Source: NZ Department of Conservation
Date: 19 May 2026
Native migratory fish have been detected nearly 300 km inland from the Whanganui River mouth in recent research aimed at guiding restoration of the river.
The research, conducted in partnership by Ngāti Hāua Iwi Trust and the Department of Conservation, has involved surveying 16 sites through the catchment using methods including environmental DNA (eDNA) analysis.
Results showed torrentfish, an endemic freshwater fish most closely related to cod, and tuna/longfin eels were present at Waimiha in the Ongarue River, 297 km from the sea.
DOC Programme Lead Jane Taylor says finding migratory fish so far inland is a good sign for the awa.
“There’s a lot against these fish. The tiny juveniles that migrate upstream are swimming against the flow, steep climbs, waterfalls, pollution, floods, and predation; not to mention human-made barriers. The fact that any of them make it is astounding.
“Some of the fish, like eels, are great climbers, but natural waterfalls and man-made dams, fords, and culverts can block their passage. If a fish isn’t able to complete both the freshwater and saltwater parts of its lifecycle, you can imagine which way the population will go,” Jane says.
May 23 is World Fish Migration Day, a global initiative aimed at raising awareness of the importance of free-flowing rivers. This year’s theme is ‘we are river people’.
Pou Taiao Te Whiringa Kākaho Kuru Ketu says Whanganui iwi, as river people, have an inalienable interconnection with Te Awa Tupua (the Whanganui River), and its health and wellbeing.
“Through this joint effort we take another step towards fulfilling our shared responsibilities as tāngata tiaki, enhancing both the wellbeing of Te Awa Tupua and the relationships that connect people to it,” Kuru says.
The study also identified the Manganui-o-te-Ao and its tributaries as a biodiversity hotspot, with seven threatened species present, including piharau (lamprey), torrentfish, īnanga and two species of mayfly.
Jane says this information will help to build a better picture of biodiversity in the catchment and influence shared restoration efforts.
Background information
Environmental DNA (eDNA) analysis of water samples involves finding the tiny traces of DNA left behind by fish and water-dwelling creatures as well as the plants, animals, birds and insects in the surrounding land.
NATURE LOOKS DIFFERENT FROM HERE
Nature isn’t scenery. Nature is a society that we rely on for everything, every day. It’s behind our identity and our way of life.
Contact
For media enquiries contact:
Email: media@doc.govt.nz