Big fish recover more slowly from being caught

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Bigger is not necessarily better, at least for the well being of fishes caught by anglers, according to a study to be published in a forthcoming issue of the journal Fish Physiology and Biochemistry.

The authors found that large bass exhibited elevated concentrations of plasma potassium, sodium and glucose relative to small fish following the exercise challenge. In the case of blood potassium levels, even four hours of recovery were insufficient to allow recovery to basal levels in the large bass.

The anaerobic energy expenditure of the large fish was also found to be greater than that of the small fish, with concentrations of plasma and muscle lactate (a metabolic waste) in the larger fishes being significantly greater than that in the smaller fishes.

The overall picture of the larger fishes requiring additional time to clear metabolic disturbances in muscle and blood plasma indicates that smaller fishes possess an improved ability to recover from disturbances.

This is supported by the fact that the larger fishes had significantly lower levels of phosphocreatine (an energy-storing compound) than the smaller fishes.

According to author Cory Suski, "Before we began the research, we predicted that the larger fish would respond and recover from exercise more quickly, providing another size-based advantage for larger fish, but we found the opposite to be true.”  She added that the results of this study emphasise the need to treat big fish gently so they can be caught again in the future.

For more information, see the paper: Gingerich, AJ and CD Suski (2011) The effect of body size on post-exercise physiology in largemouth bass. Fish Physiology and Biochemistry doi:10.1007/s10695-011-9510-3

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