Tag Archive UKZN

A tagging study : movements of KwaZulu-Natal yellowfish in the upper uMngeni River.

Riverine ecosystems are affected by anthropogenic activities and environmental changes. One of the ways in which to evaluate the effect of these impacts is assessing the behaviour ecology of fish populations. Fish behaviour tells us how fish adapt to human activities (survival and recruitment) and how they improve their use of ecosystem resources. Behavioural variables include habitat selection, reproduction and reproductive strategies and migration behaviour. Information on fish behaviour can be used in conservation of fish and the aquatic ecosystems they occupy.

As part of a study on the uMngeni River we will be looking at the reproductive biology and migration behaviour of the KwaZulu-Natal yellowfish (Labeobarbus natalensis). This involves evaluating the location, timing and duration of spawning migrations of yellowfish in the uMngeni River. Thus far, 22 yellowfish have been tagged with VI tags (Figure 1) at the inlet of the uMngeni River into Midmar dam, with the intention to tag more over time. We would like to call on all anglers in the upper uMgeni River for the assistance in recording data from any tagged yellowfish they may catch as this will aid the study immensely.

We need your help ! In the event that a tagged yellowfish is caught please, at best, take note of the following and let us know:

1. The location (include site coordinates if possible)
2. The date
3. The VI tag number (e.g. D 55)
4. The standard length of the fish (mm)*
5. The weight of the fish (g)
6.Note any abnormalities (e.g. deformity, disease or injury)
7. Photo of VI tag and full body photo (see examples below)

Figure 1: Orange arrows shows : on the left, the placement of the VI tag behind the eye, and on the right the placement of the VI tag in relation to the body of the fish.

Please Contact the following people below with any information or questions:
Pumla Dlamini: pumladlamini1@gmail.com, Matthew Burnett: matthew@riversoflife.co.za and Dr. Gordon O’Bien: obrien@ukzn.ac.za

 

* Standard length :

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Tales of a 6-months internship with the AER Team by Emily Winter

Emily Winter shares some of the highlights of her six-month internship with the Aquatic Ecosystem Research Group.

Back in April, I was pleased to be met with a welcoming and enthusiastic group at UKZN, who readily introducing me to the research themes, team members and field sites. I was eager to challenge myself and quickly got stuck into some fish surgery practice with Céline and Matthew, in preparation for the FishTrack project in the uMngeni catchment. I soon overcame my fear of croc-infested waters and could be found checking nets and electro-fishing at Fountain Hill Estate in search of the Natal yellowfish. I was excited to be assisting Matthew and co in the development of their new, real-time telemetry project.

Assisting Matt in catching yellow fish in Fountainhill Estate (Wartburg)

While also assisting with the quarterly REMP (River Eco Status Monitoring Programme) surveys, my own project was developing under the watchful eyes of Gordon and Celine, and in June I joined the SAPPI team to explore the lower Thukela catchment and monitor its fish and invertebrate communities. A hypothesis was born, and I focussed my investigations on the use of the Nembe and eMandeni tributaries by fish when the Thukela river is in flux. My fish identification and surveying skills progressed rapidly with the support of Mahomed, particularly in distinguishing between the small barb (Enteromius) species, and I was proud to be able to lead similar surveys in July and August. The opportunity to survey the Thukela fishway with Gordon, David and Mphatheni was a particular highlight, with initial results suggesting that the structure does not function as a migration corridor as well as would be hoped.

Conducting REMP surveys in the Umgeni with Fortunate and Pumla.

In the final few months, I was very fortunate to be invited to contribute towards international efforts for a review paper on African fish migrations (yet to be published). The experience has been invaluable in developing my scientific critique, writing and collaboration skills and I have learnt a considerable amount about African freshwater ecology in the process. Despite returning to Europe, I am excited about continuing this trend, maintaining connections with my new South African friends and colleagues, and developing ways in which we can work together in the future. With the help of Mahomed, I will be remotely completing the ‘Tributary Refuge’ project on the Thukela and I look forward to sharing the results with the wider research community when the time comes.

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Tagging Natal Yellowfish in the uMngeni River

The tagging of Natal Yellowfish (Labeobarbus natalensis) in the uMngeni River,

Figure 1: One of the tagged Natal Yellowfish at Albert Falls dam, showing the good size and condition of fish needed for tagging.

As part of the uMngeni Fish track study headed up by the Aquatic Ecosystem Research Group a yellowfish tagging survey was organised. This is for the component of the real time remote monitoring project that is crucial in assisting AER to understanding Natal Yellowfish behaviour and establishing the remote monitoring network. Having tagged fish in the river will allow the team to assess yellowfish movements and strategically place water probes and remote stations to obtain data in real time. This is exciting to see as some of the results start to come in.
The AER team went out to Albert Falls Dam and Fountain Hill Estate to tag Natal Yellowfish. The fish were caught using gillnets and electro-shocking. Gill nets were monitored constantly to prevent injury to fish. Suitable fish were remove from the net immediately on capture and then transferred to a holding net. Electroshocking was using in shallow fast flowing rocky habitats, suitable fish caught were transferred to a holding net. In total 3 fish were acquired that were fit to be tagged.

Figure 2: Catching yellowfish using the electro-shocking method at Fountain Hill Estate, one can see the yellowfish in front of the excited researchers

Tagging procedures took place under 17 minutes for each fish. The procedure requires surgically implanting of the tag into the abdominal cavity. Two fish surgeons were scrubbed up to maintain a sterile environment while operating, the surgical equipment was sterilized beforehand in an autoclave and opened on site during the operation. Assistants helped handle the fish and non-sterile equipment while the surgeons operated. These steps were taken to create a sterile environment around the incision to prevent infection. The following steps were taken to ensure a smooth quick operation; Fish were anaesthetized using phenoxyethanol. Once signs of narcosis were shown, the fish was then moved onto the operating table and put into position. A pipe pumping water over its gills was maintain throughout the operation to minimize exposure of the fish to the air. An incision was then made in the area between the pelvic fins and anal fin into the abdominal cavity being careful not to cut too close to the anus or pelvic fins. This insertion cuts through to the abdominal cavity were the tag is the inserted. The tags aerial is set using a spinal needle and then once the tag is in place the abdomen is stitched up using suture material. Wound-gel is then applied over the wound to protect it from bacterial infection and allow the mucus layer to recover. To further assist with this anti-biotics are applied. Finally, the fish is placed into a recovery container and held there until signs of narcosis are no longer evident. The fish is then release by allowing it to swim away from the tagger.

All three fish were successfully tagged and released. The Fountain Hill yellowfish named “Drone” is already swimming around one of our remote stations and providing us with valuable data. The two Albert Falls yellowfish (named David and Fortunate) were released and picked-up within the dam later in the day. The AER team is currently setting up the remote network to be able to track them. The tagging procedure was a great success and will get better as we expand the study showing how fish can help us monitor the environment in real time.

Figure 3: Shows the release of the Natal Yellowfish after the tagging procedure, swimming freely on its own.

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