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)
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
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)
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