Maloti Minnow [ Brochure pdf]                                                                                                 

The Endangered Maloti Minnow finds the Highlands of Lesotho a suitable habitat.

Maloti Minnow or scientifically known as the Pseudobarbus quathlambae, is small fish that is no less than 5cm in length. It enjoys very high quality water and is therefore a good indicator for water quality. It thrives in highly oxygenated, very clean and shallow areas of rivers and streams. Latest findings on the occurrence of the small fish is that it is more abundant in the Phase 1B catchment in Senqunyane, Bokong and Jorodane rivers than in any other rivers in the highlands.

The Pseudobarbus quathlambae has been classified a critically endangered fish according to the International Union for the Conservation of Nature and Natural Resources. Because of its conservation status world wide and it limited distribution within the sub-continent, it was identified for specialised studies in order to determine the extent of possible impact by the implementation of the Lesotho Highlands Water Project (LHWP).

Quite a substantial part of its habitat will be seriously impacted by the impoundment of Mohale dam. The ultimate opening of Mohale-Katse tunnel threatens the Minnow existence by exposing it to greater possibility as prey to bigger fish. Such threat also seems probable from other developmental programmes like fishing as a tourism promotion. Results have shown the importance of Mohale population as a genetically distinct and which therefore deserves conservation. The Minnow population at Matsoku is under a similar predicament.

Fortunately there are other suitable catchments outside Mohale where the small fish could be translocated as part of the LHDA mitigation and conservation plan. The LHDA will ensure that the translocation is not effected in areas where trout is present. The proposed conservation plan is envisioned to comprise of determining sanctuary sites outside Mohale catchment, actual translocation, designing of holding facilities and a captive propagation. It is also proposed to construct barriers for those fish that would not be translocated to guard against the impact of a full supply level situation in the reservoir.

The later move is anticipated to have adverse impacts as it will tend to fragment the Mohale population and isolate individuals upstream of the barrier. It is also anticipated that abundance in such a confined space will result in population decline as a result of anthropogenically induced impacts caused by inhibited migration of fish from other rivers. This will cause disruption of gene flow between the 1B rivers, the result would be a disruption in gene variability and creation of a genetic bottleneck. On the other hand relocation of the Minnow to river reaches historically void of fish may affect sensitive resident aquatic biota endemic to the recipient system.

It would therefore be imperative to study the selected areas to guard against the anticipated cause-effects. Mitigation measures should include monitoring of the transplanted fish populations to establish success rates, ensuring that rivers selected as recipient systems contain adequate and suitable resources as well as habitat to sustain the introduced Minnow stock, ensure that sufficient numbers are introduced to circumvent probable genetic variation loss, founder effects, bottlenecks and inbreeding effects.

To achieve a long-term conservation objective a two-step action will be adopted. The first step of activities will allow for timely impoundment of Mohale dam. The second step of activities will include facilitating for medium to long term conservation through community involvement based on suitable long term management strategy and appropriate policies to support the conservation process.

JLB Smith Institute of Ichthyology is undertaking the study under the auspices of Contract LHDA No. 1041.