Lake Nokoué

Lake Nokoué
Denham Waters
Lake Nokoué seen from space (false colour)
Lake Nokoué is located in Benin
Lake Nokoué
Lake Nokoué
Coordinates6°26′00″N 2°27′00″E / 6.433333°N 2.45°E / 6.433333; 2.45
Basin countriesBenin
Max. length20 km (12 mi)
Max. width11 km (6.8 mi)

Lake Nokoué is a lake in the southern part of Benin. It is 20 km (12 mi) wide and 11 km (6.8 mi) long and covers an area of 4,900 ha (12,000 acres).[1] The lake is partly fed by the Ouémé River and the Sô River, both of which deposit sediments from throughout the region in the lake.[2]

The city of Cotonou sits on the southern border of the lake. Sections of the population of Cotonou have been displaced by coastal and lake flooding.[3] On the northern edge of the lake is the town of Ganvié.

Economy

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Mennonite missionary in a dugout canoe, similar to the ones used by local artisanal fishermen

Because of its diverse wildlife, the lake provides an important source of food and economic activity for these towns.[3] Fishing is best when water is low between November and June.[1] Fishing is typically of 30 species of fish, with fish from the Cichlid, Clupeidae and Penaeidae families making 85% of the catch.[1] The fishery became more stressed during the 1990s, as more people began fishing on the lake.[1] Fishing is typically artisanal, with small crew dugout canoes catching small batches of fish.[1] The estimated fish production of the lake is 2 tonnes per hectare per year.[4]

The lake is also used for Acadja, a type of fish breeding facility.[1]

Hydrology

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The lake, in large part, is a lagoon.[5] With the surrounding low-lying topography, the lake is expected to double in size and flood as the current global climate change gradually affects the sea level.[3] This development carries a risk of future salinisation, which will make the freshwater lake more brackish and potentially change its ecology.[3] Different sections of the lake currently alternate between freshwater and brackish ecosystems at an average depth of 1.5 m (4 ft 11 in).[1] Normal temperatures throughout the lake are between 27 and 29 °C (81 and 84 °F).[1]

The lake is a site of deposition of both pesticides and heavy metals from upstream industry and human habitation.[4] Though the pesticides are only present in fish at less than toxic levels,[4] the heavy metals in the waters can reach levels in fish both unhealthy for humans and the fish.[citation needed]

The lake village of Ganvie on its northern shore

Geology

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The floor of the lake is a mixture of sand, muddy-sand and mud layers.[1]

Ecology

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Lake Nokoué has at least 78 species of fish.[5] A number of bird species exploit the wide variety of fish as food, as well as species of otter.[5]

References

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  1. ^ a b c d e f g h i ATTI – MAMA, CYRIAQUE. "CO-MANAGEMENT IN CONTINENTAL FISHING IN BENIN: THE CASE OF LAKE NOKOUE" (PDF). Proceedings of the International Workshop on Fisheries Co-management. Archived from the original (PDF) on 2016-11-16. Retrieved 2016-11-16.
  2. ^ Gadel, F.; Texier, H. (1986-06-01). "Distribution and nature of organic matter in recent sediments of Lake Nokoué, Benin (West Africa)". Estuarine, Coastal and Shelf Science. 22 (6): 767–784. Bibcode:1986ECSS...22..767G. doi:10.1016/0272-7714(86)90098-3.
  3. ^ a b c d Bicknell, Jane; Dodman, David; Satterthwaite, David (2012-01-01). Adapting Cities to Climate Change: Understanding and Addressing the Development Challenges. Earthscan. pp. 120–122. ISBN 9781849770361.
  4. ^ a b c Yehouenou A Pazou, Elisabeth; Aléodjrodo, Patrick Edorh; Azehoun, Judicaël P.; van Straalen, Nico M.; van Hattum, Bert; Swart, Kees; van Gestel, Cornelis A. M. (2014-01-01). "Pesticide residues in sediments and aquatic species in Lake Nokoué and Cotonou Lagoon in the Republic of Bénin". Environmental Monitoring and Assessment. 186 (1): 77–86. doi:10.1007/s10661-013-3357-2. ISSN 1573-2959. PMID 23942697. S2CID 35119898.
  5. ^ a b c Laudelout, A.; Libouis, R. (2008-04-15). "Chapter 12: On the feeding ecology of the pied kingfischer at Lake Nokoue, Benin. Is there competition with fishermen?". In Cowx, Ian G. (ed.). Interactions Between Fish and Birds: Implications for Management. John Wiley & Sons. pp. 165–177. ISBN 9780470995365.
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