About UNEP UNEP Offices News Centre Publications Events Awards Milestones UNEP Store
UNEP Website GEO Home Page

Resource degradation

Coastal and marine habitats are being physically eroded and biologically degraded through unsustainable rates of resource extraction (including intensive commercial fishing, mining of sand dunes and clearing of mangrove forests). The harvesting methods are also damaging, as in coral extraction and the use of dynamite in fishing. Activities further inland, such as damming of rivers, increased use of fertilizers and clearing of natural vegetation, also affect the coastal zone. Population growth and migration to the coast, together with rapidly expanding tourism and industrial activities, encourage high rates of infrastructure development, modifying the physical and ecological environment of the coastal zone. Lack of formal protection, sustainable development policies and inadequate resources to implement coastal and marine management have contributed to the pressures, although the situation in many countries is now changing.

Coastal drift (erosion and deposition of dunes, beaches and shoreline) is a natural phenomenon but human action can alter natural patterns. Clearing of forests and natural vegetation inland leads to increased soil erosion and increased sediment load in rivers. Sediment is eventually deposited on the seabed, smothering benthic communities and coral reefs. In contrast, when rivers are dammed upstream, sediment settles before reaching the river mouth, thus depriving coastal zones of sediment. In Western Africa, damming of the Upper Niger, Benue and Volta rivers has altered the flow reaching the Niger Delta, and local subsidence is proceeding at 25 mm per year (World Bank 1996). In Ghana, construction of the Akosombo dam in 1965 accelerated coastal erosion west of Accra to 6 metres per year, and in Togo and Benin coastal retreat has exceeded 150 metres over the past 20 years (UNEP 1999).

In Northern Africa, 40-50 per cent of the population in the Mediterranean countries lives in coastal areas (UNEP 1996), with population densities reaching 500-1 000 inhabitants/km2 along the Nile Delta (Blue Plan 1996). In Western Africa, about onethird of the total population is concentrated on a coastal band 60-km wide between Senegal and Cameroon, and large-scale urban growth has occurred from Accra to the Niger Delta, an environmentally sensitive portion of the African coastline.

Annual fish catch per capita (kg): Africa

In Africa and most of its subregions, the per capita fish catch has stagnated for some 30 years - but in Southern Africa it has fallen sharply

Note: fish catch includes marine and freshwater catches but excludes crustaceans and molluscs

Source: compiled from Fishstat 2001 and United Nations Population Division 2001

The coastal zone is also receiving increasing numbers of tourists - in South Africa, for example, the industry grew at 7 per cent a year during the late 1990s (SADC 2000). According to FAO (1998), 38 per cent of Africa's coastal ecosystems are under high levels of threat from development-related activities. The exceptional demand for infrastructure development often results in uncoordinated and poorly planned or sited construction which can in turn cause habitat loss, destabilization or mining of dunes for construction materials, and draining of coastal wetlands. Economic costs are further inflated as governments and investors have to spend large budgets on mitigation and rehabilitation.

The demand for fisheries resources is also increasing. The marine fisheries of Africa have developed significantly over the past 30 years, and most demersal stocks are now thought to be fully exploited (FAO 1996, FAO 1997). The fishery sector contributes more than 5 per cent to GDP in Ghana, Madagascar, Mali, Mauritania, Mozambique, Namibia, Senegal and Seychelles, and the shrimp fishery on the Sofala Bank in Mozambique contributes 40 per cent of the country's foreign exchange (FAO 1997). From 1973 to 1990, fisheries supplied some 20 per cent of the animal protein intake of the population of sub-Saharan Africa. However, per capita fish catch (see figure above) has been fairly static since 1972, except in Southern Africa where it has fallen sharply (FAO 1996, FAO 1997). The Cape rock lobster and abalone catches have declined steadily since the 1950s, causing concern over the sustainability of these populations and leading to the setting of annual catch limits (FAO 1997).

In Southern Africa, declining catches, together with a decrease in the mean sizes of fish caught, have led to calls for the protection of line fish stocks. Today fisheries management measures include minimum size limits, bag limits, use of appropriate fishing gear, closed seasons, control agreements with foreign fleets and establishment of marine reserves. In Western Africa, a Sustainable Fisheries Livelihoods Programme aims to develop social and human capital in fisheriesdependent communities, whilst enhancing natural habitats in those communities.

Addressing coastal and marine degradation
The Convention for the Protection, Management, and Development of the Marine and Coastal Environment of the Eastern African Region (Nairobi Convention) of 1985 is a UNEP Regional Seas Programme initiative, under which the erosionassociated impacts on ecosystems and species are dealt with proactively. Although all affected countries are party to the convention, it is not legally binding, and has received insufficient funding for application of many of the activities. National efforts to regulate coastal development include the introduction of integrated coastal management policies, requirements for environmental impact assessments to be conducted, and establishment of marine national parks. The Indian Ocean Commission has facilitated the development of a Regional Sustainable Development Policy and a coral reef monitoring and action programme. In Central and Southern Africa, most countries have, or are preparing, Integrated Coastal Zone Management Plans. Africa is the top regional recipient of GEF biodiversity funds, about one-third of which are directed towards projects in coastal, marine and freshwater ecosystems.