| Tridacna derasa | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Subclass: | Heterodonta |
| Order: | Cardiida |
| Family: | Cardiidae |
| Genus: | Tridacna |
| Species: | T. derasa |
| Binomial name | |
| Tridacna derasa | |
Tridacna derasa, the southern giant clam or smooth giant clam, is a species of extremely large marine clam in the family Cardiidae.
The southern giant clam is one of the largest of the "giant clams", reaching up to 60 cm in length. [3] The species is also known as the smooth giant clam because of the relative lack of ribbing and scales on its thick shell. The smoothness of the southern giant clam's shell and its six to seven vertical folds help to distinguish it from its larger relative, Tridacna gigas , which has four to five folds and a rougher texture. Lack of scutes (scale-like protrusions of the shell) that are present in most other Tridacna species is a defining characteristic of this species, although in aquacultures specimens have been observed to develop scutes in at least one abnormal case. [4] The mantle usually has a pattern of wavy stripes or spots, and may be various mixtures of orange, yellow, black and white, often with brilliant blue or green lines. [5] Derasa produce the color white in their mantle using multi-colored crystalline pigment cells, while T. maxima cluster red, blue and green cells. [6]
The southern giant clam is native to waters around Australia, Cocos Islands, Fiji, Indonesia, New Caledonia, Palau, Papua New Guinea, Philippines, Solomon Islands, Tonga and Vietnam. [7] Populations have also been introduced to American Samoa, Cook Islands, Marshall Islands and Samoa, and reintroduced after extinction in Guam, the Federated States of Micronesia and Northern Mariana Islands. [3] The southern giant clam is found on the outer edges of reefs at depths of 4 to 10 meters. [5]
The Tridacna clam has muscles for opening and closing its shell and a foot for attaching to reef substrate. It respires through gills and feeds through a mouth. [8] Most clams fulfill their nutritional requirements by filter feeding and absorbing dissolved organic compounds from the water, but Tridacna clams have gone further than this by using symbiotic algae, zooxanthellae, in their tissues to manufacture food for them. [8] [9] Through photosynthesis the zooxanthellae transform carbon dioxide and dissolved nitrogen, such as ammonium, into carbohydrates and other nutrients for their hosts. [9] [10]
When Tridacna clams first attain sexual maturity they are male, but about a year later become hermaphrodites, possessing both male and female reproductive organs. However, the release of sperm and eggs are separate in order to prevent self-fertilisation, although self-fertilisation can occur. The breeding season of the southern giant clam usually occurs in spring and summer, although they may be induced to spawn through the year. [9] [11]
The southern giant clam is classified as Vulnerable (VU) on the IUCN Red List, [1] and is listed on Appendix II of CITES. [12] The southern giant clam is a popular food item and aquarium species, and has therefore been hunted extensively throughout its natural habitat. [5] However, specimens traded today tend to be the result of aquaculture farms rather than wild-caught individuals, because the southern giant clam was one of the first clams to be bred commercially. [5] This occurred at the MMDC Giant Clam Hatchery in Palau, which focused on Tridacna derasa in pioneering large-scale developments. [13]
Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two shells of equal size connected by two adductor muscles and have a powerful burrowing foot. They live in both freshwater and marine environments; in salt water they prefer to burrow down into the mud and the turbidity of the water required varies with species and location; the greatest diversity of these is in North America.
The Pacific geoduck is a species of very large saltwater clam in the family Hiatellidae. The common name is derived from the Lushootseed (Nisqually) word gʷídəq.
Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus Symbiodinium, but some are known from the genus Amphidinium, and other taxa, as yet unidentified, may have similar endosymbiont affinities. The true Zooxanthella K.brandt is a mutualist of the radiolarian Collozoum inerme and systematically placed in Peridiniales. Another group of unicellular eukaryotes that partake in similar endosymbiotic relationships in both marine and freshwater habitats are green algae zoochlorellae.
The giant clams are the members of the clam genus Tridacna that are the largest living bivalve mollusks. There are actually several species of "giant clams" in the genus Tridacna, which are often misidentified for Tridacna gigas, the most commonly intended species referred to as “the giant clam”.
Tridacna is a genus of large saltwater clams, marine bivalve molluscs in the subfamily Tridacninae, the giant clams. They have heavy shells, fluted with 4 to 6 folds. The mantle is brightly coloured. They inhabit shallow waters of coral reefs in warm seas of the Indo-Pacific region. These clams are popular in marine aquaria, and in some areas, such as the Philippines, members of the genus are farmed for the marine aquarium trade. They live in symbiosis with photosynthetic algae (zooxanthellae). Some species are eaten by humans.
Tridacna squamosa, known commonly as the fluted giant clam and scaly clam, is one of a number of large clam species native to the shallow coral reefs of the South Pacific and Indian Oceans. It is distinguished by the large, leaf-like fluted edges on its shell called 'scutes' and a byssal opening that is small compared to those of other members of the subfamily Tridacnindae. Normal coloration of the mantle ranges from browns and purples to greens and yellows arranged in elongated linear or spot-like patterns. Tridacna squamosa grows to 40 centimetres (16 in) across.
The maxima clam, also known as the small giant clam, is a species of bivalve mollusc found throughout the Indo-Pacific region. They are much sought after in the aquarium trade, as their often striking coloration mimics that of the true giant clam; however, the maximas maintain a manageable size, with the shells of large specimens typically not exceeding 20 centimetres (7.9 in) in length.
Hippopus hippopus, also known as the Horse Hoof clam and Strawberry clam, is a species of Giant Clam in the Family Tridacna and the family Hippopus. Hippopus is delicacy in many southeast asian countries due to its high quality meat.
Tridacna crocea, the boring clam, crocus clam, crocea clam or saffron-coloured clam, is a species of bivalve in the family Cardiidae. It is native to the Indo-Pacific region. It is occasionally found in the aquarium trade where it is often simply referred to as crocea.
Tridacninae, common name, the giant clams, is a taxonomic subfamily of very large saltwater clams, marine bivalve molluscs in the family Cardiidae, the cockles.
The hawksbill sea turtle is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in the genus Eretmochelys. The species has a worldwide distribution, with Atlantic and Indo-Pacific subspecies—E. i. imbricata and E. i. bissa, respectively.
Neoglyphidodon melas is a damselfish from the Indo-West Pacific. It often makes its way into the aquarium trade. It grows to a size of 18 cm (7.1 in) in length.
The fishing industry in the Maldives is the island's second main industry. According to national tradition in the words of former President Maumoon Abdul Gayoom, "Fishing is the lifeblood of our nation, it is inborn. From the soil on which we live, to the sea around us, it remains an integral part of our existence. Fishing, and our country and its people, [are] one and shall remain inseparable forever." The Maldives has an abundance of aquatic life and species of fish. Common are tuna, groupers, dolphin fish, barracuda, rainbow runner, trevally and squirrelfish and many more. Aside from being of essential importance to the economy, fishing is also a popular recreational activity in the Maldives, not only among locals but by tourists. The islands have numerous fishing resorts which cater for these activities.
Aquaculture in Vanuatu exists on a small scale, both commercially and privately. Several aquacultural efforts have been made in the country, including attempts to raise Pacific oyster, rabbitfish, Malaysian prawn, and tilapia. Experiments with Kappaphycus alvarezii and three species of giant clam were carried out by the Fisheries Department in 1999. The official Fisheries Department records state that $1165 US of cultured coral was exported from the country in 2000, with 275 pieces in total. The cultivation of Macrobrachium lar in taro terraces is practiced for subsistence purposes, and Macrobrachium rosenbergii has been identified by the Vanuatu government as a high-priority species.
Aquaculture in the Marshall Islands is governed by the Marshall Islands Marine Resources Authority. A hatchery for giant clams has been established by the national government in Likiep Atoll, and at least one other clam farm is in operation in Mili Atoll. At the CSD-16 Partnerships Fair in 2008, Erik Hagberg suggested that Holothuroidea cultivation is a viable option for developing aquaculture in the country.
Coral aquaculture, also known as coral farming or coral gardening, is the cultivation of corals for commercial purposes or coral reef restoration. Aquaculture is showing promise as a tool for restoring coral reefs, which are dying off around the world. The process protects young corals while they are most at risk of dying. Small corals are propagated in nurseries and then replanted on the reef.
Saltwater fish, also called marine fish, are fish that live in ocean water. Saltwater fish can swim and live alone or in a large group called a school.
Tridacna noae, also known as Noah’s Giant Clam or the Teardrop clam, is a species of giant saltwater clam. Up until recently, T. noae was mistaken as being part of the giant clam species Tridacna maxima, but is now known to be its own independent species. It has a broad distribution in the Indo-Pacific.
The Coral reefs of Kiribati consists of 32 atolls and one raised coral island, Banaba, which is an isolated island between Nauru and the Gilbert Islands. The islands of Kiribati are dispersed over 3.5 million km2 (1.4 million sq mi) of the Pacific Ocean and straddle the equator and the 180th meridian, extending into the eastern and western hemispheres, as well as the northern and southern hemispheres. 21 of the 33 islands are inhabited. The groups of islands of Kiribati are:
The Coral reefs of the Solomon Islands consists of six major islands and over 986 smaller islands, in Oceania, to the east of Papua New Guinea and northwest of Vanuatu. The Solomon Islands lie between latitudes 5° and 13°S, and longitudes 155° and 169°E. The distance between the westernmost and easternmost islands is about 1,500 km (930 mi). The Santa Cruz Islands are situated north of Vanuatu and are especially isolated at more than 200 km (120 mi) from the other islands. The Solomon Islands has the 22nd largest Exclusive Economic Zone of 1,589,477 km2 (613,701 sq mi) of the Pacific Ocean.
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This article incorporates text from the ARKive fact-file "Tridacna derasa" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL .
