A rare galaxiid fish population in Central Otago will benefit from the installation of a fish barrier weir to protect its habitat in Thomsons Creek.

The barrier has been constructed in Thomsons Creek in the Manuherekia catchment southwest of Omakau township, a tributary to the Manuherikia River.

Thomsons Catchment Project manager Nicola McGrouther said the project grew from a galaxiid survey of the whole catchment in January 2021.

“The Thomsons Catchment Project’s overall goal is to increase galaxiid numbers through the use of a fish barrier, wetland riparian planting and fencing, to be followed up by fish monitoring,” she said.

The fish barrier in Thomsons Creek near Omakau. PHOTO: Thomsons Catchment Project

“Design criteria included installing the weir across Thomsons Creek, to stop fish access upstream, but also to allow floods to pass safely over the structure.

“The fish barrier will ensure that undesired species of fish, which prey on the Roundhead Galaxids, are restricted in their access to these fish populations, enabling them to thrive.”

Roundhead Galaxias are non-migratory, so they do not migrate from the waterway from where they hatched.

Thomson Creek was temporarily diverted around the weir site during construction to allow for suitable foundation material to be installed

ORC chair Gretchen Robertson said the council was thrilled to be able to get behind the Thomsons Creek project. 

“This is about environmental gains and much-needed positive community focus,” she said.

“The fish barrier will protect native fish from predation from trout and perch. Central Otago Roundhead Galaxiids are special native fish with the same conservation status as the rare South Island Kaka.”

The Ministry for the Environment co-funded the $150,000 Thomsons Catchment Project through a Jobs for Nature grant of $110,000 and an Otago Regional Council (OCR) contribution of $40,000.

An open day at the Thomsons Creek weir is planned for the future.

Read more about the project here.