The inventory of small reservoirs has updated the current status of water resources in Lesotho lowlands. Of the 572 reservoirs visited, siltation to the extent of 85% was found in more than half (56%). 80% of these silted reservoirs were smaller than 1ha in size.
This brings the estimate of the total number of functional reservoirs in the Lesotho lowlands to almost 400 with a total surface area of 430ha, if we reject those where siltation is more than 95%. They have been classified into four major size classes with sub-groups. Class I, of reservoirs greater than 10ha, includes only seven reservoirs which represent 2% of the total number of functional reservoirs.
It is important for the Fisheries Section to continually update the reservoir inventory and also to field-check the problem of siltation. Follow-up action to control siltation should be taken by the Fisheries Section or any other department in charge of the maintenance of reservoirs.
CPUE or catch per unit effort provides a useful yardstick to monitor changes that occur in reservoir fish fauna. It gives a relative measure of the abundance of fish species present in a reservoir.
In the fish stock assessment conducted by the project in 15 selected reservoirs, the highest number of fish species encountered in a single reservoir was seven. A large quantity of fish of indigenous species were found in the largest impoundments. In sharp contrast, reservoirs smaller than 10ha have small populations of common carp and catfish.
The high CPUE and the length frequency analysis in the three largest reservoirs indicated that the fishing pressure is low. The use of nets will not only benefit fishermen but also help to improve reservoir productivity, maintaining the species at their optimum level of production.
Monitoring of fishing activities highlights the poor catches of local fishermen. These are not enough to satisfy their economic needs and efficiently exploit the fish population.
To assess the potential for the development of a fishery, an order-of-magnitude estimate may be sufficient, until the fishery actually develops. In most cases, very crude sampling would be adequate. When a fishing activity takes place, the fishery itself may be used to refine the estimates.
It is recommended that the Fisheries Section should choose this combined approach -- test fishing and catch monitoring of reservoirs -- in a regular programme of small reservoir assessment. Test fishing guidelines adapted to Lesotho conditions are proposed in paragraph 6.1.2. They are easy to apply and give a good indication of the present fishing pressure and the possibilities for increasing it.
A comparison of the results of small-scale fishing gear confirms that gillnets have the best catch potential for capture fisheries. Results from floating longlines for cyprinids are poor, and handling is time-consuming. The standard model of fish pot catches only fingerlings. Improved handline fishing methods, using lighter lines and smaller hooks than those commonly used by local fishermen, yield higher catches.
Attempts at fish enhancement and improvement of fishing gears could aim at encouraging gillnet fisheries, sport fishing and handline fishing. Improved handline fishing methods should be extended to local fish catchers. Facilities to produce fingerlings are limited in Lesotho; fingerlings of target species are available in South Africa.
The Fisheries Section should obtain fingerlings from the cheapest sources to meet the needs of small reservoir fisheries enhancements and aquaculture.
Fishery legislation in Lesotho is presently regulated by Proclamation No 45 of 1951, which is outdated. Socio-economic studies of local communities living around selected reservoirs often showed a clear conflict in ownership and control. Questions on ownership of reservoirs and surrounding lands often yielded varying answers.
Information on the supply and demand of local and export-quality freshwater fish is not readily available.
Reservoirs can be classified by size according to the management interventions proposed for determining the extent and potential output of the resource. Only four reservoirs, covering 147ha, may be able to sustain an extensive gillnet fishery. The potential of capture fisheries for these larger dams can be estimated at between 1.5 and 10 tonnes. From the large number of medium and small-size reservoirs and ponds, only 84ha were identified as suitable for aquaculture. These small reservoirs could yield 85–125 tonnes/year. These figures, added to the potential production from the domestic fish pond scheme (52 tonnes) show that fish production potential in the Lesotho lowlands could be estimated at between 140 and 200 tonnes in the areas currently under water. This potential, even if fully exploited, can hardly meet local demand but can at least reduce fish import by a fifth.
Management strategies proposed (Chapter 9.5) depend on the conditions around each reservoir, such as the kind of ownership and control of the dam. These include (i) part time commercial gillnet fishery, (ii) recreational fishery (iii) unmanaged fishery and (iv) fish culture.
In large fresh water impoundments, gillnet fisheries should be introduced by promoting small-scale concessional fisheries. Economic simulation exercises (Chapter 9.3) seem to illustrate the profitability of a part-time gillnet fishery in one particular dam. However, a rotating fishery (a system of tapping different sources one after another) that exploits the four larger dams would represent better use of the modest investment (boat, gillnet). This activity should generate useful revenue during the four-month fishing period (January to April).
Extensive fish culture and fish-cum-duck farming are considered suitable for reservoirs smaller than 10ha.
It is recommended that the Fisheries Section should:
revise fishery regulations to accommodate proposed management options and improved fishing gears;
establish a regulatory framework for assigning control and monitoring of reservoir resources to local communities;
conduct a Rapid Rural Appraisal (RRA) around dams in order to establish a socio-economic basis for fisheries management;
include questions on fish consumption patterns on Government household-income and expenditure surveys;
use the limited staff and operating resources available, to develop fish farming and fisheries activities in Lesotho.
The Fisheries Section now has enough knowledge about reservoirs; it should go a step further and start introducing management. It should identify other Government agencies, local community organizations, NGOs and entrepreneurs who work with small reservoirs and inform them about the resource potential and management options.
Staff of agencies and organizations interested in small reservoir fisheries should be trained in fish production methods for application on their reservoirs.
The Fisheries Section, in collaboration with other development agencies, should prepare extension materials for use in promoting small reservoir fishery management.
Appendix 1 provides the main information gathered on the 16 selected reservoirs.
