Kelp regeneration in Tutukaka Harbour

Tutukaka Harbour has been subject to sustained negative impacts over the past several decades; including substantial sedimentation from land clearing and development in the catchment, excess nutrients and pollutants from agricultural, domestic, and recreational sources, and overfishing of ecologically important key species, such as kōura (crayfish) and tāmure (snapper). The result is a highly degraded ecosystem, dominated by kina barrens where there were once flourishing kelp forests and a pronounced decrease in biodiversity of both fish and invertebrate life. Ecklonia kelp forests are amongst the most important habitats for biodiversity and primary production in the coastal ecosystems of northern Aotearoa and their regeneration is a critical step in restoring the mauri of our coastal moana. While it is imperative that the underlying causes of overfishing and environmental impacts are addressed, this project aims to investigate the potential benefits of “reseeding” Ecklonia kelp forests in areas of the harbour that have been most impacted. 

This video shot by Glenn Edney reveals the degradation of the seabed.

Te Whanga Hauora o Tutukaka: Restoring the kelp forests of Tutukaka Harbour 

Ocean ecologist Glenn Edney and Hamish Clueard (Ti Aki tai, Ngati Toki, Te Waiariki, Ngati Takapari) are leading the Te Whanga Hauora o Tutukaka kelp regeneration project. After months of community engagement and planning, the first stage of the project is underway. A generous donor has provided a 40-foot refrigerated container for kelp propagation. The kelp spores will be grown in bins in the temperature-controlled container.

When the propagules are ready to transplant into the harbour, two methods will be trialled.

Green gravel is a recent innovation with trials underway in several locations globally, including the Love Rimurimu project in Wellington Harbour. The propagules are grown on gravel in the refrigerated container and then placed in harbour. The team will monitor the gravel and protect them from grazing.

The green gravel solution. Image Credit Green gravel

The second trial will grow the kelp on a rope line suspended with anchors and floats two metres above the seabed. This pilot may lead to a marine permaculture project in the open ocean.

Once the team has successfully propagated eklonia, they intend to make plants available for other community groups on the East Coast. A trial in the Kaipara Harbour is also possible.

Benefits of seaweed

Seaweed is an efficient producer of oxygen and kelp forests can sequester more carbon than rain forests. They have advantages over terrestrial plants in that they require no, or minimal support structures and have no problems with water supply. Microalgae supply half of the planet’s oxygen[i]. When we humans find value in a species, such as sheep, wheat or roses, their population rapidly expands. When we learn to value seaweed more, we will find ways to support its proliferation with huge areas of the ocean ready to benefit.

Tāmure (snapper) and eklonia. Image Credit Glenn Edney

In Tai Tokerau seaweed can provide many benefits additional to climate healing and biodiversity. It is super-nutritional for people and animals, is an excellent fertiliser for garden and farm, and developing a seaweed industry will create economic opportunities.

The elephant in the room

The reason kina barrens exist is overfishing. Populations of tāmure (snapper), and koura (crayfish) that normally predate them are no longer in balance. Our challenge is to find a way to extend reserves or rahui to give our coastal environment a chance to regenerate for the benefit of all. With more people following the lead of Glenn and Hamish we can provide the coming generations with abundant sustainable kaimoana, and heal the climate.

“Mena kei te hauora te moana ka pera ano te hauora o te iwi”

 If the ocean is healthy so too will the people be healthy


[i] Robyn Williams, ‘Microscopic Algae Produce Half the Oxygen We Breathe’, Sound, ABC Radio National (Australian Broadcasting Corporation, 25 October 2013), https://www.abc.net.au/radionational/programs/scienceshow/microscopic-algae-produce-half-the-oxygen-we-breathe/5041338.

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