| 1. |
Anaerobic and aerobic energy production during and after induced bursts of maximum swimming activity were measured in four size classes of rainbow trout fry at 4, 12 and 20°C.
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| 2. |
The rate of phosphocreatine (PCr) utilization during burst activity appeared independent of size and temperature. On average the concentration of PCr dropped from 5.8±1.0 to 1.5±0.7 [(V)\dot]O2 \dot V_{O_2 }
r): maintained for several hours before or after induced burst activity;maximum rate (
[(V)\dot]O2 \dot V_{O_2 }
max): attained for a few minutes during and immediately after an induced burst of activity;net recovery
[(V)\dot]O2 \dot V_{O_2 }
: amount of oxygen consumed during recovery time minus the amount due to routine rate during this interval.
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| 5. |
The routine rate of
[(V)\dot]O2 \dot V_{O_2 }
is affected by temperature but less so by the age of the fry. On the other hand,
[(V)\dot]O2 \dot V_{O_2 }
max and net recovery,
[(V)\dot]O2 \dot V_{O_2 }
increased strongly with age at the two lower temperatures. Aerobic scope for activity increases with size and is maximum at 12°C.
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| 6. |
The age-dependent changes of
[(V)\dot]O2 \dot V_{O_2 }
are discussed in relation to the differentiation of the swimming musculature and to hydrodynamic changes, since between a body length of 1 and 10 cm, the fish move through a range of Reynolds numbers from approximately 102 to 104.
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| 7. |
It appears, furthermore, that with increasing size, more energy is liberated during the recovery period than would be required for repapying the true oxygen debt. This may be due to an elevated activity during poststimulus excitement.
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