Results
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The biophysical reef monitoring at Lakshadweep islands covering three islands revealed the presence of live coral cover of 53.5%, 53.6% and 58% and dead coral of 27.3%, 25.8% and 24.1% at Kavaratti, Kadmat and Agatti respectively. Agatti island showed the highest coral cover of 82.1% followed by Kavaratti and Kadmat 80.8% and 79.4% respectively. The average relative abundance of each category of benthos was studied at Kavaratti, Kadmat and Agatti along with the pooled data given in Tables 1-3. The outer lagoon reefs off Lakshadweep had a much higher coral cover and the status of coral growth in all the three islands are found to be “good”.
For the purpose of an easy understanding, the variations in percentage cover encountered under the transects for the benthic biota are grouped under 5 main categories: hard corals, total algae, soft corals, other invertebrates and rubble which shows the domination of hard corals and algae in all the three surveyed islands .
The summary of observed benthic coverage under transects (n=18) were averaged and recorded in Table 4. Twenty one genera of corals were recorded in the three surveyed islands of Lakshadweep (Table 5). Bottom coverage at Kavaratti, Kadmat and Agatti shows both tabular and branching Acropora dominance (15.8% and 14.7%) with a greater diversity followed by encrusting and massive corals (12.7% and 11.8%). A highest coverage of 12.3% coralline algal cover was recorded in all the surveyed islands.
Acropora sps. dominated in all the three islands followed by other major corals Fungia, Porites, Montipora, Pavona, Goniopora, Favites, Favia, Astreopora, Pocillopora, Psammocora, Stylophora, Goniastrea along with two new records of Siderastrea (Kavaratti and Agatti) and Seriatopora (Kavaratti) (Table 5).
Leptoria and Symphillia is a new record to the three islands (Kavaratti, Kadmata and Agatti); Goniopora and Stylophora are new records to Kavaratti and Agatti while Goniastrea, Astreopora, Montipora and Millepora are new to Agatti and Favia is new to Kadmat and Agatti.
Stress tolerant Porites sp. is common in all the study areas. Encrusting corals are healthy and unaffected by the anomalous temperature while largely unaffected tabular and massive Favia are also observed in the survey (55% healthy coral) .
The condition of reefs surveyed varied from healthy to heavily impacted by natural and anthropogenic factors. Of these siltation and cyclone damage appeared to be important. Degradation of dead coral through bioerosion and wave action has led to increased sand and rubble formation, increasing stress through abrasion and suffocation which was observed in most of the survey .
Coral reef resources/ Marine Vertebrates
The major benthic animals other than the corals observed were algae, polychaetes, clams, barnacles, starfishes, sea anemones, sea cucumbers, sponges, octocorals (dominated by Alcyonians and Nephthids more than gorgonids) and black corals. Large varieties of coral reef fishes included from smallest to the biggest like squirrel fishes, parrot fishes, butterfly fishes, surgeon fishes, trigger fishes, damsel fishes, clown fishes, eels, wrasses, emperors, snappers, groupers, barracudas, porcupine fishes, crustaceans like crabs and shrimps, molluscans/shells and echinoderms are regularly seen around the three islands. Fishes like sharks, rays and octopus were also observed in the surveyed three islands.
Dolphins and flying fishes are observed in Kavaratti Island. Marine turtles are more in Agatti than in Kadmat and Kavaratti islands. The commonest olive riley and green turtle are observed during diving while the other species like hawksbill, leatherback and loggerhead are also common in all the three surveyed islands (Divers, per. com.). Marine mammals of Lakshadweep are virtually unstudied.
