A stretch of seafloor in the eastern Bay of Plenty that had all but run out of green-lipped mussels now holds an estimated 45 million of them, and the iwi behind the turnaround wants two more years of protection to make the recovery stick.
Te Rūnanga o Ngāti Awa is asking Fisheries New Zealand to extend a temporary ban on gathering green-lipped mussels, known as kuku, from part of Ōhiwa Harbour between Whakatāne and Ōpōtiki. The closure was first put in place in November 2024 and is due to expire in November 2026. Submissions on the proposed two-year extension close at 5pm on Friday 21 August, according to RNZ.
The scale of the recovery is hard to overstate. A 2019 survey found just 80,000 green-lipped mussels left across the entire harbour, a population that had once been so abundant local people knew the area as a food basket, Te Kete o Tairongo. By December 2024 a survey led by Waikato University marine science professor Kura Paul-Burke counted around 45 million mussels spread across roughly 11 hectares of the western harbour floor, up from 3.5 hectares in July 2023, figures published by the Ōhiwa Harbour restoration project show.
Just as telling as the raw count is the age of the mussels. In July 2023 about 90 percent of the population were juveniles. By December 2024 the mix had shifted to 60 percent babies, 24 percent teenagers and 16 percent adults, a sign the reef is now growing, breeding and sustaining itself rather than depending on constant reseeding.
The collapse had a clear culprit. Eleven-armed sea stars, known as patakaroa, had built up in plague numbers and were eating their way through the old mussel beds faster than the shellfish could replace themselves. Charles Bluett, Te Rūnanga o Ngāti Awa customary fisheries officer, told RNZ that without intervention the harbour “may take a century to get back to where we were”.
Rather than wait, the iwi went to work on the seafloor. Divers trapped and physically removed hundreds of sea stars from the historic beds. At the same time the team grew mussel spat, the tiny larvae that eventually settle and attach, on lines woven from tīkouka, the native cabbage tree, then reseeded the old beds once the spat were mature enough to hang on to the bottom by themselves. Predator control has continued alongside, giving young mussels roughly the year they need to reach maturity.
The approach has drawn attention well beyond the Bay of Plenty. The project won the National Supreme Award at the Ministry for Primary Industries awards at Parliament in 2025, and Paul-Burke and the team have been invited to speak at the International Shellfish Restoration Forum in Washington and to share their methods with Indigenous restoration researchers at the University of Sydney. The work has also featured on BBC World.
Much of what makes the Ōhiwa effort stand out is that it blends mātauranga Māori, the knowledge held by local hapū about how the harbour used to work, with marine science surveys and monitoring. The spat lines made from cabbage tree are a good example, an inexpensive natural material used in place of imported plastic ropes, which also break down cleanly if they are lost.
The temporary closure the iwi wants to extend is small, covering about 0.1 square kilometres along roughly 650 metres of coast near Harbour Road. It is not a total ban on fishing, only on taking green-lipped mussels from the restored beds, and it applies to everyone. Even so, enforcement has been a challenge. RNZ reported that one person was caught over summer with close to 800 mussels illegally gathered from inside the closed zone.
Ngāti Awa argues that two more years of protection would let the reef keep maturing before any harvest resumes, protecting the investment of the past several years. The alternative, reopening the beds in November, risks stripping out breeding adults just as the population reaches the point where it can support gathering again in a lasting way.
The recovery matters beyond the shellfish themselves. Green-lipped mussels are natural filter feeders, and a single adult can clean many litres of water a day, so a healthy bed helps keep the wider harbour clearer and supports the fish, birds and other life that depend on it. Restoring the mussels is, in effect, restoring the plumbing of the whole estuary.
People who want to have their say on the proposed extension can make a submission to Fisheries New Zealand before the 21 August deadline. Full details of the recovery work are set out by the Ōhiwa Harbour restoration project.
What do you think of the Ōhiwa Harbour turnaround, and should the harvest ban be extended? Share your thoughts in the comments below.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job 🙂
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