July 19, 2019 — Just as lions are apex predators on land, lionfish in Florida are an underwater force to be reckoned with. The biggest threat they pose, however, is not their venomous spines. It is the alarming speed and ferocity with which they invade new waters, eating prey that have not evolved to recognize them as a predator, stealing food from important commercial fish like snapper and grouper, and spawning baby lionfish at incredible rates.
In the 1980s, lionfish (native to the South Pacific and Indian Ocean) were introduced to Floridian waters, possibly by humans who bought them as exotic pets and later released them to the ocean. Over the next decades they spread rapidly, and today they have thoroughly invaded their preferred warm waters in the Atlantic, Gulf of Mexico, and Caribbean, damaging the native coral reef systems and food webs.
“The destructive nature of the lionfish invasion is partly to blame on their reproductive success,” says Montana Airey, a masters student at Columbia University who studies lionfish. “They can produce thousands of eggs every week, which after hatching can spread widely on ocean currents. Also, since they are invaders, their prey don’t recognize them as dangers, so they can eat without much effort.”
As adults, lionfish tend to be slow-moving and stay local, not straying far from their settled reef home. The invasiveness of lionfish is therefore thought to happen when they are small, larval fish being carried to new places by currents. However, researchers have little information about how grown lionfish might invade or move to new waters because tracking small marine organisms poses difficulties.
One way to investigate their movements, though, is to study their ear-bones.