Cameroon’s Aristide Kamla has been awarded a 2024 Whitley Award for his work to save African manatee habitat from an invasive species.

By Daniel Graham

Published: Wednesday, 01 May 2024 at 19:02 PM


Lake Ossa is one of Cameroon’s largest lakes. It’s a designated wildlife reserve and home to the secretive African manatee.

Much like the other two species of manatee – the Amazonian and West Indian – the African manatee faces threats from poaching and entanglement in fishing nets. Pollution from human activities is also a significant threat, with agricultural activities and the construction of dams contributing to nutrient enrichment in places.

Lake Ossa has been hit particularly badly, and an invasive weed called giant salvinia has spread rapidly across the wetland area.

The weed forms a thick carpet on top of the water’s surface, which prevents manatees from coming up to breathe.

Recognising the issue, Aristide Kamla, Founder and CEO of the African Marine Mammal Conservation Organization, knew he had to act. Together with his team, Kamla introduced a natural predator to Lake Ossa, the salvinia weevil. Remarkably, since its introduction, the weevil has reduced the invasive weed by more than 70 percent.

Kamla is now working to identify the source of the nutrient pollution that fuelled the outbreak, which covered half the lake’s surface in 2021.

Kamla’s pioneering work to save African manatee habitat from the invasive species has been recognised by the Whitley Fund for Nature (WFN), who have presented Kamla with a 2024 Whitley Award – an honour that recognises and celebrates grassroots conservation leaders.

Saving the African manatee

Lake Ossa is one of Cameroon’s largest lakes and a designated wildlife reserve. Credit: African Marine Mammal Conservation Organization
Aristide Kamla, Lake Ossa, Cameroon
Agricultural activities as well as the construction of dams contribute to nutrient enrichment in Lake Ossa, causing the invasive Salvinia molesta weed to spread rapidly. Credit: African Marine Mammal Conservation Organization
Aristide Kamla, Cameroon fieldwork
Giant salvinia forms a thick carpet on top of the water’s surface that prevents manatees from coming to the surface to breathe. Credit: African Marine Mammal Conservation Organization
Salvinia weevil
Kamla and his team used biological control – the salvinia weevil – to clear most of the Salvinia molesta plant species from Lake Ossa. Credit: African Marine Mammal Conservation Organization
Aristide Kamla, community fieldwork
Actively engaging the local community – inviting people to witness weevils feeding on the invasiveplants – helped inspire trust in Kamla’s work. Credit: African Marine Mammal Conservation Organization
Aristide Kamla
Aristide Kamla has become the country’s foremost specialist in manatees, addressing threats to its freshwater habitat from rapidly expanding invasive species and pollution. Credit: African Marine Mammal Conservation Organization

Kamla worked closely with the local fishers in the first study of manatees in Lake Ossa, a biodiversity hotspot which supports about 17,000 people, including more than 300 fishers.

With his Whitley Award funding, Kamla plans to continue to reduce Salvinia coverage in Lake Ossa; identify the main sources of nutrient enrichment in the lake through water quality monitoring campaigns.

His team will deploy an acoustic sensor system to detect and deter artisanal logging activities on the islands of the lake and the forest bordering it, as well as support local fishers to develop fish farming to reduce their impact on the lake and enable recovery of this freshwater ecosystem.

Find out more about Aristide Kamla and the 2024 Whitley Awards.

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