"Objective Science for Conservation"






The Pacific Ocean

The Pacific Ocean is the largest and deepest ocean. Its 181 million square kilometer surface is greater than that of all the land masses combined. The Pacific Ocean holds 714 million cubic kilometers of water with an average depth of 3940 meters. The deepest place on Earth is in the Mariana Trench where the sea floor is 11034 meters below the sea surface. From its base on the seafloor to the volcanic peak, Mauno Loa in the Hawaiian Island archipelago is taller than Mount Everest in the Himalayas. Nine seas rim the Pacific Ocean basin. The Bering Sea, Sea of Okhotsk, and Sea of Japan are temperate waters in the north and northwest Pacific. The East China Sea, South China Sea, Java Sea, Arafuna Sea, and South Coral Sea are in subtropical and tropical regions along the western Pacific. The Polar Sea lies along the shore of Antarctica. Ocean currents circulate in the Pacific including the North Pacific Current, California Current, Kuroshio Current, North Equatorial Current, South Equatorial Current, Humboldt Peru Current and East Australian Current1. The Earth’s climate is dictated by the immense capacity of the Pacific Ocean.

The Pacific Ocean holds the greatest biodiversity of tropical marine fauna in the world. The waters between the Philippines, Malay Peninsula, and New Guinea known as the Indo-West Pacific hold 6000 species of mollusks, 800 species of echinoderms, 500 reef forming coral species, and 4000 species of fish2. The Pacific Ocean has rich and poor feeding areas between which migrate many species of marine mammals and birds. Nine of 11 species of baleen whales migrate annually between tropical and polar regions of the Pacific3 and some shearwaters transit between southern hemisphere breeding islands and northern hemisphere winter quarters. Some species of albatross traverse thousands of kilometers in a few days to find food in temperate ocean regions that they will feed to their chicks on tropical islands4. Thus, the Pacific Ocean holds a diversity of species unique to particular regions while sharing other species across its vast expanse. 




1: Leier, M. 2000. World atlas of the oceans. Key Porter, Toronto.  2: Biggs, JC. 1999. Evolution 53:326-335. 3: Bowen, WD and DB Siniff 1999 Biology of Marine Mammals (Reynolds & Rommel, eds.), Smithsonian. 4. Whittow, GC. 1993. Birds of N. Am. No. 66, Am. Ornithol. Union.



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The Pacific Ocean

Marine Mammals of the Pacific

Birds of the Pacific

Fish of the Pacific





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