Comoros

The densely populated Comoros is one of the world’s poorest countries. Deforestation and conversion of land to agriculture are creating massive problems of soil erosion, particularly in Nzwani (Anjouan) and Mwali. The subsequent heavy siltation may be affecting large areas of the reefs offshore. Fisheries are important, with over 4 500 registered fishermen operating from traditional boats in nearshore waters. Reef walking by fishers gathering octopus and small fish is causing some degradation of reef flats. Blast fishing is also reported to be a problem on Mwali. There is little or no information regarding overfishing problems in the Comoros, although as population densities continue to rise this may create significant problems.

Eritrea

The reefs of Eritrea are extensive and suffered little human impact before the 1990s. Since then there have been small increases in both the coastal population and fisheries. Commercial trawlers, including licensed vessels operating from Saudi Arabia, fish mostly in deeper water away from the reefs, although there are thought to be some reef-associated species in their catch, and there is concern that this might indicate they are straying into reef areas. Artisanal fisheries target a broad range of species, including finfish, molluscs, sea cucumbers and pearl oysters. There is also a commercial fishery for the aquarium trade, and around 100 000 fish were exported between 1995 and 1997. The most important and diverse reefs, around the offshore islands including the Dahlak Archipelago, remain in relatively good condition despite the lack of legal protection. By contrast some of the coastal reefs have suffered from development and land reclamation, notably around Massawa.

French Mayotte

Mayotte’s reefs are relatively well studied, and harbor more than 200 species of coral. They were adversely affected by a bleaching event in 1982-83, which apparently caused mortality and degradation on about 36 percent of the fringing reefs. Crown-of-thorns starfish outbreaks since 1983 have been a major problem, although a bounty system resulted in fishermen collecting large numbers, with a peak of some 8 000 collected in 1998. The 1998 bleaching event caused even more widespread mortality, with greater than 90 percent mortality recorded on the outer slopes. Recovery from this event is now being noted, particularly on the inshore reefs. Fisheries and tourism are important activities, with some 3 600 fishermen and 9 000 visitor arrivals per year in the late 1990s. Two protected areas have been established, although these only cover some 2 percent of the total area of the lagoon. A comprehensive management plan for the lagoon was under development in late 2000.

French Réunion

Réunion, a territory of France, only has a few fringing reef communities restricted to its leeward western shores, although corals are found growing directly on volcanic substrates in the southeast. Although not extensive, these reefs have been well studied. An estimated 1 000 species of fish occur in the surrounding waters, including 250-300 reef-associated species, and 149 recorded coral species. The 1998 coral bleaching had some impact, particularly where corals were already stressed by other factors, but recovery was good in almost all areas. Coral cover at a number of survey sites on the outer reef slopes and lagoons was at 30-50 percent after the bleaching. The majority of the people of Réunion live close to the coast and have had a major impact on it. There were some 641 registered commercial fishers in 1996, most of whom were operating in nearshore areas. Overexploitation of coastal fishes has been occurring for some time, and destructive fishing practices have been reported.

Madagascar

Madagascar is one of the world’s largest islands. Along with the Indian sub-continent it was separated off from the rest of Africa during the Jurassic, and was then separated from the Indian subcontinent (and the granitic Seychelles) during the late Jurassic/early Cretaceous. There are clear differences between the physical conditions and resulting ecological communities on the east and west coasts. The east coast is steep and, in places, mountainous. This is matched by a steeply shelving bathymetry and narrow continental shelf. The central and southern sections of this coast are dominated by vast sandy beaches and barrier islands and there is no offshore reef development. Further north the coastline becomes more complex, with a number of embayments and rocky headlands as well as offshore islands. There are a number of emergent fossil reefs along the more northerly sections of this coastline. Active coral growth is also widespread in the north, often growing on fossil structures offshore, although not always contributing to active reef accretion. There is a submerged and fragmented barrier reef described off Toamasina, although the recent status of this is unclear. Discontinuous fringing reefs also occur off the coast around Foulpointe and Mananara, Nosy Boraha (Sainte Marie Island), and the Masoala Peninsula.

Mauritius

Mauritius is almost completely encircled by fringing reefs, with substantial lagoon and barrier reef development on the east and southwest coasts. The lagoons are dominated by algae, but with some areas of seagrass. The reef slopes have a clear spur and groove zone. Below about 20 meters there is usually only a thin veneer of coral rock overlying volcanic rocks. Rodrigues is the oldest of the volcanic islands and has a highly developed reef structure, although a true barrier reef has not formed. The island is totally encircled by reefs, with wide shallow reef flats extending out from the shore – in the east this narrows to 50 meters in places but is more typically 1-2 kilometers wide, while at its widest extent in the west it reaches 10 kilometers. Seagrasses are widespread in the lagoon, and reef flats and mangrove communities are reported to be increasing. The outer slopes are steep, and have 50-70 percent coral cover. In Mauritius the 1998 bleaching event affected 30-40 percent of corals, though very few died. The high rates of survival have, in part, been related to overcast and windy conditions for much of February and March, which were associated with cyclone Anacelle and which mitigated the warming impacts observed elsewhere in the region. Many of the reefs around Mauritius have been degraded by human activities. Problems include high levels of sedimentation and pollution arising from the clearance of the forest and subsequent agricultural runoff. Further pollution comes from domestic and light industrial effluents. There has also been direct damage to the reefs – blast fishing was a problem in the past and anchor damage continues. Large areas are also affected by crown-of-thorns starfish, which have undergone population explosions since the early 1980s. Tourism is a critical sector of the economy, and Mauritius had 487 000 arrivals in 1996. Coastal development to cater for this industry has added significant impacts, notably through pollution, but also through coral and shell collection for sale to tourists as well as direct diver impacts.

Mozambique

Mozambique has a long coastline facing the Mozambique Channel and Madagascar. In the north, heavily faulted Cretaceous to Tertiary sediments line the coast. South of Angoche the coastline is dominated by Quaternary to Recent sediments, largely sands interspersed with heavy alluvial deposits, particularly in the central region between Angoche and Bazaruto Island where some 24 rivers meet the coast, including the large delta areas of the Zambezi and Save Rivers. In many areas the sands form flat plains, although high dune systems are also common, particularly in the southern third of the country where they often lie in front of coastal barrier lakes and swamps. There are several offshore island groups, including a number of small coralline islands directly south of the border with Tanzania, the Quirimbass Archipelago, and two short island chains due south of Angoche – the Primeiro and Segundo Archipelagos. Larger islands include those of the Bazaruto Archipelago and Inhaca Island in the far south. The continental shelf is less than 20 kilometers wide in the north, broadening to a maximum of about 130 kilometers in the center of the country and then narrowing again in the south. Mozambique has a large coastal population. The majority of these people moved to urban areas during the civil unrest which ended in 1992. These are a source of considerable pollutants to nearby coastal waters as most sewage is untreated. Away from these urban areas much of the coastline is dominated by slash-and-burn agriculture, which releases sediments and nutrients into nearby waters. Tourism is growing, particularly in the south, and is generally considered detrimental to the environment, especially vehicular or camping-based tourism from South Africa which brings few benefits to the country, and may lead to unsustainable levels of recreational fishing and damage to turtle nesting beaches. Efforts to develop coastal resorts have also been poorly controlled to date, although this may be changing. Most reef-based tourism operates around the Bazaruto Archipelago and there is evidence of significant damage to reefs caused by divers and boats.

Sao Tome and Principe

The islands of Sao Tome and Principe, situated in the equatorial Atlantic about 300 and 250 kilometers (200 and 150 miles), respectively, off the northerwest coast of Gabon, constitute one of Africa's smallest countries. Both are part of an extinct volcanic mountain range, which also ../../includes the island of Bioko in Equatorial Guinea to the north and Mount Cameroon on the African west coast. Sao Tome is 48 kilometers (30 mi.) long and 32 kilometers (20 mi.) wide and the more mountainous of the two islands. Its peaks reach 2,024 meters (6,640 ft.). Principe is about 16 kilometers (10 mi.) long and 6 kilometers (4 mi.) wide. Both islands are crossed by swift streams radiating down the mountains through lush forest and cropland to the sea.

Seychelles

The Seychelles is a very large archipelagic nation in the Western Indian Ocean. The 115 named islands and atolls together with their associated reef systems can be clearly divided into two distinct regions: the high islands to the north and the low coralline islands spread over wide areas to the south and southwest. The Seychelles Bank lies at the northernmost point of the Mascarene Ridge and is a large, shallow area (some 31 000 square kilometers) of water, mostly above a depth of 100 meters. In its center are a number of high granitic islands of continental origin. These have been described as a “micro-continent”, having been left behind during the northwards migration of the Indian sub-continent about 135 million years ago. These are surrounded by widespread but discontinuous, fringing reefs. Along the east coast of Mahé and the west coast of Praslin such fringing reefs are well developed. Reef flats reaching over 2 kilometers in width and terminating in a high algal ridge are followed by a reef slope descending to a floor typically at 8-12 meters. Such clearly zoned reefs are less apparent in more sheltered locations where more complex reef formations have developed. Coral cover varies, being virtually absent from some former reef structures, but abundant in other areas, including non-reefal slopes and granitic surfaces.

Somalia

Somalia has 3300 km of coastline, of which 1300 km face the Gulf of Aden from Raas Caseyr to the border with Djibouti, and the balance faces the Indian Ocean ( Fig. 1). The western part of the north coast between Saylac and Berbera is shallow with exposed, high energy sandy beaches. The central portion between Berbera and Bosaso consists of mainly shallow, sandy shorelines, rarely broken by protruding rocky outcrops and cliffs which may extend into the shallow water. In the eastern part between Bosaso and Raas Caseyr high mountains reach the sea. The area is characterised by rocky shores with steep cliffs, often interspersed by short segments of narrow sandy beaches. The northern coastline is relatively straight and consists mainly of beaches. Small rocky promontories occur only in a few localities. A raised fossilised seabed backs most of the beaches. There are no perennial rivers along the northern coast of Somalia. Freshwater reaches the coast only during irregular flash floods following torrential rains. The surface run-off from land has no significant influence on the marine environment. Most nearshore subtidal areas are shallow with sandy substrate, occasionally interspersed by fields of cobbles or boulders and by rocky outcrops. Steep rocky cliffs usually continue as shallow sand areas under the water surface. Coral growth is limited, partly by a lack of suitable substrates and partly by hydrographic conditions. Occasional coral growth has been observed in the eastern and western part of the coastline. Extensive coral reefs, possibly the largest ones of the entire Gulf of Aden, occur in the vicinity of Saad ad-Din Island. Smaller coral reef areas exist west of Xabo and between Buruc and Bosaso.

South Africa

Although reef communities extend into the waters of South Africa it is arguable whether these are true reef structures. There are three main areas: the northern, central and southern reef complexes. All are submerged communities growing over late Pleistocene dune and beach sequences, and reaching a minimum depth of about 8 meters. Diversity is lower than the reefs of more northern countries, with only 43 species of scleractinian coral recorded. Coral cover (hard and soft) is high, however, making up almost 50 percent of benthic cover (and 95 percent of the live cover). These reefs were largely unaffected by the 1998 coral bleaching event. Large numbers of divers visit the reefs, with over 90000 recreational dives per year, mostly visiting Two Mile Reef in the central complex. Lying offshore, these areas are not threatened by terrestrial sources of pollution or sedimentation, and they are protected within the St. Lucia Marine Reserve (a part of the wetland park). Artisanal fishing is permitted in much of the reserve.

Sudan

The Sudanese Red Sea coast is approximately 750 km long inclusive of bays and inlets, extending from 18°N at the Eritrean border to 22°N at the Egyptian border ( Fig. 1). Average annual rainfall is 111 mm (varying from 36 mm at Halaib to 164 mm at Suakin) and the coastal plain is very dry. Sudan lies within the desert and semi-desert sub-zone, and there is no perennial water flow to the sea. Only after torrential rains, which occur mainly in November and December, there is occasional freshwater influx into the Red Sea. In most parts of the Sudanese Red Sea water transparency is very high, reaching up to 70 m. Surface temperatures range between 26.2 and 30.5 °C, and salinity is high (39 - 41 ppt). From May to October, surface currents flow in a southerly direction, for the rest of the year they flow northwards. Port Sudan is the largest coastal city with a population of ca. 390,000. At present the natural resources of the Red Sea are under-exploited due to a lack of marketing, transport facilities and cold storage. There is no offshore oil exploitation and the contribution of fisheries and tourism to the GNP is < 3%, and subsistence fisheries are only locally important. The primary industries are maritime shipping and port-related activities. Tourism and fisheries have a great growth potential, as does shrimp aquaculture.

Tanzania

The coastline is taken from Petroconsultants SA (1990). Coral reefs have been digitised at 1:5,000,000 from UNEP/IUCN (1988). Mangrove areas are taken from summary map of a more detailed mangrove forest inventory (Ministry of Lands, 1990), supported by NORAD, based on aerial photography taken in 1988/9.

Information provided by ICLARM - The World Fish Center, with support from the International Coral Reef Action Network (ICRAN). ReefBase: Oliver, J. and M. Noordeloos. Editors. 2002. ReefBase: A Global Information System on Coral Reefs.