Media Release: Lost fish species released at Zealandia to help restore freshwater ecosystem; a first for NZ

Zealandia Te Māra a Tāne welcomes a new fish species to its waters – a fish that plays a unique role in the freshwater ecosystem. 

From Friday 12 May, 160 toitoi/common bully (Gobiomorphus cotidianus) will start being released at Zealandia to make the Wellington ecosanctuary their new home. This is the first time toitoi have been translocated in modern times and is likely the first freshwater fish translocation that has been done within Aotearoa New Zealand for restoration reasons. 

Toitoi are found across Aotearoa but have declined in many places. They have been completely lost to the upper reaches of the Kaiwharawhara catchment, including Zealandia.  

This project, in partnership with mana whenua, Taranaki Whānui ki te Upoko o te Ika, is part of a recent freshwater focus for Zealandia Te Māra a Tāne. The sanctuary is on a 500-year journey to create a corner of the world where New Zealand’s unique animals and plants can thrive in healthy, vibrant ecosystems—not just in the forests, but beneath the surface of the waters as well.   

“Freshwater biodiversity is in trouble across Aotearoa. Poor water quality, habitat loss and disrupted connectivity are taking their toll on our unique species and ecosystems. This is why Zealandia is currently taking action to care for freshwater in the sanctuary and beyond,” said Jo Ledington, Zealandia’s General Manager for Conservation and Restoration. 

“By bringing back toitoi we’re working towards whole ecosystem restoration. Each species within an ecosystem plays an important role and makes it a richer, healthier and more resilient place,” she continued.  

Kākahi, or freshwater mussels, were reintroduced to Zealandia in 2018. They rely on toitoi as ‘public transport’, shuttling their kids off to a different part of their freshwater home. Adult kākahi ‘sneeze’ their larvae (glochidia) into the water, which then attach onto the gills or fins of a nearby fish (preferably toitoi) to catch a ride away from their parents. Their unique relationship triggers and nourishes the larvae’s development into juvenile mussels. 

Last month, Zealandia, Taranaki Whānui ki te Upoko o te Ika, and Rōpū Tiaki (a co-management group for the Parangārahu Lakes) began the translocation process which will see the freshwater fish journey from the Parangarahu Lakes to eventually live in Roto Māhanga, Zealandia’s upper reservoir.  The fish have been in quarantine for three weeks to monitor their health as they adjust to their new environment before they are released to Zealandia’s waters. 

Toitoi collection at Lake Kohangapiripiri. Photo credit Rebecca Chrystal

Zealandia is at the headwaters of the Kaiwharawhara catchment, and this work will help create richer more interconnected ecosystems that will trickle downstream. It is a key part of the sanctuary’s 100-year beyond-the-fence partnership project, Sanctuary to Sea Kia Mouriora te Kaiwharawhara.   

Rediscovery of mātauranga Māori through research is an important part of this translocation, helping to inform the collection, monitoring and release of the fish.  

“We have focused a significant part of our research into mātauranga Māori and weaved what we have learned into the project so far.  For example, researching traditional catch methods and using the maramataka to inform our decisions. We’re all learning together,” said Zealandia’s Bicultural Engagement Lead Ranger, Terese McLeod (Taranaki Whānui, Clan McLeod). 

She continued, “It’s been special to begin resurfacing some of the mātauranga around this species. This translocation has also been an opportunity to initiate a relationship with a species that we typically haven’t had much awareness of at Te Māra a Tāne. It’s been wonderful observing people embracing learning about toitoi and getting excited.” 

The fish have come from Kohangapiripiri in the Parangarahu Lakes, where previous kākahi populations have been sourced from. These lakes are cared for by Rōpū Tiaki which is a co-management group consisting of Greater Wellington Regional Council (GWRC) and iwi, Taranaki Whānui ki Te Upoko o Te Ika - Port Nicholson Block Settlement Trust (PNBST), who Zealandia is working closely with. 

“We want to acknowledge our incredible partners Rōpū Tiaki, Taranaki Whānui, Ngāti Toa Rangatira and the Holdsworth Charitable Trust, for their support,” said Dr Danielle Shanahan, Chief Executive of Zealandia Te Māra a Tāne. 

“We are also looking to our community to help us care for this taonga now, and into the future. One day, we hope the waters of the Kaiwharawhara that flow out from Zealandia will also be safe and welcoming for these incredible fish,” added Dr Shanahan.   

“Te Rōpū Tiaki are proud to have had the opportunity to work with Zealandia on the toitoi translocation from Roto Kohangapiripiri to Roto Māhanga / Te Māra a Tāne,” said the collective.  

They continue: “These toitoi have an important role to play in improving water quality and supporting the precious kākahi already translocated to Roto Māhanga. We look forward to seeing our toitoi in their new home and watching them thrive as the ecosystem is restored.  

“We would like to acknowledge the incredible amount of work and research put in behind the scenes that made this project all the easier to support and approve. Through this project we have collectively built our knowledge and understanding of the mātauranga and other science needed to undertake such a translocation, and will use that to inform the next toitoi translocation.

“Te Rōpū Tiaki look forward to continuing to partner with Zealandia and supporting each other’s work towards restoration of both the Parangārahu Lakes and Te Māra a Tāne.” 

More information on the toitoi translocation: https://www.visitzealandia.com/Whats-On/ArtMID/1150/ArticleID/468  

Donate to Zealandia’s freshwater efforts: https://www.visitzealandia.com/Appeal  

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