Migration of Atlantic salmon smolts and post-smolts in the RiviSre Saint-Jean, QC north shore from riverine to marine ecosystems

The characteristics of the Atlantic salmon (Salmo salar) smolt run of the RiviSre Saint-Jean, Quebec, Canada, in 2009 and 2010 were determined using acoustic telemetry. Tagged smolts were tracked from freshwater release sites for 17 km, then through the estuary and for their entry into the Gulf of St. Lawrence. The smolt migration began in both years at water temperatures of 10 A degrees C, but lasted twice as long in the cooler year. The smolts in 2009 crossed the river to ocean boundary faster than the smolts of 2010, despite being similar in size. Smolt speed over ground increased from the river to the estuary to the marine environment. Smolts migrated both during the day and the night, but most movements began near or just after sunset, with increasingly nocturnal movements in the ocean. Smolts crossed the estuary during ebbing tides and moved faster during the night than the day. The tide cycle also influenced estuarine smolt travelling rates, but only secondarily to the diel cycle.