Bras d'Or Lake location of choice for smolting salmon, study finds

An eight-year study shows healthy salmon smolts tend to stay in Bras d'Or Lake in Cape Breton instead of going directly into the ocean.

The study traced salmon migration from Middle River to Bras d'Or Lake using electronic tags to track the fish.

Researcher Bruce Hatcher, the director of the Bras d'Or Institute at Cape Breton University, says the lake is a good place for salmon to go through smoltification, the process where they change from being freshwater fish to saltwater fish.

"They have to go through an … adolescent transition from being a juvenile fish, called a smolt, to being a young adult salmon and that is associated with, as with humans, with major physical changes in their body," he said. 

Mi'kmaq knowledge incorporated

He says that near the entrances of the lake the salt water is not as salty as the ocean.

The smaller salmon tended to go straight to the ocean, which was just over half of the tagged fish.

"Our current working hypothesis on that is the Bras d'Or Lakes are not as productive as the ocean and there's not as much food available."

Alicia Penney, a graduate student from CBU who was a part of the study, said they also used knowledge from the Unama'ki Institute of Natural Resources in Eskasoni to help get their results.

"This is where the hypothesis for this paper has come from that some of these salmon are able to continue their life cycle in the Bras d'Or," she said. "We've drawn on that long history of traditional knowledge."

She says the results will help them understand the salmon populations.

Want to curb decline

"The more we know about, the better we can manage these populations and make sure that we don't accidently contribute to their decline any further," said Penney.

Hatcher says they are now looking at the adult salmon migration in the Bras d'Or Lake.

The study was conducted by several institutions that are part of the global Ocean Tracking Network headquartered at Dalhousie University.