Waituna Creek Restoration Project

A fish habitat restoration project in Southland’s Waituna Creek has proven it’s possible to support thriving native fish populations in an intensively farmed catchment. 

November 2022

A collaborative fish habitat restoration project in Southland’s Waituna Creek has proven that it is possible to support thriving native fish populations in waterways with poor water quality.

Three years after the Living Water-led Waituna Creek rehabilitation project began, Cawthron freshwater ecologists were delighted to see a ten-fold increase in the number of native fish present in areas of the stream where they trialled habitat restoration interventions.

Cawthron Restoration Ecology Team Leader Dr Robin Holmes says the intervention involved doing a stocktake of fish species and numbers in the Creek, before pinning logs to the Creek bed in a 100m long study reach.

“The logs provide native fish with a place to escape predators, find protection from strong currents, seek shade from harsh sun during the day, and feed and breed,” Holmes says.

“We found this an extremely effective method for increasing the overall numbers of fish in the Creek and for increasing the resilience and diversity of species present, but we also managed to attract the Giant Kōkopu back into areas of the Creek where it hadn’t been present at all prior to our project which is fantastic.” 

Cawthron freshwater ecologist Dr Simon Stewart says the success of this project demonstrates the value of breaking some of the bigger challenges facing freshwater ecosystems down into their component parts and tackling them individually, in particular, treating the issue of water quality separately from that of restoring fish habitats.

“This is a working area – an agricultural catchment and a network of waterways which are essentially drains,” Stewart says.

“We need to improve water quality, but that’s a much bigger, longer-term challenge, and it’s important not to let that hold us back from taking on other freshwater environmental challenges in the area that are easier to address.

“Lowland streams with poor water quality can often be put in the ‘too hard basket’ when in actual fact fish can actually thrive in these streams with some quite straight forward interventions. 

“Supporting them to do this is a really positive step for enhancing biodiversity and supporting local ecosystems in the Creek and in the Ramsar listed Waituna Lagoon downstream.

“We’ve been so pleased to work with Living Water – a partnership between the Department of Conservation and Fonterra – on a project like this which has involved so many partners and stakeholders in Southland, including Iwi (Te Rūnaka o Awarua, Ngāi Tahu), Te Ao Marama, Fish and Game, Environment Southland, and local landowners.”

Both Stewart and Holmes hope the study can shine a light on important lowland freshwater environments are.

“They have huge potential to support our national freshwater fish populations and we’d love to see barriers removed so that more projects like this can be greenlighted and we can start to see an improvement in the biodiversity of our creeks, streams and rivers.

Share this article