Fish come in all shapes and sizes, from short and fat to long and thin and variations in between. Despite this diversity, researchers are relatively adept at predicting how well fish can swim from their body shape. But tropical coral reef fish are the most diverse in the oceans, and their juveniles vary widely in their swimming ability. Rebecca Fisher and Derek Hogan took on the challenge of exploring the relationship between body shape and swimming ability in the juveniles of 100 species of tropical fish from 26 families (p. ). Having measured the fastest sustainable swimming speed of each fish, they then measured the dimensions of the fishes' bodies and fins. They found that a simple model which took into account the length and depth of the body, and the dimensions of the caudal fin at the back of the fish could accurately predict swimming performance. Different body dimensions explained 69% of the variation between different fishes' swimming performance, and the model worked equally well on all of the species, which came from reefs as far apart as the Caribbean and the Australian Great Barrier Reef. The model's success means that it can be used to predict swimming ability in small juvenile fish, which are very difficult to study in the lab.
Fisher, R. and Hogan, J. D. (
2007
). Morphological predictors of swimming speed: a case study of pre-settlement juvenile coral reef fishes. J. Exp. Biol.
210
,2436
-2443.
