East African Marine
About the Area
On Mafia and other islands, patch reefs predominate on the western side and well-developed fringing reefs on the eastern side, that may be among the finest remaining reefs in the region, supporting 350 species of fish and 40 families of corals.
Another portion of this ecoregion, the Basaruto National Park supports a diverse range of marine habitats, including deep-sea areas, coral reefs, rocky intertidal areas, sandy beaches, tidal sand flats, seagrass meadows, and mangrove communities - also home to several endemic marine species (100 individual dugongs and all five species of sea turtles).
Important species include the Dugong (Dugong dugon), breeding Humpback whale (Megoptera novaenglia), Blainville's beaked whale (Mesoplodon densirostris), Gervais' beaked whale (M. europaeus), Green sea turtle (Chelonia mydas), Loggerhead sea turtle (Caretta caretta), Hawksbill sea turtle (Eretmochelys imbricata).
Bird species such as the Roseate tern (Sterna dougallii), Greater crested tern (Thalasseus bergii), Masked booby (Sula dactylatra), and Brown noddy (Anous stolidus), and mollusk species such as the Pearl oyster (Pinctada margaritifera) and the Red helmet shell (Cypraecassis rufa) are also found here.
The major causes of coastal degradation are:
- Agriculture and deforestation that have lead to severe erosion with flushing of sediments, affecting rivers and coral reef areas.
- Domestic, agricultural, and industrial pollution.
- Tourism and associated over collection of shells and corals. The Pearl oyster (Pinctada margaritifera) has reportedly been overharvested to the point of virtual extinction and the Red helmet shell (Cypraecassis rufa) has become rare due to heavy collection pressures by the ornamental shell industry.
- Heavy exploitation of mangroves for firewood, charcoal production, and protein resources such as fish, crustaceans, and mollusks. The abundance of mangrove oysters (Crassostrea cucullata) has been decreasing rapidly because of the high level of uncontrolled exploitation.
- Overfishing and the use of destructive fishing practices (e.g. dynamite, toxins, harpooning, nets with smaller than legal mesh size) are problematic.
Western Indian Ocean on the eastern coast of Africa
Why are baleen whales so called?
The baleen whales are named for their feeding apparatus, a series of transverse plates of comb-like baleen which descend from the roof of the mouth. The baleen act like a sieve, allowing a whale to strain food out of the water-food that includes small fish and plankton.