Attached
Coral reefs are known to undergo phase shift in to macro-algae and reefs have lost the capacity to
remain in or return to a coral-dominated state. This shift will not only affect corals, but the others
heavily depend on heterogeneous habitat afforded by corals. Sallitivu in Panichchankerni, Eastern
province, is a small island (41328 m2
). The Island is surrounded by a ring of coral reef with an
elevated breaking reef crest, seaward slope and centred shallow lagoon (<1.2m at high tide). The
shore is entirely a thick layer of washed coral rubbles. The archived aerial photographs confirmed
these coral rubbles present only after 2004 tsunami.
Underwater visual census were carried out within the reef lagoon and three sites in reef slope using
30 m long belt transect. In addition to diversity of corals and algae, percentages of live, dead and
bleached coral cover were recorded. The reef lagoon is shallow (10-60 cm) and much of the reef
crest is exposed at low tide. Within the reef lagoon, the live coral cover was <5%. Around 15%
was observed recently bleached, 12% were overgrown by algae; Padina sp, Halimeda sp,
Sargassum sp, Caulerpa recemosa and Dictyota sp, and the rest was dead corals smothered by
sediments. The seaward slope with high wave action was mostly smothered dead corals with live
corals <3%. Coral colonies were represented by Acroporidae (branching and table corals)-
Acropora cytherea, A. divaricata, A. formosa, A. gemmifera, A. grandis, A. hemprichii, A.
hyacinthus, A. latistella, Acropora sp., A. nobilis, and A. robusta; (Foliaceous)-Montipora
aequituberculata and M. hispida; Faviidae (sub massive and encrusting)-Favites halicora, Favites
spinosa, Leptastrea purpurea and Platygyra daedalea; Pocilloporidae (Lace/cauliflower) -
Pocillopora damicornis; Poritidae (Massive/submassive)-Porites evermanni, P. paliformis, and P.
rus. Live corals observed were immature. Southern end of the reef slope had emerging corals
among unstable coral rubbles. It is assumed that the degradation was started post-tsunami and
continued due to natural stresses. The recovery of corals may hindered by macro-algal growth and
resulting accumulation of sediments, smothering due to less wave action within reef lagoon and
resulting recruitment and settlement failure. Recent bleaching would be due to exposure to direct
sunlight during the change of tides and low sea level. Increasing oxygen level due to algal blooms
would also prone for bleaching. Avoiding such undesirable phase shifts from coral dominance to
algae and reverse them when occur, requires an urgent reform of scientific approaches to
understand the processes causing the degradation. A better understanding on why some reefs
rapidly degrade and others do not is critical. Most reef conservation efforts are directed toward
reserve implementation, but new approaches are needed to sustain ecosystem function since
demarcation of a marine reserve alone would not benefit in improving reef resilience
