In November 2014, SOS grantee Endangered Wildlife Trust (EWT) completed the second ever translocation of a highly threatened indigenous fish species for conservation purposes in South Africa.
This translocation intervention is a significant milestone identified in the Sandfish Biodiversity Management Plan which was recently gazetted for public comment by the Department of Environmental Affairs in South Africa.
According to EWT’s Alwyn Lubbe the Cape Critical Rivers (CCR) team successfully translocated 338 juvenile Sandfish from the lower reaches of the Biedouw river, where they were not likely to survive, to a pristine stretch higher up in the river. “Here these juveniles will be able to mature without the risk of predation by other fish” he explains.
The story began in October 2013 when the CCR team undertook a two week survey of the Doring River, a of which the Biedouw is a tributary. A key finding from this survey was the high number in the Biedouw of juvenile Endangered Clanwilliam Sandfish (Labeo seeberi) – a species previously not known to spawn in that system.
Unfortunately, observations suggested that there was no recruitment from these juveniles as they are heavily preyed upon by alien invasive fish species in the Biedouw and Doring main stem, and are also at risk of dying when the pools in the Biedouw dry up during the summer months.
Following a subsequent Cape Critical Rivers Steering Committee meeting it was reasoned that the management of a key habitat for the recruitment of the species might prove to be critical for its survival. It remains to date the only documented spawning site for the species outside the Oorlogskloof Nature Reserve.
At this meeting, the partners representing the CCR team (Endangered Wildlife Trust, Department of Environment and Nature Conservation, CapeNature and the Freshwater Research Centre), decided unanimously that the Biedouw could be the new refuge for the Sandfish.
The long-term goal established was to rehabilitate the Biedouw River by removing alien fish and plants and reduce the over-abstraction of water during the summer months by local farmers. This would provide suitable habitat for spawning and young Sandfish and thereby improve Sandfish survival prospects.
The short-term goal was to translocate juvenile Sandfish from the lower stretches of the Biedouw River - where pools dry up during summer and the fish live in great danger from predation alien fish species - to the upper reaches of the river, where there are permanent pools and no alien fish predators.
Before the translocation effort, the team went through a rigorous, peer-reviewed risk assessment of the proposed intervention using the framework of the IUCN Translocation Guidelines to ensure all elements of the translocation maximized conservation benefits, minimized risk and ensured the ethical welfare of the translocated individuals.
“Considering that during the Doring River system survey in 2013, the team sampled just 45 adult Sandfish in the entire survey, this translocation of 338 individuals represents a significant improvement in the likelihood of increasing the abundance and genetic variation of mature adult Sandfish in the Doring mainstem and in turn will facilitating their ongoing spawning in tributaries”, Alwyn adds.
In all, the translocation was a huge success. It was a great example of the potential for collaboration between government and private nature conservation organizations.
“What is more, I know the team is really looking forward to returning to the Biedouw next year. We just might see a viable Sandfish population in its upper reaches yet”.
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