Seafood Magazine: Creating a sustainable mussel spat supply with mātauranga Māori

Shared with permission from Seafood New Zealand Magazine - June 2021:

Indigenous knowledge and expertise are at the forefront of creating more sustainable pathways for the largest and most valuable aquaculture industry in Aotearoa New Zealand: mussles.

Every year, thousands of kilometres of commercial spat-catching rope is cast into the sea with hopes of catching tiny seed mussels or spat. This wild spat is critical to supply mussel farms for the upcoming season. These ropes are made from strands of polypropylene designed to mimic feathery seaweed and hydroids that spat like to attach to during their settlement phase. With the growing movement away from plastic products throughout the country and the world, mātauranga Māori (Māori knowledge) may have a unique solution for the green-lipped mussel industry.

Kohunga Kutai is a collaboration of marine scientists, iwi and Māori aquaculture businesses that are using mātauranga Māori and science to develop and test native plant fibres as an alternative to plastic for catching mussel spat for aquaculture.

Funded by the Sustainable Seas National Science Challenge’s Innovation Fund, Kohunga Kutai is co-led by Andrew Jeffs (University of Auckland) and Nicola MacDonald (Ngāti Manuhiri Settlement Trust). This kaupapa was initiated in partnership with Ngāti Manuhiri and Ngāti Rehua, and is guided by kairaranga (master weavers) and a kaumātua who are matatau (expert) in the use of traditional plant fibre products.

Native plant materials such as muka fibre from harakeke (flax), kuta (swamp reed) and tī kōuka (cabbage tree) have a wide variety of traditional uses including anchor ropes and lashing waka components, fishing, and for holding live mussels.

This research project is an example of mai i ngā maunga ki te moana (mountains to the sea) where the indigenous knowledge of the ngahere (forest) is informing better practices in the moana (ocean).

“We are guided by mātauranga Māori of the relationship between kutai (mussels) and plant fibres because kutai are known to have a strong affinity for these natural fibres when placed in the sea”, says MacDonald.

“This relationship is not surprising from a biological science perspective, given that the larvae of many mussel species, including green-lipped mussels, selectively settle on filamentous organisms, especially seagrasses and seaweeds”, says Jeffs.

The research is guided by mātauranga Māori and tikanga, from informing the most suitable native plants through to how the research is conducted. “The mātauranga Māori component of the project takes a holistic approach involving many hui and wānanga with hapū members to discuss the take (issue) and the kaupapa (opportunity) to be involved”, says MacDonald.

Ngāti Manuhiri and Ngāti Rehua are ideally placed to lead the development of this comparative given their underlying mātauranga Māori of the cultivation of these plants, the different sources of fibres, and how to extract and prepare them.

The first six months of the two-year project have focused on determining the most suitable fibres for commercial spat collection through a comparative study and then testing these fibres in real-life industry settings.

Kaiwhatu (a muka fibre craftsperson) from Ngāti Manuhiri and Ngāti Rehua, and Katarina Tawiri from Te Kohinga Harakeke o Aotearoa—National New Zealand Flax Collection have guided the identification of 12 potential plant fibres, their sources, and how to prepare the material for testing.

To test the durability of the 12 plant fibres, the project team partnered with three Māori aquaculture businesses in Te Ika-a-Maui/North Island. They are providing access and use of their farm infrastructure, facilities and staff.

Using samples of these 12 fibres prepared by the kairaranga, the project team are doing a series of field experiments on Aotea Marine Farm’s spat collection site in Aotea Harbour to confirm their effectiveness for catching mussel spat.

The effectiveness of spat collection of the three most durable fibres will be tested in partnership with Rough Waters Ltd’s inshore mussel farm in the Hauraki Gulf; and Whakatōhea Mussels’ offshore mussel farm operation in Te Moana-a-Toi/Bay of Plenty.

“Industry partners are critical to the success of the project, as they are providing their input to ensure the natural fibre products are effective in a commercial setting”, says Jeffs.

Developing a commercial-scale, natural spat-catching product will not only help the aquaculture industry become more sustainable, but it will also build and strengthen cultural capital.

Invigorating and applying mātauranga Māori for the management of taonga (treasured) native plants and kutai, in partnership with science, provides an exemplar of research that is collectively embracing new opportunities for a blue economy.

“Our project is showing that mātauranga is an ongoing process of learning – it is more than historical knowledge informing the present”, says Jeffs. “Mātauranga is alive and happening today, generating valuable outcomes for the wellbeing of te Taiao (environment), Māori communities, and the wider industry.”

Two research summaries will be available on the project webpage (sustainableseaschallenge.co.nz/kohunga-kutai) later this year. One will present results of the comparative study, and the other on the durability of the fibres after 1 month at sea.