Gibb, A. C.; Dickson, K. A.: Functional morphology and biochemistry: Is there a correlation between metabolic enzyme activity and swimming performance?

Many animals, including marine fishes, are difficult to study in their natural habitat. Consequently, little is known about their routine behavior and locomotor performance. Comparative physiologists and ecologists have searched for a specific morphological, physiological or biochemical parameter that could be easily measured in a captive, frozen, or preserved animal, and that would accurately predict the routine behavior of that species in the wild. Many investigators have measured the levels of activity of specific enzymes involved in energy metabolism in the body musculature of marine fishes, generally assuming that high specific activities of enzymes involved in aerobic metabolism are indicators of high levels of aerobic performance and of sustained swimming ability and that high activities of anaerobic metabolic enzymes indicate high levels of burst swimming performance. In this paper, we review the comparative data that support this hypothesis. Perhaps more importantly, we outline recent studies we have conducted that specifically test the hypothesis that levels of enzyme activity in the myotomal musculature of fishes correlate with locomotor performance. In these studies, we combined the fields of biochemistry and functional morphology by measuring enzyme activities and swimming performance in the same individuals and comparing this relationship across several different species. Finally, we suggest areas of further investigation that may provide biochemical indices that are accurate predictors of animal performance.