PANGANI BASIN WATER BOARD

B. 6 Fisheries
Fisheries are often a vital source of animal protein to rural African communities, In 1970, the NYM fishery
supported 3,161 fishers, who landed 28,509 tonnes of fish between them. By 1983, there were 1,342
fishers, who managed to land just 2,430 tonnes of fish (Vanden Bossche and Bernacsek, 1999).
Typha and papyrus cover almost half of Lake Jipe’s surface, and has almost halted fishing activities on
the Tanzanian side of the lake (Sarmett and Kamugisha, 2002). On the Kenyan side of Lake Jipe, some
200 villagers in three villages are said to rely on the lake’s fisheries. Besides problems associated with
water weed, the siltation of the lake is also a threat to the fishery (Musyoki, 2003).
Villagers around the Kirua Swamp downstream of the NYM dam complain of fish declines due to the
regulation of water flow from the dam (Sarmett and Kamugisha, 2002).
B.7 Soils
Most of the Pangani River Basin comprises a crystalline and limestone geological series, along with patches
of lacustrine deposits. Closer to the coast, the geology is one of fluvial and estuarine deposits. Areas close
to Mt. Meru and Mt. Kilimanjaro are typically highly fertile alkaline volcanics (Geological Survey, 1960). This
combination of soils of lacustrine and volcanic origin, as well as areas of high average annual rainfall mean
that parts of the Pangani River Basin have come to be seen as the ‘breadbasket’ of Tanzania.
The principal concerns regarding the soils of the Pangani River Basin (PRB) are reduction to soil fertility,
and soil loss to erosion. Stoorvogel and Smaling (1990) estimated that arable Tanzania soils lost 27 kg
of N, 9 kg of P 2
O 2
and 21 kg of K 2
O per hectare per annum in 1983. They predicted that, by 2000, these
rates of loss would increase to 32 kg of N, 12 kg of P 2
O 2
and 25 kg of K 2
O per hectare per annum if
the nutrient losses observed in 1983 were not reversed. For nitrogen and phosphorous, these rates of
loss are equivalent to 251,448 tonnes and 115,112 tonnes per annum respectively. Losses, Stoorvogel
and Smaling claimed, were due to three factors: first, the normal harvest of the crop, through which
most nutrients are lost. Second, through the removal of crop residues. For example, when beans are
harvested in Arumeru District in the Arusha region, the whole plant is removed from the ground. Third,
through erosion, particularly as a result of cultivation of steep slopes (Kaihura et al., 2001). It should be
noted that not all agriculture within the Pangani River Basin is deleterious (Kaihura et al., 2001).
B.8 Summary of points
The resources of the Pangani River Basin (PRB) are all heavily exploited. In this section, we first briefly
summarise the important contributions that these resources make to the PRB and, in the second part,
summarise the threats to them.
PRB resources
• Forests play a crucial role in the PRB’s hydrology, serving to regulate water run off, minimise erosion,
store and purify water. In the PRB, they also make a vital contribution to global biodiversity. In the PRB’s
forests some of the world’s highest levels of species endemism and biodiversity are to be found.
• Water in the PRB is integral to the Basin’s agricultural economy, its power generation, its urban,
industrial and domestic demands and to livestock. Swamps are also common in the Basin and
play a vital role in water retention and regulation.
• The Basin contains four Protected Areas (PAs). Kilimanjaro, in particular, plays an important role
in the nation’s tourism economy, and also harbours a wide array of plant and animal species.
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