Marlins light up their stripes to coordinate attacks on schools of fish, a study has found.
Large fish with long, pointed bills are fast swimmers that hunt in groups, where each animal takes turns attacking their prey like sardines.
One species, the striped marlin, can measure up to 12ft in length and weigh up to 450lbs and can swim at over 50mph.
Drone footage captured by scientists at Humboldt University has revealed the previously unseen dynamics of hunting fish, showing how a marlin in a group will light its stripes before it mounts a attack, and then dim it when it’s done.
The next marlin to mount an offensive will light its own stripes while it lasts, scientists have found. It is assumed that this method is used as a means of communication with other marlins as an intention to attack, while also potentially confusing the prey.
“It has long been known that striped marlin can change the brightness and intensity of their stripes,” Dr Alicia Burns, a research fellow at Humboldt University and lead author of the study, told The Telegraph.
“Most of the observations in the past came from fishermen – so it was assumed that the marlin’s color change was just a result of being excited or stressed.
“However, what we have shown seems to be a link between color change and hunting behavior.
“What’s interesting about marlin is that they hunt in groups so the potential of color change being used as a signal between predators is really interesting.”
The fish has two chromatophores in its skin that can change color when signaled by its nervous system. It is thought that one of the pigments overlaps the other of the bands and reveals the glowing bright blue bands when activated.
Color changes may have a secondary purpose
The team’s discovery indicates that marlins have more complex communication channels than previously suspected.
Scientists have suggested that the color changes may serve a secondary purpose of confusing their prey.
The researchers now aim to further explore this idea while answering additional questions, such as whether marlins use their remarkable color-changing abilities in any other context.
They are also interested in knowing if they still change color when hunting alone, how the changes affect their prey and if other predatory fish species use similar color changes.
Marlins have been known to attack humans in the past but prefer to avoid humans as part of their own self-preservation.
“Fortunately for humans, marlin have a strong instinct for self-preservation like most animals, and will try to avoid harm to themselves,” said Dr Burns.
“But if you see a marlin with glowing stripes near you, it could mean there are some sardines hiding under you so it’s best to start swimming just in case.”
The study was published in the journal Current Biology.
