Scientists survey fynbos fish populations in the Overberg region. Riaan van der Walt (Fynbos Fish Trust) with spotted bass.
Image: LoveGreen Communications
Freshwater fish endemic to the Cape Fold Ecoregion in the Western Cape are on the brink of extinction.
Conservationists warn that without immediate intervention, fynbos fish—some of which have survived for over 20 million years—could disappear entirely.
The crisis is particularly severe in the Overberg, where species like the Heuningnes redfin (Pseudobarbus sp. nov. ‘Heuningnes’), Heuningnes galaxias (Galaxias sp. nov. ‘Heuningnes’),and Agulhas kurper (Sandelia sp. nov. ‘Agulhas’) are at risk.
These fish, found nowhere else in the world, are battling multiple threats, including invasive species, habitat destruction, and the impacts of climate change.
The decline of South Africa’s freshwater fish mirrors a global trend. A 2021 World Wildlife Fund(WWF) report found that freshwater biodiversity is being lost at twice the rate of forest or ocean biodiversity. Without intervention, one in four freshwater fish species could vanish forever.
The fynbos fish crisis is driven largely by human activity. “One of the biggest threats is alien invasive fish that were brought in for angling in the 1930s, particularly bass species,” said Riaanvan der Walt of the Fynbos Fish Trust.
The Nuwejaars catchment is now overrun with bluegill sunfish, Mozambique tilapia, and spotted bass—aggressive predators that hunt native fish, while common carp degrade water quality.
Water abstraction, pollution, and agricultural runoff further threaten the delicate ecosystem.
Climate change has exacerbated the crisis, with three major flooding events in the past two years destroying fish habitats and silting up smaller tributaries.
The Nuwejaars River Nature Reserve (NRNR) is leading efforts to protect these fish through the Nuwejaars Fynbos Fish Project. Funded by Fondation Segré through the International Union for the Conservation of Nature’s (IUCN) Save Our Species programme, the project aims to map fish populations and develop a long-term conservation strategy.
“In these dark, peat-stained waters, our fish have been hiding from invasive predators, but they won’t survive much longer without intervention,” said Ross Kettles, NRNR’s Operations Manager.
In 2024, the project team sampled nearly 200 sites along 41 kilometres of river. While Agulhaskurper were found in multiple locations, Heuningnes redfins were discovered at only 16 sites, while Heuningnes galaxias were recorded at 42 sites—numbers that point to a dire situation.
The project has also involved collaboration with leading scientists, including Professor Albert Chakona of the South African Institute for Aquatic Biodiversity (NRF-SAIAB), faunal ecologist Dr Martine Jordaan of CapeNature, and freshwater expert Dr Jeremy Shelton.
“Conservation is not only the mandate and responsibility of the provincial conservation agency—it is a team effort,” said Dr Jordaan. “Landowners and NGOs play a critical role in projects like the Nuwejaars Fynbos Fish Project.”
While the situation is bleak, efforts are underway to restore and protect these ancient species.
The Mohamed bin Zayed Species Conservation Fund is supporting the next phase of conservation planning in 2025, and environmental education initiatives have been launched in local schools to raise awareness.
Landowners and farmworkers are also being urged to play their part. “A starting point is to not relocate or stock non-native fish in dams, rivers or streams,” advised Kettles. “Pollution also affects these fish, so avoiding littering is crucial.”
The NRNR is restoring river systems by removing invasive alien plants—an effort that is helping rebuild habitats for fynbos fish and other wildlife.
“More than anything, we want people to know about and take pride in our region’s fynbos fish,” said Kettles. “The more we know, the better we can prevent their extinction—especially under our watch.”
IOL