We used genetic analyses to determine the origin of sockeye from Canada's two most important salmon rivers, the Fraser and Skeena; Fraser sockeye migrate through a region with salmon farms, and Skeena sockeye do not.
Consider, in contrast, sockeye salmon, whose migration in the Pacific Northwest has been analyzed in a new study based on location data garnered over 56 years.
Pavey, S. A., Nielsen, J. L. & Hamon, T. R. Recent ecological divergence despite migration in sockeye salmon (Oncorhynchus nerka).
Specifically, sockeye salmon that survive migration are expected to pass Bonneville Dam on average 2.5 days earlier per generation (0.3 SDs) than the population average, based on a probabilistic model of temperature-induced mortality, and historical records of migration time and temperature.
Healey [27] documented similar migration times of sockeye through the Strait of Georgia, although he found that most sockeye took the Juan de Fuca Strait exit.
The upstream migration of adult sockeye salmon (Oncorhynchus nerka) in the Horsefly River was monitored by a DIDSON imaging sonar during the dominant stock-cycle year 2005 using a systematic 20-min h−1 sampling scheme.
These same individuals were also biopsied, (blood and gill tissue samples, and energetic status) to assess the physiological and energetic correlates of migration success in sockeye salmon (Cooke et al. 2005, 2008b).
For example, Quinn and Adams (1996) showed that warming water owing to dams in the Columbia River has led to earlier migration times for sockeye salmon, although the genetic basis for this change is not known.
Thomson, K.A., Ingraham, W.J., Healey, M.C., Leblond, P.H., Groot, C. and Healey, C.G. (1992) "The influence of ocean currents on latitude of landfall and migration speed of sockeye salmon returning to the Fraser River" in Fisheries Oceanography.
In case study II, we assessed whether microparasites already carried by salmon in the marine environment may be associated with premature migration mortality of return-migrating adult Sockeye Salmon in the marine and freshwater environment.
