Sad news for the fish : 2016 IUCN revision of the conservation status of fishes in KZN

Sad news for the fish : 2016 IUCN revision of the conservation status of fishes in KZN

From the 19th to 23rd of September the Ezemvelo KZN Wildlife Freshwater Ecologist (Skhumbuzo Kubheka) and the leader of the Aquatic Ecosystem Research Programme (Dr. Gordon O’Brien) attended an IUCN red list assessment workshop for freshwater fishes in South and southern Africa. The workshop was attended by fisheries scientists from throughout the region representing many hundreds of years of experience from the region, including one of the “fathers” of southern African fishes; Prof. Paul Skelton.

KwaZulu-Natal has a relatively rich diversity of freshwater fishes with close to 100 species occurring in the province. Many of these fishes are endemic to the province, and many locally restricted populations of species believed to occur within the region have demonstrated to be new species restricted to KZN. In the last five years a number of new species of barbs, now classified as the genus Enteromius spp., mormyrids, cichlids, gobies and catfishes have been discovered and described or are being described.

With existing knowledge of our KZN fishes and this new species information UKZN and Ezemvelo KZN Wildlife were able to look for these fishes especially in areas where threats to the wellbeing of our aquatic ecosystems are known. Over the past three years we’ve been working in many rivers throughout the province as a part of our research with support from Ezemvelo KZN Wildlife, Umgeni Water, the Department of Water and Sanitation and the National Research Foundation. We have observed a concerning decline in the average diversity and abundance of many populations of fishes in the province. These changes have largely been associated with the change in distribution of alien fishes that predate and compete with our fishes, land-use practices, pollution and importantly, the current drought. There has been a considerable change in the availability of surface water in our rivers, dams and wetlands throughout the province with the coastal region of central and northern KZN especially threatened. Within this region, many rivers have dried out completely and remnant populations of fishes in pools and floodplain pans etc. have been removed due to pollution, habitat change and harvesting by local communities for subsistence and commercial trade. Although many of these systems normally fluctuate between a wet and dry phase with droughts periodically occurring, we have not observed such extreme conditions from 1990’s. During the drought of the 1990’s the threats to the wellbeing of the rivers were considerably less when compared to the threats to rivers today.

During the IUCN red list assessment workshop hosted by the South African National Biodiversity Institute (SANBI) held at the South African Institute of Aquatic Biodiversity (SAIAB) in Grahamstown, regional scientists and conservationists were able to review and address the conservation status of existing and new fishes in KZN. Key outcomes include the revision of a range of new fishes for the province and the listing of many species as threatened due to multiple stressors including land-use practices, water quality, flow and habitat alterations, disturbance to wildlife by many rural and urban communities, alien fishes and plants and the drought.

Noticeable outcomes include a reminder of the local extinction of the Maloti minnow from the Mkhomazana River below Sani Pass in the upper Mkomazi catchment in KZN. The historically common Redtail minnow (Enteromius gurneyi) has now been listed as a threatened species for the first time due to a lost almost half of its habitat and water quality and alien species threats. Two new freshwater dolphin fishes from the Mhlatuze River (Marcusenius caudisquamatus) and Mkuze River floodplain (Marcusenius kozi) have been discovered and immediately listed as Endangered and Data Deficient, which needs to have remaining locations verified urgently. We’re also now aware that the Chubby head minnow (Enteromius anoplus) populations are a complex of species which may need some protection when unpacked. Our local Striped robber (Brycinus lateralis) is also unique and may be listed as a protected species after we validate its remaining distribution in the floodplain region of northern KZN. Similarly, there seem to be a few new Stargazers (Amphillus spp.) in the province whose conservation status needs to be evaluated urgently. Our Bowstripe minnow (Enteromius viviparus) is also a unique species that is limited to KZN that makes this another endemic to the province. Our rare Inkomati chiselmouth from the Phongolo Catchment has been re-classified from the genus Varicorhinus to Labeobarbus nelspruitensis to complement the existing Natal scaly and Largescale yellowfish. With the establishment of many barriers to migration, such as dams and weirs, throughout the province we have seriously reduced the distribution of all four of our catchment scale migrating Anguillid eels in the province. These amazing migrators originate in the Indian Ocean, migrate into and up rivers where they can live for up to 40 years! Many of the eels we still have above many barriers may be remnants from a time before dams were built. We have a researcher in our group who will be looking into this issue over the next four years.  In consideration of the other rare fishes from the province including our snake catfish (Clarius theodorae) and coastal endemics the Blackspot climbing perch (Microctenopoma intermedium), Manyspined climbing perch (Ctenopoma multispine), Sibayi goby (Silhouettea sibayi), Natal topminnow (Aplocheilichthys myaposae), and the Killifishes (Nothobranchus spp.) we just don’t have enough information to address the conservation status of these species for now. We’ll also be turning some attention to this area with Ezemvelo KZN wildlife and looking into the current wellbeing of these species.

The take home message is that KwaZulu-Natal that had fewer than three freshwater fishes listed as threatened prior to the early 2000’s may now be tripled, with some species possibly being listed as Endangered or Critically Endangered. These fishes represent just less than a 10th of the freshwater fish diversity in the province, which now faces a real threat of extinction! All of us who live in the province need to use its water resources to obtain water for our homes and industries, we need to release wastes into them, harvest fish and swim in them, but we also need to care for them and the animals within them who also need them. You can only look after what you know so get into the game! Take your kid fishing! Go catch a Tigerfish or a yellowfish, put on some goggles and go and look for some minnows! And pick up a book about our rivers and what lives in them!

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