The Shortjaw Kōkopu is considered a threatened species of fish in gradual decline. It is also known to be secretive and hard to find. Recent eDNA testing by Friends of Waipāhihi Karori Stream has revealed that it is one of several native fish species living in the catchment.

“For the last few years, our Friends group has been undertaking quarterly monitoring of the health of the stream at three sites in the upper catchment with the support of Mountains to Sea Wellington Trust”, says Friends Group coordinator Joanne Davidson.

“We had done some initial eDNA testing which told us both species of Tuna (shortfin eels and longfin eels), a couple of species of Bully and Kōaro were in the catchment. We also knew from earlier Greater Wellington Regional Council testing that Banded Kōkopu were there too.”

The Friends group was formed when Andrea Skews, Chairperson of Karori Residents Association saw an opportunity to get community involved in the care of the stream. “Reports on water quality were a “D" and I felt having our community involved in the care and condition of our stream would empower us to do more than just moaning about the bad news stories online" said Skews. “we are so lucky to have local leaders with the credentials they hold, volunteering to drive this group, not to mention the support of Wellington City Council, Mountains to Sea and local land owners".

Over the summer, the Friends Group undertook testing outside of their normal operating area to get a picture of what was happening in other areas. This included additional eDNA testing, undertaken with financial support from Lyon Marine Research Limited and Terawhiti Charitable Trust, to get a better sense of what species were living across the catchment.

The Group also received support from Kinnoull Station and local resident Roger Askin to access different parts of the catchment and get the most out of the investment in eDNA testing. Greater Wellington and Mountains to Sea staff also helped on the additional testing days.

“Waipāhihi Karori Stream is relatively unusual in that the urban area is in the upper part of the catchment and there is a large downstream catchment with a lot of regenerating bush. This means the Stream is most polluted in the upper catchment, whereas the more common pattern is for urban streams to become more polluted as you move downstream”, says Ms Davidson.

“Our water quality testing had indicated that the Silver Stream tributary (which runs through Long Gully Bush Reserve) was in pretty good health, and when we got the eDNA test results back from Wilderlab it was easy to see the positive impact of this for biodiversity. Several sensitive macroinvertebrate species that need good water quality were present along with five species of fish, including the Shortjaw Kōkopu”.

The more polluted areas of the catchment still support a range of biodiversity and fish species. Kaharore Bully, Common Bully and Tuna/Eels are all living in the suburban area.

“We often have Tuna visit when we are doing our testing, and we know they are well-loved by residents. Even in the Cambell/Donald Street part of the catchment, which has very few open areas remaining, the eDNA testing showed that both species of Tuna there,” says Ms Davidson.

The Friends Group hopes to secure financial support do some more eDNA investigation in the future to better understand the distribution of the Shortjaw Kōkopu across the catchment. The Group, which operates under the umbrella of Karori Residents Association, has a Memorandum of Understanding with Wellington City Council and is also progressing a restoration project in the stream area by the path between the swimming pool and RSA.

“The site of our restoration project is a particularly yucky and often smelly part of the stream. Given its accessibility to the public, we think there’s a real opportunity to show the difference we can make for te mana o te wai (the wellbeing of the water itself) through community action and care”, says Ms Davidson.

People who want to support or join the Group’s efforts can connect with them via their Facebook group at: https://www.facebook.com/groups/fowks

Notes:

• eDNA stands for “environmental DNA”. Environmental DNA is genetic material that is shed by organisms as they move in, through and around their environment.
• The Group used eDNA freshwater sampling kits and sequencing services provided by Wilderlab. More information about their services is available here: https://wilderlab.co/
• Results from the Group’s eDNA testing (and other publicly available testing results) can be viewed on the Wilderlab website here: https://wilderlab.co/explore
• The presence or lack of macroinvertebrates such as insects, worms and snails gives a biological indicator for the ecological health of a waterway, based on the sensitivity of each species to pollution.

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