Nelson researchers are a step closer to developing a way to grow the likes of oysters, scallops and seaweed in deeper, rougher water.
About 45 minutes from Nelson, in the heart of the Tasman Bay, the Cawthron Institute is using what used to be a mussel farm to trial how to grow the seafood in the open ocean.
Cawthron’s programme leader Kevin Heasman says the site, which is about 23m deep, is perfect for testing.
“It can get quite rough out here but not as rough as it would in the full open ocean. So, this is like a transition site where we can test things and if things are successful, we can move it right out into the more exposed sites.”
At the site, below the surface, is an experimental structure that the team designed to sit about 11m underwater. The oysters, for example, are in small boxes, inside a larger custom-built contraption.
The trial species are usually grown closer to shore, in more sheltered conditions, but with climate change and less space available the researchers are hoping to give the aquaculture industry more options.
“It’s not the silver bullet,” Heasman said. “It’s not a case of everyone’s going to move out here. But it provides new opportunity, new sites, new water conditions.”
This week the Cawthron team travelled to the site to check on the progress of the oysters and scallops. First they pulled up the oysters, which are relatively robust, and were happy with their size.
But the scallops are what the team was holding their breath about. They’re a more delicate seafood to farm, don’t like to be moved around, and cannot be out of the water for long. But fortunately, they were larger than expected and most had survived.
Cawthron’s operations co-ordinator Nicholas Scott said it can be a bit stressful.
“When you put things in the water for three months and just wait to come out three months later and you see that result, it’s really positive,” he said.
It’s hoped more species could be added to the trial, which will continue for three seasons, giving confidence to the aquaculture industry to develop commercial models.
