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 gt 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 animals
  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
plt0.01
8
plt0.001
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 plt.02
14
Comparison of Ucrit performancewith fast-start
performance
plt0.05
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
plt0.005
r 0.574 plt.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