High Seas North Pacific Salmon Food Webs

Using biochemical proxies to measure conditions experienced by maturing salmon on the high seas.

The conditions experienced by salmon while in the open ocean north Pacific, and the role of these conditions in their health, survival and reproductive success, is one of the least understood aspects of their life cycle, in large part because of the difficulties in making in situ measurements. However, evidence of competition (e.g., between pink and sockeye salmon) indicates that food may be limiting on the high seas, while changing ocean conditions (e.g., increasing ocean temperature) may affect salmon health through, for example, physiological stress and extending the migration distance required to reach favourable habitat.

The Plankton Ecosystems Lab uses two complementary biochemical approaches to retrieve information from the tissues of returning fish that inform their life history experience in the north Pacific. Specifically:

  • Carbon and Nitrogen elemental and stable isotope ratios;
  • Otolith microchemistry.

This project aims to advance understanding of:

  • The role of ocean conditions in the health and survival of Pacific salmon, and;
  • The impact of changing ocean conditions on marine survival and stock returns.

Lab Personnel:

  • Dr. Boris Espinasse (PDF) – north Pacific ISOSCAPES;
  • Caroline Graham (MSc candidate) – high seas salmon diet database development;
  • Jacob Lerner (PhD candidate) – Chinook salmon trophic ecology.

This project is intersecting with the International Year of the Salmon (2019-2022), with the 2019 Gulf of Alaska being used to analyse salmon food web dynamic and ground truth Isoscapes.