Fringing reefs extend along the coasts of Kenya and Tanzania as far as the Ruvuma River, which forms the Tanzania-Mozambique boundary.
[4] Seagrass beds are found in clear, shallow lagoons between the fringing reefs and the shore, and between offshore islands and the mainland.
Other important mangrove forests in Tanzania are in Lindi and Tanga, at the mouths of the Wami, Ruvu, Matandu and Ruvuma rivers, and on the Mafia Archipelago.
[5] Fringing reefs are uncommon along the Mozambican coast, limited by freshwater input from numerous rivers, and cold-water upwelling in the Mozambique Channel.
Soil erosion from agriculture and grazing has increased the amount of silt carried by rivers into the coastal waters, damaging reefs and seagrass beds.
Over-fishing and exploitation of seashells, corals, turtle shells, for tourist souvenirs are diminishing marine fauna.