Q&A: WWF’s six-point plan to save native fish

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Africa is home to over 3,281 freshwater fish species, yet one in four are now threatened with extinction, according to a new WWF report. In an exclusive interview with Conservation Rising, Eric Oyare, WWF Africa Freshwater Lead, explains the disappearance of these species is largely as a result of almost 300 freshwater-related invasive species.

• “When fish disappear, we lose much more than biodiversity. We lose nutrition, income, and cultural identity. Species like Nile perch or water hyacinth have overwhelmed native fish, destabilising entire ecosystems,” says Oyare.

• As Africa prepares for the Ramsar COP15 conference, Mr. Oyare urges governments to adopt World Wildlife Fund’s emergency recovery plan, a six-point roadmap to restore river flows, control invasive species and revive critical freshwater habitats for the millions who depend on them.

More details

Why does the just released 'Africa’s Forgotten Fishes' report by the World Wildlife Fund (WWF) matter now?

The report is important because, as a continent, we are facing many challenges in the freshwater sector. Freshwater or inland fisheries contribute significantly to community livelihoods, our economy and food and nutrition security. If you walk into an African home, especially around lake regions or river basins, over 70% of the meals are fish-based. So the economic and cultural value of fish is huge. What this report is asking is: have we forgotten our cultural relationship with key freshwater biodiversity and fisheries that support our food and livelihoods? We are asking: in the 70s and 80s, were there fish that were common in our culture but are now missing? For example, in the Luo community, fish like Kamongo, the African Lungfish (Protopterus aethiopicus) were common, but now you hardly see them. The report reveals which freshwater fishes are endangered or near extinction, and why, from invasive species, pollution, encroachment to blocked or disconnected rivers that disrupt fish migration and breeding or spawning.

Has it taken too long to act on the loss of freshwater species?

No, science has always shown we are losing biodiversity. According to WWF’s Living Planet Report released in 2024, we’ve lost 87% of our freshwater biodiversity over the last 50 years. That’s a huge decline. This hasn’t happened suddenly. Climate change, riverbank encroachment , pollution and dams have contributed. For example, car washing in Kisumu or damming of rivers like the Seven Forks along the Tana River have visibly reduced fish populations. So, no, it’s not that we didn’t know. The data has been there. The problem is we haven’t taken a keen interest to value our fisheries, realise the negative impacts of the decline and respond/act collectively. The effort has been fragmented. That’s what the freshwater biodiversity emergency recovery plan, in this report is calling for: joint action to reduce extinction drivers and restore ecosystems.

The report highlights invasive species as a major threat. What exactly are invasive species, and how do they affect freshwater fish?

We’ve identified over 286 freshwater-related invasive species across Africa. These are species not native to the ecosystem. For example, the Nile perch was introduced from South America to address declining stocks of native fishes and boost production. But it has predated on and cannibalised native species and disrupted lake ecosystems.

Now, most Lake Victoria catch is Nile perch, but it was not originally there. It feeds on smaller fish and dominates the system, that’s what makes it invasive. The same applies to some tilapia species and even to water hyacinth, which blocks oxygen and kills other aquatic life. In total, we’ve tracked over 286 freshwater-related invasive species across Africa, not just fish, but also plant species like Salvinia molesta found in Zambia, which spreads rapidly and suffocates entire freshwater bodies it infests. In Kenya, we’ve seen how water hyacinth (Eichhornia crassipes), though a plant, is a major aquatic invasive species. It was introduced into lakes and blocks oxygen circulation, suffocating fish and other aquatic life. This interference with natural balance is what defines a species as invasive.

How do you identify and monitor these invasive species?

We use a few approaches. One is taxonomic surveys, where scientists directly observe species through photography, community interviews, diving and camera footage. The second is a powerful tool called eDNA, environmental DNA. Like DNA testing in humans or animals, eDNA collects samples from the environment (such as water bodies), which are then analysed in labs to identify what species are present, native, non-native and invasive. We applied eDNA in five sites: River Limpopo (Mozambique), Lake Kyoga (Uganda), Mara River (Kenya), Mara Wetlands (Tanzania) and the Congo River (DRC). The eDNA approach lets us trace which species are native and which are non-native, and among the non-native, which are invasive. That level of scientific profiling is crucial for mapping threats across freshwater ecosystems.

We worked in partnership with national fisheries research bodies in each country. Kenya Marine and Fisheries Research Institute (KMFRI) in Kenya, National Fisheries Resources Research Institute (NaFIRRI) in Uganda, and the Tanzania Fisheries Research Institute (TAFIRI) in Tanzania and equivalent bodies in Mozambique and DRC. Their labs, tools, and scientific expertise helped us test biological control options safely, ensuring we don’t introduce solutions (like weevils or pesticides) that could cause further harm. For example, in Lake Victoria, water hyacinth has reduced due to joint biological and manual removal efforts involving government, donors and local communities and fishers.

How can we ensure effective control of invasive species across countries?

We need stronger transboundary collaboration and harmonised cross-border action. Even when frameworks exist, like the Lake Victoria Basin Commission, we still face weak implementation. For example, Uganda has made major progress reducing water hyacinth, but Kenya and Tanzania lag behind. Without a joint response, it keeps spreading. Similarly, in the Ruvuma River between Tanzania and Mozambique, unregulated artisanal mining in northern Mozambique is causing pollution downstream. These are regional problems, but action remains national and fragmented. WWF is working to develop transboundary programmes that look at rivers from source to mouth, with coordinated interventions to protect catchments. That’s how we ensure sustainable use and conservation across borders.

Are there major political or financial barriers to implementing transboundary fresh water conservation plans?

Yes. A major issue is the commodification of water. Countries at the river source prioritise their own interests, like building dams for energy without considering downstream impacts. For example, Ethiopia’s Omo River feeds Lake Turkana in Kenya. But upstream dams are reducing water flow, affecting ecosystems and livelihoods downstream. Yet Ethiopia sees the river as a national resource. Another case is the Nile. Countries upstream must protect it to ensure Egypt survives. That’s why a catchment-wide conservation approach is vital. If Tanzania’s rivers feed Kenyan ecosystems, we must work with Tanzanian communities to conserve the source because what happens upstream determines what happens downstream. Rivers don’t follow political borders. Many that feed Amboseli National Park, Athi River and Nairobi, like the Kimana, Rombo and Sabor, rise in Tanzania’s Kilimanjaro region. If deforestation or pollution damages those sources, biodiversity in Kenya’s savannahs, rural and urban water systems suffers. Transboundary conservation must become real, not just policy.

What is the WWF calling for next in this report?

We want to make this report actionable by implementing the six-point emergency recovery plan for freshwater biodiversity. They include letting rivers flow more naturally, improving water quality, protecting and restoring critical habitats and species, ensuring the sustainable use of freshwater resources, preventing and controlling invasive species and removing obsolete river barriers and dams. We hope our partners, governments and communities will join us in putting this into practice to secure Africa’s freshwater ecosystems for future generations.