Reimagining native aquaculture in NZ with low impact on fish and environment

Plant & Food Research is trialling a native snapper (tāmure) at its first prototype open ocean aquaculture development near Rangitoto ki te Tonga, D’Urville Island at the top of the South Island. 

Comprising pen, feeder buoy, mooring and supporting technology, the system is claimed to be the first of its type and it’s also the first time a new finfish species has been trialled in New Zealand away from the sheltered coastline; currently only Chinook salmon is raised commercially in sea-based aquaculture.

The leader of the Whakapōhewa ki ahumoana – Reimagining Aquaculture program for Plant & Food Research in Nelson, Dr Suzy Black, said it was good to see the 2000 snapper settle into their new ocean home after more than nine years of research towards this development of a low-impact, open ocean mobile aquaculture system designed around the needs of the fish.

“We transferred our snapper to the pen in April because the sea is still comparatively warm now, which they like.

“These are snapper raised from wild stock held in our finfish facility onshore, so the ocean is very much home for them; although this particular generation may see a few interesting sights for the first time — with potential visits from fur seals, sharks and other new friends,” Black said.

Dr Suzy Black

The pen is submerged approximately 10–15 m below the surface to protect the fish from the turbulence of waves. The prototype is tethered to the sea floor via a mooring and will swing around the mooring naturally every 12 hours with the tides, within the bounds of four navigation aids (cardinal marks) that mark the four corners of the trial area.

While fish health is the focus of this trial, the ultimate aim is the creation of a mobile system that can move around the ocean, development of which continues onshore.

“This really is ‘reimagining aquaculture’ — it’s blue-skies thinking for the blue economy where finfish aquaculture is designed around the needs of the fish and has a low impact on the environment in the open ocean.

“There are many ways the pens could be mobile — pens could be moved around a series of moorings at different times of the year depending on water temperature, or a more ‘Roomba-style’ autonomous pen could slowly move around within the bounds of predetermined area,” Black said.

Another first is yet to come when Black’s team transfer Chinook salmon (hāmana) to the pen (replacing the snapper) during winter; currently Chinook salmon (also known as King salmon) are farmed in pens in sheltered waterways in commercial aquaculture operations.

“Once we have seen enough of how snapper grow and cope in an open ocean pen, we will swap them out with salmon. These are proof-of-concept trials and knowing that yes, we can successfully raise a new aquaculture finfish species like snapper as well as a valuable species like Chinook salmon in the open ocean is very exciting. This research is of huge interest to the aquaculture industry and to the government who continue to invest in the economic and environmental potential of open ocean aquaculture,” Black said.

Image credits: Plant & Food Research