|Figure 2c.1: Map of Africa showing coastal countries, cities, and EEZ|
There are various definitions of the geographical, legal and functional scope of a coastal zone. According to Clark (1996), 'at a minimum, the designated coastal zone includes all the inter-tidal and supra-tidal areas of the water's edge; specifically all the coastal floodplains, mangroves, marshes and tide-flats as well as beaches and dunes and fringing coral reefs.' Africa's 40 000 km coast consists of a narrow, low-lying coastal belt which, as shown in Figure 2c.1, includes the continental shelf and coasts of 32 mainland countries.
Coastal ecosystems and issues relating to management of the coast often cross political boundaries and frequently extend inland. Similarly, the boundaries of marine ecosystems do not necessarily correspond with those of Exclusive Economic Zones (EEZ)-the 200 nautical-mile zones from the land edge of coastal states where they have sovereign rights over natural resources and over certain economic activities. Discussion of issues affecting the coastal environment may therefore extend beyond country borders or over more than one sub-region. There may therefore be some overlap in the analyses presented here.
Coastal ecosystems are some of the most biologically productive in the world, occupying only 8 per cent of the earth's surface but accounting for 26 per cent of all biological productivity (Hare 1994). These high productivity rates result from the extreme climatic and physical conditions of coasts, and the dynamic nature of the forces acting on these zones. Opportunistic organisms have adapted to these conditions and their rapid rates of growth and reproduction when conditions are favourable have led to high productivity rates.
The African coastal zone supports a diversity of habitats and resources encompassing mangroves, rocky shores, sandy beaches, deltas, estuaries and coastal wetlands, coral reefs and lagoons. Coral reefs and mangroves are especially important features because they protect the coastline by moderating storm and wave impacts and because mangroves stabilize sand and soils, cycle nutrients, absorb and break down waste products, provide wildlife habitat, and maintain biodiversity. Reefs and mangroves also contribute significantly to the economies of coastal countries by providing opportunities for tourism and for harvesting of resources. For example, mangrove species are used extensively by local communities for construction material, fuel, food and animal fodder, and for medicinal preparations. Mangroves extend from Senegal to Angola on Africa's west coast and from Somalia to South Africa on the east coast. Coral reefs- some of them spectacular-are abundant in the Red Sea and the Western Indian Ocean.
Figure 2c.2: Contribution of fish to the African diet
Periodic upwelling in African waters encourages diverse and rich production in fisheries, including crustaceans, fish, and molluscs. In 1997, total marine fish catch exports from Africa contributed US$445 million to countries' economies (FAOSTAT 2001). Fisheries in estuaries and lagoons also contribute to national economies, accounting for over three-quarters of fishery landings in Africa (IPCC 1998). Fisheries also provide significant amounts of employment, particularly in small islands such as Cape Verde and Seychelles where more than one-third of agricultural workers are employed in the fisheries sector (FAO 1996). Artisanal fishing activities are also an important source of income for coastal communities and fish is an important source of protein for many African populations, as shown in Figure 2c.2.
Oil and gas reserves and other mineral deposits, including diamonds off the western and south-western African coast, are additional important economic resources for coastal countries. For example, in Benin, Ghana, Nigeria, Sierra Leone and Togo the majority of industries and oil and mineral mining activities are located in the coastal zone.
The ports of Mombasa, Maputo and Durban are also major trade centres. Industrial development has expanded in the neighbouring areas to take advantage of opportunities for trade, tourism and other commercial activities opened up by the ports.
The highly attractive and diverse resources of the coastal and marine environments mean that coastal areas in Africa (as elsewhere in the world) are experiencing rapid population growth, industrial expansion and infrastructure development. Most colonial settlements in Africa were established along the coast in order to maximize trade opportunities and this has resulted in all but three of African countries from Mauritania to Namibia having their capital cities on the coast. A large proportion of Western Africa's urban population also now lives in coastal cities. The exceptional demand for resources and infrastructure development in the coastal zone is putting pressure on fragile ecosystems and 38 per cent of Africa's coastal ecosystems are under severe threat from developmentrelated activities (FAO 1998). The major challenges facing coastal African countries at present are coastal erosion, the potential impacts of climate change, overharvesting of resources and pollution. Although the causes of coastal erosion and climate change are entirely different the effects of climate change are so frequently and so firmly interlinked with those of erosion that they are described in the same sections in the following analyses.