High Tech Science Aids Trout Advocacy

Fish & Game is using cutting edge science to find out more about our rivers and advocate for trout protection.

Staff use eDNA – or environmental DNA – like detectives use DNA to solve a crime.

By simply scooping up small amounts of water, new technology can identify DNA markers left behind by fish in the environment, and the team can see if fish are present in a river and if they are actively reproducing.

Senior Fish & Game officer Dr Matt Kavermann says new techniques and tools included in spawning surveys over the last four years, such as eDNA assessment, and the results these are yielding, continue to add to Fish & Game’s knowledge of trout spawning activity and populations in New Zealand waterways and the overarching protection this could provide all species in these environs.

Results indicate that the extent of trout distribution and spawning is far greater than originally thought.

“Wellington Fish & Game has been at the forefront of improving trout spawning sampling techniques and piloting eDNA assessment; this is now being used extensively across the country, including by other agencies, for determining what species are present in our rivers and streams.”

In the past, Wellington Fish & Game has had the veracity of traditional trout spawning techniques called into question by some regional council staff.

“The results of our combined eDNA, drift diving and electric fishing sampling has helped verify the accuracy and validate Fish & Game models identifying likely and confirmed trout spawning habitat,” says Kavermann.

“It has also had the added benefit of helping us identify spawning sites we didn’t know existed. This, in turn, can drive regional councils to improve the accuracy of their natural resources database.”

Most importantly, though, because there is a specific stipulation in the Resource Management Act to protect trout spawning habitat, the results of our work mean authorities have a legal requirement to safeguard these waterways and Fish & Game can advocate for that to happen.

“It’s a win not just for trout but native freshwater species too.”