Post on 26-Nov-2021
Health of Fraser Salmon: Symptoms, Diagnosis, Treatment and Lessons Learned
Dave Levy
FNFC AGM Nov. 3’20davidlevy@shaw.ca
Health of Fraser Salmon: Focus on Sockeye and Chinook
Status
Symptoms Diagnosis
Treatment
Lessons Learned
2
COSEWIC Assessment of Chinook Salmon
Designatable Unit (DU) COSEWIC Status
Lower Fraser, Ocean, Fall Threatened
Lower Fraser, Stream, Spring Special Concern
Lower Fraser, Stream, Summer (Upper Pitt) Endangered
Lower Fraser, Stream, Summer Threatened
Middle Fraser, Stream, Spring Endangered
Middle Fraser, Stream, Fall Endangered
Middle Fraser, Stream, Spring Threatened
Middle Fraser, Stream, Summer Threatened
Upper Fraser, Stream, Spring Endangered
South Thompson, Ocean, Summer Not at risk
South Thompson, Stream, Summer 1.2 Endangered
North Thompson, Stream, Spring Endangered
North Thompson, Stream, Summer Endangered
3
SARA-listing Prospects for Pacific Salmon
Designatable Units Endangeredor Threatened under COSEWIC
Listed under SARA?
Okanagan Chinook No
Interior Fraser Coho No
Cultus Lake Sockeye No
Sakinaw Lake Sockeye No
Interior Fraser Steelhead No
11 Fraser Chinook DUs Under Review
9 Fraser Sockeye DUs Under Review
5
Factors Contributing to the Decline of Fraser Salmon
Industrial fishery in Late 1800’s
1915
Hell’s Gate Slide
Focus for today:
• Ocean conditions
• Climate change
• Predation
• Endangered salmon
6
Predation
• Between 1970 and 2015, the annual biomass of Chinook salmon consumed by seals and sea lions increased from 68 to 625 metric tons.
• Consumption of Chinook was twice as large as resident orca consumption
• Has Steller Sea Lion Predation Impacted Survival of Fraser River Sockeye Salmon?
Climate Change in the Fraser River
Potential Responses:1. Avoidance2. Mitigation3. Proactive Adaptation
Healthy stocks Depressed stocks with good rebuilding prospects
Depressed stocks unlikely to respond to management intervention
"No fish stock, however small, will be arbitrarily written off, and where possible, it will be attempted to conserve and rebuild small and remnant stocks."
Salmon Strongholds: a Proactive Approach to Salmon Conservation
What is a Salmon Stronghold?
• wild salmon populations and habitats are strong and diverse, with high intrinsic potential to produce salmon;
• a priority-ranked watershed that is part of a comprehensive and proactive conservation strategy
Four Take Home Messages
1. Both Fraser sockeye and Chinook have declined synchronously with salmon runs between Washington and SE Alaska. Marine factors are implicated.
2. To conserve and protect Fraser salmon, strategies are needed to better understand fluctuations in marine survival due to climate change.
3. Proactive conservation strategies are needed: do we want to rebuild depressed stocks or do we want to develop effective approaches that conserve and protect existing strong populations?
4. It is questionable whether endangered Pacific salmon populations will ever be SARA-listed owing to the operation of mixed stock fisheries and unacceptable socioeconomic consequences.