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Recent Report on Coral Reefs of Krusadai Island
CSMCRI B H A V N A G A R Recent Report on Coral Reefs of Krusadai Island Krusadai, ha ° 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) 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,
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Red arrow indicates – Kappaphycus
Blue arrow indicates – Hypnea bed Photograph (taken during May 21-23, 2008) of live coral bed (visible erect brown portions) in the vicinity of the area where Kappaphycus was observed in Krusadai. Note also the co-presence of Hypnea. (Photograph is in support of ref. 5 and contradicts the assertion of coral invasion by Kappaphycus narrated in the Current Science paper). 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)
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CSMCRI Navigation channel Kappaphycus deposited area
B H A V N A G A R Navigation channel Kappaphycus deposited area 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. One possibility is that the plants from cultivation site at in the vicinity of Pamban Bridge may have been brought by the water current through navigation channel and deposited over the near by spring coral. It may be noted that CSMCRI had maintained Kappaphycus germplasm in Krusadai itself (0.82 km from current observation site) but this was stopped in Nov 2003 and all material brought back to the mainland. Monitoring of Krusadai during did not reveal any obvious presence of Kappaphycus and it is therefore unlikely to be the cause of the present occurrence.
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The distribution of the Kappaphycus as confirmed through a survey on May 21, 2008 is mainly scattered over a small area (15 m x 15 m area). Even today, Kappaphycus is confined to the same reported areas mentioned by the authors of the Current Science paper, i.e., there is no obvious evidence of any further spreading. 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. Prior to the present survey undertaken on 21 May, 2008 and 23 May 2008 by Dr. K. Eswaran, the previous survey of the area by CSMCRI was in March The scientist (Dr. M. Ganesan) engaged in that survey has stated that he did not come across any Kappaphycus in the course of that survey. Although the present situation may have resulted from drifted material, one concern is that, whereas till 2000 CSMCRI was the only organisation which had possession of this alga, it has now become transformed into a commercial crop and it has become available to a much larger cross section of people through horizontal diffusion. Since 2002 other research organisations/universities, who laid their hands on Kappaphycus, have also begun to publish research articles on Kappaphycus biology and cultivation. CSMCRI B H A V N A G A R
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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.
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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 severe grazing by fishes. Due to this reason only the Kappaphycus germplasm maintenance activity at Kurusadai Island was discontinued in December 2003 (pl see attached word file). 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
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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.
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CSMCRI B H A V N A G A R Growth of Sargassum on corals located within 3 m radius of patch containing Kappaphycus
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Halimeda gracilis grown on spring coral at Krusadai Island
CSMCRI B H A V N A G A R Halimeda gracilis grown on spring coral at Krusadai Island
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CSMCRI B H A V N A G A R Growth of Caulerpha racemosa and Acanthopora spicifera on coral at Kurusadai
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Natural spring (finger) coral without any seaweed
CSMCRI B H A V N A G A R Natural spring (finger) coral without any seaweed
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