UC research may save the Canterbury mudfish from extinction

09 August 2018

New University of Canterbury research into the nationally critical kōwaro/Canterbury mudfish, and how they are likely to respond to increased drought intensity, offers some hope for saving the native species from extinction.

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    As a newly released Department of Conservation report shows kōwaro/Canterbury mudfish are slipping towards extinction, UC Master of Science student Christopher Meijer describes his new research as a first for kōwaro. “Particularly for identifying the risk of climate change to this unique species.” Photo credit: Angus McIntosh/University of Canterbury

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MSc student Christopher Meijer sets a trap for kōwaro. Photo credit: Angus McIntosh/University of Canterbury

New University of Canterbury research into the nationally critical kōwaro/Canterbury mudfish, and how they are likely to respond to increased drought intensity, offers some hope for saving the native species from extinction.

As a newly released Department of Conservation report shows kōwaro/Canterbury mudfish are slipping towards extinction, UC Master of Science student Christopher Meijer describes his new research as a first for kōwaro.

“Particularly for identifying the risk of climate change to this unique species,” he says.

“This study also provides evidence that the land around the waterways likely plays an important part in ongoing kōwaro persistence, and we can help them by changing the way we manage the areas next to waterways.”

Conservation Minister Eugenie Sage released the New Zealand Threat Classification System report on freshwater fish today, which shows serious concerns remain for the continued existence of the native Canterbury mudfish, which is on the brink of extinction in the Threatened – Nationally Critical category.

Under current conditions, these highly threatened mudfish are unlikely to cope with increased drought intensity associated with climate change, Chris says. However, improvement of the riparian margins will likely offset some negative effects, improving the future prospects for this unique Cantabrian fish.

“Working in the Waianiwaniwa River system, I saw a system-wide loss of most reproductive adults in populations affected by drought. Reductions in mudfish food as well as mudfish death during long periods without water likely drove these population changes.”

Riparian plants were linked with increased land-based prey entering the water, and this food source could offset some changes induced by increased drought, Chris says.

“Although willows provided food and cover, they increased pool drying, so switching to native plants that use less water will also help kōwaro.”

UC Freshwater Ecology Professor Angus McIntosh of the School of Biological Sciences, notes that there is funding available to assist farmers and other landowners in restoring areas of unproductive land, such as ponds, springs, swamps and wetlands, to create biodiversity nodes across the Canterbury Plains.

“Ultimately, restored ponds and springs may serve as homes for future dispersals by kōwaro or human-assisted translocations of this important native species,” Professor McIntosh says.

“Kōwaro have adaptations, such as gas exchange across their skin, that allow them to inhabit bodies of water which dry for short periods. This allows kōwaro to avoid predation and competition by living in waterways that other fish can’t. However, this research highlights that mudfish survival in periodically dry waterways is threatened by an increase in the frequency of drought from climate change. There is certainly a limit to what the mudfish can withstand.”

This work is aligned to research being undertaken by UC conservation geneticist Associate Professor Tammy Steeves, involving Ngāi Tūāhuriri, in which UC researchers are collecting DNA information from kōwaro in an effort to make it more resilient to future environmental change.

Professor McIntosh also led new research that found that a shrinking river is less able to support larger predatory fish, such as the highly-valued sports fish like brown trout or at-risk native fish like galaxiids and eels.

For further information please contact:

Margaret Agnew, Senior External Relations Advisor, University of Canterbury
Phone: +64 3 369 3631 | Mobile: +64 275 030 168margaret.agnew@canterbury.ac.nz
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