1. Fishing for mechanisms regulating senescence in
sockeye salmon
Steven Roberts
Tom Quinn
Leslie Jensen
Caroline Storer

2. photo: Foist

3. Salmon Senescence
• Rapid decline to death
• Alongside other complex physiological process
• Rates of senescence vary within population and across populations
• Arrival date to spawning ground correlates with rate of senescence
(Hendry et al 2003)
• Bear predation plays a role in driving rates
(Carlson et al 2007)

4. What physiological process regulate senescence?

5. Rationale
• Better understand how environmental change might effect senescence
physiology
• Determine other traits that could be impacted by selective pressures
• Model system for studying aging in other taxa

6. Preliminary Investigations

7. Carlson and Quinn 2007
Preliminary Investigations
Hansen Creek
Small tributary of Lake Aleknagik
Nearly uniform top to bottom: 4m wide & 10cm deep riffles
Annual spawning population of 3,000 – 20,000 sockeye
Stream life annually averages below 10 days (usually 7-14)

8. Preliminary Investigations
Hansen Creek

9. Approach
• Sample fish (brain tissue)
• Select candidate genes
• Characterize gene expression patterns for select genes

10. Preliminary Investigations
relative gene expression
Cortisol axis

11. Preliminary Investigations

12. Preliminary Investigations
Chaperones
relative gene expression

13. Preliminary Investigations
HSP70
relative protein
expression
*Liver

14. Preliminary Investigations
relative gene expression
olfaction repro
learning
immune
aging

15. Summary
• Baseline information on physiological changes between “arriving” and
senescent salmon
• Cortisol signaling declines temporally
• Molecular chaperone protein (HSP) is upregulated at senescence
• Molecules controlling “other” primary physiological process are differentially
expressed
• Receptor (NMDA) associated with aging and memory in other taxa declines in
senescence

16. Future direction
• Compare expression in populations with different rates of senescence
• Characterize corresponding protein expression levels
• Take a non-biased approach to identify differences (NGS, Differential Display)
• Explore genetic (SNP) and epigenetic (DNA methylation pattern) differences