A particularly important and sensitive period for salmon is the smolt life stage – when, after time spent in freshwater nursery areas, they transform themselves for life in saltwater and make the long migration to the sea. Very little is known about this life stage, and past research has mostly been limited to laboratory studies or snapshots of smolt distributions at sea. Advances in technology have allowed researchers to begin to better understand the factors that affect the migration of salmon smolts.
Using a technology called acoustic telemetry, the Pacific Salmon Ecology and Conservation Laboratory at the Faculty of Forestry is gaining insight into the life of wild smolts. The research group has been surgically implanting very small acoustic transmitters into smolts as they leave their natal lakes and head towards the ocean. The fish are then tracked using various underwater listening stations.
Nathan Furey, a doctoral student in the Department of Forest and Conservation Sciences, along with his research group (led by professor Scott Hinch) are looking to better understand the behaviour of smolt, and the factors that contribute to their survival.
Furey describes the group’s research, “For this work, our research group has largely used the Chilko Lake population as a model – an important stock of Fraser River salmon that spawn and rear over 600 km upstream from the ocean. Our research group has spent multiple years tagging salmon smolts in the spring as they leave for the sea, using small acoustic tags. Those tags each transmit a unique acoustic barcode that is heard and recorded by underwater listening stations throughout their migration route from the Chilcotin region, down the Fraser River and up the BC coast.
We use this data to understand what biotic, environmental, and oceanographic factors affect smolt behaviour and survival. Similar to work we pioneered on adult fish 10 years ago, we also are able to non-lethally biopsy smolts as we tag them, allowing us to compare their disease status and physiological state at release to subsequent success in migrating through the Salish Sea.
Furthermore, this work allows us to better understand the migration behaviours and routes used by smolts as they navigate the Salish Sea. This type of information is being used to develop simulation models to better understand how individual behaviours and ocean conditions interact to affect the marine migrations of salmon smolts.”