Biodiversity in our rivers

by CapeNature

CapeNature ecologists Dr. Martine Jordaan and Jeanne Gouws were fortunate enough to get out into the field (or rivers in this case!) just before lockdown. And what special fish they found!

By Dr Martine Jordaan and Jeanne Gouws, CapeNature ecologists

March 2020 saw the recording of three new sites in the Tradouw mountains with intact populations of Cape kurper (Sandelia capensis) and Cape galaxias (Galaxias zebratus).  These two freshwater fish species are indigenous to the Western Cape Province. This find will present new State of Biodiversity distribution points.  A population of Breede River redfins (Pseudobarbus sp. nov. ‘Breede’) in the Grootvadersbos River, which were previously recorded in 1986, was also found to be doing well. The work was done in collaboration with the Grootvadersbos Conservancy on a project funded by the Table Mountain Fund.

Tradouw River. Site about 2km upstream of waterfall in Tradouw pass. Dr Martine Jordaan (CapeNature Ecologist Fauna), Aileen Anderson and Ricardo Januarie pulling a seine net through the pool. Aileen and Ricardo are from the Grootvadersbos Conservancy

In addition to discovering new populations, the status (relative abundance and population size structure) of these populations was recorded with the aim of including the data in the next Red List Assessment for freshwater fish.  Genetic samples and voucher specimens were collected for the national fish museum in Grahamstown and will form part of the ongoing taxonomic revision of Galaxias zebratus and Sandelia capensis.  While each of these species are currently single widespread species, there is ongoing scientific evidence for the existence of several genetically unique lineages (14 and counting for G. zebratus!) which may be described as new species in the near future.

This work highlights the important role CapeNature plays in documenting the unique biodiversity of our province.  By providing biological material to taxonomic studies our ecologists play a crucial role in contributing to the documenting of the unique biodiversity of our province. Correct and updated taxonomy is fundamental to informed conservation and feeds into conservation planning and land use decision making.

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