A new food frontier
‘‘It’s a huge opportunity . . . we have a blank canvas here to do it right.’’ Kevin Heasman, Cawthron Institute aquaculture scientist
The open ocean is calling to aquaculture as a new frontier, and scientists are optimistic for the future of the industry.
Cawthron Institute aquaculture scientist Kevin Heasman said open or ‘‘exposed’’ ocean aquaculture, which Cawthron had been studying since 2003, had ‘‘huge potential’’ for existing industry organisations and for newcomers that didn’t have access to sheltered coastal areas.
Open ocean farming had the potential to turn vast swathes of the ocean into productive space with minimal negative impact on the environment, and potentially provide greater resilience in the face of climate change, Heasman said.
‘‘It’s not going to replace existing aquaculture – it’s going to expand it.
‘‘From a New Zealand perspective, we’ve got all this water, we’re lucky in that we don’t have a close neighbour – that makes [open ocean aquaculture] quite attractive.’’
The United Nations recognises about 6 million square kilometres as New Zealand, and the vast majority of that space is ocean. Aquaculture currently only takes place relatively close to the shore, taking up less than 1 per cent of the coastline.
Cawthron has three experimental open ocean mussel farms – in Pegasus Bay, Hawke’s Bay, and the Bay of Plenty – in conjunction with organisations in the aquaculture industry, including iwi Whakato¯ hea in Opotiki.
Results have been promising, not only for mussels but for finfish as well. NZ King Salmon this year successfully trialled open ocean salmon farming in Cook Strait, and is looking to expand down the South Island’s east coast.
In 2016, New Zealand’s aquaculture sector generated over $500 million in revenue and employed more than 3000 people. It has a goal of reaching $1 billion in sales by 2025.
Cawthron received a $6 million fund from the Ministry of Business, Innovation and Employment for research in 2016, which has gone towards practical testing of conditions, structures, and the environmental impact.
Heasman said the process so far had involved testing things like how farmed species such as mussels and seaweeds performed in the open ocean environment, what other organisms frequented or influenced the farms, and how the farms influenced their surroundings.
‘‘It’s a huge opportunity, and we’ve learned from past mistakes, not just in aquaculture but generally. We have a blank canvas here to do it right.’’
A lot of the research was going into the structural requirements
needed to withstand open ocean conditions, he said.
‘‘The biggest challenge at the moment is technology, being able to get something out there that’s cost-effective, sustainable, and suitable for the animal.’’
Heasman said the open ocean didn’t have to mean a long boat trip out to sea, but could be any location exposed to the rough conditions that bays were sheltered from.
‘‘It doesn’t necessarily mean 200 kilometres out to sea. If you’re 5km off the East Cape and a storm comes past, you would feel pretty exposed . . . going into open ocean means you have to adapt to that energy.
‘‘You might have a wave that takes 14 seconds to pass and is nine metres high, or you might have a short choppy wave that’s 2m and over in eight seconds, and structures need to withstand both.’’
Aquaculture farms in the open sea were more mobile, he said, so warming temperatures or changing conditions could lead to whole farms being moved, for example.
‘‘Things are going to change – we have to accept that. But what we have to do now is learn as much as we can and change with it.’’
The Marine Farming Association, Sanford and Whakato¯ hea were approached for comment.
The Cawthron Institute is hosting a symposium on open ocean aquaculture next month, aimed at bringing everyone from industry experts to complete newcomers up to speed on the potential of the venture and the role in climate change adaptation offshore aquaculture could have.
There will be speakers on the science and engineering challenges of exposed aquaculture from Norway, Germany and Cawthron.