5.4 POLLUTION OF MARINE AND COASTAL ENVIRONMENT
The threats to aquatic biodiversity in the Region come from municipal, agricultural, and industrial activities. The key sources of pollution in the Regions’s coastal
Districts are waste products from coconut oil extraction, discharge of human excreta, and solid waste especially plastics into streams, wetlands and the sea. Litter entering
the marine environment is known to kill sea turtles, dolphins and sea birds UNEP, 1995. An assessment in 1994 indicated a ‘high’ domestic pollution for Sekondi-
Takoradi Metropolis compared to Nzema East, Ahanta West and Jomoro EPA, 2004. The projected pollution indices for domestic and industrial pollution Table 7
indicate that by the year 2020 pollution in the coastal Districts would have increased severalfold from the 1994 estimates.
Table 7: Pollution indices in four coastal districts
DISTRICT Domestic Pollution Index
1994
Domestic Pollution Index
2020 Industrial
Pollution Index 1994
Industrial Pollution Index
2020 Nzema
East 249 527 5
100 Ahanta
West 261 521 5
111 Ahanta East
672 1702
39 827
Jomoro 194 406 4
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Source: World BankEPA 1996
5.5 COASTAL EROSION
The Ghanaian coast is exposed to various degrees of erosion with moderate rates occurring in the Western Region World BankEPA, 1996; Armah and Amlalo, 1998.
Erosion at Essipon Turtle Cove in the former Shama Ahanta East District, Busua in Ahanta West and Axim in Nzema East District has resulted in loss of sea turtles
nesting beaches. In adition fish landing sites at Princess Town, Poasi Nkontonpo and Essipon have been deserted as a result of severe coastal erosion EPA, 2004.
Generally, the natural causes of erosion are compounded by the effects of human- induced vegetative loss or deforestation. Re-inforcements of waves due to adjacent
headlands and man-made structures like breakwaters at the Takoradi Port, Bosumtwi Sam Fishing Harbour and Naval Base at Sekondi seem to be the most likely cause of
erosion at Princess town, Adjoa, Nkontompo, and Essipon. Sand and stone winning activities along the coast especially in Axim have led to considerable sea erosion
which continues to threaten some communities in that area. Other human causes arise from improper land use such as bush burning, over-grazing and other forms of
agricultural land use.
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5.6 CHANGES IN SPECIES COMPOSITION AND TROPHIC BALANCES
Some species such as the gastropods Cymbium spp. and the spiny lobster Panulirus sp. appear to be declining in abundance while the sea star Astropecten sp. and other
starfishes have disappeared completely. The triggerfish Balistes capriscus was of little interest prior to 1973 but assumed great importance in the demersal fishery from
that year Mensah and Koranteng, 1988 to 1987. The species has since disappeared Mensah and Quaatey, 2002 a phenomenon that has been attributed to changes in
physical oceanographic parameters in the Gulf of Guinea Koranteng et al., 1996; Aggrey-Fynn, 2007. Collapse of the grey triggerfish Balistes capriscus fishery in
Ghanaian waters since its dominance in the demersal fishery in the 1970s and 1980s is a major example of a fish species under threat of extinction.
5.7 INCREASED POPULATION DENSITY