Checking up on a dream stream

Written by Sarah Wilcox.

It looks idyllic. The beautiful Huaki Stream meanders over rocks, through kauri forest, with lush nīkau palms forming a canopy overhead. It’s shady and cool on a hot summer’s day. But what’s under the surface – is this stream as healthy as it looks?

That question was top of mind for a group of Te Roroa iwi and DOC freshwater specialists who spent a day documenting and sampling along different stretches of the stream.  

The group used many different established methods – including collecting different bugs, counting fish, sampling the environmental DNA in the water, and scrubbing rocks to measure how much algae was growing on them.

Three different species of fish were found at this site (tuna/longfin eels, redfin bully and banded kōkopu) as well as a species that’s unique to this region – and is named after it! It’s a shrimp-like crustacean called Phreatogammus waipoua.  

The data they get from this stream and others in the catchment provides the health (or condition) of the freshwater ecosystem and an opportunity to track changes in the future.

Snow Tane, general manager Te Roroa Development Group is right behind the work.   

“It’s absolutely critical. If we find that one area of the catchment is vibrant and one is in decline, we can follow up with questions like: what are the factors behind the difference, what are the mitigations, how can we put them in place and see if they are working or not?”  

He says the way they went about the data capture was refreshing. 

“I noticed that the first time the teams went out, they came back absolutely buzzing. Some local people have been working in the taiao space all their lives, so they have this affinity with it. This is a next step to learn the techniques and take over the monitoring in the future.” 

“It’s built really good capability and some succession in our people. They’ll go back to day jobs next week but are on another tier because of this opportunity – some are also young enough to do something a bit more formal from here.”  

The Huaki Stream is a tributary of the Waipoua River in Northland. It enters the river from the north, not far from Tane Mahuta, and drains a large wetland. Wetlands provide important habitat for many native species, like the ones we found here. 

Snow fondly recalls the abundance of fish in the Waipoua River in his early years.  

“When I was a young fella it was absolutely thriving. Salt water species came right up – you could catch mullet, herrings and even kahawai. Mum reported catching snapper in the river!” 

“It’s a big ask to get back to those levels. But the data is pushing us to get a handle on western science or find mātauranga-based tools and solutions – some of which may have been used in other areas.”  

Other monitoring work indicates that a weir, which is part of a concrete ford on the lower river, is preventing fish moving freely up and downstream. It’s likely to be reducing the number of fish in the upper reaches.

Snow agrees with what’s been found.  

“I’ve seen a decline in whitebait not getting up the river in the numbers they used to. Installing a fish pass on the ford has helped increase the stocks but a permanent solution, like removing the weir, would be a step in the right direction.”  

“I think having data to inform our next steps is essential. We know what needs to happen but we have to take our whānau along and build the social license. Being able to share information at the right level is key to making progress for the taiao.”  

To watch how we did the monitoring, check out this video.

This project is part of DOC’s Ngā Awa River Restoration Programme and National Monitoring Programme.

Read more about Te iwi o Te Roroa and the Waipoua River restoration work.