Tatawa Besar is a large island in central Komodo that offers two great drift dives. The island creates an eddy, and the currents here almost always run south, irrespective of the tides. This makes Tatawa Besar a good choice when the currents are too strong elsewhere. The entry point for both dives is at the northern tip of the island, where the current splits. Descend to around 20-25 m where there are several large rocks harbouring numerous species of angelfish, batfish and sweetlips. Out in the blue schools of fusiliers feed, with giant trevally and blue fin trevally cruising past. It is worth spending some time exploring this area, as there are many treats to discover. After 10 minutes or so, you can choose whether to head east or west. Photographers may prefer the east coast in the morning and the west in the afternoon, to take advantage of the best light conditions. The east side is more commonly dived, and here the reef boasts some of the best coral cover in the park. The reef drops away steeply to about 25 m, but is best at 8-15 m. Large prostrate sponges, hydroids, and hard corals, combined with the colourful dendroneptha soft corals give way to fields of corpora and other hard corals. There are large rocks along the way providing havens for large sweetlips and groupers. It is difficult to dive this site without encountering one of the many resident hawksbill turtles, and keep an eye out for cuttlefish that are also often seen. At the end of the drift the reef drops away more steeply and the currents come to a complete stop. The water here is greener, flowing out from the nearby mangroves, and provides another dimension to the dive with entirely different coral species. The coral garden at 5 m is a great place to end the dive. The west coast of the reef can be dived along the reef slope, or up in the shallows. On the reef slope there is good coral cover, and it is best at the reef edge from 8-15 m. There are lots of angelfish of many different species, red-toothed triggerfish, lionfish and scorpionfish. Occasionally pelagics swim past in the blue water, and at the right time of the year manta rays. Alternatively you can drift through the shallows above 8 m where there are many large rocks, coral heads and porites. Between these outcrops schools of sweetlips, mangrove jacks, trevally and snapper cruise. The fish life here can be stunning and diverse. Under one rock a pair of stonefish are often seen—good luck finding them! About half way down the reef cover deteriorates, and it is better to move to the shoulder of the reef and follow the drift until the current stops. On a strong fall the current can push out from the reef a little, so be wary and avoid being pulled out into the choppy channel. Whether following the east or west shores, the drift on Tatawa Besar can become quite fast. But stay close to the reef and enjoy the ride, because towards the end the drift meets a counter current and everything slows down nicely.
Not to be confused with the blacktip shark, Carcharhinus limbatus. The blacktip reef shark (Carcharhinus melanopterus) is a species of requiem shark, family Carcharhinidae, easily identified by the prominent black tips on its fins (especially on the first dorsal fin and the caudal fin). Among the most abundant sharks inhabiting the tropical coral reefs of the Indian and Pacific Oceans, this species prefers shallow, inshore waters, and its exposed first dorsal fin is a common sight in the region. Most blacktip reef sharks are found over reef ledges and sandy flats, though they have also been known to enter brackish and freshwater environments. This species typically attains a length of 1.6 m (5.2 ft). Blacktip reef sharks have extremely small home ranges and exhibit strong site fidelity, remaining within same local area for up to several years at a time. They are active predators of small bony fishes, cephalopods, and crustaceans, and have also been known to feed on sea snakes and seabirds. Accounts of the blacktip reef shark's life history have been variable and sometimes contradictory, in part reflecting geographical differences within the species. Like other members of its family, this shark is viviparous with females giving birth to two to five young on a biennial, annual, or possibly biannual cycle. Reports of the gestation period range from 7–9, to 10–11, to possibly 16 months. Mating is preceded by the male following closely behind the female, likely attracted by her chemical signals. Newborn sharks are found further inshore and in shallower water than adults, frequently roaming in large groups over areas flooded by high tide. Timid and skittish, the blacktip reef shark is difficult to approach and seldom poses a danger to humans unless roused by food. However, people wading through shallow water are at risk of having their legs mistakenly bitten. This shark is used for its meat, fins, and liver oil, but is not considered to be a commercially significant species. The International Union for Conservation of Nature has assessed the blacktip reef shark as Near Threatened. Although the species as a whole remains widespread and relatively common, overfishing of this slow-reproducing shark has led to its decline at a number of locales.
Bleaching occurs when corals expel their symbiotic zooxanthellae - pigmented, algae-like protozoa that live within the coral's cells. High temperature, pollution or other stresses can cause the coral to expel its zooxanthellae, leading to a lighter or complete loss of color.