BACKGROUND AND PROBLEMS
The Guinea
Current is the dominant feature of the shallow ocean off the coast
of countries in Western Africa stretching from Guinea Bissau in
the north to Angola in the south. The distinctive bathymetry, Hydrography,
productivity and trophodynamics of this shallow ocean quality it
as a Large Marine Ecosystem (LME) and is indeed recognised as one
(n°28) of the fifty LMEs delineated globally. The oceanography
of the two Congos and Angola further to the south is influenced
by the Guinea Current and thus there is ample justification for
including the tree countries in the Guinea Current Large Marine
Ecosystem (GCLME). The northern subsystem of the GCLME is thermally
unstable and is characterised by intensive seasonal upwelling while
the southern half, which is generally thermally stable, depends
on nutrient input originating from land drainage and river flood
and turbulent diffusion, although less intensive and periodic upwellings
have been reported. These characteristics combine to make this area
as one of the orld's most productive marine areas that is rich in
fishery resources, petroleum production, and an important global
region of marine biological diversity.
Approximately 40% of the region's 280 million people live in coastal
areas and are dependent on the lagoons, estuaries, creeks and inshore
waters surrounding them. Rivers and lagoons serve as important waterways
for the transportation of goods and people. They are also important
sources of animal protein in the form of fish and shellfish. Unfortunately,
pollution from residential and industrial sources has affected the
waters of the GCLME, resulting in habitat degradation, loss of biological
diversity and productivity, and degenerating human health (IOC-UNESCO
& IAEA Marine Environmental Laboratory).
In the coastal pelagic fishery, economically important species are
linked to the availability of phytoplankton and zooplankton. The
target species off the Coast, Ghana and Togo are Sardinelia aurita, Sardinelia maderensis, Scomber japonicus and Engraulis encrasicolus. In Ghana, for example,
small pelagics contributed 125,000t and 247,000t to the total marine
production of 234,000t and 371,000t in 1985 and 1992 representing
54 and 66 percent of the fisheries yield respectively, indicating
their importance to food security of the region. Further south from
Benin to Democratic Republic of the Congo, the target species are
Ethmalosa fimbriata, Sardinella maderensis, lisha africana. Demersal fisheries, of higher economic value than pelagics,
have as their targets croakers, Pseudotolithus elongatus, Psendotholitus senegalensis, Pseudotholitus typus, polymenids, Galeoides decadactylus, polydactylus quadrifilis, grunters, big eye tuna, Brachydeuterus auritus, catfish, Arius sp. Pomadasys sp soles and Cynoglossus sp In the highly lucrative
coastal demersal shrimp fishery, the pink shrimp Paenus notialis is dominant but other
target species include the Parapenaeopsis atlantical and Penacus kerathurus. Shimpring grounds cover
2,500 mi² off Nigeria, 190 mi² off Cameroon and 180 mi²
off Benin. Exclusively exploited by small scale operators with passive
cane or netting gear in the estuaries, and with miniature trawls
in the surf zone, white shrimp, Nematopalaemon hastatus a major fishery off Nigeria
- Cameroon. Potential is about 150,000t/Year off Nigeria. The shrimp
resources of the ecosystem are an important export species.
The rich fishery resources are both locally important resident stocks
supporting artisanal fisheries, and transboundary stradding and
migratory stocks that have attracted large commercial offshore foreign
fishing fleets from European Union, Eastern Europe, Korea and Japan.
Since the 1960s, the offshore commercial fishing efforts have exerted
extreme pressures on the resources, placing the fisheries at risk
of collapse. This is exacerbated by the present of local industrial
fleets, predominantly nationally owned or part of joint ventures
operating in each others water under bilateral agreements, as the
existence of a large artisanal sector with strong traditional roots
and powerful social and political impacts. Catch per Unit Effort
(CPUE) is exceeding sustainable yields in some countries (Ajaji,
1994, The Status of marine Fishery Resources of the Gulf of
Guinea: In: Proc. 10th Session FAO, CECAF, Accra, Ghana, 10-13 October
1994) while species diversity and average body total lengths of
the most important ish assemblages have declined. The negative trends
of over-exploitation of fish and fisheries from lack of management
and adequate forecasting system have economic and food security
implications not only for the 280 millions people of the region
and the growing food (protein) needs of the region will need to
be examined in the context of the substantial extent to which foreign
fleets are exploiting the fishery resources of the GCLME.
Mangroves of the GCLME are a particularly important resource for
coastal communities. They are used for firewood, fish smoking, building
materials, salt production, oysters and fisheries and medicinal
purposes. Unfortunately, overuse and, to a lesser extent, pollution
has severely damaged the mangroves. Urban expansion and industrial
growth has led to mangrove reduction to such an extent that several
species once present are no longer found. In many instances mangrove
areas have been reduced to saline grasslands of Paspalum vaginalum.
Mangroves, typically Rhizophara sp, Conocarpus sp, Avicennia sp, Mitragyna inermis, Laguncularia ap, occur almost everywhere
along the coast in the GCLME and are dominant in certain places
such as the Niger Delta of Nigeria where the mangrove swamp forests
extend over an area of 9,000 km2 between the region of Benin River in the West and the
Calabar-Rio del Rey estuary in the East. Mangrove forest provide
the nutritional inputs to adjacent shallow channel and bay systems
that constitute the primary habitat of a large number of aquatic
species of commercial importance. The importance of mangrove areas
as spawning and breeding grounds for many transboundary fish species
and shrimps is well known. Beside the rich flora, there is a diverse
array of associated fauna including small mammals such as statungas, otters, Atilax paludinosus, Dasymys incomtus and large mammals such as Cephalophus sp. Molluscs found in this habitat
include Crassostrea gasar, cams Arca senilis, Volutes Cymbium pepo, cones, cowries and conches.
These molluscs form an important basis for fish and bird food chains
as well as being a major food humans. Mangroves still harbour at
least three species of crocodiles, one known locally as alligator,
and the endangered west African manatees Trichechus Senegalensis. Presently the mangrove
forests are under pressure from over cutting (for fuel wood and
construction timber) and from other anthropogenic impacts thereby
jeopardising their roles in the regeneration of living resources
and as reservoirs of biological diversity.
The
physical destruction of coastal habitats including wetlands cause
the loss of spawning and breeding grounds for most living resources
and the loss of the rich and varied fauna and flora of the region
including some rare and endangered species. In Ghana, 55 percent
of the mangroves and significant marshlands around the greater Accra
area has been decimated through pollution and overcutting. In Benin,
the figure is 45 percent in the Lake Nouake area, in Nigeria, 33
percent in the Niger Delta, in Cameroon, 28 percent in the wouri
Estuary and in Côte d'Ivoire, about 60 percent in the bay
of Cocody.
Agriculture is important to all countries in the region, both at
subsistence and commercial level. A number of rural and agriculture
practices impact the marine and coastal environment. The use of
chemical fertilisers and pesticides has markedly increased with
the development of commercial agriculture and the need to improve
food production and protest human health against insect-borne diseases.
Although organochlorine based pesticides are still used, awareness
of their danger has spread so the majority are now organo-phophorous
and carbamate based. Run-off of these chemicals may reach surface
or groundwater where they may persist for long periods. Investigations
of PCBs have shown they exist at a background level but are not
a problem yet Inorganic, especially nitrate and phosphate based,
fertilisers are being used on an increasing scale. Substantial quantities
of nutrients originating from domestic and agricultural effluents
which are used in primary production are carried to the sea through
river outflows It is estimated that approximately 30% of fertilizer
applied are actually utilised by the plants while the reminder finds
it way into the atmosphere or into surface waters. These nutrients,
when coupled with sewage pollution, are a serious threat to lagoons.
(Portmann, J.E, Biney, C., Ibe, C. and Zabi, S. (1989), State of
the Marine Environment in the west and Central Africa Region, UNEP
Regional Seas Reports and Studies, No. 108
Nearly
all major cities, agricultural plantations harbours, airports, industries
as well as other parts of the socio-economic infrastructure in the
region are located at or near the coast. This is due in part to
the richness of natural resources in the coastal areas of the Gulf
of Guinea and partly also as a result of the history of early European
contact. The result is that unplanned urbanisation and development,
including habitat destruction of coastal areas coupled with the
rush to industrialise, exert phenomenal pollution pressures on this
international body of water (WACAF Intersecretariat Co-ordination
Meeting, Rome, 1993).
The stresses arising as result of these complex and interactive
human developments are leading to increases in harmful impacts on
the environment and natural resources of the GCLME :
Large-scale changes in the abundance levels of the
resident fish stocks near shore and the conditions affecting
the sustainability of the stradding (shared) and highly migratory
fisheries of the region, both of which have food security and
economic implications to the 280,000,000 people of the region;
The physical destruction of coastal habitats including
wetlands, mangroves, and the loss of spawning and nursery grounds
for living resources and the loss of the rich and varied fauna
and flora of the region including some rare and endangered species;
Uncontrolled and haphazard urbanization of coastal
areas across the region that result in use conflicts and impose
great stresses on environment and resources
Input of largely untreated sewage into the coastal
environment impacting on health, tourism and fisheries. Sewage
treatment facilities are very limited throughout the region
and raw sewage is discharges both into coastal lagoons and the
rivers flowing into them. This, combined with the limited tidal
water exchange of lagoon, has led to widespread eutrophication;
Discharges of untreated or partially treated industrial wastes
directly into coastal water bodies that contaminate marine
life and pose serious threats to human life
Use of pesticides especially organochlorine group
of compounds in agriculture and human health protection results
in an input of residues to the coastal environment that are
harmful to living resources;
Risks from petroleum pipeline development and accidental
spills of petroleum products and operational discharges from
shipping (e.g. ship wastes) and the accidental introduction
of toxic chemicals and exotic species that seriously damage
the receiving ecosystem, leading to food and habitat loss;
Harbour construction activities that generally
alter long shore current transport of sediments and in many
cases have led to major coastal erosion and siltation problems;
Large amounts of sediments emptied by the many large
rivers in this region that are important sources of nutrients
and suspended matter to the coastal and marine environment contributing
to eutrophication and harmful algal blooms with serious implications
to ecosystem and human health;
Apparent increase in the frequency and extent of coastal
erosion placing fishing and other coastal communities in danger
from loss of roadway and habitable lands.
Most
of the countries in the region are oil producers and a few (e.g.
Angola, Cameroon, Gabon and Nigeria) are net exporters. The number
of offshore platforms and various export/import oil terminals means
an inevitable exposure to oil pollution (such as Shell in Nigeria).
According to the World Bank (1995), oil producing companies in Nigeria
alone discharge an estimated 710 tons of oil yearly. An additional
2100 tons originate from oil spills. The patterns of onshore-offshore
winds and ocean currents mean that any oil spill from any of the
offshore or shore bases petroleum activities translate easily into
a regioanl problem. Most of the countries also have important refineries
on the coast, only a few of which have proper effluent treatment
plants, thereby adding to the threat of pollution from oil.
The
CGLME is one of the most endowed areas of the globe in terms of
rivers. Ten 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. Land run-off is an important
source of nutrients and suspended matter to the coastal and marine
environment. However, excessive nutrient loading causes eutrophication
and harmful algal blooms. The rivers transport industrial wastes
especially from mining and other land based sources, thereby, contributing
significantly to the global pollution loading of international waters.
Alterations to flow regimes from dam construction (for irrigation
and power generation), together with wave action have led to severe
coastal erosion problems, issues which are expected to be addressed
in a parallel GEF project in the Volta river fine Basin. 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 silation problems.
Erosion rates caused by port structures in Liberia, Togo, Benin
and Nigeria vary on the average between 15-25 m per year and threaten
infrastructure and service. Actions to control erosion around these
ports are critically important to maintaining their vitality as
sites for growing tourist, recreational, commercial and defence
needs. |