This project used acoustic transmitters to tag sockeye salmon smolts in British Columbia’s Tsilhqox Biny (formerly known as Chilko Lake). Researchers from the Ocean Tracking Network (OTN) examined how environmental and genetic characteristics influenced salmon migration, behaviour and survival as young fish made their first migration from rivers to the open ocean.  

This was one of the first studies to use miniaturized transmitters in a large-scale tracking project of juvenile salmon, with more than 2,500 fish tagged. The project revealed the technical feasibility of tagging smaller smolts with the new tags; previous tag models would have been too big for 98 per cent of the population. 

Tracking revealed that more than half of the tagged fish did not survive river movements to enter the open ocean—a distance of more than 1,000 kilometres. Further results showed distinct patterns in both behaviour and survival—in small, clear, upper-river reaches, downstream migration largely occurred at night at speeds of up to 50 kilometres per day and coincided with poor survival. Only 60 to 80 per cent of smolts survived the first 80 kilometres of their downstream journey. 

A parallel laboratory study of tagged fish documented high short-term survival and unhindered swimming ability, eliminating negative effects of tagging as a mortality cause. This suggested that, in nature, predation was the main source of mortality in smolts. Additional field work documented large scale predation by adult bull trout, which fed almost exclusively on sockeye smolts. 

Yearly workshops put on by the OTN Pacific salmon group include other academic stakeholders, government, community, and ENGOs. This group has also helped author CSAS reports in order to improve management of Pacific salmon at the federal level.