Galaxias sp. nov. 'Goukou’ is known only from a single locality in the upper Goukou River (Chakona et al. 2013). It qualifies for the Vulnerable category under D2 because it has a very restricted range with less than five locations and there is a potential threat of invasion by invasive alien species that occur in the lower section of the Goukou River mainstem. However, more surveys are required to determine the full extent of its occurrence.
Distribution
Currently only known from a single locality in the upper Goukou River, Western Cape Province, South Africa (Chakona et al. 2013), within a single sub-quaternary catchment. The lineage could potentially occur in the forested upper reaches of the Goukou River, but more surveys are required to determine its extent of occurrence. This lineage was not recorded from the Kleinkruis River, a west bank tributary of the Goukou River. It has also not been recorded from adjacent river systems which were extensively surveyed between 2008 and 2010 (Chakona et al. 2013). Galaxias sp. nov. 'Goukou’ is therefore a narrow range endemic restricted to the Goukou River System.
Only one subpopulation is known from a deep peat stained pool in the upper Goukou River.
Threats
The species is potentially threatened by invasion of the upper Goukou by invasive alien fish species that occur in the mainstem Goukou River. Currently, the presence of the dense stand of Prionium serratum (palmiet) and reeds seem to have formed an effective barrier that has prevented invasion of invasive alien fishes into the upper Kleinkruis and upper Goukou rivers (Chakona pers. obs).
Conservation
Galaxias sp. nov. 'Goukou' occurs in a formally protected area (Spioenkops Nature Reserve). The upper catchment of the Goukou River is also in good natural condition with indigenous forest as it occurs in private land at the edge of Grootvadersbosch Nature Reserve. However, without natural physical barriers (waterfalls) to prevent invasion by invasive alien species, these systems remain potentially vulnerable despite occurring within reserves.
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