Manta Survey at Komodo National Park
Depth: - m
Duration: 60 min
- Slight - able to hold position with little effort.
The green sea turtle (Chelonia mydas), also known as the green turtle, black (sea) turtle, or Pacific green turtle, is a large sea turtle of the family Cheloniidae. It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans. The common name comes from the usually green fat found beneath its carapace. This sea turtle's dorsoventrally flattened body is covered by a large, teardrop-shaped carapace; it has a pair of large, paddle-like flippers. It is usually lightly colored, although in the eastern Pacific populations parts of the carapace can be almost black. Unlike other members of its family, such as the hawksbill sea turtle, C. mydas is mostly herbivorous. The adults usually inhabit shallow lagoons, feeding mostly on various species of seagrasses. Like other sea turtles, green sea turtles migrate long distances between feeding grounds and hatching beaches. Many islands worldwide are known as Turtle Island due to green sea turtles nesting on their beaches. Females crawl out on beaches, dig nests and lay eggs during the night. Later, hatchlings emerge and scramble into the water. Those that reach maturity may live to eighty years in the wild. C. mydas is listed as endangered by the IUCN and CITES and is protected from exploitation in most countries. It is illegal to collect, harm or kill them. In addition, many countries have laws and ordinances to protect nesting areas. However, turtles are still in danger because of several human practices. In some countries, turtles and their eggs are hunted for food. Pollution indirectly harms turtles at both population and individual scales. Many turtles die caught in fishing nets. Also, real estate development often causes habitat loss by eliminating nesting beaches.
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.