Session Name: Contributed
Presentation Title: Phenological diversity of salmon smolt migration timing within a large watershed and
implication for match-mismatch dynamics
Presenter Name: Charmaine Carr-Harris
Authors: Charmaine N. Carr-Harris*1,2, Jonathan W. Moore2, Allen S. Gottesfeld1
Skeena Fisheries Commission, 3135 Barnes Crescent, Kispiox BC, Canada V0J 1Y4 (email:
charmaine@skeenafisheries.ca, Tel: 1-778-789-3234)
Earth to Ocean Research Group, Simon Fraser University, 8888 University Drive, Burnaby, BC Canada,
V5A 1S6
Abstract: While there is growing concern that climate change might drive phenological mismatches
between predators and prey, it is possible that within- and among-species phenological variation may
provide resilience against such mismatch. One key life-history event that may be vulnerable to climateinduced mismatch is the seaward migration of juvenile salmon, an economically and culturally important
group of species, in relation to seasonal abundances of marine zooplankton. Here we quantified
phenological diversity of outmigration timing among salmon subpopulations within a large watershed
and its implications for climate-induced phenological mismatches with their zooplankton prey.
Specifically, we sampled juvenile sockeye salmon throughout the spring and early summer in the estuary
of the Skeena River, a vast watershed with numerous locally adapted salmon populations that supports
commercial, recreational, and First Nations fisheries, and used genetic stock identification to link the fish
to their populations of origin. We found that sockeye salmon were migrating through the estuary for at
least 50 days, with peak emigration for different populations varying by over 5 weeks. The outmigration
timing of specific populations was related to geographic factors including elevation of the rearing lake
and the river distance between individual rearing lakes and the estuary, with different populations
arriving 2 days later for every 100 m of elevation, or 4 days later for every 100 km of river distance.
Concurrently we quantified the estuarine prey of juvenile sockeye salmon and discovered that
zooplankton species composition and abundance varied throughout smolt migration period and the
different salmon subpopulations encountered different prey abundances upon ocean entry.
Furthermore, this marine ecosystem has warmed by over 0.7 °C over the last 50 years. Together these
results indicate under-appreciated phenological diversity in this harvested meta-population, suggesting
potential population-level response diversity and metapopulation-level resilience to climate change.
Student presenter: Yes
Presentation type: Oral