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Locomotor performance can influence an animal's fitness by affecting
foraging success, reproduction, and habitat selection . Thus, differential survival in some habitats may be a function of relative locomotor capacity. Physical performance has been shown to constrain behavioral and
ecological options in lizards and snakes. Few studies have investigated
the ecological role of variation in performance
among conspecific fish . Here we show that locomotor performance
of blacknose dace (Rhinicthys atratulus)
was found to tightly match the base flow conditions at the site they were captured from. Some of this work is described in the following publication:
Nelson, J.A. P. S. Gotwalt and J.W. Snodgrass. 2003. Current Velocity Structures Swimming Performance of Blacknose Dace (Rhinichthys atratulus). Canadian J. of Fish. Aquat. Sci. 60(3): 301-308.dacepap.pdf
Collecting Fish from Beaver Run, Maryland
Fish of similar size from three local watersheds
were subjected to a modified critical swimming speed; fish were
exposed to increasing velocity increments of 5 cm/s at 5 minute
in
tervals.
Swim tunnel used to measure performance of dace
The modified Ucrit procedure used to test the fish was very repeatable. Below is a graph of a subset of dace swum a second time one month after the first swim without knowledge of their performance in the first swim.
Swimming performance tests were performed without knowledge of the base current flow at the sites where the fish were captured. Results revealed a positive, significant (p<.0001) relationship between mean base flow and mean Ucrit.See below:
This close coupling of swimming performance and base flow suggests an unprecedented structuring of animal capacity by environmental conditions in this species. Evidence from other fish studies suggests this coupling could be due to physiological plasticity or natural selection. Swimming performance has been shown to improve after training protocols, which suggests that physiological capacity is malleable.However, there is also evidence that natural selection can have divergent effects on geographically close populations.
This relationship was not due to size differences. See below:
Current work is focusing on whether these differences in swimming performance between geographically close dace populations are the product of physiological plasticity or natural selection.
Here you see undergraduate Chris Simonetti sprinting dace in a computer controlled sprint chamber with laser detection of fish position. See :
Nelson, J.A., P. S. Gotwalt , D.W. Webber and S. Reidy. 2002. Beyond Ucrit: Matching swimming performance tests to the physiological ecology of the animal, including a fish "drag strip". Comparative Biochemistry & Physiology. 133/2 pp 289-302
for a description of the sprint chamber.