Recent Report on Coral Reefs of Krusadai Island Krusadai, ha ° N ° E ° N ° E The reefs in this area are narrow fringing reefs located 150 to 300 m. from the shore of the islands and patch reefs rising up from depths of 2 to 9 m. and extending up to 2 km. long and 50 m. wide. Large areas of these reefs are in generally poor condition due to destructive human activities of the 150,000 persons living along the coast. Nutrient and other pollution loads are high due to agriculture, deforestation, industry, urbanization and septic pollution. It appears that the Coral reefs of the Gulf of Mannar Marine National Park seem to be healthy and in good condition, despite high rates of sedimentation and other threats.[1) However, live coral cover is only about 35%. Various algae cover much of the dead coral.[2)fringing reefspatch reefs Edward J. K Patterson, Mathews Edward G., Patterson Jamilla, Wilhelmsson Dan, Tamelander Jerjer, Linden Olaf (April 2007) Coral Reefs of The Gulf of Mannar, Southeastern India-Distribution, Diversity and Status, special Research Publication # 12, Suganthi Devadason Marine Research Institute, J.K. Patterson Edward, Director, 44 Beach Road, Tuticorn, Tamil Nadu, India [ 2.Venkataswaran Dr. V (January 2000) Status Survey of Gulf of Mannar Coral Reefs, Marine Biological Station, Zoological Survey of India, Ministry of Environment and Forests, Govt. of India, 100 San Thome High Road, Chennai, India, CSMCRI B H A V N A G A R

Overall view of Coral Reef in Krusadai island showing that the healthy live corals are largely free of any seaweed (photo taken on 21 May, 2008). It may be noted from the previous slide that ca. 30% of the corals are live corals and the rest are dead corals which serve as the host for algal inhabitation (Venkataswaran 2000) CSMCRI B H A V N A G A R

Navigation channel. A very heavy water flow is occurring during north east monsoon period from Palk Bay side to Gulf of Mannar. This makes it possible for occasional drifting of Kappaphycus alvarezii from cultivated sites to distant locations such as from Palk Bay side to Krusadai Island. We observed that the plant settlements over the coral are near by the navigation channel and not in other areas. The navigation channel is just 10 meter away from the observed coral bed with Kappaphycus. The plants are likely to have been brought by the water current through navigation channel and deposited over the near by spring coral. Kappaphycus deposited area Navigation channel CSMCRI B H A V N A G A R

The distribution of the Kappaphycus is scattered over a small area. CSMCRI divers surveyed the coral reef of same species ca. 100 meter away from the observed site of Kappaphycus. There is no accumulation or attachment of Kappaphycus in this location. This indicates that the plant attached to the coral reef is on account of the forced drifting aided by water currents and not invasion. Indeed, even today, after a lapse of 8 months, Kappaphycus is confined to the same reported areas mentioned by the authors of the Current Science paper site by the authors in current site. It may be noted that CSMCRI took the assistance of Mr.Nambueswaran,fisherman, Pamban, who had helped previously the authors of the Current Science paper. Among they surveyed area (1sq.km. we found <5% area with Kappaphycus and other areas are absolutely free from Kappaphycus. ) CSMCRI B H A V N A G A R

Kappaphycus trapped in between natural bed of spring (finger) coral. Note that the live corals remain largely free of seaweed. CSMCRI B H A V N A G A R

Photographs of coral in association with Kappaphycus (photographs taken by CSMCRI on 21 May, 2008). Note that the live part of the coral with healthy buds remains intact and does not host the alga. The alga provide evidence of heavy grazing by fishes which would promote fish population in the area. CSMCRI EIA studies conducted in 2002 also indicated sporadic occurrence of Kappaphycus in in situ condition at Vilundi theertham CSMCRI B H A V N A G A R

The next four slides show the seaweed diversity within a 3 m radius of a patch where Kappaphycus was located. The last slide also shows the complete absence of any seaweed on live Spring coral in confirmation of the view that live corals do not favor algal settlement. These slides do not in any manner suggest any invasive nature of Kappaphycus; instead there is evidence of healthy co-habitation. CSMCRI B H A V N A G A R

Growth of Sargassum on corals located within 3 m radius of patch containing Kappaphycus CSMCRI B H A V N A G A R

Halimeda gracilis grown on spring coral at Krusadai Island CSMCRI B H A V N A G A R

Growth of Caulerpha racemosa and Acanthopora spicifera on coral at Krusadai CSMCRI B H A V N A G A R

Natural spring (finger) coral without any seaweed CSMCRI B H A V N A G A R