Biologist ‘gobsmacked’ the salmon sperm he helped freeze 20 years ago may now boost a dwindling stock

After a particularly bad year for salmon returns because of a landslide near Big Bar, the Carrier Sekani Tribal Council partnered with the Spruce City Wildlife Association in Prince George, to use salmon sperm they cryogenically froze 20 years ago, to try to replenish a Chinook salmon stock.

Dustin Snyder, a spokesperson for the Spruce City Wildlife Association, said that 1,600 out of the 2,000 eggs they fertilized in September have survived. This is lower than what they usually see when using fresh salmon sperm, or milt, but they are excited to be reintroducing genetic diversity that has likely been lost.

Biologist Brian Harvey helped the Carrier Sekani collect the milt 20 years ago in the Endako River and was “gobsmacked” when he heard they’re now successfully using it. 

“When I heard about it, I mean the first thing I thought [was it’s] fantastic because that’s why it was done all those years ago… It’s kind of a genetic insurance policy,” he said. 

“Carrier Sekani was certainly among the most keen and I think what really hit me when I learned that they had done this, is that they hung in there for 20 years,” said Harvey, who took this photo 20 years ago while out in the field. (Photo by Brian Harvey)

Right now, the eggs are still in the process of growing at Spruce City Wildlife’s hatchery in Prince George, said Christina Ciesielski, Carrier Sekani’s fisheries program manager, a program which monitors river and fish health.

The eggs will remain there until the spring when temperatures are warm enough to release the smolt into the Endako River near Burns Lake.

“Everything seems to be good. So we try to disturb them very, very rarely just because they are so sensitive right now,” said Snyder.

These salmon are not part of the three runs that scientists say are at complete risk of extinction after the landslide in the Fraser River this year, however their population has steeply declined. 

Insurance policy

Harvey was not involved with fertilizing eggs with cryogenically frozen milt in September, but he trained members of the the nation 20 years ago how to cryopreserve salmon sperm in the field using a method he developed with portable cooling containers. 

“I was promoting it as something that could be used as a kind of insurance policy or a backup, because we were losing a lot of genetic diversity in salmon stocks,” he told Radio West host Sarah Penton.

“So it was groundbreaking, I think, in the sense that we we did find who wanted to do it and a lot of cases it was First Nations. Carrier Sekani was certainly among the most keen and I think what really hit me when I learned that they had done this, is that they hung in there for 20 years.”

The idea was “not an easy sell back then,” said Harvey.

“I was the guy who was driving around in his Honda Civic with liquid nitrogen and trying to get people to freeze salmon sperm.”

The salmon eggs after they were fertilized with 20-year-old milt. (Submitted by Spruce City Wildlife Association)

Harvey said while some were really enthusiastic about the idea, others were resistant to it, because they were concerned having a “backup” would stop people from addressing the issues that are causing salmon populations to dwindle in the first place.

“The argument against it is a very good argument, which is if you do what’s called a ‘techno fix’, like freezing sperm, starting a gene bank, then that means you’re not going to do all the things you really should be doing like saving and controlling overfishing and reducing pollution, and especially restoring the environment,” he explained.

‘It’s wonderful’

Ultimately, Harvey is glad that by freezing milt 20 years ago, it’s been a helpful backup for when unforeseen circumstances, such as the massive rock slide near Big Bar which hindered the salmon migration this year, decimating some salmon stocks.

“That had nothing to do with with restoring the environment or anything, it was just the hand of God,” he said.

“And so that’s what this was for. It seems to have worked. It’s wonderful.”

The landslide near Big Bar has not been entirely cleared yet, and until it is, all salmon that migrate through the Fraser River remain at risk of not reaching their spawning grounds.   

Read more at CBC.ca