Indian Ocean

The Indian Ocean is the third largest of the world's five ocean basins (after the Pacific Ocean and Atlantic Ocean, but larger than the Southern Ocean and Arctic Ocean). Four critically important access waterways are the Suez Canal (Egypt), Bab el Mandeb (Djibouti-Yemen), Strait of Hormuz (Iran-Oman), and Strait of Malacca (Indonesia-Malaysia). The International Hydrographic Organization decided in 2000 to delimit a fifth world ocean basin, the Southern Ocean, which removed the portion of the Indian Ocean south of 60 degrees south latitude.

body of water between Africa, the Southern Ocean, Asia, and Australia

20 00 S, 80 00 E

almost seven times the size of the US

66,526 km

northeast monsoon (December to April), southwest monsoon (June to October); tropical cyclones occur during May/June and October/November in the northern Indian Ocean and January/February in the southern Indian Ocean

the counterclockwise Indian Ocean Gyre comprised of the southward flowing warm Agulhas and East Madagascar Currents in the west, the eastward flowing South Indian Current in the south, the northward flowing cold West Australian Current in the east, and the westward flowing South Equatorial Current in the north; a distinctive annual reversal of surface currents occurs in the northern Indian Ocean; low atmospheric pressure over southwest Asia from hot, rising, summer air results in the southwest monsoon and southwest-to-northeast winds and clockwise currents, while high pressure over northern Asia from cold, falling, winter air results in the northeast monsoon and northeast-to-southwest winds and counterclockwise currents

oil and gas fields, fish, shrimp, sand and gravel aggregates, placer deposits, polymetallic nodules

occasional icebergs pose navigational hazard in southern reaches

major chokepoints include Bab el Mandeb, Strait of Hormuz, Strait of Malacca, southern access to the Suez Canal, and the Lombok Strait

marine pollution from ocean dumping, improper waste disposal, and oil spills; oil pollution in Arabian Sea, Persian Gulf, and Red Sea; threats to coral reefs; loss of biodiversity; endangered marine species 

northeast monsoon (December to April), southwest monsoon (June to October); tropical cyclones occur during May/June and October/November in the northern Indian Ocean and January/February in the southern Indian Ocean

the Indian Ocean fisheries are the third most important in the world, accounting for 15.5%, or 12,220,000 mt of the global catch in 2020; tuna, small pelagic fish, and shrimp are important species in these regions; the Food and Agriculture Organization delineated two fishing regions in the Indian Ocean:

Eastern Indian Ocean region (Region 57) is the most important and the fifth-largest-producing region in the world with 8.4%, or 6,590,000 mt, of the global catch in 2020; the region encompasses the waters north of 55º South latitude and east of 80º East longitude, including the Bay of Bengal and Andaman Sea, with the major producers including India (2,362,481 mt), Indonesia (1,940,558 mt), Burma (1,114,777 mt), Bangladesh (877,837 mt), and Sri Lanka (373,369 mt); the principal catches include shad, skipjack tuna, mackerel, shrimp, and sardinellas

Western Indian Ocean region (Region 51) is the world’s sixth-largest-producing region with more than 7.1% or 5,630,000 mt of the global catch in 2020; this region encompasses the waters north of 40º South latitude and west of 80º East longitude, including the western Indian Ocean, Arabian Sea, Persian Gulf, and Red Sea, as well as the waters along the east coast of Africa and Madagascar, the south coast of the Arabian Peninsula, and the west coast of India; major producers include India (2,207,125 mt), Oman (580,048 mt), Pakistan (341,730 mt), and Mozambique (274,791 mt); the principal catches include skipjack and yellowfin tuna, mackerel, sardines, shrimp, and cephalopods

Regional fisheries bodies: Indian Ocean Tuna Commission, Commission for the Conservation of Southern Bluefin Tuna, Regional Commission for Fisheries (Persian Gulf/Gulf of Oman), Southeast Asia Fisheries Development Center, Southwest Indian Ocean Fisheries Commission, South Indian Ocean Fisheries Agreement