Environmental Pressures on the Western Indian Ocean / The Nairobi Convention Area / UNEP Regional Sea
The environmental and economic health of the marine and coastal environment of the Western Indian Ocean (WIO) region —present and future—is outlined today in a report that underlines growing concern from pressures such as physical alteration and destruction of habitats, pollution, over exploitation of fisheries, as well as the risks from maritime traffic and climate change.
The report, the Marine Biodiversity Assessment by the UN Environment Programme (UNEP), predicts that the outlook for biodiversity in marine and coastal waters is uncertain and will be influenced by decisions taken by policymakers and investments to protect the region.
The marine and coastal resources of the Western Indian Ocean are rich with diverse assets that provide important economic and social opportunities for the human population, which in turn has developed a strong reliance on these resources for commercial opportunity and gain, food, recreation, and transport.
These resources have facilitated job creation and improved livelihoods in coastal regions. In the Republic of South Africa, in 2000, the estimated value of the direct benefits derived from all coastal goods and services was approximately US$25 billion, with indirect benefits contributing a further US$19 billion. Tourism is the largest direct source of income injecting more that US$6 billion dollars per year in the WIO region and fisheries generate about 4.8% of the global fish catch, equivalent to about 4.5 million tonnes per year.
Increasing human and environmental pressure on the marine and coastal ecosystems, however, has increasingly changed the functioning and structure of many of the components of coastal and marine ecosystems.
In recognition of the mounting pressures, the governments of the region and especially coastal stakeholders appear to be increasingly aware of the value of the seas and coast and of the importance of effective management. Consequently, the protection, in the form of marine protected areas and improved management, has most recently been receiving high priority in the region.
At the national level governments in the WIO region have established a network of more than 70 designated marine protected areas (MPAs) covering up to 8.7% of the coastline in Kenya, 4% in Mozambique and 7.9% , in Tanzania.
At the regional level, several, policies and protocols used to govern the regional coastal environment have been revised or adopted. i.e the Nairobi Convention was revised in 2010 and the Protocol on land-based sources and activities was adopted on 1April 2010.
The Marine Biodiversity Assessment report for the Nairobi Convention area, highlights the physical alteration and destruction of habitats in the form of coastal erosion, coral reef degradation and land conversion for agriculture, urban development, and extensive deforestation as the main cause for a reduction in biodiversity, alteration of ecological structures and overall decline in the productivity of coastal and marine ecosystems which further reduce the capability of providing expected ecosystem services.
The estimated loads of organic material (BOD), suspended solids, nitrogen and phosphorous generated from municipal wastewater in coastal areas in the WIO region range from 4,000 to 97,000 tones per year mainly concentrated around urban centres, affecting some of the most productive areas of the coastal and marine environment such as estuaries and near shore waters.
One of the biggest challenges faced by fisheries managers in the WIO region is the dramatic growth of industrial tuna fisheries and the rise in illegal, unreported and unregulated (IUU) fishing which contribute to overfishing. More than one million tonnes of tuna are caught annually and several species of tuna are now considered over-fished.
Increasing maritime oil transport also presents a major threat to the biodiversity of the coastal and marine environment. Many oil tankers and ships now sail between Madagascar and the African mainland instead of passing offshore in the high seas. Pollution, such as tanker washing, sewage, garbage and alien species, are carried in ballast water and are already affecting the marine environment.
The number of ships transiting through the major ports in the region is on the rise and the composition of that traffic is also changing. The total tonnage of ships and cargo has increased from around 130,000 tonnes in 1990 to around 220,000 tonnes in 2008.
Current assessments indicate that climate change in the WIO region is increasing environmental variability, with ramifications for weather, fisheries and biodiversity.
The ongoing positive trend in upper ocean temperature has in the past decade led to the destruction of about 50% of the corals in the region. While many have recovered, the communities have changed considerably.
Oceanographic effects from climate change, such as elevated water temperatures and changes in storm frequency, have also contributed to increased variability in fish catches and species composition. For example, the 1997-98 El Nino led to a dramatic decline in the tuna catch in the WIO region. The coral bleaching event of 1998 reduced hard coral cover throughout much of the WIO region by between 30% and 95%, to a rubble and algal dominated coral reef system in the inner Seychelles and Grand Recif of Toliara in Madagascar.
The Marine Trophic Index (MTI), which describes the position of a marine organism in the food chain and is a biodiversity indicator of sustainable exploitation of marine resources, increased steadily until the late 1970s and has declined substantially since then.
Five species of marine turtles found in the WIO feature are on the International Union for Conservation of Nature (IUCN) Red List of Threatened Animals and are listed on the Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Hawksbill and leatherback turtles are categorized as “critically endangered”, and the green, loggerhead and olive ridley as “endangered”.
Concern for the protection and conservation of marine and coastal resources of the region can be traced back to the 1980s. In 1985 governments in the region adopted the Convention for the Protection, Management and Development of the marine and coastal environment of Eastern Africa (Nairobi Convention). The member countries include Comoros, France La Reunion, Kenya, Madagascar, Mauritius, Mozambique, Seychelles, Somalia, South Africa and Tanzania.