Tanzania is endowed with a high diversity of coastal and marine ecosystems, including sandy beaches, cliffs, major estuaries, mangrove forests, coral reefs, seagrass beds and muddy tidal flats.
Some of Tanzania’s marine animals are counted among most endangered mammals, such as the dugong, eight species of dolphins, humpback whales, all five species of sea turtles found in the Western Indian Ocean, hundreds of species of reef fish, the rare and threatened coelacanth, the threatened coconut crab, and a wide variety of birds and seabirds. The birds of Tanzania include a total of 1,108 species, of which 23 are endemic, 4 have been introduced by humans, and 43 are rare or accidental.
The Tanzanian coastline has well developed coral and barrier reefs which vary in species diversity, including an estimated 150 species of corals in 13 families. A wide range of important and valued species are found along the coast namely 8,000 species of invertebrates; 1,000 species of fish; 5 species of marine turtles, and many seabirds. Over 500 species of commercially important fish and other invertebrates are commonly found in coral reefs.
Seagrass beds are highly productive and serve many ecological functions. The most extensive seagrass bed is found in the Tanga coast, delta Ruvu, Wami and Rufiji rivers, Mafia and Songo songo archipelago and around Kilwa. Altogether, there are 12 species of seagrass off the coast of Tanzania.
Rivers, including the Pangani, Wami, Ruvu, Rufiji, Matandu, Mbemkuru, Lukuledi and Ruvuma all flow to the Indian Ocean and influence the coastal environment through the creation of productive brackish water environments in estuaries; maintenance of deltas, tidal flats and shorelines; and nourishment of mangroves and seagrass beds.