Open Access Research Article

Bathymetric Characteristics of Lake Malombe, Malawi

Msiska OV1*, Chigona G2, Banda J3 and Bulirani A4

1Fisheries Consultant, Mzuzu, Malawi

2Hydrographic Unit, Monkey Bay, Malawi

3Fisheries Research Institute, Monkey Bay, Malawi

4Ministry of Agriculture, Irrigation and Water Development, Lilongwe 3, Malawi

Corresponding Author

Received Date: August 06, 2021;  Published Date: September 21, 2021

Abstract

The Lake Malombe floor was subjected to a bathymetric study to determine the physical features that have been influenced by periodic desiccation and refilling during evolution of the lake. This lake fish resources have undergone major declines in catches from a maximum of 12, 000 to 3, 000 tons between 1976-2016, creating adverse effects on livelihoods of communities. This prompted a number of scientific studies, of which this is only one. The cross-section of the lake floor was found to be composed of a steep slope on the eastern side, a trough and ridge in the middle followed by a gentle zone in the west. The southern portion is shallow and muddy. Distribution and concentration of biological organisms are influenced by the nature of the bottom such that the mud-water interface is critical to zoobenthos colonization. The lake was computed to cover 31,020 ha with a maximum depth of 5.6m; indicating shallowing from 7m in 1993 and 17m in 1950s. Thus, a further possibility of drying are speculated if the trend continues; this could adversely affect energy and irrigation developments downstream. Therefore, the regulatory barrage installed downstream on the Middle Shire should be replicated by similar control between Lake Malawi and Upper Shire, otherwise as the lake shows signs of shallowing it could threaten sustainability of any projects downstream. Regarding regeneration of fish resources, attention should also be given to benthic browsers and low oxygen tolerant species because of the rich anaerobic zoobenthos.

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