4,7,8,9 . brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by NOPR