Nelson-based aquaculture firm New Zealand King Salmon Investments believes fish-farming in Cook Strait, using newly emerging submersible technology being developed in Norway, is the route to realising its ambitions for expansion.

Speaking in Norway last week, NZKS managing director Grant Rosewarne told BusinessDesk that accelerating advances in undersea fish-farming technology were a potentially game-changing development for the company, which has struggled with permissions both to expand and relocate its current operations in the Marlborough Sounds.

"I think we're on the cusp, for the first time, of having the prospect of realising a massively valuable industry," said Rosewarne, who believes farming of the high-value, Pacific King salmon variety could become as valuable as the dairy industry in New Zealand over the next 30 years, but at a fraction of the environmental cost and area required by dairying.

"What would be the capacity there? At least 100,000 tonnes," he said of Cook Strait's potential to host NZKS's future operations, which currently produce around 8,000 tonnes annually of the fish, which it sells locally and for export using nine sites in the Marlborough Sounds, covering a total of 17 'surface hectares' for total revenues in the last financial year of $136 million.


While its current sites could support 12,000 tonnes a year by 2032, Rosewarne's focus is on a much larger expansion, based in part on the example of Norway, which is seeking to make aquaculture and conventional fishing the country's largest industry as it starts the transition away from the oil and gas production which has made the Nordic country one of the richest in the world.

"Every (Cook Strait-based fish-farming) pen can produce a thousand tonnes, so could we fit 100 pens in there?" he said. "Every pen is about half a surface hectare, so you'd need probably 400 surface hectares - the size of a reasonable-sized land farm.

"But the value that would be produced would be exponentially greater."

Deployment of the first such pens was perhaps up to five years away and would require extensive testing first, he said. Norwegian innovations with submersible, offshore fish-farming are developing more quickly than expected, based on presentations to a large New Zealand contingent that attended last week's biennial global aquaculture conference, Aquavision, in the coastal Norwegian city of Stavanger.

"We'd probably start by putting a pen out there (in Cook Strait) and see what happens, not even put any fish in it, see if we can make it go up and down, see how we go with storms," Rosewarne said.

The company would need to find sites in the often rough waters of the strait between the two main islands of New Zealand that offered some shelter, was deep enough to ride out the biggest waves while submerged, and in areas where cold currents were prevalent.

The offshore farming concept gained cautious early endorsement from the head of the Environmental Defence Society's environmental policy group, Raewyn Peart, who also travelled to Norway for the presentations.

"If we're going to expand salmon farming, or fin-fish farming of that kind, I think the only option is to go offshore," she said in an interview with BusinessDesk.


"Marlborough Sounds is full, pretty much. So if we want to expand this industry, and it is certainly in global terms pretty small in New Zealand, we need to look at going offshore.

"It clearly deals with the issues of water flow, dispersion (of uneaten food and waste) and benthic (sea-floor) impacts if you're in essentially deep, fast-flowing areas. Of course, we have migratory whale species and resident whale and dolphin species, so there would need to be careful investigation of appropriate sites.

"If we can remove any conflicts out there, there will be far less landscape conflicts because they will be out to sea and presumably you won't be able to see them from shore."

NZKS is particularly focusing on emerging technologies that would allow fish-farms to be submerged, although how the fish would be fed and gain occasional access to oxygen, which salmon require, is still being developed.

Large, offshore structures such as ship-sized barges or oil platform-style farms, which were also displayed at last week's conference, are not being pursued for offshore fish-farming in New Zealand by NZKS.

That is because the company has been at the centre of one of the most significant Resource Management Act decisions of recent years, with the Supreme Court's 2014 ruling that protection of 'outstanding landscapes' trumped questions of economic benefit in resource consent applications.

NZ King Salmon new high flow Waiata farm in Pelorus Sound. Photo / Supplied
NZ King Salmon new high flow Waiata farm in Pelorus Sound. Photo / Supplied

The so-called 'King Salmon decision' saw the company granted just three of nine additional sites it had sought in the Marlborough Sounds.

It is now waiting on decisions, stalled under the previous government and now sitting with Fisheries Minister Stuart Nash, on applications to move several of its current installations to deeper locations in the Sounds with stronger water flows.

Peart welcomed statements from Rosewarne that NZKS had no interest in attempting to farm salmon in Fiordland, where Southland local government interests are examining the potential for the industry.

"We have no aspirations or plans around Fiordland," Rosewarne said.

The Ministry for Primary Industries primary industries outlook, published last week, identified aquaculture as the fastest-growing element in a forecast for annual seafood exports rising from $1.8 billion this year to $2.1b by 2022, with aquaculture export earnings forecast to reach $430m this year and nearly $600m in 2022.

- Pattrick Smellie travelled to Norway as a guest of Aquaculture NZ.