Tony Farrell Zoology Department & Faculty of Land and Food Systems

1. Adult salmon in hot water Outline 1. Fraser River adult sockeye salmonmigrations & temperature changes 2. Aerobic metabolic scope- a predictive tool for temperature effects? 3. Broader applications in aquatic ecosystems? Tony Farrell Zoology Department & Faculty of Land and Food Systems University of British Columbia,Canada

2. CANADA PacificOcean Sockeye salmon: post-glaciation invaders British Columbia Fraser RiverWatershed Vancouver • 130 Fraser River sockeye salmon populations • Return every 4 years in mid/late summer • ~30-day to migrate upriver & spawn

3. Acoustic biotelemetry of migration behaviour: individuals vary in marine migration route & speed A caveat when predicting population behaviours QCI ? JS FraserRiver POST detection array JDFS

4. Fish temperature increases abruptly on river entry ShuswapLake LowerFraserRiver • Avoidance behaviours provide only temporary temperature relief • Fraser R. gradually cools after the August peak temperature Data from an I-button temperature logger for an individual sockeye approaching theFraser R. & during its ~30 day upstream migration

5. 22 20 18 16 14 12 10 1-Jul 16-Jul 1-Aug 16-Aug 1-Sep 16-Sep Fraser River temperature during sockeye upriver migration 2004 max River temperature, oC average min Date Based on historical data (60 years to 2003) from temperature loggers in lower mainstemFraser River near Mission Source: Pacific Salmon Commission

6. Climate change for the lower Fraser River Peak river temperature has increased ~1.8oC during past 55 years Temp, oC • Salmon are facing increasingly warmer temperatures as the spawning dates of sockeye are unchanged (genetically determined) • Massive in-river sockeye mortality in particularly hot summers, e.g. 2004 Hypothesis: High water temperature  en-route deaths

7. What river temperatures have been experienced? Depends on salmon population & timing of river entry Percentage of fishencountering a rivertemperature (up to 2003) Derived by combining historical river temperature data & migration data (~60/10 years)

8. Summary so far … Sockeye have been in the Fraser R. for last 10,000 years,exploiting the habitat revealed by retreating glaciers. Sockeye spend 2 years growing in cool Pacific Ocean, but mustmigrate up the warmer Fraser R. in the summer to spawn once. Peak summer Fraser R. temperatures have increased ~2oCover the past ~50 years & now exceed 20oC. Recent river temperature exposures during migration can beestimated for salmon populations from historical data.

9. Topt Maximum MR Q10-driven increase in maximum MR up until Topt = aerobic scope, the energy available for activity Why is temperature so important for salmon? Temperature controls metabolic rate Metabolic rate Q10-driven increase in resting MR Resting MR Temperature (oC)

10. Topt Aerobic scope Tcrit Temperature (oC) Temperature determines aerobic scope Topt Tcrit Metabolic rate Temperature (oC) Tcrit = no aerobic scope Topt = max aerobic scope

11. Topt AerobicScope Tcrit Temp. How is aerobic scope measured in adult salmon? Mobile swim tunnel respirometry Measure a fish’s oxygen consumption (Mo2) Aerobic scope = (maximum Mo2 while swimming -routine Mo2) Perform experiments at different water temperatures

12. 12 A 10 8 6 4 2 0 B 10 Weaver Creek Sockeye Topt = 14.3oC Scope = 7.9 mg O2 kg-1 min-1Tcrit = 20.4oC Aerobic scope (mg O2 kg-1 min-1) 8 6 4 2 0 C Chehalis River Coho Topt = 8.1oC Scope = 7.5 mg O2 kg-1 min-1Tcrit = 17.0oC 10 8 6 4 2 0 0 5 10 15 20 25 o Temperature, C Topt Aerobic scope vs. temperature profilesfor three Fraser R. salmon populations Gates Creek Sockeye Topt = 16.3oC Scope = 10.7 mg O2 kg-1 min-1Tcrit = 24.4oC Gatessockeye Topt Weaversockeye Topt Chehaliscoho Solid line = interpolated from field data (N>30) Broken line = extrapolation to Tcrit (Lee et al. 2003)

13. 12 16% 9 12% Gates Creek Aerobic scope (mg O2 kg-1 min-1) Sockeye Temperature frequency distribution 6 8% 3 4% 0 0% 0 5 10 15 20 25 Temperature (°C) 12 16% 9 12% Weaver Creek Aerobic scope (mg O2 kg-1 min-1) Sockeye Temperature frequency distribution 6 8% 3 4% 0 0% Hell’s Gate 0 5 10 15 20 25 Temperature (°C) 12 16% 9 12% Chehalis Aerobic scope (mg O2 kg-1 min-1) Temperature frequency distribution Coho 6 8% 3 4% 0 0% 0 5 10 15 20 25 Temperature (°C) • Key points • Populations vary in their: - absolute aerobic scope, - Topt (= max scope) - Tcrit (= no scope) • As little as 6oC between Topt and Tcrit • Population variability appears to match their experiences Lee et al. 2003

14. 30% 100% 75% 20% Percentage of maximum Aerobic scope Temperature frequency distribution 50% Gates Creek Sockeye 10% 25% 0% 0% 0 10 15 20 25 o Temperature ( C) 30% 100% 75% 20% Percentage of maximum Aerobic scope Temperature frequency distribution Weaver Creek 50% Sockeye 10% 25% 0% 0% 0 10 15 20 25 o Temperature ( C) Does an abnormally warm year matter for salmon migration? 2004 = Red temperature data Farrell et al. 2008

15. Tcrit =20.4oC Topt = 14.3oC Survival to spawning area of 2004 Weaver sockeye Biotelemetry on 5 different dates during seasonal river cooling N = # of individual fish Todd Mathes M.Sc. thesis

16. Summary so far … Sockeye metabolism & aerobic scope are temperature-dependent. Aerobic scope is the energy available above routine needs& has a Topt & Tcrit. Peak summer river temperatures have exceeded Tcrit for somesockeye salmon populations & these periods are associated with“missing salmon”. Topt & Tcrit are likely to be stock-dependent. Thus, predictionsusing aerobic scope data should be done at the population level.

17. e 120 de de de cg 100 * * bf * de fg d * 80 e * c * a f bf 60 a 15 17 19 21 23 15 Recovery Heart rate (beats min-1) Temperature (ºC) = Resting fish = Swimming fish (70% Ucrit) Why don’t sockeye salmon like it hot? Heart can no longer pump enough blood Acute DToC: sockeye resting or swimming at a constant ~70% Ucrit Steinhausen et al. 2008

18. Cardiac arrhythmias develop at high temperature Cardiac output (ml min-1 kg-1) Acute DToC: resting chinook salmon Clark et al. 2008

19. Can aerobic scope provide a broader conceptual framework forpredicting climate change impacts in aquatic ecosystems? Pros: - Metabolism of most aquatic vertebrates, all invertebrates & all phytoplankton is governed by temperature - Metabolic rate is key to growth & survival behaviours - Growth and population measure reflect aerobic performance Cons: - Necessary data base is largely lacking - Examples limited to Pacific salmon (our work), Atlantic cod, & ocean pout (Hans Pörtner et al.) Possibly salmon sharks & tuna (Barbara Block et al.) Pörtner and Farrell (2008) www.sciencemag.org/cgi/reprint/322/5902/690.pdf

20. Conceptual framework beyond aerobic scope- growth & abundance?

21. Conceptual framework for species interactions? • Under the warming scenario the“reds” could: • Dominate over the “blues” • - Be resource-limited by the “blues”

22. Some life stages will be the most temperature-sensitive A series of aerobic scope curves during growth Spawners Growing adults Scope for performance Sequence of life stages Juveniles Eggs, early larvae Temperature (oC) Aerobic thermal window

23. Maria Linda Erika Conclusions Aerobic scope holds promise for predicting the effects oftemperature change on Pacific salmon populations. Potential exists for a broader conceptual application to aquatic ecosystems, but more data are needed. Scott Hinch, UBC Tim Clark (UBC); Karl English (LGL); David Welch (Kintama) David Patterson, DFO