Black Mudfish relocation and habitat restoration unlocks Tainui’s Hamilton housing development

At a glance...

The client

Tainui Holdings Ltd wanted to develop land for housing in the Rotokauri area of Hamilton.

The challenge

Black mudfish are a protected species with unique habitat requirements. There presence at the site created challenges for managing the effects of land development.

The results

We were able to secure resource consent by restoring habitat, relocating and monitoring the fish.


In order to develop land for housing in the Rotokauri area of northwest Hamilton, Tainui Holdings Ltd needed to secure resource consents. They approached us to conduct an Assessment of Environmental Effects as part of the application process, which uncovered a population of highly protected black mudfish in watercourses within the property. Unless these fish were appropriately protected, work could not go ahead.

The ask

Our client needed a robust Assessment of Environmental Effects (AEE) as part of their resource consent to develop land for housing. Completing the assessment involved collaborating with a number of other consultants, and determining how to protect a population of black mudfish living in drains within the site.

“In our initial AEE, we discovered that there were black mudfish in the area. We would need to offset this somehow, applying scientific theory with our working knowledge of ecology to find a great solution.”

Phil Taylor | Senior Freshwater Ecologist at Ecological Solutions

The fish were living in the drains that would need to be filled as part of the development. Work could not go ahead until a suitable plan was formed and approved by council to protect them.

Why us?

This project had been attempted by another consultancy but without success. We were asked to help based on our experience working with similarly sensitive species both in and out of the Waikato area. Our reputation for finding innovative solutions to complex ecological challenges had caught the attention of our client.


Our solution

“What began as a simple AEE became more and more complicated. In this case, the development could not go ahead without the removal of some of the drains that were inhabited by the mudfish.”

Because of this, we needed to offset the loss of habitat by moving them to another suitable habitat. Relocating black mudfish requires a careful approach. They have specific habitat needs, so the greatest care must be taken in both identifying new locations and safely transporting them.

Fortunately, an area of wetland within the site was able to be restored and black mudfish relocated.

“We needed to move all the eels out of the new mudfish habitat because they predate on black mudfish. This was another consent requirement and goes to show how complex ecology can be.”

Work was carried out to restore potential mudfish habitat within the site, to create a habitat complexity and refuge areas suited to mudfish, and control structures to reduce access by eels. We also developed a revegetation plan for the area.
This kind of restoration activity is a great way to not only minimise ecological impact of developments, but to actually add ecological value to them.

The results

The client’s resource consent was approved in a timely manner and the development was allowed to go ahead. The commercial value of the project was protected, helping to open up more land for housing while generating returns for investors.

The black mudfish were moved to a suitable, safe habitat, and we have scheduled ongoing monitoring over the next 5 years ensure that they remain protected for the long-term.

“Although we successfully completed the relocation of the black mudfish, we have been monitoring them each year since. We do this to make sure the population is thriving, and that no new threats have arisen in their new habitat. This protects the ecological integrity of the area and our client’s project for the long-term.”

One step further…

Relocation is a complex and ever-evolving scientific process. To learn more each time and improve our methods, we often monitor the relocated species for a few years. 

In the years following this project, we continue to monitor the mudfish using trapping and eDNA. By tracking their health and population size, we know how they are thriving in their new habitat. 

This work helps us to track the success of our solutions, continue protecting at-risk species, retain the resource consent for our client, and learn more about the ecology of complex flora and fauna in New Zealand.

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