Around this time last year, Grieg Seafood’s British Columbia salmon farming operations were battling a major harmful algal bloom that ultimately led to the loss of over 50 percent of the company's total biomass in two of its BC locations.

But that was actually good news, according to Rocky Boschman, managing director at Grieg Seafood BC.

"Ten years ago, I'm certain we would have lost 100 percent of the fish," he told IntraFish. "Sometimes Mother Nature kicks you so hard you don't have an answer for it. But you can measure improvements over the years."

Grieg’s first-quarter financial report showed harmful algal blooms continue to represent a "high biological risk" for British Columbia. Fish survival rates for Grieg's BC operations in 2019 decreased to 87 percent, a 6.5 percent decline from the previous year.

And those statistics could also be much worse if not for the company's measures to mitigate the effects of algal blooms, he said.

About three years ago, Grieg BC installed new aeration systems at all of its farms. The company has also installed skirt systems at the two farms that were impacted by last year's algal blooms.

The skirts, which the company touts as a non-chemical treatment option for sea lice, are designed to protect newly released smolt in the sea, and Boschman said they are providing other advantages.

"We've seen data to show they're doing what we hoped they would do," he said of the skirts. "They're further stabilizing the environment within the pen. In a way, we've created a semi-enclosed farming system, a barrier to the plankton moving into the pen. With aeration, we're able to stabilize the temperature, oxygen and salinity inside the pen."

Grieg BC also has its own plankton monitoring program.

"Within Grieg BC, we have a couple of very expert personnel whose only job is to focus on plankton, to research plankton, and to be that resource to the farmers on a 24/7 basis," he said.

Dry weather bodes well for BC salmon

Nicky Haigh, a BC-based senior phytoplankton analyst and CEO of Microthalassia Consultants, told IntraFish things have been quiet in BC this year compared to last year, though the alagal bloom season has only begun.

Last summer a large snowpack and unusually warm weather contributed to an increase in the number of harmful algal blooms in the region, she said.

But this year, there is a below-average snowpack -- veering on 40-year lows -- and meteorologists are predicting an unusually dry season as a result.

What happens in Norway stays in Norway

It's unlikely BC would experience anything similar to what occurred has been occurring in Norway over the past month, where a algal bloom known as chrysochromulina has killed millions of fish.

"The losses in Norway are amazing," she said. "It's way more than we've ever seen here in the way of mortalities."

BC has a more robust plankton monitoring program than other salmon farming regions, largely because its industry has been dealing with algal blooms consistently since the 1980s.

"We're the ones who have, over the years, become the most proactive about looking at plankton because we have had the most problems with it," she said.

The chrysochromulina strain is the third most common strain of harmful algae in BC, and the region lost fish to that particular bloom in the late 1980s and early '90s, she said. But its threat today is not as significant as heterosigma akashiwo, which was responsible for Grieg's losses last year.

"We get heterosigma bloom on the coast every year; we've had maybe one or two years out of 20 where we've been doing harmful algal bloom monitoring that we haven't seen a heterosigma bloom," Haig said.

Haigh has been the program manager and senior phytoplankton anaylst of BC's Harmful Algae Monitoring Program (HAMP) since it was formed in 1999.

The program was started on the impetus of BC salmon companies and includes salmon giants such as Grieg as members.

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Aquaculture

Grieg BC chief heads confidently into algal bloom season