Student fisheries research in BC: Nathan Furey

Nathan Furey (University of British Columbia): Variability in migration routes influence early marine survival of juvenile salmon smolts

When considering migrations by salmon, most think of the upstream spawning movements by adults. Although less visible, the downstream migrations by juvenile salmon “smolts” are no less impressive as they leave natal lakes and head to the open ocean. For many Pacific salmon, the Strait of Georgia represents not only the first exposure to estuarine or marine waters but also an important migratory corridor to the open Pacific. How smolts move through the Strait of Georgia, however, is largely unknown, nor how migratory route can influence migratory success. Over the past decade, acoustic telemetry has been used to track movements of individual salmon smolts through the Strait of Georgia to the Pacific Ocean. We used information collected on over 850 sockeye and steelhead salmon smolts tracked with acoustic transmitters between 2004 and 2013 to characterize migration routes in the Strait of Georgia and link movements to subsequent survival. Both species exhibited disproportionate use of the most eastern route in the Strait of Georgia (Malaspina Strait). Steelhead using Malaspina Strait experienced improved survival to the Pacific Ocean. While many smolts moved across the northern Strait of Georgia acoustic array with no indication of long-term milling or large-scale east-to-west movements, large proportions (20-40% of sockeye and 30-50% of steelhead) exhibited a different behavior, apparently moving in a westward or counterclockwise pattern. Westward movements result in a net transport of smolts from Malaspina Strait to the Strait of Georgia, particularly for steelhead. Counterclockwise movements may be due to the currents in this area during the time of outmigration. We successfully described migration routes of smolts through the Strait of Georgia at a resolution previously unknown.

The paper was recently published in the journal Plos One and can be found here.

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The BC-Student Subunit is excited to present a series profiling recently published research by students in British Columbia. If you would like to have your research included, please contact Sean Naman (naman@zoology.ubc.ca) for more information.