‘Fantastic discovery’: Seafood company to use semi-closed pens to fight sea lice

Grieg Seafood Ltd.
Grieg Seafood fish-farming pens are shown.

An international seafood company with fish farms all over the world says trials have shown a dramatic decrease in the need for sea lice treatments.

Now, Grieg Seafood plans to build three semi-closed systems at its fish farms in Esperanza Inlet north of Nootka Island.

The company says more testing is underway but admits it accidentally discovered a potential way to protect its farmed salmon and wild salmon from getting sea lice.

Grieg was experimenting with a semi-closed system to protect farmed salmon from harmful plankton using enclosures that can be lowered and raised around fish pens. It then discovered the number of lice showing up in its farm was reduced dramatically.

“What we learned is that when the barriers were in place it really reduced the interaction between salmon on the farm and wild salmon moving by the farms,” said Rocky Boschman, Managing Director for Grieg Seafood BC Ltd.

“Not only was the mortality of our salmon lower, but there were way fewer sea lice on our farm. It really has been a fantastic discovery for us. There was literally almost no lice there and no treatment was needed.”

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According to the company, the system was used successfully to rear several generations of fish at Grieg’s farms in the Sunshine Coast region.

“This new system utilizes retractable barriers, which are capable of being lowered to 15 metres, fully encapsulating the sides of the farm,” the company said.

“This has several benefits, including preventing the lateral interaction of wild and farmed salmon populations, providing protection for farmed populations from harmful algae, and allowing our farmers to better control water quality in the system using a unique aeration technology.”

However, a west coast environmental group says Grieg’s plans are a false solution to the problems that salmon farming poses to wild salmon.

“When you look at what the problems are, the disease transfer, the transfer of lice back and forth, none of these problems would be solved by this. When they call it semi-closed containment, it’s much more semi than closed,” said Dan Lewis, executive director of Clayoquot Action.

The federal government says fish farming companies must transition away from open-net farms by 2025.

Clayoquot Action says in 2020, a report was released by Fisheries and Oceans Canada which stated floated closed containment requires another two to five years of further review. In other words, the technology is not ready, and will likely not be ready by 2025.

“Wild salmon in Clayoquot Sound are rapidly approaching extinction,” said Lewis. “In the Megin watershed, just north of Tofino in Ahousaht territory, the Chinook salmon population has declined by 98 per cent, with just 21 Chinook returning to the river in 2021.”

Meanwhile, Boschman said Grieg is “working really hard” to be a partner in sustainability.

“It’s good that people are challenging us, that’s what we are responding to,” he said.

Dean StoltzDean Stoltz

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