National Observer, Local Journalism Initiative Reporter
An international aquaculture company has launched a trial of a new salmon farm containment system expected to drastically reduce the exchange of sea lice between wild and farmed fish. Cermaq Canada has stocked close to half a million Atlantic salmon smolts in a new semi-closed containment system (SCCS) in Millar Channel on the west coast of Vancouver Island. It is the first time the technology has been tested in Canadian waters.
Sea Lice Issue
Salmon farm opponents have long argued traditional open-net pen systems promote the growth and spread of fish parasites along with other diseases. High concentrations of sea lice are particularly dangerous to wild juvenile salmon.
If the technology is successful, it might allay some concerns of aquaculture critics about the dangerous decline in wild salmon stocks on the B.C. coast.
The semi-closed containment system
The SCCS is a water-pressurized bag made out of a flexible, durable polymer material that surrounds the traditional net pen system — creating a barrier between the farmed fish and the open ocean.
Harmful algae and sea lice are generally found closer to the ocean’s surface, said Linda Sams, sustainable development director of Cermaq Canada.
One aim of the new technology is to keep those pathogens from entering the system by drawing in seawater from deeper depths (between 22 and 27 metres) where algae and sea lice are less likely to be, Sams said.
The system also greatly reduces the interaction between farmed and wild salmon, which, in turn, reduces the transfer of other pathogens between the two populations, she said.
“Our fish enter the ocean environment free from disease and pass through several rounds of vaccination and health monitoring before being sent to an ocean farm,” Sams said.
Farmed fish do encounter naturally occurring diseases, parasites and other organisms once placed in seawater, but Cermaq trials of the technology in Norway showed minimal introduction of such pathogens into the system, she said.
Additionally, the tarpaulin bag prevents wild fish from getting trapped in the pens, and keeps seals and sea lions out, preventing risk to the animals and damage to farm nets and fish, according to a Cermaq fact sheet.
Organic waste, such as food remains and fish feces, leave the system into the ocean through an exit at the bottom of the polymer bag.
The website of the company that produced the system for Cermaq, FiiZK, states the technology allows sludge to be collected and pumped to another location or filtered.
However, Cermaq Canada wasn’t able to clarify if the waste collection technology was being used with the system in its B.C. trial before publication deadline.
The cost of the new technology is up to five times more than traditional salmon farm systems.
One of four systems
The system is one of four that the Canadian government is examining as it develops its 2025 plan to transition away from open-net pen salmon farms on the Pacific coast.