Sustain Episode 7: Farming the sea – Seaweed aquaculture research in New Zealand

Mentioned in this episode:

GUESTS:
Prof Andrew Jeffs.
Clare Bradley.

Institute of Marine Science.
Sustainable Seas Challenge: Seaweed Sector Framework
University of Waikato.
Lucas Evans.
Greenwave Aotearoa
Ministry of Primary Industries

Cyclone Gabrielle

DEFINITIONS:
Iwi: Iwi-related groups are defined as whakapapa-based kinship groupings with a Māori descent line, such as a waka grouping or confederation.
Ice-ice: A disease affecting farmed seaweed.
Aquaculture: Farming of aquatic plants and animals.
Monoculture: The cultivation of a single crop in a given area.

FURTHER READING:
Underwood, L. & Jeffs, A. March 30, 2023. Settlement and recruitment of fish in mussel farms. Published in Aquaculture Environment Interactions.

Transcript

EP7: FARMING THE SEA – SEAWEED AQUACULTURE RESEARCH IN NEW ZEALAND

Dr Pauline Herbst interviews Prof Andrew Jeffs, from the Institute of Marine Science at the University of Auckland Clare Bradley, CEO of AgriSea.

Pauline: Hello and welcome to Sustain!, a project of Ngā Ara Whetū: The Centre for Climate, Biodiversity and Society. Not for the first time, dairy farming is in the international spotlight with regards to climate change. It’s a big part of New Zealand’s identity and its economy. So what are the alternatives? One suggestion is turning to what has been called the blue economy, our oceans, and in particular, aquaculture.

I’m Pauline Herbst and joining us today is Professor Andrew Jeffs from the Institute of Marine Science at the University of Auckland. And Clare Bradley, the CEO of AgriSea, to talk about seaweed farming. Andrew, first of all, let’s define seaweed. This used to be thought of just another plant in the sea, as opposed to a set of distinctive and important species. What is seaweed and why is it so important for our oceans and planets?

1. INTRO: WHAT IS SEAWEED AND WHY IS IT SO IMPORTANT? (00:00)

Andrew: Seaweed is not actually a plant as such, scientists don’t think it’s a plant, but it is pretty much the same thing as a plant that lives in the sea. It fixes sunlight and combines it with nutrients that it takes out of seawater. And it’s the part of the basis of the food chain, and particularly in coastal waters, it’s really, really important. There’s lots and lots of different types of seaweed. For example, in New Zealand, there’s hundreds of different species, and they often have other roles in the marine environment. They provide structure, so you can have forests of seaweed that stand up tall and then fishes, crabs and other organisms live amongst them.

And also some of them have important chemical properties, which are also important in terms of feeding into food chains or interacting with other organisms. They’re a very important part of coastal ecosystems or marine ecosystems generally and often overlooked, we see seaweed on the coast and just don’t realise what an important function they actually have in our environment.

PH: And from what I understand, kelp is the term commonly used to refer to over 100 species of large brown seaweed. And that’s a seaweed forest, so to speak.

AJ: Yes. Kelp are very important in temperate regions of the world where they’re only found and that includes New Zealand. Kelp’s almost a collective term that really undervalues what is a diverse group of incredibly important organisms, particularly in this part of the world.

2. SEAWEED HARVESTING VS. SUPPLY CHAINS (02:27)

PH: The 2021 to 2030 decade has been named the United Nations Decade for Ocean Science for Sustainable developments and the United Nations Decade for Ecosystems Regeneration and Restoration. Now, in terms of developments, Clare, your family has been involved in the seaweed economy for a couple of decades. Do you want to tell us a little bit more about how you came to be involved in seaweed?

Clare: Sure thing, actually, my mother and father in law were first and foremost schoolteachers, and stumbled across seaweed as an input into farming and agricultural practice. They researched seaweeds all around the world. Different types, what they were good for, and then came down and researched here in Aotearoa, which species we had, which were in abundance, and it was really evident to them that there wasn’t the ability to have a seaweed supply chain taken out of the wild ecosystem, if you like.

So they started combing the beaches after storms, primarily for one of our large brown Ecklonia radiata, and utilising this in a way to ferment it, to extract some of those really good chemicals and plant nutrients that enable us to feed them back into animals, soils and plants.

And so they started building a very small business. My husband, Tane, used to ask to pay for his stall on the way out of the Titirangi markets after he’d sold some goods to growers. And now, almost 30 years later, we’ve got a team of 35. We still rely on that coastal stormwash, but we’re really, really cognizant of the fact that there is also an ecosystem on the beach that relies on that storm-cast seaweed. So we ensure that it’s always done by hand, never by machines.

It’s done by people who leave at least 30% on the beach to enable sand hoppers and the rest of that ecosystem to thrive. One of the challenges for a business like us, who really focus on the impact that we can have into our food production systems, is that it’s hard to scale from beach-cast seaweed. And while we’ve got markets that are potentially interested in our products, we’ve held back, we’ve had a really long-term view. Our role now is helping encourage the potential increase of seaweed farming as a supply chain. We must not take our wild stocks. Like Andrew said, it’s a habitat, and the simple fact that it’s really important for our ecosystems, but also our economy. No seaweed, no fisheries.

PH:  So a couple of questions from that. Can anyone just harvest seaweed or is there a particular quota, and how does that link into the historical indigenous collection of this incredibly important food source and resource?

CB: So there’s two different things. There’s the legal way, and then there’s a moral and ethical way. Sometimes those things have a little juxtaposition at times. Legally, you need to get a permit to collect seaweed from the beach if you’re using it for commercial use. You cannot collect from any beach, there are only certain beaches that you’re able to collect from, you need to track it. It’s all GPS-located and reported around where you are collecting seaweed and how you are selling that on. That’s the legality of a beach-cast framework.

In the early 2000s, a number of seaweed species were earmarked for the quota management system, so that’s our fisheries system and one of those is a total allowable catch. You can actually cut macrocystis, our giant kelp down in the South Island, you can actually cut some of that from the ocean. For us as a family, we saw that we did not believe that that was going to be the right framework to put seaweed in to manage it, because you rely on these large QMA areas and then you encourage people to go to the easy to access areas to harvest their take from the wild.

And often that’s the food basket of a remote community. They rely on the sea to feed them in these remote communities. If you destroy the habitat, like I said, not only no commercial fisheries, but also, especially for our indigenous communities in these remote areas, that is their food source. Again, this moving towards a farmed seaweed production system for utilisation is really important. But we’ve also got restoration work that needs to happen as well.

3. WHAT DOES THE RESEARCH SAY ABOUT THE ENVIRONMENTAL IMPACT OF SEAWEED FARMING? (07:16)

PH: Andrew, do you want to give us a little bit of a background of the recent project that you’ve been working on with the seaweed and mussel farms?

AJ: We’ve had an interest in trying to understand the impact of seaweed and mussel farming, which is collectively known as non-fed aquaculture. That’s growing organisms in the sea without providing them with food, they’re just extracting what they need from their environment. Shellfish like mussels, for example, which we farm extensively in New Zealand, just filter the seawater and make a living out of filtering the particles out of the seawater.

And likewise, seaweed is using the sunlight and the nutrients that are in the water. And so up until now, we’ve had relatively little information for New Zealand about what the ecological effects of those activities are. We’ve initiated some research looking at that, and the results have been quite surprising in terms of, when we install these farms they actually become a very important habitat, particularly for fishes, but also for increasing biodiversity in our coastal ecosystems.

For example, one of the things we found was that where we have shellfish and seaweed farms that fishes, the larval fishes, which drift around in the sea looking for a suitable habitat to set up home, they like these farm systems and they go and move into them. They settle in them, and what’s more, they also establish in them.

So they’re great nursery habitats. When we measured the extent to which those habitats, you could call them artificial seaweed farms and mussel farms, were attracting those baby fish. It was at similar levels to nearby natural habitats, which is really quite astounding. So these farms are actually contributing to fisheries production in quite a significant way and having a positive effect on our coastal ecosystems.

PH: So where were these farms that you were doing these tests with?

AJ: These farms were in the Firth of Thames in the Hauraki Gulf, and included a farm that had Ecklonia radiata, which Clare was talking about, we call it common kelp. Common kelp is also found on natural reefs nearby, and we compared the arrival of fish to those natural habitats, and compared it to the farms.

PH: And is GreenWave, are either of you involved with GreenWave?

CB: Yes. We’re a partner on the GreenWave Aotearoa project, but we’ve also partnered offshore with the original GreenWave in the US, where we’ve opened our US company and are working with them really closely there as well. GreenWave Aotearoa, is a funded research project to see if we can farm Ecklonia radiata, primarily in the Hauraki Gulf, Firth of Thames area, but also down further into Bay of plenty. It’s a collaborative research project with a number of partners; Andrew’s been doing some work, University of Waikato, Lucas Evans and the mussel farming team up in Coromandel, some of our local iwi, Ngai Tai ki Tamaki as well as, up in Coromandel.

We’re all pitching in to see where are the places we can enable some of the levers for seaweed farming. In the US, the original GreenWave is really about how to, again, scale seaweed farming, but in a way that provides education and farmer-to-farmer support. How can they free up that information, and share information between seaweed farmers to enable the growth of the sector?

Which is really important so we don’t run into what we have potentially on land around seed, because how do we then free up, and enable access to seaweed seed, for want of a better word, that is not controlled by one entity, and that is worked through in a really authentic way with our local tangata whenua that ensures the protection of that IP.

PH: And Andrew, is that what your project was involved with? The GreenWave, what was your involvement there?

AJ: Basically looking at some of those environmental aspects of the Greenwave farms with Ecklonia radiata on them, to get a bit of an understanding of how they were affecting the marine life around them and what some of the benefits would be.

4. BIOREMEDIATION, FERTILISERS & FARM RUN-OFF (11:36)

PH: Clare, looking through some of the work that your company has done, I was quite intrigued by something called the Hauraki Bioremediation Project. Could you tell us a little bit more about this work?

CB: The idea came about talking to some researchers from the University of Waikato who had used seaweed farming as a way to soak up excess nutrients on the back of a prawn farm. And we thought, wow, that’s really fascinating. We’ve got a lot of nitrogen and phosphorus, these, kind of, free nutrients, for want of a better word, running down our riverways. We thought, I wonder if we could use this seaweed growing system in a way to soak up some of those excess nutrients, to provide a bit of bioremediation, which is basically an environmental soaking up of excess nutrients and then turn that seaweed into products.

There’s some environmental benefit, and some potential economic benefit. We ran a pilot in Kopu, near Thames, and this has been, again, pretty surprising because we knew some of the growth rates of ulva, the sea lettuce, which is free floating. It doesn’t need to attach to a substrate. In the research labs, they had potential growth rates that were really good, but they were being fed nutrients in a lab situation. What we found when we were growing this seaweed on land from this diffused source of river water, which is pretty muddy, you had pretty astounding growth rates, even throughout what was a really tricky, summer last year with a lot of high rainfall, high freshwater coming into the system, and the nitrogen and phosphate removal was really, really high. Up to 90% of nitrogen removal in the water that we were able to filter, and around about 70% of the phosphorus removed.

So it’s providing this environmental service to extract these nutrients. But then it’s turning those nutrients into seaweed biomass that can then be utilised in products, like the ones we make, back into farming or another suite of products that are in development.

PH: Andrew, when we were chatting briefly before the show, we were talking around how New Zealand is a very heavy user of particular fertilisers and nutrients, and that we have quite a runoff in our oceans. What are the effects of those runoffs?

AJ: When you look at the global map of fertiliser use, New Zealand’s got some of the highest, if not the highest, rates of artificial nitrogen and phosphorus application to our pastureland of any country in the world. We also have very high rainfall in many of those areas. It’s what makes our pastures grow so well. The combination of those two things, it runs off into the sea, particularly nitrogen, it’s very, soluble. That’s a problem for farmers losing those nutrients, but it’s also a problem for the coastal environment that it turns up in. Somewhere like the Firth of Thames in the Hauraki Gulf, the amount of nitrogen arriving from the pastureland into the coastal waters is driving a lot of productivity, or plant growth.

And that’s fine during the day when there’s sunlight to make the plants grow. But at night, the plants switch back to respiring. They’re taking up oxygen because they have to stay alive. When they do that, there’s such an abundance of the floating plants there that they basically strip the water column of oxygen and make it very difficult for other species such as fishes and what have you to to live in those waters.

There’s just not enough oxygen for them to breathe. That’s what we call a phytoplankton bloom, or an algal bloom. That’s problematic in a number of places around New Zealand. Coming back to what Clare was saying, that’s one of the great advantages for seaweed farming in New Zealand is that, in coastal waters, it can help to remove some of those excess nutrients that we are washing off the land and into our coastal ecosystems which are causing quite significant problems in terms of the way those ecosystems work.

5. SEAWEED’S MULTIPLE USES: FROM ICE CREAM TO PLASTIC ALTERNATIVE (15:57)

PH: And Clare, your company has been using seaweed as an alternative to some of those fertilisers. What other things can seaweed be used for in seaweed farming? You mentioned the sea lettuce, the Ulva species, and that can be used fresh in salads or soups, or dried as a food wrap. I believe the other main seaweed foods that can be used in New Zealand or New Zealand species areWakame (Undaria pinnatifida), karengo, and bladder kelp, which can be roasted as chips or dried as seasoning, apparently, which sounds quite delicious.

What are some of the other uses that seaweed can have for New Zealand? Particularly in this broader idea of a global economy.

CB: This is the incredible thing, there are so many potential uses of seaweed. And traditionally, yes, we know that as a food source, in many Asian countries and here in New Zealand, the karengo in particular was used by Māori. But there’s a whole suite of products, and where we need to think about it for New Zealand is, where are we going to compete on the world stage, and in this seaweed sector, are we going to try and compete against low labour units of seaweed farming out of the Philippines and Asia and compete in that traditional food space?

It’s not really our area of expertise. It’s a very long-held traditional knowledge. Where else can we look for high-value, unique attributes of our beautiful seaweeds? Or secondly, a biorefinery approach, and that’s one of the approaches that we’ve taken at AgriSea is utilising this. Ecklonia radiata as a biostimulant or an adjunct and semi-replacement of our fertilisers on land.

But from there we also create a small waste stream of biomass that’s not fully utilised. And we’ve been working with Scion in New Zealand to then turn this into something called nanocellulose. We can turn that into crystals, and that’s been started to be tested in electronics. We can turn it into scaffolds where we can start to grow cells onto the scaffold system, coming out of our seaweeds.

There’s a whole range of uses that can be that lower-value, high-volume commodity end, all the way through to some of the higher-value products. I think there is a bit of an argument of both, because the investment to get right to that high-value nutraceutical, I think at our latest seaweed summit, one of the team talked about the millions and millions and millions and millions of dollars that needs to be invested to get into that pharmaceutical, and there’s about a 1% success rate. So if we’re thinking about, strategically, where to put our time, energy and money into growing this, this wonderful sector that has potential environmental and economic benefits, we’ve got to have our eyes open, to both the volume and value play at the same time.

AJ: I think Clare’s really touched on it there, that there’s a huge variety of products that are potentially useful, industrial products. It’s used widely for generating things like food ingredients. For example, seaweeds farmed overseas are very common ingredients in frozen foods, particularly ice creams. It’s what’s called mouthfeel, improving the way that the ice creams freeze and present themselves when you actually eat them, you notice they taste smooth and creamy without putting a lot of cream in them.

PH: That’s right. And you did an experiment with some of your students?

AJ: Yes, just in my aquaculture class. I made up two batches of ice cream, one with some seaweed ingredient in it and a lot less cream, and the other one with full cream. And the students made up ice creams and had to score which ones they thought they were and they couldn’t tell the difference.

So, you know, there’s an example of where we can use a valuable ingredient from seaweed to replace something that has a significant environmental cost, and there’s also health benefits associated with eating seaweed versus full fat cream.

6. PROFESSIONAL ORGANISATIONS: THE SEAWEED SUMMITT (20:21)

PH: Clare, you mentioned the seaweed summit. There’s another one coming up in October this year, I believe, and I don’t think these summits have been running for too long. Has it been since around 2021? Do you want to tell us a little bit more about that?

CB: Yes absolutely, I’d love to. The Aotearoa New Zealand Seaweed Association was established just a couple of years ago, like you say about 2021. We ran our first summit to bring the sector together to focus on, what are the high value uses of seaweed that we can create in New Zealand? Where are the gaps in regulations, or research or marketing, that need to be identified? And put some resources to create an area where we can upskill our sector and learn from each other.

They say that the rising tide floats all boats. It’s not about individuals going out there and doing things. What can we do collectively together to build a new sector for New Zealand that can contribute to the environment and to the economy. But there’s also, at our summit, a focus on Māori-led space in the seaweed sector, a focus on international information research, a focus on New Zealand businesses, what they are doing, what the economics look like. How can we supersede this? There’s a quite a range of diverse speakers sharing their knowledge, so if anyone’s interested in seaweed, it’s definitely the place to come and be. You’ll get to hear from people that are on the ground doing the mahi, the business opportunities, the environmental enhancement, as well as the regulatory space.

7. AN ECOSYSTEM-BASED MANAGEMENT APPROACH (22:10)

PH: I’m interested in that. You say there are a lot of Māori-led businesses there because the Sustainable Seas Challenge were identifying what an EBM approach to aquaculture could look like in New Zealand. It’s a relatively undeveloped space in the industry, as you’ve already mentioned, and we’ve got a large number of native endemic species, over 900, and some quite unique species that have never been discovered before.

Professor Wendy Nelson here at the University of Auckland discovered two entirely new species. So just to explain the EBM approach, as you probably know, it’s an ecosystem-based management approach. And one of those considerations is collaborative decision making, who needs to be at the table and who’s going to be making these decisions. I believe, Andrew, you were saying that around 50% of aquaculture at the moment in New Zealand is Māori-led and owned and Clare, that would be the same with your company as well. How are these different businesses being brought to the table, and how is this collaborative decision-making being made with governments?

CB: This EBM  approach basically is kaitiakitanga. If we look back into indigenous values and ways of utilising resources, then that’s what it is. This ecosystem-based approach is basically what Māori have been doing with their resources since being here in Aotearoa. There are some incredible groups forming in this space, and then some of them are shy to put their head above the parapet. There’s a lot of work happening in the undercurrents to establish what does Māori-led seaweed aquaculture look like? What mistakes can we not repeat that we’ve done on land? Large-scale monoculture farming that requires heavy inputs is not good for anybody. How can we look at, what does a thriving natural ecosystem look like? And then repeat that in the ocean

We have a really close relationship with the Ministry of Primary Industries, with the aquaculture team, always bringing these thoughts, these potential pitfalls, these opportunities, this thinking into their sphere so that they don’t forget about, yes great, there’s an awesome economic opportunity. But what are the implications for our remote coastal communities? How do we make sure that we are restoring the potential advantages back into those communities who actually care and have cared for these resources for many, many years?

So there’s a lot of conversations and there’s a lot of work still to be done. But I think the main thing is opening up the conversations, sitting around the table and talking these things through.

PH: Andrew, do you have anything to add to that?

AJ: From what I see, the members of the aquaculture industry, of which there’s a very significant stakeholding from Māori, they’re actively investigating what the opportunities are and looking to find a way forward with seaweed farming. I’m sure that in the next ten years, we’re going to see some significant development in that space.

And I would imagine, in a typical way that what is a very new activity for humans, commercial aquaculture, it tends to be that someone discovers something, how to do it. Next thing you know, it expands rapidly until it fills the market space. And so, I would expect to see that happening here. Māori would be major participants in that simply because they own, or have a major shareholding in, the water space that’s available for farming marine species in our coastal waters.

8. WARMINGS SEAS, CLIMATE CHANGE AND CYCLONE GABRIELLE (26:14)

PH: And how is the research that you’re doing? How can it contribute and how some of the results you found contributing in tying into aquaculture?

AJ: The results we’ve got basically paint a picture of a very benign activity or in fact, an activity that is actually very positive for our coastal environment and can help regenerate our degraded coastal ecosystems, particularly for a species like the common kelp that Clare was talking about, where there is some work trying to farm that species.

Kelp are unusual, unlike land plants, they grow from the base. And that’s because they expect the tips of the plants to be bitten off by fish or swing hoppers and things, but also they just break off and degrade in the environment. That’s how kelp feed their nutrients and energy, sunlight energy, that’s been fixed into coastal ecosystems.

That’s why they’re so important. If you’ve got a bunch of coastal kelp farms doing that, then you’re contributing to the overall productivity of coastal ecosystems. So there’s some really significant benefits that our coastal ecosystems can have from establishing a larger-scale kelp farming.

PH: You hear, anecdotally, a lot of people saying that seaweeds are incredibly important for carbon stores. Is there any scientific value to that?

AJ: There’s quite a lot of current scientific debate about it. The estimates are that around 10% of kelp or seaweed productivity ends up captured in the seabed as a sequestered carbon, but actually measuring it is very, very difficult. There’s quite a lot of research at the moment, worldwide, trying to figure out how that works, which species are responsible and how we might actually go about enhancing it.

I think the evidence is sufficient to show that seaweeds certainly contribute to carbon sequestration. So, again, if we’re farming more seaweeds in our waters, then we can expect to be increasing the amount of carbon sequestered. The other thing is that, at the end of the day, seaweeds are also fixing carbon dioxide out of the atmosphere and helping to reduce greenhouse gases.

So the more seaweed we can farm, we’re ultimately making a difference to the greenhouse gas situation.

PH: I was just thinking around the warming seas phenomenon. How is that relating to our ocean ecosystems and to seaweed in particular?

AJ: Certainly, in parts of New Zealand, we’re seeing warming oceans, and we’re also seeing heat wave events. These are periods where we have elevated water temperatures well above what the long term averages are, and both of those aren’t particularly great for seaweeds because many of the species we have in New Zealand are colder water species and a heat wave event can impact them quite severely.

And it’s not confined to New Zealand. We’re seeing, worldwide, a shift in the distribution of seaweeds due to warming waters. It’s not the only thing affecting seaweeds in New Zealand. There’s a major issue in, particularly in Northeastern New Zealand, we’ve overfished some of our key fisheries, rock lobsters, we call them crayfish, and snapper, which are very important predators of sea urchins, or kina, and those kina populations have got out of control because they’ve got no predators eating them.

So they’ve just gone rogue, large numbers of them. They’ve basically mowed down huge areas of kelp forests, particularly Ecklonia radiata, the common kelp. That’s left large tracts of coastal reef systems just barren and unproductive, and covered in starving urchins. Consequently, we’ve lost the habitat structure which all the baby fishes and things go and hide in, but also we’ve lost a huge amount of productivity out of our coastal ecosystem.

So it’s a further concern about how we care for our seaweed in our environment, the existing natural seaweed, because they’re so important to our coastal ecosystems.

PH: And Clare, on the ground, what have you noticed in terms of climate change and how it may have been impacting or changing seaweed and seaweed gathering?

CB: So one of the most significant events of the last couple of years is Cyclone Gabrielle. I think we really were tuned in to the effects on land, but many of us didn’t realise the effects down in our oceans. Not only were fishing nets pulling up large holes off land or things like that, but actually the smothering effect that the sediment has had on our ocean forests.

We really noticed that at the beachfront, our coastal communities saying to us, hey, it’s not washing up and we’re not getting seaweed washup, specifically from that region. But again, like Andrew talks about with the complete ecosystem imbalance in the Northeast with those kina, that’s the same thing. Sometimes these are really remote coastal communities who really have little other economic opportunity in their region.

So collecting seaweed and selling that to the likes of ourselves and other companies actually does make a difference. When you’re then having that supply chain not washing up on shore, that has a really felt effect in that region. Not only what’s happening in the ocean with ecosystems, but what we do on land has a really huge effect, through that sedimentation, that the light into the column, the inability for seaweed to grow through this smothered sediment is an issue.

As we go forward, if we’re going to have more and more of these extreme weather events, then there is a worry.

9. MONOCULTURE FARMING & AQUACULTURE (32:00)

PH: I just want to pick up on something you said earlier around monoculture farming and seaweed farming, from what we’ve discussed today, certainly seems to have a great number of benefits. I’m looking here at an infographic from the Sustainable Seas National Science Challenge, and we will have a link to this in the show notes. It has a whole lot of really positive benefits of seaweed farming.

But then there were also some of the concerns that you’ve both mentioned. We have to keep an eye out in the future as this industry grows. A couple of those that came initially to mind, a disease like we see in a lot of the salmon farming that hasn’t been well-regulated, and I believe there is some disease in other seafood industries not here in New Zealand, such as ice-ice.

What can you comment on how we could try and avoid issues such as disease, contaminants, litter from the farming activities, and a blocking out of the light underneath, potentially for other species. Clare, do you have any ideas on this?

CB: It’s not my area of expertise at all, but from what I’ve seen I think the net benefit of seaweed farming is positive. But we do also have to think about, what could some of those potential negative effects be? And that monoculture piece for me, and what I’ve seen in the on land agricultural systems, it’s never a good thing.

Monoculture doesn’t really occur in nature. However, in the ocean where we don’t have fences and we’re not keeping things out, if we’re getting mussels rehabitating areas and fish in nurseries, already we’re building a lovely ecosystem. But it’s one of those things just to have in our mind of, if we had thousands of hectares of a single species of seaweed, what are the potential negative effects of that?

So it’s, again, net benefits I can see for seaweed farming, but it’s being cognizant of other flow-on effects.

PH: Well, from what you’re saying, it sounds like it would be very difficult to have an artificial monoculture with seaweed farming. And Andrew, perhaps this is something that’s more your area.

AJ: You place anything in the marine environment and there’s lots of things going to settle on it and establish. That’s certainly what we found looking at mussel farms and kelp farms, you’re establishing a whole lot of biodiversity, basically establishing a little mini-ecosystem around the farm and some of that is good for the farm, it’s helping to keep the water clear so that the light penetrates a little bit deeper from the filtering animals.

Some of it’s not going to be so good because you’re going to probably get fish that eat seaweed coming in and inhabiting those areas. You’re going to lose some of your production. You’ve got to work with the ecosystem that you’re operating in and trying to keep any of those out, as Clare explained, you can’t put a fence up to keep the rabbit fish off your seaweed

10. EXOTIC CAULERPA AND ROGUE SEAWEED (35:08)

PH: I just had a thought around those kina that you said were going rogue. There’ve been a lot of signs being put up on my local beaches around here, talking about exotic Caulerpa and this invasion that’s come into New Zealand waters. You mentioned, Andrew, just anecdotally in one of our discussions, that you were doing some preliminary work around seeing how this exotic seaweed could be, or first of all, could you tell us why Caulerpa is such a problem?

AJ: We have several native Caulerpa species in New Zealand and they’re part of the ecosystem. We’ve accidentally introduced two species from overseas and they do rather well, particularly in the northern waters where they’re being introduced. They form thick mats on the seafloor and basically smother marine life that lives on flat seafloor areas and exclude other organisms.

And there’s been similar Caulerpa species introduced in places like the Mediterranean. They’ve had very significant impacts, particularly on fish production and on seafloor organisms. Some of the work we’ve been doing has been trying to work out a way of killing this seaweed to try and basically contain it, or even eliminate it.

There’s others who are also working in that space, and there’s some active programs. I think even Clare’s company has been looking at harvesting it and seeing if there’s a potential way of utilising it for commercial use. With our study, we’ve been looking at using intense ultraviolet light as a way of sunburning them and killing them.

And certainly one of the species looks very vulnerable to ultraviolet light. And so we’re just finishing some sea trials at the moment, which look very positive. And we’re starting to import a bigger, bigger unit, a massive UV lamp to basically run some larger sea trials to see if we can start to use the technique to control it in some areas.

PH: Clare, I’d be interested in hearing more about how you could potentially utilise this invasive species.

CB: We were pretty worried about the spreads and what had been happening. So we looked to run a bit of a trial to see if we could make a nanocellulose scenario out of it, like we’ve done with Ecklonia. It turns out that it’s a kind of a unicellular, it doesn’t have the same sort of structure as our kelps, but we did manage to make xylose, like a sugar out of it, which could be interesting for platform materials, but it’s not really our area. We did see that we could make something out of it. The whole point there was, could we create something that then feeds back into the eradication efforts? Because it’s costly to do all this work. There’s large areas that it has taken over and we’re going to need all hands on deck.

11. CONCLUSION: NEXT STEPS FOR AQUACULTURE (38:00)

PH: To finish off, I’d just like to hear what are the next steps for both of you, Andrew, next research steps for you into seaweed farming. Is there any work there?

AJ: There’s lots of work to do with seaweed farming. Where do I start? We’ve got over 900 species of seaweed to work with in New Zealand. Many of them we know very little about. I suspect many of them have got valuable chemicals and ingredients that we could utilise.

We really need to get to grips with that relatively quickly, and we also need to understand more about some of the species that have got potential about how we actually grow them efficiently. Are they easy to grow or aren’t they? And if they are then that provides a path forward for starting an industry. And I think those are some of the things we need to be having a closer look at.

PH: And Clare, what are the next steps for AgriSea?

CB: AgriSea have a lot of long term plans around how we can create value from seaweed. We’re really clear that we are not seaweed farmers. We are seaweed innovators. We try to create the value for seaweed farming to happen as a commercial activity in New Zealand. I think that the work that we do as ANZSA, as a sector group, is really important in terms of, like Andrew said, where do you start? There’s a whole range of species and things that we can look at. We’ve been working on a prioritisation plan for, what do the target species look like? Are there markets? Are they multi-use? Is it high-value? Can we scale it? Have we closed the life cycle so we can farm it?

Which then whittles down some species and what they are best used for. Focusing on that prioritisation of area of focus, as well as working really closely with the government to understand the regulatory barriers, and sometimes those regulations are there for really good reasons. But there’s also some complexities and maybe just a lack of understanding about how we can work with and through those regulations. Demystifying it for people who would be and want to be seaweed farmers. So again, it’s about that education into our people who are going to look at seaweed farming and prioritising where we put our time and energy behind.

PH: Well thank you, both of you, for your time. This has certainly been a lot to think about with regards to aquaculture, seaweed farming, some of the benefits and some of the uses for Aotearoa New Zealand.