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Guinea Current Large Marine Ecosystem Project

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Guinea Current Large Marine Ecosystem Project Guinea Current Large Marine Ecosystem Project 02 June 2003 draft Regional Project Coordinating Centre, Abidjan, Cote d’Ivoire, April 2003 A Programme of the Governments of the GCLME countries, with the assistance of GEF/UNIDO/UNDP/UNEP and US-NOAA 1.0 INTRODUCTION 2.0 PHYSICAL AND BIOGEOCHEMICAL SETTING 2.1 HYDROLOGY 2.2 GEOLOGY AND GEOMORPHOLOGY 2.3 OCEANOGRAPHY 2.4 IMPORTANT ECOTONES 2.41 MANGROVES/COASTAL FORESTS 2.42 AQUATIC FLORA AND FAUNA 2.5 MARINE MAMMALS AND TURTLES (ENDANGERED SPECIES) 2.6 FISHERIES 2.61 ARTISANAL FISHERIES 2.62 COMMERCIAL/INDUSTRIAL FISHERIES 2.63 Turtles and Marine Mammals 3.0 SOCIO-ECONOMIC AND DEVELOPMENT SETTING 3.1 HUMAN DEVELOPMENT AND DEMOGRAPHY 3.2 TOURISM 3.3 GOVERNANCE AND POVERTY 3.4 PHYSICAL ACTIVITIES IN THE COASTAL ZONES OF THE GCLME 3.41. Manufacturing 3.42. Agriculture 3.43. Oil and Gas 3.44. Salt Production 3.45. Sand Extraction 4.0 LEGAL, REGULATORY AND INSTITUTIONAL SETTING 5.0 MAJOR TRANSBOUNDARY PERCEIVED PROBLEMS AND ISSUES 1. Decline in GCLME fish stocks and non-optional harvesting of living resources; 2. Uncertainty regarding ecosystem status and yields in a highly variable environment including effects of global climate change; 3. Deterioration in water quality (chronic and catastrophic) pollution from land and sea based activities, eutrophication and harmful algal blooms; 4. Habitat destruction and alteration including inter-alia modification of seabed and coastal zone, degradation of coastscapes, coastline erosion; 5. Loss of biotic (ecosystem) integrity (changes in community composition, vulnerable species and biodiversity, introduction of alien species, etc). 6.0 FUTURE PERSPECTIVES AND NEXT STEPS 7.0 TRANSBOUNDARY DIAGNOSTIC ANALYSIS METHODOLOGY: SUMMARY AND WAY FORWARD 8.0 GCLME TDA 9.0 STAKEHOLDER ANALYSIS 10.0 ENVIRONMENTAL QUALITY OBJECTIVES 11.0 BIBLIOGRAPHY 1.0 BACKGROUND AND INTRODUCTION The shared transboundary waters off the Gulf of Guinea are defined by the Guinea Current Large Marine Ecosystem (GCLME) which extends from Bissagos Island (Guinea Bissau) in the north (Latitude 11o N, Longitude 16o W) to Cape Lopez (Gabon) in the south (Latitude 0o 41’S, Longitude 8o 45’E) (Binet and Marchal, 1993) (figure 1). The oceanography of the waters of the Democratic Republic of Congo, Republic of Congo and Angola is influenced by the Guinea Current thus giving ample justification for including the three countries in the Guinea Current Large Marine Ecosystem (GCLME). Thus, the GCLME area includes the Exclusive Economic Zones (EEZ) of sixteen countries, namely: Angola, Benin, Cameroon, Congo, Côte d’Ivoire, Democratic Republic of Congo, Gabon, Ghana, Equatorial Guinea, Guinea, Guinea Bissau, Liberia, Nigeria, Sao Tome & Principe, Sierra Leone and Togo. The coastal habitats in the Guinea Current LME include near shore waters, salt marshes, mangrove swamps, estuaries, lagoons as well as other blackish water bodies. The total length of coastline in the Region is nearly 7,600 km including that coastline of the island State of Sao Tome and Principe and the insular parts of Equatorial Guinea (i.e. Bioko and Annobon islands). Angola has the longest coastline of about 1,650 km. The lagoons covering more than 100 square kilometres include Nokoue and Porto Novo in Benin; Ebrie, Aby-Tendo-Ehy, and Grad Lahou in Cote d’Ivoire; Nkomi, Idogo, Ngobe, and Mbia in Gabon; Keta in Ghana, and Lagos and Lekki in Nigeria. Table 1: Continental Shelf Area and Exclusive Economic Zones (EEZ) of GCLME Countries Country Continental Shelf (km2) EEZ (km2) Guinea Bissau 45,000 156,500 Guinea 47,400 71,000 Sierra Leone 25,600 165,700 Liberia 18,400 229,700 Cote d’Ivoire 10,200 104,600 Ghana 23,700 218,100 Togo 1,300 2,100 Benin 3,100 27,100 Nigeria 46,300 210,900 Cameroon 10,600 15,400 Equatorial Guinea 14,710 283,200 DR Congo 1,150 1,000 Congo 11,300 60,000 Gabon 46,000 213,000 Sao Tome et Principe 1,459 160,000 Angola 51,000 330,000 (Source: FAO, 1997 & World Resources 1994-1995) 2.0 PHYSICAL AND BIOGEOCHEMICAL SETTING The Guinea Current coastal area is marked by characteristic low lying topography and interspersed with marshes, lagoons and mangrove swamps. Major geomorphic features of the continental shelf include bathymetric undulations of sand ridges, canyons, gullies, dead Holocene coral banks, pockets of hard ground and rocky bottoms (Awosika and Ibe, 1998). Submarine canyons are found in some places: off the Vridi canal (Trou Sans Fond), in Cote d’Ivoire; off west Nigeria (Avon Deep), off the Volta Delta in Ghana; off the west coast of the Niger Delta (Mahin Canyon) and off the Calabar estuary both in Nigeria (Allersma and Tilmans, 1993). Three subsystems have been delineated in the Gulf of Guinea LME, each defined by its particular characteristics, which nevertheless contribute to the functioning of the ecosystem as a whole (Tilot and King, 1993). These include: • Sierra Leone and Guinea Plateau: from the Bijagos Islands (Guinea Bissau) to cape Palmas (Liberia/Cote d’Ivoire). This area is characterized by the largest continental shalf in West Africa and has large riverine inputs, giving thermal stability. • Central West African Upwelling: from Cape Palmas to Cotonou (Benin). This thermally unstable subsystem is characterized by seasonal upwelling of cold, nutrient-rich, subthermocline water, which dominates its annual cycle and drives the biology of the subsystem. • Eastern Gulf of Guinea: from Cotonou to Cape Lopez (Gabon), including the offshore islands of Bioko and Sao Tome and principe. This area is cahracterised by thermal stability and a strong picnocline. It depends on nutrient input from land drainage, river flood and turbulent diffusion for its productivity (Tilot and King, 1993; Binet and Marchal, 1993)). 2.1. HYDROLOGY, SEDIMENTATION AND COASTAL EROSION: Three narrow coastal sedimentary basins, with a few volcanic intrusions and outcrops of hard rock forming the major capes, have developed on the edges of the coastline along the Guinea Current region namely: the Côte d'Ivoire basin, the Niger basin (Delta) and the coastal basins from Gabon to Angola (R.E. Quelennec, 1987). All along these three coastal sedimentary environments there is strong influence of the pattern of river basins drainage. Numerous small rivers and four major river systems drain the whole coast of the GCLME from Guinea Bissau to Congo. The GCLME is one of the most endowed areas of the globe in terms of rivers. Twelve major rivers, including the Congo (Congo), Niger (Nigeria), Volta (Ghana), Wouri (Cameroon), Comoe and Bandama (Côte d’Ivoire), enter the ecosystem from an extensive network of catchment basins transporting great quantities of sediments. These rivers contribute over ninety-two million tons of sediment per annum into the Gulf of Guinea (Mahé, 1998; Folorunsho et al., 1998). During the 1970s and 1980s, river inputs decreased in the region coinciding with the period of the sub-Saharan drought (Lamb, 1982) which resulted in reduced flows of almost all the rivers (Mahé, 1998). Land run-off is also an important source of nutrients and suspended matter to the coastal and marine environment. Substantial quantities of nutrients originating from domestic and agricultural effluents, which are used in primary production, are carried to the sea through river outflows. However, excessive nutrient loading causes eutrophication and harmful algal blooms. The rivers transport industrial wastes especially from mining and other land based activities, thereby contributing significantly to the global pollution loading in international waters. Among the most important rivers are: • the Niger, which drains an area of over 1 million km 2 ; • the Volta river, with a drainage basin of 390,000 km 2 (World Bank, 1994); • the Congo river, the second largest mean annual run-off and catchment area in the world, with freshwater run-off and sediment discharge estimated at 30-80 tons/km 2 • Comoe River in Cote D’Ivoire. However, for energy, irrigation and flood control purposes, most of these rivers have been dammed, with, as a consequence, significant alteration of their hydrology and their sediment flow, creating inevitable downstream impacts and accelerating coastal erosion processes, an. issue to be addressed by the Cote d’Ivoire National demonstration project and also in a parallel GEF project in the Volta River Basin. In terms of impact, the coastal basins, particularly along the Niger delta, are gradually subsiding because of the natural geology of the area, but also because of human activities, such as oil mining and natural gas exploitation. These factors are combining to cause displacements of structures, people and economies of coastal communities and urban centres. Harbour construction activities have altered longshore current transport of sediments and in many cases have led to major erosion and siltation problems. In terms of coastal processes, physical alteration, habitat modification and destruction, coastal erosion constitutes a serious problem in many countries in the GCLME. The rate of the coastal retreat can average several metres per year (for example erosion rates caused by port structures in Liberia, Togo, Benin and Nigeria sometimes reach a staggering 15-25 m per year). Although the coastline is highly subject to natural erosion and sedimentation processes due to high wave energy, strong littoral transport, etc., erosion has been intensified by human activities, notably through sand mining and exploitation, disturbance of the hydrological cycles, river damming, port construction, dredging, mangrove deforestation, etc. These are particularly relevant for the Western part of GCLME and mainly for the coastal countries Benin, Côte d'Ivoire, Ghana, Nigeria, Togo. Examples of coastal erosion rates in western Africa are given in UNEP (1999) as follows: • Liberia - mean recession of 2m per year around Monrovia • Ghana - 6m per year west of Accra since the closing of the Akosombo dam in 1964 • Nigeria - a coastal recession of about 500m has been recorded at Victoria Island since the construction of the Lagos Harbour in 1907.
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