Mussel ropes

Awhi mai awhi atu means embrace here and embrace there, reflecting how mātauranga Māori and science work together to solve environmental issues. Lead researcher for the Awhi Mai Awhi Atu project Associate Professor Kura Paul-Burke explains how mātauranga and tikanga Māori are aiding kuku recovery.

Transcript

Voiceover

The Sustainable Seas National Science Challenge Tangaroa programme has run from 2014 to 2019. It’s been exploring the development of ecosystem-based management founded on and informed by mātauranga and tikanga Māori.

Marine scientist Associate Professor Kura Paul-Burke from Waikato University has been working alongside four iwi, including her own, and three regional councils to find ways to restore the mussel beds that were showing alarming signs of decline in Ōhiwa Harbour.

It’s a project that’s likely to have many applications beyond the work that’s currently under way.

Associate Professor Kura Paul-Burke

The Awhi Mai Awhi Atu project – awhi mai means and awhi atu means embrace here, embrace there, and that signifies the coming together of mātauranga Māori with Western science to better assist the recovery of our mussel populations and management decisions here for Ōhiwa Harbour.

In 2007, here in this harbour, there were four traditional mussel beds which had sustained generations and generations of iwi and surrounding community members. Of those four beds, one of those was approximately 2 kilometres in length and had an estimated 112 million mussels in it. Fast forward to 2019, and three of those beds are no longer present. There’s only one – in 2019, there was only one traditional mussel area left, and that had an estimated 80,000 mussels in it.

There had been building concern over a number of years, and then eventually in 2003, Ūpokorehe, which is one of the iwi here on the harbour on the eastern side of the harbour, they put a camera on the back of a dinghy and tried to collect evidence to quantify their concerns. They then used that underwater video footage to get a rāhui or 186A temporary 2-year closure from the then Ministry of Fisheries, and then in 2007, Ngāti Awa, the Rūnanga o Ngāti Awa, who was the iwi on the western side of the harbour, joined forces and they then also applied for the extension of that rāhui. They kept extending that rāhui for a consecutive 8 years.

That rāhui was really important because it eliminated human overharvesting from the problem. And then people started thinking that maybe after large rain events when there’s slips and all that sedimentation comes into the harbour as well and they smother the mussels, so there were a number of different theories as to why they were disappearing.

In 2009, while we were diving, we came across 672 tonnes of the 11-armed sea star or it’s Māori name pātangaroa, and that equated to around 1.2 million just in one small space in one mussel bed. And so the predation of sea stars on the mussels is one of the major factors that we have here in this harbour.

While we were trying to figure out what to do with all the sea stars and disappearing mussels, we set up a trial. And that trial was to answer a number of questions. And the first was, can we grow our own mussels from Ōhiwa for Ōhiwa in Ōhiwa? And at the same time, if we were to throw mussels on lines as in a small aquaculture-type project, could we then relocate those mussels to the bottom of the harbour? And if we did, would they reattach and feed and recruit or have babies?

So these mussels have been in here for a couple of years now, and look, we’ve got new, new growth here.

While we were trying to figure out how to keep sea stars away from the mussels on the bottom, we developed a series of steel rebar wire cages to keep the sea stars away from the mussels. And then we started to think why not use more biodegradable, more sustainable natural resource materials? And so we turned to the esteemed Roka Hurihia Ngarimu-Cameron, who is a master weaverist, to help us design cages and natural resource lines.

Whaea Roka Hurihia Ngarimu-Cameron

Oh look at that, yes.

Associate Professor Kura Paul-Burke

Lovely.

Whaea Roka Hurihia Ngarimu-Cameron

Beautiful.

Our first materials that we used, of course, naturally was the harakeke. And we trialled out the tī kōuka and also the kiekie. So they went down, and we whiried those – whiri is a three-braid – so we plaited up these resources.

We started with the harakeke green off our pā harakeke, and we also used the mussel shell, which we call the kuku or the kūtai, to extract the fibres from our harakeke. So to extract, we take off, expose, flick under and take off, and that’s the skin, and that’s the beautiful fibres that all the spat in our ocean can cling to once we weave it up.

Associate Professor Kura Paul-Burke

They’re completely natural.

Whaea Roka Hurihia Ngarimu-Cameron

They found that they wore where they were attached to the buoys and also to the sinkers. So the next round, I thought back to my ancestors, to our tūpuna, and I thought about the tāruke, which is the crayfish pots that they made to catch crayfish. And they use the pirita, which is the supplejack, so I thought, ooh, I will use those too.

Associate Professor Kura Paul-Burke

As of October 2020, we have three new mussel beds growing in the harbour, all within close proximity to our restoration stations. And those three new mussel beds combined have an estimated 200,000 mussels of varying sizes within them. And our last remaining traditional mussel bed has moved from 80,000 mussels in 2019 to an estimated 260,000. So it’s small gains, and we’re hoping the trend continues upwards.

Sea stars are predating heavily upon the mussels here in Ōhiwa Harbour, so one of the questions that we’re asking is why are there so many sea stars and what are the best ways to manage them into the future? So Megan Ranapia is a PhD student at the University of Waikato, and like myself she also whakapapas to this harbour. And so that’s what she’s going to look at for her PhD. It’s a huge question in a really complex system harbour that stuff has multiple impacts coming in on a daily basis.