Lionfish are carnivores that can eat other fish up to two-thirds their own length, while they are protected from other predators by long, poisonous spines. In the Pacific Ocean, Hixon said, other fish have learned to avoid them and they also have more natural predators, particularly large groupers. In the Atlantic Ocean, native fish have never seen them before and have no recognition of danger. There, about the only thing that will eat lionfish is another lionfish they are not only aggressive carnivores, but also cannibals.
"In the Caribbean, few local predators eat lionfish, so there appears to be no natural controls on them," Hixon said. "And we've observed that they feed in a way that no Atlantic Ocean fish has ever encountered. Native fish literally don't know what hit them."
When attacking another fish, Hixon said, the lionfish will use its large, fan-like fins to herd smaller fish into a corner and then swallow them in a rapid strike. Because of their natural defense mechanisms they are afraid of almost no other marine life. And the poison released by their sharp spines can cause extremely painful stings to humans even leading to fatalities for some people with heart problems or allergic reactions.
"These are pretty scary fish, and they aren't timid," Hixon said. "They will swim right up to a diver in their feeding posture, looking like they're ready to eat. That can be a little spooky."
Their rapid reproduction potential, Hixon said, must now be understood in context with their ability to seriously depopulate coral reef ecosystems of other fish. Parrotfishes and other herbivores prevent seaweeds from s
|Contact: Mark Hixon|
Oregon State University