A Vancouver Island biologist says that the decades-old practice of clipping the adipose fin on Coho salmon fry is hurting the fish and affecting their ability to compete in the wild.
B.C. hatcheries remove the tiny fins -- located near the tail -- while the fish are very small in order to keep track of returning stocks and differentiate them from wild salmon.
But when University of Victoria biologist Tom Reichen tested the swimming abilities of clipped fish, he found that fin-clipping impacted the salmon.
"The one that had the adipose was swimming more efficiently," Reichen told CTV News.
"The fish without the adipose fin had to move its tail about 10 to 15 per cent greater amplitude than one that had the adipose."
He says that means that adipose clipping could make hatchery fish less likely to survive.
"Hopefully, they'll eventually up come up with a method that's a little less invasive," he said.
But Scott Melville, manager of the Capilano River Hatchery in North Vancouver, says that adipose clipping is the least invasive way to mark fish, and there are no plans to end the practice.
"We've been doing it for 50 years and it's been pretty successful in identifying the things that we need," he told CTV News.
The Capilano River Hatchery clips more than 500,000 fry each year.
With a report from CTV British Columbia's Shannon Paterson
