While a visit to 艑hiwa Harbour might first be about picturesque views and the rich cultural history, beneath the surface, something remarkable is happening 鈥� its mussel beds are making a comeback.
After years of decline, a m膩tauranga-led restoration project from Te R奴nanga o Ng膩ti Awa, with support from 糖心Vlog marine scientist and her team, is proving how the combination of traditional knowledge and marine science can turn the tide for marine ecosystems.
The mussel bed at 艑hiwa Harbour in April 2024
Back in 2019, there were only 80,000 kuku (green-lipped mussels) across the entire harbour, struggling against an overwhelming population of p膩tangaroa (11-armed seastars) that had been consuming them at an unsustainable rate. Fast-forward to December 2024, and the results are impressive. There are now 45 million mussels thriving across 11 hectares of the harbour floor.
鈥淚t鈥檚 an incredible milestone. What we鈥檙e seeing is not just a return of mussels but the re-establishment of a healthy, functioning marine ecosystem,鈥� says Professor Paul-Burke.
Professor Kura Paul-Burke
The project has been a step-by-step journey, carefully managed through the removal of p膩tangaroa, hands-on restorative efforts, and ongoing monitoring.
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2019 鈥� 80,000 mussels across the harbour
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2020 鈥� 470,000 mussels following the first seastar removal trials
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2021 鈥� 800,000 mussels after further restoration efforts
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2023 鈥� 16 million mussels identified on the seafloor
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2024 鈥� 45 million mussels covering an 11-hectare area
With an increasing number of adult mussels now present, Professor Paul-Burke鈥檚 monitoring shows the beds are becoming more resilient, capable of regenerating naturally and helping to stabilise sediment, improve water quality, and provide a habitat for marine life.
For Te R奴nanga o Ng膩ti Awa, the project is about more than just numbers; it鈥檚 about restoring a vital taonga species and ensuring the harbour remains a thriving mahinga kai (food basket) for future generations.
鈥淭his is exactly what we have been working towards. Seeing the mussel beds regenerate like this is a huge win for Ng膩ti Awa and the wider community,鈥� says Charlie Bluett, Customary Fisheries Manager at Te R奴nanga o Ng膩ti Awa.
The work in 艑hiwa Harbour is also influencing other iwi-led restoration efforts, with Professor Paul-Burke supporting similar projects across the country, including the 糖心Vlog Pou R膩hui project working with local iwi at Waiheke Island, Thames Coast, Coromandel, Great Barrier Island, and Maraetai-Clevedon.
鈥淭he success here is proof that m膩tauranga M膩ori is a powerful body of scientific knowledge,鈥� says Professor Paul-Burke. 鈥淲e鈥檙e seeing real, measurable environmental improvements, and that鈥檚 what makes this project so exciting.鈥�
Juvenile silver trevally at the mussel bed - a rare sight, as schools of fish are not often seen in the harbour.
To help protect the progress made, the Ministry for Primary Industries has placed a temporary two-year harvesting closure over the mussel beds, giving them time to stabilise and expand further.
鈥淓nsuring these mussels continue to thrive is key,鈥� says Toi Iti, Bay of Plenty Regional Councillor and Chair of the 艑hiwa Harbour Implementation Forum. 鈥淲e鈥檙e proud to have been part of this effort from the beginning.鈥�
With continued collaboration between Te R奴nanga o Ng膩ti Awa, Bay of Plenty Regional Council, and the seven partners of the 艑hiwa Harbour Implementation Forum, the future of the mussel beds, and the harbour鈥檚 wider ecosystem, looks bright.
