Indigenous fish have lived in the rivers and streams in the Cape Fold Ecoregion for millions of years.
They’re known as fynbos fish, living hidden in these waterscapes that were once surrounded by fynbos.
The Nuwejaars Wetlands Special Management Area is no exception. Here you’ll fynbos fish species – two of which you’ll find nowhere else in the world.
However, fynbos fish face many threats.
In fact, freshwater fish species are considered some of the most threatened in the world. In the Nuwejaars Wetlands, invasive alien fish are the biggest concern. Species such as spotted bass, Mozambique tilapia and bluegill sunfish predate on the indigenous fish, in particular the juveniles. Other threats include poor water quality and a changing climate that is changing the habitat of these fish.
In the NWSMA, we needed to find out more about our indigenous fish.
Supporting the NWSMA Fynbos Fish Project
Funders Fondation Segré through IUCN Save Our Species came to the rescue – supporting the NWSMA Fynbos Fish Project. And we teamed up with key partners, including the Fynbos Fish Trust, the NRF-South African Institute for Aquatic Biodiversity (NRF-SAIAB) and CapeNature.
Three staff members were appointed in 2024: Supervisor Anja Vos, and Environmental Monitors Breyton Murtz and Janlu Nieuwoudt. And the funds allowed us to retain four internal jobs. Nets were kindly borrowed from Bionerds, while new nets were being procured. And then the team started working to map where our indigenous fish species occur, the health of these populations, the quality of the water and the threats they face.
Heuningnes redfins (Pseudobarbus. sp. nov. ‘heuningnes’)
Heuningnes redfins are listed as Endangered on the South African National Biodiversity Institute Red List. They only occur in the Heuningnes River system – in other words the Nuwejaars River and streams, Grashoek River and the Kars River. Most notable are the red fins – usually brighter in the males during breeding season. You can also see white specks on their faces during breeding season. They have two pairs of barbels near the mouth. The size varies from 28mm to 136mm in adults.
Heuningnes galaxias (Galaxias sp. nov. ‘heuningnes’)
This tiny fynbos fish only occurs in the Heuningnes River System (which includes the Nuwejaars River and wetlands) and the Ratel River System. It’s a lineage called Heuningnes galaxias (Galaxias sp. nov. ‘heuningnes’). In the past, it was believed that only Cape galaxias (Galaxias zebratus) occurred across South Africa. But work by Prof Albert Chakona from the NRF-South African Institute for Aquatic Biodiversity (NRF-SAIAB) has found several diverged lineages, of which Heuningnes galaxias is one. This threatened fynbos fish (listed as Endangered on the IUCN Red List) is threatened with extinction – and invasive fish are a major reason for this. The good news is that our fynbos fish team are finding populations of these galaxias in our rivers.
Galaxias sp. nov. ‘nebula’
A second galaxias lineage also occurs in the Nuwejaars River – the Galaxias sp. nov. ‘nebula’. There are a number of notable differences between the two, with the eye of the Galaxias sp. nov. ‘nebula’ much smaller than the Heuningnes galaxias, while the body shape is also different. This lineage is widely distributed across 17 isolated river systems from the Olifants on the west coast to the Bitou River system on the south coast. In our Nuwejaars wetlands, these two co-occur in the same streams.
Agulhas kurper (Sandelia sp. nov. ‘Agulhas’)
It’s believed that the Cape kurpers you’ll find on the Agulhas Plain are a new lineage. They’re currently known as Sandelia sp. nov. ‘Agulhas’. These are our biggest indigenous fish species – growing to more than 20cm in the Nuwejaars system. They feed on insects and other macroinvertebrates. This lineage is still listed as ‘data deficient’, and we are learning more about them through this Fynbos Fish Project.
Other indigenous fish species
Other than these four fynbos fish species, our project team has also found other indigenous freshwater fish species, including:
– Gilchristella aestuaria (Estuarine roundherring)
Observation © janlu_n on
– Pseudomyxus capensis (Freshwater mullet)
Observation © janlu_n on
– Mondactylus falciformis (Cape moony)
Observation © janlu_n on
Field assessments
Over the course of 2024, the Nuwejaars Fynbos Fish Project team has sampled 141 sites in order to attain detailed data on fish populations.
Surveys include setting and retrieving nets to capture fish at each site, collecting data on the fish caught – including the species, abundance estimates, length and tail fork of sample species, and fish health assessments. They also collect data on the habitat – including the presence of invasive alien plants, water body dimensions, water body site assessments and water quality testing.
These surveys have been taking place across 41km’s of rivers and streams in the Nuwejaars Wetlands SMA. However, the team found populations in a number of interesting tributaries, which resulted in us expanding the scope of our field surveys, to include neighbouring properties.
The value of the data
The data is fed through to partners, who are using it to feed into area-wide conservation policies, and further research. It is also being used to determine the updated Red Listing status of our fynbos fish. And project partner, the Fynbos Fish Trust is using the data to compile a conservation mitigation plan, to determine the best ways to protect the species.
Developing skills through partnerships
The Fynbos Fish Trust team underwent extensive training from key partners throughout the year. Project partner, the Fynbos Fish Trust, visited the Nuwejaars wetlands on a number of occasions to provide training. The NRF-SAIAB team, led by Prof Albert Chakona, and Dr Martine Jordaan of CapeNature also visited the NWSMA early in 2024. They hosted a two-day practical workshop to guide species identification and data-sampling methods. Water-quality training was provided by the Whale Coast Conservation in March. And in April, the team attended a detailed South African Scoring System (SASS5) workshop, hosted by the Freshwater Research Centre.
In June 2024, the team attended a practical workshop hosted by the Grootvaderbosch Conservancy. South Africa’s foremost fynbos fish experts attended this workshop, to together plan how best to protect fynbos fish species across the Cape Fold Ecoregion, where these threatened indigenous fish occur. And in September 2024, experts from the NRF-SAIAB team including Senior Curator Roger Bills, and members of the Refresh Project team (including the South African National Biodiversity Institute) visited the Nuwejaars wetlands during the Great Southern BioBlitz event, to learn more about our fynbos fish, and to provide additional training to the team.
Raising awareness of our fish
As we learn more about these fynbos fish, it’s crucial to share the information. The NWSMA is made up of 25 landowners and the community of Elim. Farm staff are also active on the NWSMA. So the Fynbos Fish Project team works with landowners, farm teams and our own staff members to showcase these secretive species hidden in the rivers and streams on their properties. This includes in-person communications, monthly newsletters, a Whatsapp campaign and attending exhibitions and expos where relevant. It also includes awareness days, where experts join us to provide skills to our staff members on important themes, including watercare. We have partnered with the Western Cape Department of Agriculture for this training.
At the same time, the team is rolling out an Environmental Education programme with children in the Overberg, to showcase these fish and the habitat in which they live. Schools that have already visited the wetlands to learn about the species over the course of the year include the Khula Learning Centre in Bredasdorp, and the Bredasdorp Primary School; and Zoetendal Academy from Agulhas. The team is visiting schools that cannot travel to the wetlands, including the Elim Primary School and the Mispah School for Learners with Special Educational Needs.
Our communications campaign includes raising awareness of the Fynbos Fish Project via the Nuwejaars platforms, including the website and social media.
Our sincere thanks to Fondation Segré through IUCN Save Our Species for the support.
This project is supported by Fondation Segré through IUCN Save Our Species. Its contents are the sole responsibility of the Nuwejaars River Nature Reserve and do not necessarily reflect the views of the IUCN or Fondation Segré.
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