Figure 14.2 Bagamoyo District, Wami and Ruvu Deltas
Figure 14.3 Rufiji District, Rufiji Delta
While the mangroves of Tanzania are rich in biodiversity, habitat loss and modification are high, leading to a decline of biodiversity. The land in the deltas is largely used for farming, as forest reserve, for harvesting of forest products (eg, for charcoal, poles, and timber), for prawn farming, fishing, and salt-making. The human settlement in the Rufiji Delta is larger than in the other deltas. In the Ruvu Delta, seasonal settlement by charcoal-makers is common.
Local fishermen complain that fish catches are declining sharply and that they have to go further out to the deep waters, an indication that fish numbers have declined in shallow waters. Also, the fishermen complain that catches now consist of juvenile fish, a further indication of over-fishing and habitat degradation.
Over-harvesting for construction poles, firewood, charcoal, and timber for furniture and boat-building threaten the mangrove ecosystem. Products from the mangroves such as poles and thick logs for boat-making are not easily available these days. Other threats include clear-cutting for agricultural expansion, salt-making, urban development, construction of tourist hotels, creation of prawn farms, siltation from upper catchment areas, and poor fishing techniques, such as the use of dynamite and poison. In addition, the burning of coral for the production of lime, which is very common in Bagamoyo, threatens the stability of the shoreline. This practice destroys the reef from which coral is taken and destroys the protective belt of mangrove forests. (Bryceson, 1981; Mitzlaff, 1989; UNEP, 1989)