Damsels In Distress Chemically Call For Help

A dusky dottyback considers whether the damselfish will fit in its mouth. Photo by Christopher E. Mirbach 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" ...