Perched atop an abyss

the world's second largest freshwater lake is in dire straits. Africa's Lake Victoria, the source of the mighty Nile river, has been beset by innumerable ecological irritants, which threaten to jeopardise the economic well being of the locals of the region. The list of problems haunting the lake - which stretches across Kenya, Uganda and Tanzania - reads like a roster of disasters and includes changes in food chain, species extinction, anoxia or oxygen depletion, algal bloom, pollution, overfishing, colonisation by the water hyacinth and various human activities.

However, it is the introduction of a fish called the Nile perch (Lates nilotica) - a voracious predator that is mostly associated with negative ecological impact, especially species extinction and interference with food chains or energy flows - in the lake's ecosystem that has had the worst impact.The perch, which can attain weights of 100 kg, was introduced in the Ugandan side of the lake in 1962-63, and has spread throughout the lake since then.
A colonial blunder The tale of the disaster unraveling in the east African lake regions has its roots in the blunders committed by the colonial experts. Initially, the ecological disaster had remained restricted as an issue of purely academic interest, to be discussed in local and international conferences. The 1962-63 introduction of the perch into Lake Victoria was seen as a major blessing and gift to the three emerging young nations of Kenya, Uganda and Tanzania. It was said to be the realisation of a desire to convert what was seen as a mainly 'less' productive indigenous fish species into a more 'productive' larger group. Known as Mbuta locally, the perch was expected to feed on the myriads of smaller fish that had evolved in Lake Victoria and serve as a cheap and abundant source of protein, not just around the lake but in distant urban centres like Nairobi, Mombasa and Dar-es-Salaam. The colonial initiators were aiming to curb malnutrition, especially protein deficiency, while boosting internal and external trade apart from turning fishing in the lake into a principal form of recreation for tourists.

However, that dream has turned into a nightmare. Experts from the Kenya Marine and Fisheries Research Institute (kemfri) say that at least 300 species of the indigenous and rare Haplochromines are extinct because of the depredations of the perch. Lake Victoria's indigenous tilapia species - the Oreochromis esculentis - has suffered the same fate; so have catfish, lungfish and certain types of prized salmon which have vanished from many sections of the lake. Fishery experts including those from Uganda's Fisheries Research Institute (firi) say that the perch is even resorting to 'cannibalism' - devouring its own kind - in some parts of the lake where other fish species are extinct.
Troubles' galore The extinction of the lake's salmon has also been hastened by modern fishing methods including the indiscriminate use of gill nets and trawlers (which have replaced the traditional fishing boats) that trap the fish going upstream to breed. Pollution of rivers along the lake, that served as breeding grounds, is yet another notable factor. Major urban centers around the lake empty their sewerage and industrial wastes into these waterways, which also collect much of the pesticides and fungicides used in the surrounding plantations of tea, coffee, cotton and sugarcane. Besides, the destruction of the lake's wetland vegetation, including the papyrus (small aquatic plant belonging to the sedge family) has also had a negative impact on the survival of fish.

The depletion of the Haplochromines has had the most devastating effect. Haplochromines' diet consists of algae and phytoplankton. Experts point out that the increasing blue-green algae bloom - the result of the decrease in Haplochromines' numbers - is robbing the lake of oxygen, leading to possibly adverse changes in the food chain. There has also been an increase in 'basic' nutrients - zooplankton, phytoplankton and detritus. A 1994 research paper by kemfri says that more dissolved oxygen is used or trapped in the increased oxidation and decomposition process by bacteria. Therefore, enormous quantities of dead fish floating in many parts of the lake are a common sight. This, experts say, is due to anoxia or reduction of oxygen within the lake waters.

The recent invasion of the lake by water hyacinth has added to the woes. The plant has swamped the Ugandan side of the lake after being washed down river Kagera from Rwanda.Uganda had been forced to seek assistance in the form of equipment from the Netherlands for removal of the water hyacinth - a project that failed miserably. The water-weed is now rapidly blocking the source of Nile near the Owen Falls, where Uganda's principal hydro-electric power plant is located.

The disaster has spread to the Tanzanian and Kenyan sides of the lake where fisherfolk are finding it difficult to reach their landing beaches. The increase in the numbers of freshwater snails that carry bilharzia parasites (flat-worm that cause intestinal disorders) is also being associated with the water hyacinth invasion.

Efforts to undo the damage and save the various fish species have been half-hearted at best. Local researchers and their counterparts from Britain and the us believe that some of the extinct species could be reintroduced in future through special breeding programmes and collaborative ventures.

Ironically, some of the development programmes themselves have served to deplete the fish species. A good example is Kenya's Lake Basin Development Authority's United Nations Development Programme supported project for the reclamation of swamps and wetlands which will be used for cultivation of rice and sugarcane. According to kemfri, this project has destroyed a major sanctuary for fish in the main lake. The draining of the swamps, which harboured smaller lakes, has reconnected them to the roaming grounds of the perch.

The micro sufferers
Four years ago, fish factories in Nairobi, Kenya, welcomed low-income women accompanied by children seeking to buy or collect the 'cheap' remnants of Nile perch that had been processed for export or local sale. The unwritten rule was that the remnants - the head, tail and bones with minimal flesh - were usually given free to the women who waited until lunch break at 1 pm. Those who did not want to wait paid nearly half-a-dollar to be allowed to carry as much remnants as possible in a 50-kg sack.

The increasing numbers of fish-eating Kenyans never paid much attention to the emerging fish processing and expor ting business because fish was, till recently, still the cheapest source of protein. Those buying a whole Nile perch paid less than half-a-dollar; fillet cost slightly less than us $1.

With the onset of 1996, things changed dramatically. The prices of fish skyrocketed four- to five-fold; a kilogram of fish fillet from the factories sells for around us $4 today, an amount which even the best-paid residents of Nairobi find difficult to dole out.

The trend is slowly spreading to other parts of the east African region. The reason is not far to find: the demand for Lake Victoria's Nile perch in Europe and the Middle East, especially Israel and Egypt, has increased by leaps and bounds. Israel alone is said to import at least us $10 million worth of the species. The Nile perch, which had been introduced to boost the nutritional and socio-economic status of the millions in the region, is ironically turning out to be a major source of poverty and exploitation in east Africa.

Refrigerated trucks and middlemen of corporate houses buy the fish at throw-away prices; fisherfolk, with no access to proper storage facilities, are forced to sell as quickly as possible. The director of kmfri, Ezekiel Okemwa, estimates that fishing activities in Lake Victoria have a commercial value of at least us $600 million annually. However, for the 35 million east Africans living around the lake region or indirectly and directly involved in the fishing business, the figure is misleading because theirs has slowly become a life of penury and misery.

However, for most observers including the fisherfolk, the unfolding ecological disaster remains the most chilling aspect of the whole issue. At least another decade's close study is imperative to understand the exact nature of this disaster. Observers are apprehensive that the resources -including a us $50 million aid from the World Bank - being marshalled to 'save' Lake Victoria, will mostly be used up in holding lengthy conferences and organising repetitive research. There are clear indications that the question of economic devastation and increased poverty among east Africans living along the shores of the lake will be down-played when only local and international experts are left to deal with the lake's ecological disaster; the need of the hour, therefore, is community participation in solving the problems that plague the Victoria.