Taieri flathead galaxias Galaxias depressiceps
The Taieri flathead galaxias (commonly referred to as Taieri flathead) is one of Otago’s unique galaxiid species. Found in tributaries of the Taieri, Waikouaiti and the Shag rivers. Classified as ‘Nationally Vulnerable’ they share the same threat status as our great spotted kiwi. Their remaining populations are typically found in shallow riffle sections of streams with gravel bottoms.
Taieri flathead special features
With its distinctly flattened head it’s no wonder Taieri flathead’s scientific name ‘Depressiceps’ directly translates to ‘pressed down head’. It has a rather snooty look about it due to its pointy nose. The colour of their bodies capture the different shades of the Taieri plains landscape – an olive grey to golden brown body with dark brown camouflage markings over their entire body. They look like they’ve been dipped in a gold dust.
Taieri flatheads are pretty cryptic and often go undetected by day, hidden amongst the gravels and cobbles. They typically grow to 100mm in length but can get up to 150mm at their largest. Don’t let their size deceive you though – these fish can live up to 8 years in age. Taieri flatheads feed on small stream invertebrates such as mayflies and stoneflies. They spawn in spring (October to November) laying tiny 2mm on the underside of rocks in riffle parts of the streams or rivers.
Habitat and threats
Taieri flathead galaxias are generally found in headwater streams small enough to step across surrounded by riparian vegetation such as grasses and tussock.
Over the last decade we have lost 25% of known galaxiid populations. These losses can be directly linked to a number of pressures. These include the introduction and spread of sports fish (trout and brook char), and changes in land use such as stock access to streams, reduction of native vegetation, land development and forest harvesting. These land use changes have been found to impact on streams and the galaxiids that live there, by increasing sedimentation, changing natural flows through water abstraction, and reducing the amount of habitat available to galaxiids to spawn.
By Lan Pham.