Open Ocean Aquaculture Trial

Plant & Food Research scientists have been developing an open ocean-based aquaculture system since 2016. It is an ambitious project to help address the need to produce protein for a growing worldwide population and support New Zealand’s thriving bioeconomy. At the heart of the system is a relocatable fish pen, able to be moved according to the biological requirements of the fish species and the environmental conditions it might be subject to. At the beginning of 2025, the prototype and systems supporting it were being tested in ocean conditions. 

In-shore aquaculture has been developed over many years in this country, but a bigger challenge is to develop systems able to support healthy fish growth, prevent any adverse effects on the marine environment and withstand the physical impacts of sometimes harsh and unpredictable offshore conditions. 

Dr Suzy Black is the Science Team Leader for Physiology and Behaviour in the Seafood Production Group at Plant & Food Research in Nelson. She explains Open Ocean Aquaculture is fish farming fish in less sheltered waters, some distance from the coast. 

Suzy says, “we’ve taken a stepping-stone approach towards being fully mobile, with the first step being development of a fish enclosure that will be tethered to a swing mooring. A thorough iterative prototyping process was undertaken by our talented team who brought together expertise in fish biology, engineering, oceanography and fluid modelling.” 

By March 2025, they were ready to test the entire system at sea, with fish in the enclosure. 

For the pilot project, the pen (smaller than commercial structures in use currently) was attached to a swing mooring and submerged 10-15 metres below the water surface. 

“We have carried out targeted studies to understand more about fish behavioural preferences, particularly around water flow and temperature. Another consideration was to utilize the power of the ocean. So, using soft-structure engineering rather than more and more steel.

Sustainability is also important. A system with low emissions and a minimal environmental footprint is essential. We also see opportunity around scalability, in that the fish enclosures could, on the one hand be very large, but then on the other be relatively small, meaning reduced barriers for investment and operation.” 

The pen was initially stocked with snapper in the summer months, to be followed by Chinook salmon (or King salmon) in winter. But, Suzy explains, “The vision is to eventually assess several other species, such as trevally, as to their suitability for production in the open ocean.” 

The potential contribution of this work to New Zealand’s bioeconomy is significant. Suzy explains, “we would see a significant increase in export earnings, as well as driving new manufacturing and export opportunities in the marine engineering and technology sectors and increasing skilled jobs in the regions. As well, the development of highly scalable, mobile production systems gives New Zealand the flexibility and resilience to cope with, and even capitalise on, changing climatic conditions.” 

 Plant & Food Research has management plans and protocols in place to mitigate potential environmental effects. As the trial is a relatively short time frame and small scale, and there are no sensitive habitats within 2km of the site, any effects are expected to be minor. 

Dave Taylor is the Technical Director for Aquaculture New Zealand (AQNZ) the national industry body for our aquaculture industry. He explains, “we are a small, dedicated team, proudly representing our marine farmers who sustainably produce premium King Salmon, Greenshell Mussels and Pacific oysters for the world. We provide support for industry in the areas of policy and planning, environmental sustainability, resilience and productivity, workforce,

communications, and marketing, and we also run what we think is New Zealand’s best primary industry conference from our offices in Wakatu, Nelson.” 

AQNZ is focused on helping the aquaculture industry continue to shape the future of sustainably produced seafood, delivering tangible benefits to rural communities, and help New Zealand transition to a lower-carbon economy. Māori are an important part of aquaculture’s future, he adds. Potential future opportunities for Māori are hardwired through the Māori Commercial Aquaculture Settlement Act, so their fortunes mirror the sector’s fortunes, and vice versa. They are already significant participants, pioneers, and innovators in marine farming and with several Māori interests with both long-standing and new involvement in aquaculture activities. 

Dave adds, Open Ocean Aquaculture (OOA) offers a transformative opportunity to sustainably expand its seafood sector, targeting a $3 billion industry by 2035. Primarily driven by salmon farming, this growth can be achieved with a relatively small footprint, at strategically located farm sites on the South Island's east coast. 

Dave adds investment confidence in the sector has been boosted by the recent Extended Duration of Resource Consents for Marine Farms Act, which has given consent certainty for the industry. Reaching the $3 billion goal is likely to come from increased production from existing inshore and newly consented open ocean marine farm space. “This expansion promises substantial economic benefits, including increased export revenue through maintaining its premium price point in the global market, regional job creation, while reinforcing New Zealand's commitment to environmental sustainability.” 

This research has been supported by MBIE’s Endeavour Fund ‘Reimagining Aquaculture’ programme and PFR’s Ngā Pou Rangahau Growing Futures Ngā Tai Hōhonu Open Aquaculture MBIE’s Strategic Science Investment Fund (SSIF).

https://www.plantandfood.com/en-nz/open-ocean-aquaculture

https://www.aquaculture.org.nz