Nursing Lake Victoria back to health | Global Ideas | DW | 02.10.2012
  1. Inhalt
  2. Navigation
  3. Weitere Inhalte
  4. Metanavigation
  5. Suche
  6. Choose from 30 Languages

Global Ideas

Nursing Lake Victoria back to health

An Oscar-nominated documentary in 2004 showed how the controversial introduction of Nile Perch to Lake Victoria ravaged its ecosystem. Global Ideas talked to an African scientist about how the lake has developed since.

Fishing Boats at Ggaba Landing Site, Lake Victoria Lizenz: +++ sarahemcc +++

Uganda, one of the nations bordering Lake Victoria, has a big fishing industry

The 2004 documentary “Darwin's Nightmare” looked at the environmental and social effects of the fishing industry around Lake Victoria in Kenya. Although it was nominated for the 2006 Academy Awards, it provoked a hostile reaction from many in Tanzania, who maintained it damaged the country's image.

Yunus D. Mgaya from the Faculty of Aquatic Sciences and Technology at the University of Dar es Salaam talked to Global Ideas about reactions to the film and the state of Lake Victoria today.

Between 1996 and 2005, Mgaya worked on a study of aquatic resources in Lake Victoria under the aegis of the Lake Victoria Environmental Management Project. Today he serves as an adviser to the Environmental Association of Tanzania and is a member of the Wildlife Conservation Society of Tanzania.

Global Ideas: Mr. Mgaya, the documentary "Darwin‘s Nightmare" was released in 2004. It received both praise and criticism. What did you think of it?

Yunus D. Mgaya

Yunus Mgaya from the University of Dar es Salaam

Yunus D. Mgaya: When I saw it for the first time I thought that it had some facts but combined with a lot of errors. It was a bit dramatized and we all thought it did not do justice to the situation in the Lake Victoria basin. For example, the way the socio-economic issues were portrayed: the filmmakers got just one side of the story. They did not bother to get the whole story and to project the truth to the public. We thought it was a waste of an opportunity.

What do you think was missing?

On the socio-economic side of things, all the positives were not projected. All we saw were prostitutes being exploited, children picking through leftovers from the fish processing plants. That‘s all they showed. And of course, the connection with the illegal arms dealing which Tanzania has nothing to do with. So to leave out all the positives was not fair.

And ecologically, a lot has happened. For example, as we speak there is a resurgence, a normalization taking place in the trophic dynamics of Lake Victora. We are now beginning to see what the lake looked like before the Nile perch boom of the 1980s and 1990s. Things have changed and are changing. But none of that was in the film.

The Nile perch wasn’t the only problem that caused the extinction of many species in the lake. Over-population around the lake and logging were also factors.

When Nile perch became the dominant species in the lake, that correlated very well with the disappearance of over 200 species. So clearly one was justified to point a finger to Nile perch dominance in the lake as a reason for the decline of biodiversity in the rest of the lake.

When you look at what has happened in the lake in the 1960s, 70s and 80s in terms of the environment and the quality of its water, clearly you can see a decline. Changes in the concentration of nutrients, nitrates and phosphates led to a shift in the food chain dynamics in the lake. You had certain species of algae dominating, out-competing species which were a favorite food for some species of fish. And when you have a dominant species of algae which is not favored as food for the fish you can guess what will happen to the species that depends on that particular food item in the lake. The deterioration of water quality, which led to a shift in the balance of species - some of which were food for the fish – led to the decline in biodiversity.

A scene from the film Darwin's Nightmare

A scene from the film "Darwin's Nightmare" shows people rummaging in fish remains

But what caused the decline in water quality? Look at what is happening in the Lake Victoria basin; look at the growth in population over the years. This was not matched by growth in infrastructure for managing and handling wastewater. It was not matched by adequate natural resource management, such as forest-management, in the Lake Victoria basin. There was a lot of pressure on forestry resources by the increase in population. We also saw agricultural practices that were not environmentally-friendly. Erosion was not probably controlled. All the industries in the major towns around the lake were emptying their waste into the lake. So the proper balance of the ecosystem of the lake could no longer be maintained.

What is the situation now?

In the early 1990s the countries in the region - Kenya, Tanzania and Uganda - which have a share of the lake, came together and decided to intervene. In 1996, the three governments submitted the Lake Victoria Environmental Management Project for approval to the World Bank. The first phase of implementation began in 1997 and lasted until 2005. Lots of work was done. Interventions were made at various levels, all the way from the grassroots, community level to the national government in the fisheries and forestry land use sector.

There were also interventions in the way the municipal management of wastewater. That led to positive change in the lake and it became a lot cleaner. After eight years of the project, the lake’s ecosystem had returned to normal. The condition of the lake is improving but a lot still needs to be done. The local population in the Lake Basin is still very poor and the lake’s environmental problems are partly a result of people not having many choices.

Until these poverty driven issues are looked into, we may not see rapid improvement of the quality of the lake water and its ecosystem. So I was surprised that the film ignored the good attributes that resulted from implementation of this project, despite its huge impact.

Many of the problems in the film had existed in Tanzania long before the film was screened. But do you think the film has managed to raise awareness of the situation?

After the film there were responses from the government. It produced a documentary to counter “Darwin‘s Nightmare.” There have also been projects put together by universities working with fisheries research institutes to study the ecology of Lake Victoria. Some results have started to come out. I would say the film did generate a lot of publicity, some of which was negative, but some good things came out of it. It put Lake Victoria on the global agenda. People wanted to come and see for themselves whether what was in the movie really existed on the ground. So in a way the negative publicity brought about intervention.

There was a big threat to the Nile perch business as a result of the movie. You could say, well, Nile perch in Lake Victoria is being overfished, so anything you can do to dampen the business is good for the ecosystem of the lake. But people who see fishery as an economic asset would certainly not be amused.

According to the Lake Victoria Environmental Management Program, many species in the lake will be extinct in 30 years’ time.

That was a prediction based on a no-change scenario, i.e. if we don‘t intervene in controlling water quality and effluents from the factories and major towns on the lake; if we reverse or stop these practices, and pollution of the lake continues. Then we would see a disappearance of a lot more species.

Is Nile Perch still the dominant species in Lake Victoria or might it also face extinction?

A Nile Perch fish

The Nile Perch from Lake Victoria can weigh up to 200 kilograms

The Nile perch is a top predator. It is still the dominant species in terms of biomass. But the quality of that biomass has changed. In the 1990s, the biomass comprised very large-sized fish that weighed up to 200-250 kilograms. These days, they weigh more like 15-20 kilograms. So there has been a decline in the size of Nile perch, which is a sign of over-exploitation. If nothing is done in terms of management of fisheries, things will look very different in the next 30 years. Nile perch won‘t be extinct but the fish might well be very small and therefore economically unviable. Biologically, Nile perch will still be there, but not commercially.

Would it better if the Nile perch died out?

People often say: why don’t we just remove the fish from the lake since it has caused so much mayhem, why don‘t we return the lake to what it was prior to the introduction of the species in the 1950s? Ecologically, it is a nightmare! But looked at in the context of the socioeconomic situation, that is a crazy proposition. Nile perch has brought many economic benefits to people surrounding the lake. But what we need to do is manage the fisheries properly.

Interview: Johanna Treblin /jp
Editor: Sonia Phalnikar