This article orginally appeared in the February 2021 edition of the Outboard Boating Club magazine.

Next time you pass under the bridge and head out to sea from the OBC cast your eye to the east, to the open water beyond Akarana Yacht Club and into Ōkahu Bay.  This year, in partnership with Ngāti Whātua Ōrakei, Revive Our Gulf plans to establish two 30 tonne mussel beds just to the south of the breakwater piles.   

For Ngāti Whātua Ōrākei, establishing mussel beds in Ōkahu Bay is the next step in a  long-term, intergenerational environmental project deeply rooted in the need to re-establish the mana (respect and standing) and the mauri (life force and spirit) of the original papakāinga (village) area after a sad history of land confiscation and desecration.  The lands around Ōkahu Bay were compulsorily purchased in 1908 and became the primary sewer line for Auckland City between 1914 and 1960.  The overland sewer created a physical barrier to access the sea, turned the area into swampland and discharged sewage into the bay, polluting kai moana (sea food) and depleting mauri.

Ōkahu Bay sewer line construction c1910
Ōkahu Bay during the construction of the sewer lines circa 1910. Photo credit: Auckland Libraries Heritage Collection 7-A2929 (E Gilling)

Ngāti Whātua Ōrākei were reinstated as kaitiaki (carers) of Ōkahu Bay as part of their Waitangi Treaty settlement redress and over the years have been working to improve the state of the bay.  They have had boat moorings removed to reduce pollution and open up the views out to Rangitoto and the wider Hauraki Gulf, providing safer access for swimmers, paddlers and sailors. They have also done pioneering work in mussel restoration, applying ingenuity and mātauranga Māori (customary knowledge) to areas such as the recruitment of spat and growing juvenile mussels.

For Ngāti Whātua Ōrākei, establishing mussel beds in Ōkahu Bay is the next step in a  long-term, intergenerational environmental project deeply rooted in the need to re-establish the mana (respect and standing) and the mauri (life force and spirit) of the original papakāinga (village) area

The mussel bed project planned for this year involves depositing two 30 tonne mussel beds just on the inside of the breakwater piles.  One of the beds will be on bare sediment; the second one will be placed on a 50m x 50m (0.5m deep) shell base.  Mussels are hardy, but as filter feeders there’s a limit to how much silt they can ingest.  The shell base both lifts the mussels out of the silt and provides hard surfaces that have the potential to recruit more mussel spat.   Having the two beds in close proximity will allow us to compare and measure the benefit of using a hard substrate versus not.   We’ll be monitoring the mussel beds over time for growth, movement, natural recruitment, predation, biodiversity, productivity and pest species.

Ngāti Whātua Ōrākei work on mussel bed restoration
Ngāti Whātua Ōrākei mussel restoration work in the past included combining Mussock™ and harakeke (flax) to recruit and grow mussels. Photo credit: Shaun Lee

Funding for the Ōkahu Bay project will be provided by The Nature Conservancy, Foundation North, Auckland Council Healthy Waters, the Ōrākei Local Board, and the Auckland Foundation’s Hauraki Gulf Regeneration Fund.  The OBC is also engaged and continues to provide logistical support to Revive Our Gulf.

60 tonnes of mussels seems like a drop in the ocean given the long-term objective of restoring the hundreds of square kilometres of mussel beds lost to dredging across the Hauraki Gulf.  However, the Okahu Bay mussel bed project is an opportunity to showcase a high profile marine restoration that’s close to downtown, and that Aucklanders can easily access and connect with. We share Ngāti Whātua Ōrākei’s long-term vision of restoring the mauri of Okahu Bay for all.   Wouldn’t it be fantastic to see abundant and clean kai moana in the bay.

Update: this article was updated to reflect the decision to move from a 20 tonne to a 60 tonne mussel deployment.