A barge collects kūtai/green-lipped mussel spat to be grown in a mussel farm and then transferred to Kawau Bay, Hauraki Gulf.
A barge collects kūtai/green-lipped mussel spat to be grown in a mussel farm and then transferred to Kawau Bay, Hauraki Gulf.
Seven million mussel spat harvested from Ninety Mile Beach Te Oneroa-a-Tōhe are on a marine rescue mission to reverse decades-long impacts of destructive fishing practices, invasive species, climate change, and acidifying waters in the Hauraki Gulf.
It’s a bivalve operation like no other that on Monday had millions of green-lipped mussels/kūtai placed into Kawau Bay by Ngāti Manuhiri Settlement Trust, a partner of the Revive Our Gulf project.
“Kūtai are absolutely crucial to maintaining the health of our wai, but our once-abundant kūtai populations have been severely depleted by human activity and climate change,” Ngāti Manuhiri Settlement Trust chief executive Nicola MacDonald said.
“By re-establishing these kūtai reefs we are taking solid and decisive action to reverse the human impacts on the Gulf, and give our wai a fighting chance to ensure it is stable enough to support us now and into the future.”
Kūtai are ecosystem engineers, providing food, shelter, and protection for diverse species as well as filtering impurities from the seawater.
“In the 1950s and 1960s, the extensive kūtai reefs of Te Moananui-ā-Toi were commercially dredged to the point of collapse. Despite the advent of mussel farming, wild mussels never returned in large numbers”, Revive our Gulf Programme director Katina Conomos said.
“Healthy shellfish in the Hauraki Gulf are key to healthy marine ecosystems. We need to bring them back. We are developing knowledge for how to restore kūtai populations in Te Moananui-ā-Toi at scale. Ngāti Manuhiri Settlement Trust is a very committed partner to this kaupapa, and their bold leadership is essential to this mission.”
The spat, or baby kūtai, were collected from Ninety Mile Beach, grown to size on a mussel farm in Coromandel, and then taken by barge to the release site.
Millions of mussel spat collected from Ninety Mile Beach Te Oneroa-a-Tōhe will help replenish stocks of the shellfish and clean up Hauraki Gulf.
This deployment is the second conducted in partnership with the Ngāti Manuhiri Settlement Trust, and is part of a project to develop knowledge around the restoration of the kūtai reefs throughout Te Moananui-ā-Toi Hauraki Gulf.
“These kūtai have come a long way to help us restore this part of Aotearoa and we’re grateful to them and those that have nurtured them to this point. One of the other problems we are facing across the Gulf is the spread of the invasive seaweed exotic caulerpa,” MacDonald said.
“Some of the techniques used to remove exotic caulerpa involve chlorine and benthic liners to smother it; however, this can have a brutal scorching effect on the seabed and upset the conditions needed for our native plants and fish stocks to thrive. Kūtai can help to filter the wai and restore it to ideal conditions for our marine life to flourish, particularly kōura (crayfish) and tāmure (snapper).”
One of Revive Our Gulf’s core partners is The Nature Conservancy, and its country director for Aotearoa, Abbie Reynolds, said the kūtai restoration project was an internationally recognised example of a successful indigenous partnership.
“The way that this project works hand in hand with mana whenua is particularly exciting, upholding the mana of all involved, and we are honoured to be a part of this important conservation work with the wider benefits that it entails.”
University of Auckland Institute of Marine Science lecturer Dr Jen Hillman, the science lead for Revive Our Gulf, describes this as cutting-edge marine research.
“We are learning as we go and it’s a huge ongoing effort. This scale of work that Ngāti Manuhiri are driving is a world first in restoring these types of shellfish,” Hillman said.
