Author Archive Matthew Burnett

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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Sampling through the cold front

The team started off the River Eco-status Monitoring Program (REMP) second quarter (July-September, 2017) with the Thugela and uMngeni River catchments. The Thugela catchment team headed for central KZN and included the Mkomazana river along Sani pass. While the Umgeni team surveyed along the uMngeni River with a few sites in the Mlazi River. It so happened that a cold front swept over the province during the week of surveying creating magnificence views of KwaZulu-Natal back-dropped by the Drakensburg mountains covered in snow. The front made for some interesting weather to survey in with cold winds and temperatures.

The survey went well and even contributed to some of the genetic work the AER is doing on barbs Enteromius sp and freshwater eels, Anguilla sp.

In total 3 eels were caught, one on the Mooi River upstream from the Mooi-Thukela confluence and two on the Mlazi. All the eels were Anguilla mossambicus.  Eight E. anoplus were caught on the Mkomazana River near Sani Pass, while ever hopefull of catching the Maloti minnouw (Pseudobarbus quathlambae) there. Other barbs, E. gurneyi were caught on the Karkloof river in the Umgeni Catchment.

With over 3000km driven so far the REMP second quarter is off to a good start. We still have the southern and northern sites to do.