Ocean Fisheries - Indian Ocean

Indian Ocean

  • The Indian Ocean is the third largest ocean, covering 73,556,000 square kilometres, or about twenty percent of the water on the Earth's surface. Small islands dot the continental rims.

The ocean's continental shelves are narrow, averaging 200 kilometres (120 mi) in width. An exception is found off Australia's western coast, where the shelf width exceeds 1,000 kilometres (620 mi). The average depth of the ocean is 3,890 metres (12,760 feet). The remaining 14% is layered with terrigenous sediments. Glacial outwash dominates the extreme southern latitudes.

The warmth of the Indian Ocean keeps phytoplankton production low, except along the northern fringes and in a few scattered spots elsewhere; life in the ocean is thus limited. Fishing is confined to subsistence levels. Its fish are of great and growing importance to the bordering countries for domestic consumption and export. Fishing fleets from Russia, Japan, South Korea, and Taiwan also exploit the Indian Ocean, mainly for shrimp and tuna. Endangered marine species include the dugong, seals, turtles, and whales. Oil and ship pollution threatens the Arabian Sea, Persian Gulf, and Red Sea.

Indian seas : Statistics
Region Area
million km²
Volume
million cu km
Mean depth
km
Max depth
km
Coastline
km
Fish harvest
million tonnes
Percent
of total
Andaman Sea
Arabian Sea
Bay of Bengal
Great Australian Bight
Gulf of Aden
Gulf of Oman
Laccadive Sea
Mozambique Channel
Persian Gulf 0.251 0.05 0.09
Red Sea 0.44 0.23 0.49 2.211
Indian Seas: Maps and descriptions

The Andaman Sea is a body of water to the southeast of the Bay of Bengal, south of Myanmar, west of Thailand and east of the Andaman Islands; it is part of the Indian Ocean. It is roughly 1,200 kilometres (750 mi) long (north-south) and 650 kilometres (400 mi) wide (east-west), with an area of 797,700 square kilometres (308,000 sq mi). Its average depth is 870 metres (2,854 ft), and the maximum depth is 3,777 metres (12,392 ft).

The Arabian Sea is a region of the Indian Ocean bounded on the east by India, on the north by Pakistan and Iran, on the west by Arabian Peninsula, on the south, approximately, by a line between Cape Guardafui, the north-east point of Somalia, Socotra and Kanyakumari (Cape Comorin) in India.

The maximum width of the Arabian Sea is approximately 2,400 km (1,490 mi), and its maximum depth is 4,652 metres (15,262 ft),

The Bay of Bengal occupies an area of 2,172,000 km². A number of large rivers – Ganges, Brahmaputra, Ayeyarwady, Godavari, Mahanadi, Krishna and Kaveri – flow into the Bay of Bengal. The islands in the bay are very numerous, including the Andaman, Nicobar and Mergui groups.

The Bay of Bengal is full of biological diversity, diverging amongst coral reefs, estuaries, fish spawning and nursery areas, and mangroves. The Bay of Bengal is one of the World's 64 largest marine ecosystems.

Kerilia jerdonii is a sea snake of the Bay of Bengal. Glory of Bengal Cone (Conus bengalensis) is just one of the seashells which can be photographed along beaches of the Bay of Bengal.

An endangered species, the Olive Ridley sea turtle can survive because of the nesting grounds made available at the Gahirmatha Marine Wildlife Sanctuary, Gahirmatha Beach, Orissa, India.

Bryde's Whale which can be seen in the Bay of Bengal is the 10th heaviest animal of the world, weighing in at 22,000 kg (48,000 lb).

Marlin, barracuda, skipjack tuna, (Katsuwonus pelamis), yellowfin tuna, Indo-Pacific humpbacked dolphin (Sousa chinensis), and Bryde's whale (Balaenoptera edeni) are a few of the marine animals. Bay of Bengal Hogfish (Bodianus neilli) is a type of Wrass which live in turbid lagoon reefs or shallow coastal reefs. Schools of dolphins can be seen, whether they are the bottle nose dolphin (Tursiops truncatus), Pantropical spotted dolphin (Stenella attenuata) or the spinner dolphin (stenella longirostris) . Tuna and dolphins are usually residing in the same waters. In shallower and warmer coastal waters the Irrawaddy Dolphins (Orcaella brevirostris) can be found.

The Great Australian Bight is a large bight, or open bay located off the central and western portions of the southern coastline of mainland Australia.

The coast line of the Great Australian Bight is characterised by stunning cliff faces (up to 60 m high), surfing beaches and rock platforms, ideal for whale-watching. The waters of the Great Australian Bight, despite being relatively shallow, are not fertile. While most continental shelves are rich in sea life and make popular fishing areas, the barren deserts north of the bight have very little rainfall, and what there is mostly flows inland, to dissipate underground or in salt lakes. In consequence, the Great Australian Bight receives very little of the runoff that fertilises most continental shelves and is essentially a marine desert. It is probably best noted for the large number of sharks that frequent its coastal waters, as well as the increasing numbers of Southern Right Whales that migrate within the region.

Economically, the Bight has been exploited over many years as part of the fishing, whaling and shellfish industries. Bluefin tuna have been a favoured target of fishing in the Bight.

The Gulf of Aden. The temperature of the gulf varies between 15 °C (59 °F) and 28 °C (82 °F), depending on the season and the appearance of monsoons. The salinity of the Gulf at 10 metres (33 ft) depth varies from 35.3 ‰ along the eastern Somali coast to as high as 37.3 ‰ in the Gulf's center, while the oxygen content in the Gulf of Aden at the same depth is typically between 4.0 and 5.0 mL/L.

A geologically young body of water, the Gulf of Aden has a unique biodiversity that contains many varieties of fish, coral, seabirds, and invertebrates. This rich ecological diversity has benefitted from the relative lack of pollution during the history of human habitation around the Gulf, but environmental groups fear that the lack of a coordinated effort to control pollution may jeopardize the Gulf's ecosphere.

The Gulf of Aden is an area known for acts of piracy,|-

The Gulf of Oman is a gulf that connects the Arabian Sea with the Strait of Hormuz which then runs to the Persian Gulf.

The Laccadive Sea lies off the southwest coast of India, north of a line extending from the southern point of Sri Lanka to the southernmost of the Maldive Islands, and east of the Maldives and the Laccadive Islands belonging to India.

The Mozambique Channel is a portion of the Indian Ocean between the island of Madagascar and southeast Africa, namely Mozambique. The channel is approximately 460 kilometers across at its narrowest point between Angoche, Mozambique, and Tambohorano, Madagascar. It reaches a depth of 3,292 meters about 230 kilometers off the coast of Mozambique. A warm current flows in a southward direction in the channel, leading into the Agulhas Current off the east coast of South Africa. It is 1600 kilometers long and its width varies from 400 to 950 kilometers.

The Persian Gulf is an extension of the Indian Ocean located between Iran and the Arabian Peninsula. The natural environment of the Persian Gulf is very rich with good fishing grounds, extensive coral reefs, and abundant pearl oysters, but its ecology has become increasingly under pressure from the heavy industrialisation and in particular the repeated major petroleum spillages associated with recent wars fought in the region.

The Red Sea occupies a part of the Great Rift Valley, and has a surface area of 438,000 km². It is 2250 km long and, at its widest point, 355 km wide. It has a maximum depth of 2211 m in the central median trench and an average depth of 490 m (1,608 feet ), but there are also extensive shallow shelves, noted for their marine life and corals. The sea is the habitat of over 1,000 invertebrate species and 200 soft and hard corals and is the world's most northern tropical sea.

The Red Sea is a rich and diverse ecosystem. More than 1100 species of fish have been recorded in the Red Sea, and around 10% of these are found nowhere else. This also includes around 75 species of deepwater fish. The rich diversity is in part due to the 2,000 km (1,240 mi) of coral reef extending along its coastline; these fringing reefs are 5000–7000 years old and are largely formed of stony acropora and porites corals. The reefs form platforms and sometimes lagoons along the coast and occasional other features such as cylinders (such as the blue hole at Dahab). These coastal reefs are also visited by pelagic species of red sea fish, including some of the 44 species of shark.

Approximately 40% of the Red Sea is quite shallow (under 100 m/330 ft), and about 25% is under 50 m (164 ft) deep. About 15% of the Red Sea is over 1,000 m (3,300 ft) depth that forms the deep axial trough. Shelf breaks are marked by coral reefs Continental slope has an irregular profile (series of steps down to ~500 m/1,640 ft)

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