Category Archive Fish

Our aquarium facilities

The Aquatic Ecosystem Research (AER) Aquarium is located at University of KwaZulu-Natal, Pietermaritzburg campus. The main purpose of building this facility is for fisheries scientists to conduct research on behalf of the department. Research to be conducted includes culture of Mozambique Tilapia, Oreochromis mossambicus, which will be used as feed for crocodile culture project, which aims to evaluate the suitability of fish as crocodile feed. Cultured Tilapia will also be used for a study that focus on evaluating the suitability of crocodile carcass as protein source for fish culture. some of the tanks will be used to culture O. mossambicus populations sampled from different rivers around KwaZulu-Natal to select suitable population for conservation of the species for Aquaculture purposes. O. mossambicus broodstock will be collected from Unizulu and culture experiment will be initiated.


Culture of Yellowfish will also be conducted in the aquarium to carry out a tag retention study on the KwZulu-Natal yellowfish, Labeobarbus natalensis. Comparing different tagging techniques and the use of external versus internal tags within a tropical terms of the aquarium progress, currently tanks, pipes and filters has been installed and the system is running very well and is in good condition for fish culture.

The following colleagues are acknowledged for operating the aquarium in success; Dr Gordon O’Brien, Matthew Burnett, Fortunate Mahlatse Mashaphu and Rendani Luthada-Raswiswi.

INVITATION – Dialogue to celebrate the World Fisheries Day and workshop on SA Fish Swimway Programme

We are pleased to announce that the SA Fish Swimway Programme will be hosting a workshop on the 21st of November 2016 in Pretoria. The University of KwaZulu Natal, together with WRC and SA Fish Swimway Programme Partners, will be hosting an event to celebrate World Fisheries Day. This will include presentations by fish specialists, followed by discussions reviewing the Swimway programme and refining the next steps. One of the speakers will be Mathew Ross, who in 2015 completed his PhD on fishway design in South Africa.  Representatives from the Kingfisher Project have also been invited, to talk about the current plans for Catchment Management Agencies in South Africa. During the workshop, we would like to specifically refine a suitable proposal that can be used for funding applications relating to fish migration in South Africa. We hope you will be able to attend ! 

Interested ? Please RSVP


The Hunt for Rare Fish

During the week of the 10th – 14th October several members of our research group, Dr. Gordon O’Brien, Mahomed Desai, Céline Hanzen and Lungelo Madiya, who were accompanied by Ezemvelo KZN Wildlife Aquatic Ecologist, Skhumbuzo Khubheka, went on a survey to locate some of our rarer fish species in Northern KZN. The area falls within the uSuthu-Mhlathuze Water Management Area and includes South Africa’s first World Heritage Site, the iSimangaliso Wetland Park as well as the Maputaland Centre of Endemism. Apart from its ecological importance, the area is also utilised for an array of socio-economic activities.

This was a preliminary survey and was meant to confirm the presence of our target species in certain systems and to collect DNA samples. Further surveys will be more undertaken that will be more protracted to allow for effective and relatively comprehensive sampling at sites.

From left - Skhumbuzo Khubekha, Dr. Gordon O'Brien, Mahomed Desai, Lungelo Madiya and Céline Hanzen

From left – Skhumbuzo Khubekha, Dr. Gordon O’Brien, Mahomed Desai, Lungelo Madiya and Céline Hanzen

The first day was just set aside for travelling and brain-storming to identify possible sites where the species could be located. Our base was Hluhluwe-iMfolozi National Park.



While the landscape is scenic and the large mammals attract many visitors , it is important to highlight and make the public aware that it is the smaller organisms that create a functioning ecosystem (such as the dung beetles pictured above). Whilst driving up from Durban we noticed that the area had received some rainfall which provided some respite from the drought that we are currently facing.

The first site was located on the southern end of Muzi Pan on the floodplain of the Mkuze River. Prior to sampling for fish we collected in situ water chemistry. With regards to this survey, fish were sampled using an electrofisher and seine nets. Thereafter, biotope details were recorded including depth, velocity, substrate and cover features.

Mahomed calibrating the water meters


Lungelo and Skumbuzo ready for sampling !





Brycinus lateralis

While the site yielded a relatively high diversity and abundance of species, none of our target species was recorded while going through the samples, until success; a single individual of a Brycinus lateralis was found! It is concerning that only a single individual was collected as unlike the other widespread Brycinus species in South Africa, B. lateralis is restricted to the Lake St. Lucia catchment.


The day we arrived, the Hluhluwe River in the reserve had reasonable flows compared to when we sampled there in September, when it was just a series of pools. Therefore, we decided to sample the river on the second day but outside of the park. However, when we arrived at our pre-selected site from Google Earth it was just a pool. Another success! We collected a few specimens of Micropanchax myaposae


Pool on the Hluhluwe river



Micropanchax myaposae (female)


Micropanchax myaposae (male)








We were somewhat surprised at collecting a resaonable diversity of species at the site given that trucks were abstracting downstream as well as the presence of relatively large quantities of solid waste.


Water abstraction on the Hluhluwe river

Furthermore, we wondered as to why the Hluhluwe river was flowing in the park but not where we had sampled. Then while looking at satellite imagery we identified a dam on the Hluhluwe River. The dam level was relatively low and consequently, there would need to be relatively high levels of precipation upstream in the catchment to fill the dam and to ensure adeqaute flows downstream.




On day three the weather turned for the worse but we nevertheless sampled. The selected site was a swamp forest stream in suburbia in Richards Bay, a predominantly industry based town.

The site was dominated by Barringtonia racemosa, a protected tree, and possessed specimens of Voacanga thouarsii whilst the understorey was dominated by ferns. It was in this stream that we recorded 7 Clarias theodorae, another rare species that we were hoping to collect. Unfortunately, the stream is negatively impacted as surface runoff from nearby hardened surfaces drain into it and noticeable quantities of solid waste were present in certain sections. In addition, stormwater drains were present adjacent to the stream and if these are blocked with solid waste and spill, the water quality will deteriorate.
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Clarias theodorae

Clarias theodorae

Unfortunately we were not able to find some of the other species that we were searching for. Although we did collect the aforementioned species that we were targeting, they were never present in relatively high  abundances. There were several other sites that we had sampled but we did not collect any of our target species. Were they not present at these sites? or are they so cryptic that we could not collect them? Do they have particular habitat requirements? These are some of the questions that need answering.

We did notice that all of the sites that we sampled were negatively impacted by anthropegenic influences. If unsustanibaly utilised and/or mismanaged we could lose our natural heritage and their associated ecosystem goods and services, upon which society itself relies.

River Health Programme : Surveys in Northern KZN

While the fieldwork and draft report has been completed for the November 2014 to March 2016 increment of the River Health Programme, another round of sampling has been completed in September/October 2016. Specimens were collected, identified, DNA samples collected and biotope features where each species was collected was recorded.


The W Primary Catchment – From the Umhlathuze to the uSuthu

The W Primary catchment is located in Northern KZN and spans from the Umhlathuze to the uSuthu River. A total of 17 sites are located in this area, with many being ecologically important due to presence of a relatively high level of freshwater biodiversity and species endemism for the province.

The area is not only important for freshwater biodiversity but terrestrial biodiversity as well.


Many of the systems within the area were completely dry or not flowing due to the intense drought the country is presently experiencing.

However, some of the sites that retained pools were identified as important refuge areas for several species of fish as well as Odonates.

Key examples of this include a site on the Nwaku River that comprised of a series of pools where a total of 304 individuals from 6 species were recorded. Species recorded included Pseudocrenilabrus philander as well as the recently red-listed Enteromius gurneyi. 


(c) christian Fry


Another important example was the site located on the Sikwebezi River. At this site the local landowner was fortunately supplying the system with surface water from his storage dam otherwise the site would have been completely dry.


Thanks to his efforts in maintaining water in the system, a total of 167 individual fish were recorded, including juveniles of migratory species such as Labeo molybdinus and Labeobarbus natalensis.

Although some systems were possessed no flows, some of the larger systems were flowing and were identified as important areas for fish populations. Unfortunately, due to time constraints these sites were not sampled as comprehensively as warranted and the intention is to re-visit these sites to obtain a better understanding of the fish populations they possess. This included the sites on the Umhlathuze River as well as sites located within the Phongolo catchment. Below are some of the species that were recorded for these sites.


Unfortunately, many of the sites within the area were negatively impacted from anthropogenic activities and influences such as industry, illegal sand-mining, solid waste and over-grazing.



Considering that society needs the ecosystem goods and services that freshwater ecosystems supply, it is critical that we effectively and sustainably manage the way we use our natural resources to ensure an optimum balance between protection and use. Education is also important if we are to ensure the protection of these vital ecosystems for the benefit of all.


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!