CONTENTS | ANB-BIA HOMEPAGE | WEEKLY NEWS
by Hamilton Vokhiwa, Malawi, December 1999
THEME = ECOLOGY
Environmental and ecological experts are stunned
by the mysterious deaths of thousands of fish in Lake Malawi.
People are worried that if they consume the fish which have died,
their health will be affected
Since early October 1999, a great number of different species are calculated to be dying everyday in Lake Malawi. The only survivor of the catastrophe is the Chambo (talapia) species which are known to thrive in the lake's shallow waters.
According to Malawi's fisheries officials, the cause of death is the chocking of deep-water fish due to a lack of oxygen. Fisheries Director Saibu Mapira explained that persistent south- easterly (Mwera) winds blowing on the lake for the past six months, have caused an abnormally huge amount of deep water, rich in nutrients and dissolved silica, but lacking in oxygen, to be pushed to the surface of the lake.
Southern Africa Development CommunityþGlobal Environmental Facility (SADC/GEF) project manager Alexander Bulilani, said in a statement, that the lake water has now taken on a green hue, which confirms a high concentration of nutrients from deeper waters.
"We have also noted a high percentage of poison-producing algae in water samples taken from different places at the SADC/GEF project site," said Bulilani, adding that the dead fish had damaged livers, "a sure sign of poisoning".
Lake Malawi, Africa's third largest lake, has an estimated 1,000 species of which ten are edible. Apart from the Chambo, which graces many a Malawian dining table and is much-sought-after in Malawi's top hotels and which has been spared from the current catastrophe, the victims are Sungwa (a type of perch), Ngumbo (lake yellow-fish), Mpasa (lake salmon) and its smaller relative, the Sanjika, Ntcheni( lake tiger), Kampango and Vundu (both of the catfish family) and the small Mbuna, tropical aquarium fish.
It is estimated that fish catches in Lake Malawi account for 80,000 tonnes per year. Most of the fish however, is consumed locally. Maldeco Fisheries, the largest company engaged in commercial fishing in the southern part of Lake Malawi, have over the past few years been recording low catches of fish.
Maldeco officials say fish catches started dwindling in 1993 when the company recorded a total fish catch of 1,495 metric tonnes, of which 530 tonnes was Chambo (tilapia). In 1994, the total catch was 1,916 metric tones while Chambo remained a constantly low.
Maldeco works closely with the Department of Fisheries and contributes to policy measures which aim to protect and conserve Lake Malawi's fish population. Officials say there are no records to clearly indicate the amount of fish exported to other countries, and how much foreign exchange Malawi generates, as fish is exported largely by informal traders.
"We are not able to satisfy local demand for fish. Therefore we do not export fish", a Maldeco official confirmed".
Lake Malawi contributes a major part of the country's total fish landings. Some scientific sources say the lake is heavily polluted and some chemical compounds accumulating in the lake can have life- long effects on people's health. Polychlorinated Biphynels (BCPS) and nitrates in the plankton (fish food), have been building up over the years in the lake (area: 28,760 square kilometres). Acid rain which abounds due to air pollution, is also said to be a contributor to the toxic accumulation.
Fisheries department officials say pesticides, fertilisers and other chemicals which have been used for many years along the lake's catchment area for agricultural purposes, have increased the nitrogen content in the plankton.
As the news of the fish poisoning has spread, most consumers have shunned buying fish from the markets and department stores. Fresh fish has attracted little attention from buyers even after they were assurance that the fish bought for sale, were truly fresh and had in fact been caught alive.
Fish accounts for over 70% per cent of animal protein in the country. Due to dwindling catches, the fish is getting too expensive and out of most households' reach.
A fisheries official said a similar incident occurred on Lake Malawi 10 years ago, only at that time, information about the reason for the poisoning was difficult to come by.
END
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