Lake Tanganyika, a shining jewel nestled in the heart of Africa, stands as a testament to the delicate balance of nature.

Its crystal-clear waters, teeming with life, have captivated explorers and scientists for centuries. However, this pristine beauty faces significant threats, challenging the very existence of one of the world's most remarkable freshwater ecosystems.

Located in the western branch of the Great African Rift Valley, Lake Tanganyika is divided among four countries: Tanzania, the Democratic Republic of the Congo, Burundi, and Zambia. 

It’s one of the oldest and deepest lakes in the world, possibly dating back about 10 million years, with a maximum depth of about 1,500 meters. This unique geological history has fostered an extraordinary biodiversity, making it a critical habitat for numerous endemic species.

According to African Centre for Aquatic Research and Education, Lake Tanganyika also has one of the richest freshwater ecosystems in the world, with over 2000 species, 500 of them not found anywhere else on earth, making the lake their home.

One of the most pressing issues is overfishing. The lake's unique cichlid fish species, numbering over 250, renowned for their vibrant colors and diverse forms, are being unsustainably exploited. These cichlids, which represent a significant portion of the lake's biomass, are critical to the ecosystem's health. 

Illegal fishing practices, such as using fine-mesh nets that trap juvenile fish, are depleting populations and disrupting the delicate ecological balance. 

A 2023 study by the University of Arizona, led by PhD candidate Tumaini Kamulali, revealed a stark reality: fishing effort has increased by 300 percent, while catch rates have plummeted by 80 percent. This alarming trend indicates a severe depletion of fish stocks, threatening the livelihoods of millions who depend on the lake.

Pollution 

Agricultural activities laden with fertilizers and pesticides, soil erosion, industrial waste from burgeoning settlements and untreated sewage seep into the lake, contaminating its waters and harming aquatic life. 

This pollution not only endangers the lake's biodiversity but also threatens the livelihoods of millions who depend on it for sustenance. 

Eutrophication, the excessive nutrient enrichment of water bodies, is leading to algal blooms that deplete oxygen levels, creating dead zones and further harming aquatic life. 

Studies indicate a steady increase in nutrient loading, with nitrate and phosphate levels exceeding safe limits in several areas.

Climate change further exacerbates these challenges. Rising water temperatures, a phenomenon described as an "endless summer effect" by researchers, are altering the lake's ecosystem, affecting fish populations and disturbing nutrient balances. 

The lake's thermal stratification, a critical factor in its ecological stability, is being disrupted. Changes in rainfall patterns lead to increased erosion and sedimentation, further degrading water quality. 

Research suggests that the lake’s habitable zones for fish have shrunk as much as 38 percent since the 1940s, and between 2020 and 2024, fish production dropped nearly 20 percent. 

These changes are not only impacting fish populations but also altering the lake's overall biodiversity, affecting species that rely on stable thermal layers and oxygen levels.

Despite these challenges, hope remains. A growing movement of scientists, conservationists, and local communities is working to restore Lake Tanganyika through sustainable fishing practices, improved water management, and climate change mitigation efforts. 

Community-based initiatives are empowering local fishermen to adopt sustainable fishing methods, such as using larger mesh nets and establishing no-fishing zones to allow fish populations to recover. These efforts not only protect biodiversity but also ensure the long-term sustainability of fishing livelihoods.

Innovative technologies are being employed to improve water quality. Wastewater treatment plants are being built to reduce pollution, and reforestation projects are stabilizing soil to prevent erosion. 

These initiatives are crucial for safeguarding the lake's ecosystem and ensuring its long-term health. The use of remote sensing and GIS technologies is also aiding in monitoring water quality and identifying pollution hotspots, allowing for targeted interventions.

Recognizing these challenges, the countries bordering Lake Tanganyika have initiated collaborative conservation efforts. In February 2025, these nations launched an initiative aimed at protecting the lake's biodiversity. 

This program focuses on sustainable resource management, pollution control, and mitigating the impacts of climate change to preserve the lake for future generations. 

The Lake Tanganyika Authority, established in 2008, plays a crucial role in coordinating these efforts, promoting regional cooperation, and implementing conservation strategies.

The Tuungane programme: A holistic approach to conservation

Lukindo Hiza, the director of the Tuungane Programme, an environmental conservation and community health initiative jointly implemented by The Nature Conservancy, Pathfinder International, the Tanzanian government, and local communities, emphasizes the need for a balanced approach between livelihood and conservation. The programme promotes sustainable fishing practices for current and future generations.

Currently, Tuungane collaborates to conserve over 40,000 hectares of Lake Tanganyika, benefiting more than 100,000 fishers by integrating traditional knowledge with modern conservation techniques. 

When the programme began twelve years ago, unsustainable fishing practices, including illegal gear use and fishing in breeding sites, were rampant. A lack of regulations further exacerbated the situation.

"One of the things we did was educating communities on sustainable fishing. We helped them establish Beach Management Units (BMUs) to promote collaborative fisheries management, good governance, and the allocation of fish breeding sites," Hiza explained. 

Tuungane worked with the Tanzania Fisheries Research Institute (TAFIRI) to collect data on fishing activities, identify breeding areas, and assess catch rates. 

Hiza said the programme uses Catch per Unit (CPU) measures to monitor fishing efforts and determine necessary interventions when catches decline.

Through this initiative, communities have destroyed illegal fishing gear, designated fish breeding sites, and received patrol boats to curb illegal fishing. These efforts have led to a notable reduction in destructive fishing activities. 

"We conduct regular evaluations every five years, and the results show improved fish production," Hiza said. "These interventions are expected to increase fish numbers in the coming years."

Apart from fishing, Tuungane Programme is also involved with forest conservation, community health programmes including reproductive health and behavioural change, forestry conservation and regenerative agriculture.

Currently, through climate adaptation, programme has covered 28,000 farmers involved with regenerative agriculture through supplying them with quality seeds as they have managed to increase productivity to at least three times.

He said the organization is sensitizing on regenerative farming as an additional economic activity to supplement incomes in a time when there is a depletion of fish stocks.

These fishermen cum farmers are being taught on regenerative agriculture, which was transformed from climate smart agriculture. 

The methods they learn include proper land use, use of water shedding, uses of improved cassava, paddy and banana seeds, intercropping, curbing soil erosion and improve soil fertility to reduce soil sedimentation to the lake, which may destroy fish breeding sites.

“Apart from proper land use, we do a collaborative forest management and use initiative by connecting communities with carbon developers such as Carbon Tanzania and they are now earning incomes through carbon credit business,” he said.

‘This modal is workable and is being accepted by communities as they are currently generating up to 1bn/- annually per village from carbon credit, which has helped them to construct health centres, schools and they see the value of conserving their forests.”

Tuungane programme has also facilitated the planting of 10 million trees including cashew nuts, fruits, tree for producing woods for construction and natural trees to preserve water catchment and sources.

According to Hiza, the programme is currently covering 3.2 million hectare, but is expected to extend to cover 6.7 million hectare of land with a population of nearly 10 million people in Tanzania and Zambia’s Lake Tanganyika basin.

To be continued….