Major foci of physiological ecology research on locomotion

1. Major foci of physiological ecology research on locomotion • partition this polygenic trait into key component processes • establish the heritability of measures of locomotor performance • demonstrate selection for locomotor performance in the field • establish the efficacy of laboratory measures of locomotor performance

2. Evidence that locomotor performance contributes to fitness in Atlantic cod • Seasonal migrations of > 1000Km • Capturing prey in 8 body length/s currents • Trawl avoidance studies • Spawning in 40cm/s currents

3. Swimming Hypothetical Ecological type Limitations relevance Fast-start Morphology; Predator avoidance; contraction kinetics; prey excitation-contraction capture coupling Burst swimming Muscle power output: Trawl avoidance; contractile machinery, manuevering through glycolytic & end - strong current fields product rates; morphology Sustained swimming Oxygen delivery; Migration; spawning in delivery of substrates moderate current fields for aerobic metabolism;

4. Performance Hypothetical Ecological test Limitations relevance Fast-start acceleration Morphology; Predator avoidance; and terminal velocity contraction kinetics; prey excitation-contraction capture coupling Burst swimming Muscle power output: Trawl avoidance; performance test contractile machinery, manuevering through U glycolytic & end - strong current fields burst product rates; morphology Critical swimming Oxygen delivery; Migration; spawning in performance test delivery of substrates moderate current fields U for aerobic metabolism; crit

5. Questions: • Can locomotor performance in Atlantic cod be adequately characterized by a single performance test ? • Does locomotor performance correlate with predatory ability ? • Are there relationships between locomotor performance and various measures of the animal’s physiology, age or morphology ? • Is there a discernable genetic link to differences in physiology or performance ?

6. plexiglass windows Receiving chamber Acclimating chamber gate H20 inlet Laser H20 outlet photo- dectors Computer & timing circuit

7. Repeatability of aerobic swimming performance p<0.01

8. p<0.001

9. Repeatability of oxygen consumption while swimming

10. Swimming velocity measured three times in an individual

11. Acceleration measured three times in a single individual

12. Swimming velocity profiles of six different fish

13. Ucrit vs. Uburst performance r= 0.574; p<.02

14. Comparison of Ucrit performancewith fast-start performance p<0.05

15. Performance Hypothetical Ecological test Limitations relevance Fast-start acceleration Morphology; Predator avoidance; and terminal velocity contraction kinetics; prey excitation-contraction capture coupling Burst swimming Muscle power output: Trawl avoidance; performance test contractile machinery, manuevering through U glycolytic & end - strong current fields burst product rates; morphology Critical swimming Oxygen delivery; Migration; spawning in performance test delivery of substrates moderate current fields U for aerobic metabolism; crit

16. p<0.005 r= 0.574; p<.001

17. The tradeoff hypothesis: • an animal which is excellent at one type of locomotor performance can only achieve this through compromise of others • support from comparisons of elite athletes • justified through muscle anatomy • justified through muscle biochemistry

18. Good athlete/bad athlete hypothesis • Good athletes will be better than average in all measures of performance • support fromhuman experience

19. Conclusions I: • Aerobic locomotor performance is repeatable in Atlantic cod • shown previously in three other fish species • Fast-start performance is repeatable in Atlantic cod • original finding for fish • Implications: Studies in to the mechanistic basis of variation in • locomotor performance can proceed with confidence

20. Conclusion II: • Metabolic rate was repeatable at intermediate swimming speeds • some variation in metabolic rate is attributable to intraspecific variation • variable confinement stress and movements probably account for much of the variation seen in resting metabolic rate measurements

21. Conclusion III: • Support for both the “good athlete/ bad athlete hypothesis and the “tradeoff” hypothesis can be taken from this study