May 9th, 2026 FSEGG seminar announcement

The 15th FSEGG seminar（2026）

May 9th (Sat), 9:00-10:30, Online (For online registration, see https://forms.gle/BYguiDUYETWR674o9)

“Environmental DNA Surveys of Marine Pacific Salmon Ecosystems from the Nearshore to the Open Ocean”

speaker:

Christoph Deeg, Ph.D. (Fisheries and Oceans Canada)

Environmental DNA (eDNA) has emerged as an indispensable tool in salmon ecosystem science, capable of characterizing the full food web surrounding salmon — from viruses to whales. Since 2019, we have conducted large-scale eDNA surveys of the Northeast and central Pacific Ocean to investigate salmon distribution and habitat use during their oceanic winter. These surveys reveal how oceanographic processes structure ecosystem composition across the Northeast Pacific and how salmon navigate multiple distinct biomes in a species-specific manner. Only “oceanic salmon species” were associated with mesoscale features linked to elevated primary production in the high seas, such as anticyclonic eddies, while all species converged on the region of the first spring blooms close to the continental shelf — a rapid ecosystem transition that draws higher trophic levels from salmon through to apex predators. In 2019, we were able to document the impacts of a marine heatwave that was associated with ecosystem-wide changes and increased cnidarian abundance coinciding with indicators of starvation in Pacific salmon, most pronounced in chum. Complementing our open-ocean work, monthly nearshore eDNA surveys conducted since 2023 off the coast of Vancouver Island have examined the early marine habitat of Pacific salmon to identify factors limiting juvenile survival. Combined with extensive traditional survey methods, eDNA documented the seasonal availability of prey and exposure to predators, pathogens, and harmful algae for juvenile salmon. eDNA based prey abundance compared with stomach contents allowed us to identify prey selectivity amongst juvenile salmon and document shifts in prey selectivity and habitat use over the first year at sea. We also detected seasonal spikes in environmental pathogen concentrations that coincided with disease outbreaks in free-living young-of-the-year Pacific salmon — outbreaks exacerbated by open net-pen aquaculture operations in the region. Together, these studies demonstrate eDNA as a powerful, multifaceted tool for salmon stewardship across life-history stages and ecosystems.