Eels out for count in Hikurangi catchment

Ben Herbert and Alan Halliday measure eels as part of the study.

A co-operative iwi, dairy business and scientific operation involving ladders and detours is helping eels bypass a major obstacle to survival in the Hikurangi swamp.

The biggest obstacle - which literally chewed up and spat out migrating juvenile eels, or elvers - was the Wairua Hydro Station turbine.

Several years ago Northpower had to construct slipways to let the juvenile eels bypass the turbine above the Omiru Falls.

For the past six years, the Hikurangi waterways and the future of the once vibrant freshwater fishery have been the centre of a programme involving five local hapu, collectively called Nga Kaitiaki o Nga Wai Maori, working with Niwa and other agencies.
Much of their work included moving juvenile eels upstream past the hydro station to help regrow the fishery upstream.

A new two-week research programme now aims to assess the success of that project.
"The Wairua River area is like a living laboratory for elver research so this project is going to be really useful," Niwa scientist Erica Williams said.

"The more we know about elvers the more effective we can be in helping eels or tuna to thrive, not just in this river, but others around New Zealand as well."

Dr Williams said very little work had previously been done in New Zealand on what made habitats suitable for eels.

Nga Kaitiaki O Nga Wai Maori member Allan Halliday said the hapu was pleased Niwa, DOC and Fonterra had recognised the issue iwi have long been concerned about.

"This project with Niwa combines Matauranga Maori, or Maori knowledge, and modern-day science. We're blending our two cultures and working together so we can overcome the many obstacles facing tuna on a daily basis," Mr Halliday said.

The study is part of the shared Fonterra and DOC Living Waters project.

The Hikurangi Swamp and Northern Wairoa River form one of five major dairy region catchments targeted for water quality improvement in Living Waters.