Winter Ecology

Despite a widely held belief that the first winter in the ocean plays a critical role in regulating salmon survival, there is a conspicuous lack of data on the winter habitat, diet, and health of these fish.

A primary focus of the Bottlenecks project is to understand if, and how, the first winter at sea regulates survival of both hatchery and wild fish. To address this objective, a detailed study is being conducted in partnership with the Juanes Lab at UVic to specifically examine the winter habitat use, diet, pathogen load, immune status, and bioenergetics of juvenile Chinook salmon. By sampling juvenile Chinook salmon from October to March, researchers will develop the first complete picture of how these fish use their environment during the winter. The condition and energy content of individual fish will be related to their previous growth history (determined from scales) and their disease status (as indicated by cutting edge molecular genetic techniques). Integrating results will provide insight into how winter conditions may interact with pathogens and growing conditions during the previous summer to control survival. Results will be incorporated into models that will simulate the response of Chinook salmon to changes in winter ocean temperatures due to climate change.

Preliminary results from the study can be found in our Bottlenecks to Survival newsletters posted on the news page and on the reports and products page.