Fish Behaviors aren’t limited by Body Shape

Darien R. Satterfield, Thomas Claverie, Peter C. Wainwright

This is a plain language summary of a Functional Ecology research article which can be found here.

We often make inferences about a person’s physical skills based on their body shape. For example, tall people are regularly told they should play basketball, and we might assume that a person with broad shoulders would be a nice addition to a football team’s defensive line. Though, a person may have the physique to perform well in a sport, if they aren’t inclined to play, we don’t expect the sport to be a regular activity for them.

An angelfish swims by the camera rig used to record the videos that behavioral data was collected from (credit: Thomas Claverie) 

In fish, body shape is thought to be related to how well a fish can swim. Fish that are shaped like tuna are thought to be better at swimming fast and far, while fish that are shaped like a butterflyfish are thought to be very maneuverable. As such, a fish’s body shape is often used to make assertions about the routine behaviors that it uses during normal activities. But just like we don’t expect every person with the build of an Olympic runner to do track, it isn’t accurate to assume that all fish with the same shape use the same behaviors.

In this study we measured the routine swimming speed, distances, turning frequency, and periods of rest that are used by coral reef fishes. We then tested to see if any of eight measurements that summarize the body shape of the fishes could be used to predict how fast or far a fish swims, or how often the fish turns or rests. We found that body shape does is not informative about the routine behaviors a fish uses. Additionally, we see that fish with highly different body shapes can be similar in behavior. Thus, caution should be used when using body shape as an indicator of fish behavior.