Cape Town – A recent FBIP-funded endeavour has turned the tables on the conservation status of a freshwater stream fish, the Maloti minnow, thought to be extinct.

Ezemvelo KZN Wildlife Freshwater Ecologist Skhumbuzo Kubheka presented his finding to a recent Symposium of Contemporary Conservation Practise to an enthusiastic round of applause.

Scientifically known as Pseudobarbus quathlambae, the Maloti minnow was last collected 80 years ago when original collections were made in the upper uMkhomazana River in KwaZulu-Natal in 1938.

Minnows form part of the Cyprinidae family and are the largest and most diverse fish family – they feed largely on freshwater invertebrates and vegetation, thus contributing to the maintenance of ecosystem structure and related provision of ecosystem services to humans downstream.

P. quathlambae prefers small streams with a water depth of about 0.5m, and slow to moderate flowing water, with boulders and cobbles as the dominant substratum.

The species also has the fortunate status of being cited on the Unesco World Heritage List where it features as a “critically endangered” fish species only found at the Maloti-Drakensberg Park.

maloti minnow
A specimen of the Maloti minnow from the Mzimkhulu River system.

Rediscovery

Kubheka said that between the time of the original collections in 1938 and the early 1960s scientists had documented ‘extermination’ of minnow populations due to predation by trout and habitat destruction.

By 1966 scientists had all but concluded that the Maloti minnow was extinct.

According to Kubheka the impending ‘extinction’ caused doubt and consternation in freshwater science circles whereby some thought that the ‘original’ Maloti minnow were brought from Lesotho.

But one scientist, Dr Paul Skelton, a freshwater fish expert, maintained that the uMkhomazana River was the ‘type locality’ of P. quathlambae.

It followed that on the 26 April 2017 P. quathlambae was ‘rediscovered’ by Kubheka and three colleagues (Nkanyiso Ntuli, Snazo Gqola, and Nozipho Mkhabela) at the adjacent Mzimkhulu River System – a first record for this river system.

The discovery was made during a survey to map the distribution and determine the status of trout in the province.

Follow-up surveys have revealed the species in four other locations, but they are confined to a small area, which Kubheka says is ‘scary’ and highlights a conservation concern.

According to Kubheka the Mzimkhulu River find also lends weight to the theory that P. quathlambae was once widespread in and around the Drakensberg Mountains.

The rediscovery was recently published in the African Journal of Aquatic Science by the researchers who represent Ezemvelo KZN Wildlife and the NRF-SAIAB (National Research Foundation – South African Institute for Aquatic Biodiversity).

habitat
Photographs of habitats where specimens of Maloti minnow were collected in the Mzimkhulu River system

What next?

The Maloti minnow has been classified as ‘endangered’ on the International Union for Conservation of Nature (IUCN) list.

Kubheka says the rediscovery has highlighted the need for extensive surveys to:

  • determine the extent of occurrence & population size of the Maloti minnow.
  • model its habitat and consider re-introducing the species
  • determine conservation status
  • identify effective conservation strategies to ensure continued existence of the species

A 2016 study by Skelton and colleagues recommended urgent conservation action for a Lesotho lineage of P. quathlambae to prevent extinction.

The study found the the Maloti minnow population had crashed following the invasion of its habitat by the smallmouth yellowfish (Labeobarbus aeneus).

Khubeka said the threat to the Maloti minnow created obligations and responsibilities on all parties, especially the conservation authorities responsible for the area, to ensure the long-term survival of the species in South Africa.

“It will be sad if we do not do much to protect what we thought we’ve lost,” he said.

The work formed part of an FBIP grant awarded to Dr Albert Chakona of the NRF-SAIAB for biodiversity surveys in inland areas.

The FBIP is funded by the Department of Science & innovation (DSI) under the Global Change Programme, and is jointly managed by the National Research Foundation (NRF) and the South African National Biodiversity Institute (SANBI).

shares