Life as a damselfish is hard. These small species are common on tropical reefs worldwide, eating tasty plankton and nipping at other fish. They’re known for their attitude and their beauty, and are often found in stunning schools that cluster around coral heads. But while they’re abundant and vibrant, what they lack are good defenses — no spines, no toxins. Indeed, they are the perfect morsel for other fish-eating fish, and they know it. The moment a predator is detected, they’ll dart for cover, their speed and agility their only hope of survival.
As perpetual menu items, damselfish have developed multiple mechanisms for detecting danger. They can even “smell” danger — when damselfish’s skin is injured, certain chemical compounds leech into the surrounding water. Other damsels can sense these chemicals — essentially “smelling” them — and when a damselfish catches a whiff of Eau de Injury, it runs and hides. But while these chemical alarms seem to benefit fellow damselfish, scientists have long debated whether the injured fish has anything to gain from sending out chemical cues. Are the compounds simply a byproduct of the physical damage? Or do they serve some greater purpose to the fish under attack?
Now, an international team of scientists have published the first evidence of an individual fish benefitting from releasing these chemical alarm cues in a new paper in Proceedings of the Royal Society B. Continue reading “Damsels In Distress Chemically Call For Help”
