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ALCOM has been assisting the Fisheries Section, Ministry of Agriculture, Botswana in implementing the project “Development of small reservoir fisheries”.

During phase one, a socio-economic survey around seven smaller reservoirs showed that there is sparse hook and line fishing on those reservoirs. The survey repudiated earlier assumptions that people in eastern Botswana do not eat fish and suggested that availability and knowledge concerning how to cook fish are the main constraints preventing people from eating more fish. The survey also concluded that fishing is a part-time activity.

These findings led to the second phase with a biophysical study of eight selected reservoirs through test fishing using the Drottningholm method. A total of 15 different species were found; the CPUE was calculated both by species and by total catch for each reservoir. The catch was dominated in mass by Oreochromis andersonii in four reservoirs, by Clarias gariepinus in three and by small Barbus spp in one reservoir.

During the second phase, Semarule dam (37 ha when full) was chosen as a reference for a one-year test-fishing cycle. Five different species were found but catches were usually dominated in mass by O. andersonii. Seasonal changes could be registered. During the period October – December 1990 and September – October 1991 the catch was dominated by the small pelagic Barbus paludinosus.

These two phases brought home the fact that fish are there but the stock is unexploited because of the lack of fishing knowledge of the local population who would like more fish if it was possible. ALCOM and the Fisheries Department therefore started a third phase in 1992 which focused more on exploitation of Small Water Bodies than on assessment.

Through collaboration with the Water Development Section (WDS) in the Ministry of Agriculture (MoA), fisheries has now been included in the water development policy as an activity in multipurpose dams. The policy has been approved by the MoA Policy Committee. But the project faced problems in getting starting with the exploitation of reservoirs in communal areas. The problems were (i) legislation; it was not possible to get a clarification on who had the legal right over the use of reservoirs and (ii) the drought in Botswana during 1992, when four of the first test-fished reservoirs dried out and little water remained in the rest.

Because of these constraints, work began with the perennial bigger reservoirs under the Water Utilities Corporation (WUC) which has a legal framework for utilizing these waters. After discussions with WUC's Dam Amenity Committee, an increase of 4 up to 9 fishing licences were granted. Each license represents an average of three fishermen and the use of 15 gillnets (25 m long/net mounted) per day all year. Meetings were held on a regular basis with WUC where the fisheries agreements for the different reservoirs were amended.

A training course was held at Gaborone reservoir for fishermen representing three licenses. Catch recording forms were edited and introduced to the licensees. Collection of monthly results was initiated. Spreadsheets for recording monthly and yearly statistics were created for the Fisheries Department.

A workshop on small reservoir fisheries and management was held in Maun (December 1992). Results from ALCOM activities and a practical test-fishing exercise using the Drottningholm method were presented.

A small marketing study in 1992 showed that big-sized bream was accepted by both supermarkets and restaurants in Gaborone and Molepolole. They said they needed a reliable and regular supply of properly handled fish.

During 1992 three additional reservoirs were test-fished, and two species, not previously recorded from test-fishing, were caught. One test-fishing exercise was also repeated in the reference reservoir, Semarule dam. A comparison was made between the Drottningholm test-nets and monomesh multifilament nets. The results are described in this paper.

An inventory was prepared based on available information gathered from the WDS and WUC as well as from field visits. More than 300 small reservoirs ranging in size from 0.2 to 130 ha have been built in rural areas of southeastern and eastern Botswana for livestock use. Three bigger reservoirs, 600 – 1900 ha, have also been constructed to supply drinking water to the main urban centres. The total estimated surface is 1390 ha for the 314 listed smaller reservoirs plus 4255 ha under WUC. WDS has indicated that perhaps as many as 50% of the smaller reservoirs (under 10ha) do not hold water any longer because of siltation and old age.

This paper also discusses the choice of different management strategies and makes suggestions for some selected reservoirs.