Young Chinook salmon will be grown in this new tank once systems to pump in fresh ocean water and oxygen and remove waste have been installed and tested. (Courtesy of AgriMarine Holdings, Inc.)

B.C.'s first closed, floating salmon-farming tank — touted as a greener alternative to traditional open-net pens — has been installed off Vancouver Island.

The first of four tanks to be used in a commercial-scale salmon-farming operation has been placed in the water of Middle Bay in Campbell River, B.C., Vancouver-based AgriMarine Holdings Inc. and the Middle Bay Sustainable Aquaculture Institute announced Monday.

The research institute, which develops closed-tank technologies for fish farming, is funded by a consortium the includes AgriMarine, Coast Sustainability Trust, the U.S.-based Gordon and Betty Moore Foundation and Sustainable Development Technology Canada, a federally funded agency.

Young Chinook salmon will be grown in the tanks once systems to pump in fresh ocean water and oxygen and remove waste have been installed and tested. For the first tank, that will be complete in the next two weeks, the company estimates.

Each tank, like the one shown here during installation, can hold about 50,000 to 75,000 fish. They start off finger-sized and reach market size in 12 to 14 months. (Courtesy of AgriMarine Holdings Inc.)

The operation has a licence to produce 1,200 tonnes of salmon a year.

Traditional net pens used for salmon farming in B.C. are open to the ocean and have been criticized for damaging the marine environment. Fisheries scientists have found evidence that salmon farms transmit parasites and pathogens such as sea lice to wild salmon, leading researchers and environmental groups to call for closed-pen farming.

In addition, waste from open-net pens is released directly into local waters and is not always carried away by tides and currents as was anticipated.

The new closed tank is a "significant milestone in the transition toward more sustainable salmon farming practices," said a news release from the Coastal Alliance for Aquaculture Reform, a coalition of environmental groups that include the Suzuki Environmental Foundation and the Georgia Strait Alliance.

'We feel we can be cost-competitive'

AgriMarine has tried growing fish in land-based tanks in B.C. — something that is done in Washington state — but found it too expensive, said company spokesman Travis Schneider. Land-based systems need additional temperature control and more complicated water-pumping systems.

This young pink salmon has been infected with sea lice, a problem fisheries scientists say is made worse by open-net salmon farms. (Alexandra Morton/Science)

With the new floating-tank technology, however, "we feel we can be cost-competitive" with net pens," Schneider added. The temperature is regulated by the surrounding seawater and can be adjusted by pumping water from different depths.

It has already been used for growing freshwater trout in China.

While net pens are cheaper to make, the floating tanks last longer and make feeding cheaper and more efficient, because none of the feed falls out as it does with net pens, Schneider said. The resulting feed savings more than offset the costs of pumping and oxygenation, he added.

"You basically get the environmental benefits for free."

However, retailers may be able to charge a premium for "eco-salmon" raised in closed pens, he said.

Because the tanks are expected to have a minimal impact on surrounding waters, Schneider expects the technology will make it possible to locate fish farms closer to urban centres. The collected fish waste may be used as fertilizer.

Ruby Berry, a spokeswoman for the Georgia Strait Alliance, said the new technology not only has benefits for the surrounding environment but also gives fish farmers more control over the quality of water their fish grow in.

"There's very high demand for fish grown in closed containment," she added.