IntroductionGalaxias 'Pomahaka' is the name given to an undescribed yet genetically distinct galaxiid species found only in the Pomahaka River of Southern Otago.
Classified as Threatened–Nationally Vulnerable the Pomahaka galaxias shares its threat status with New Zealand’s iconic blue duck/whio.
These unique galaxias are found in streams flowing into the Pomahaka River.
Pomahaka galaxias can be found in streams with strong flows to seepages and ditches small enough to step across. This variety in habitat means that they are often found in small streams flowing through farmland and in road-side ditches where you might not expect to find them.
Pomahaka galaxias are defined by their variability. They exhibit different characteristics based on the habitat they're in.
Pomahaka galaxias can have anything from a broad flattened head to a more tapered profile and large, fleshy lips. They can be golden-brown with dark splotchy markings, pale cream-coloured or anywhere in between.
Pomahaka galaxias feed on small stream invertebrates such as mayfly and stonefly larvae.
They spawn in spring (October to November), laying tiny 2 mm eggs in stream-side vegetation or amongst stones.
The variety of habitats occupied by the Pomahaka galaxias also means that this species faces a range of threats.
Predation from introduced trout and silt-loading from riverbed disturbance are the two most common and challenging pressures for the galaxias.
Land-use change in the form of stock access to streams, reduction of native vegetation, land development and poor water quality affect the Pomahaka galaxias by increasing sedimentation, changing natural flows through water abstraction and reducing the amount of habitat available to spawn.