“The study started just due to interest and a lack of understanding as to how these fish are behaving and their survival as they are migrating downstream,” said Jason Daniels, a research scientist with the federation and report co-author.

The complex technical study tracked more than 2,800 juvenile wild Atlantic salmon, known as smolt, from populations in four rivers that empty into the Gulf of St. Lawrence. They include the Southwest Miramichi, Northwest Miramichi, and Restigouche rivers in New Brunswick and the Cascapedia River in Quebec.

Smolt were collected each spring as they made their way downriver and were tagged with small acoustic transmitters that monitored migration speed and survival rates.

“Across the 14 years of study survival estimates varied without trends for the population of the Chaleur Bay, but declined for the populations migrating through Miramichi Bay,” the study report says.