The Tīkapa Moana / Te Moananui-ā-Toi / Hauraki Gulf is a special place. It is a taonga of national importance—for both people and nature. She is the ‘jewel—the sparkling blue sapphire—in Auckland’s crown’. If she is well, the people are well.
But this beloved body of water, her beaches and her islands are suffering. Much has been lost and degraded. The 2023 State of our Gulf report released by the Hauraki Gulf Forum presents this clearly. Beneath her sparkling blue surface, agricultural runoff, untreated sewage and litter pose a dangerous threat to the ecosystem and to the people who live in and visit the Hauraki Gulf.
Thankfully, not all is lost, and there is progress on many fronts—particularly since the establishment of the Hauraki Gulf Marine Park 20 years ago. However, the science and evidence are clear. Without drastic and urgent action, the Gulf’s future is uncertain.
Recent events have underscored the precarious nature of the situation and the ecological tipping points we seem intent on testing. We can increase the resilience of the Gulf to the coming storm, by improving the health of the Gulf ecosystem. But we must act quickly and at scale.
There’s a surprisingly easy way to help reverse this decline—by rebuilding the Hauraki Gulf’s mussel beds. For generations, the Gulf was flush with 1,500 km2 of mussel beds and reefs that acted as nature’s own water purification system. Just one little mussel has the power to filter enough water to fill an entire bathtub in a day.
Taking a science-based and collaborative approach, TNC is working with local partners as part of the Revive Our Gulf initiative to support the long-term aspirational goal of restoring 1,000 km2 of shellfish beds and reefs in the Hauraki Gulf.
As of 2025, Revive Our Gulf has distributed more than 37 million mussels in the Hauraki Gulf / Te Moananui-ā-Toi / Tīkapa Moana to accelerate restoration efforts and enhance climate resilience.
But decades of commercial dredging and overuse had nearly wiped out the Hauraki Gulf’s mussel beds. Without the filtering power of mussel reefs, the Gulf’s waters have become murkier and more vulnerable to the effects of increasing nutrient runoff and pollution, leaving the Gulf in great danger.
Our Goals: - Protect and restore habitat - Restore 1,000km squared of shellfish beds - Engage with iwi, community groups and shellfish farmers - Stabilise the seabed - Implement restorative aquaculture practises at a scale never witnessed in the Gulf. - Increase sustainable economic opportunities.
We must address this challenge today. That’s why the Nature Conservancy (TNC) and Foundation North established New Zealand’s first-ever conservation challenge fund to help reverse the Gulf’s decline by focusing on restoring lost shellfish beds.
CEO of Foundation North to mid-2025 Peter Tynan commented: “The Nature Conservancy has used the Challenge Fund model successfully to save habitats in other corners of the world, so we are very excited by this opportunity to try a new philanthropic model and partner with them to accelerate international support for the restoration of Tīkapa Moana Te Moananui-ā-Toi the Hauraki Gulf.”
Funds raised through the Challenge Fund between 2022 to 2025 will help speed up restoration efforts and build resilience for the rapidly changing climate. Our goal is to bring back the many ecological and economic benefits shellfish once provided whilst contributing to overall restoration efforts in the Hauraki Gulf.
The Challenge Fund has now completed its work to raise NZD $2 million to unlock the matching amount pledged by Foundation North to support shellfish restoration efforts in the Gulf. The funds have supported:
- Accelerated restoration efforts at scale—More than 28 million kūtai (green-lipped mussels) have been returned to the Gulf between 2018 and 2024. This work has created large-scale experimental sites to advance restoration science and practice in Aotearoa.
- Advanced knowledge through research and innovation—The project has supported and contributed to multiple research programmes and ongoing PhD and MSc research. These studies are deepening our understanding of shellfish restoration, from ecological function, ecological barriers and practical methods for restoration.
- Grown future leaders in marine science—Four postgraduate students (two PhDs and two Masters) have successfully graduated, with several other PhD candidates currently actively researching, and one postdoctoral researcher continues to advance the field. These emerging scientists are part of the next generation of marine restoration leaders.
- Strengthened tangata whenua leadership and capacity—The project has (and continues to) directly employ and train members from partner iwi/hapū, including Ngāti Whātua Ōrākei, Ngāti Manuhiri and Ngāi Tai ki Tāmaki. Roles have ranged from technical marine work to restoration leadership, logistics and monitoring. This increased capacity has helped shift the project toward a Te Tiriti partnership model.
- Built a community of practice—we’ve invested in the conditions needed for long-term restoration: trusted partnerships, shared learning, logistical know-how and a network of passionate people working toward a healthy, thriving moana.
TNC and Foundation North envision a Gulf restored to its previous levels of abundance. The Hauraki Gulf Challenge Fund has supported taking restoration efforts to the next level and accelerating restorative aquaculture practices at a scale never before witnessed in the Gulf.
With momentum growing, TNC will hand over our role by the end of 2026—leaving the project in the capable hands of the Revive Our Gulf Trust, with the University of Auckland and iwi partners Ngāti Whātua Ōrākei, Ngāti Manuhiri Settlement Trust and Ngāi Tai Ki Tāmaki. We look forward to seeing their future progress.
TNC is committed to scalable, restorative marine practices that align with iwi priorities and global conservation goals. Drawing on our Hauraki Gulf experience and the expertise of our global colleagues, we have developed a restorative aquaculture programme to support nature-positive aquaculture throughout New Zealand. In the struggle to balance protecting our oceans with growing seafood demands, sustainable aquaculture offers an encouraging avenue for producing seafood while boosting fish stocks.
If you want to learn more about our restorative aquaculture programme, please contact adele.holmes@tnc.org.
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