surface dominated by a major gyre (broad, circular system of currents) in the southern Indian Ocean and a unique reversal of surface currents in the northern Indian Ocean; ocean floor is dominated by the Mid-Indian Ocean Ridge and subdivided by the Southeast Indian Ocean Ridge, Southwest Indian Ocean Ridge, and Ninetyeast Ridge
major surface currents: 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
" }, "Ocean volume": { "ocean volume": { "text": "264 million cu km" }, "percent of World Ocean total volume": { "text": "19.8%" } }, "Elevation": { "highest point": { "text": "sea level" }, "lowest point": { "text": "Java Trench -7,192 m unnamed deep" }, "mean depth": { "text": "-3,741 m" }, "ocean zones": { "text": "Composed of water and in a fluid state, the oceans are delimited differently than the solid continents. Oceans are divided into three zones based on depth and light level. Although some sea creatures depend on light to live, others can do without it. Sunlight entering the water may travel about 1,000 m into the oceans under the right conditions, but there is rarely any significant light beyond 200 m.the Indian Ocean fisheries are the third most important in the world accounting for 15.3%, or 12,248,064 mt of the global catch in 2019; 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 region and the fifth largest producing region in the world with 8.5%, or 6,784,778 mt, of the global catch in 2019; 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 6.8% or 5,463,286 mt of the global catch in 2019; 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 with major producers including 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 cephalopodssome maritime disputes (see littoral states)
" } } }