FISH USE MORE ENERGY TO SWIM IN WARMER WATERS, AFFECTING OTHER ROUTINE BEHAVIOURS

Global climate change has resulted in an increase in water temperatures in marine and freshwater habitats and the trend is likely to continue in the future. A model developed by Andrew Hein and Katrina Keirsted, of the University of Florida, attempts to predict the effect of this temperature change on the metabolic cost of transport (COT) in fishes, which is a measure of the energy required to swim a given distance. The model builds on work addressing the relationship between temperature, body size and maintenance metabolism, and on the work relating temperature and body size to swimming energetics. It was validated using data from swimming experiments on 22 diverse fish specie

The model predicts that rising water temperature may increase the energetic cost of routine swimming behaviours such as foraging and migration. Further, a given increase in temperature will prompt a larger absolute change in the energetic cost in warm water than in cold water. Interestingly, the effect of temperature on COT is mainly mediated through energy expenditure devoted to maintenance and not directly through swimming energetics. To understand the potential for climate change to affect fishes and the communities they inhabit, however, these results must be integrated with work on thermal physiology of fishes at different life-stages.

Further Reading:
Hein AM, and KJ Keirsted. 2012. The rising cost of warming waters: effects of temperature on the cost of swimming in fishes. Biology Letters 8(2) 266-269.

Sartaj Ghuman is a PhD student at the National Institute of Advanced Studies, India. batalaland@gmail.com