Almost exactly a week ago to the hour I was 30 feet underwater in Bermuda watching Victor, a dive instructor from the Dive Bermuda team, spear a large lionfish that was lurking in a swimthrough at a popular diving spot off the south shores of the island called the Breakers.

Dive Bermuda operates out of a private bay owned by the Fairmont hotel chain. Photo by Mark Schulte.

Caribbean divers generally don’t kill fish, but the lionfish has been targeted with good reason. It is a particularly rapacious non-native species that was introduced to the area in 1992 when Hurricane Andrew broke an aquarium in Florida and washed six into the Atlantic. With fanning fins, jutting spines and vivid stripes, it’s striking to look at, but the lionfish’s insatiable appetite makes it a serious threat to Caribbean fish and crustaceans. In just over a month, a single lionfish can wipe out most of a reef’s fish population.

“They literally eat themselves to death,” said Anne-Marie, one of the dive instructors on our boat. She said it was unusual to find one so large around Bermuda, and supposed it had eaten thousands of reef fish. Bermuda divers sometimes capture them and bring them back to the local aquarium for dissection. She said a recent specimen was found with dozens of grouper fry in its stomach.

A red lionfish in Thailand. The one I saw in Bermuda was very similar to this. Photo by Tim Sheerman-Chase.

So there we were, awkwardly drifting in what is essentially an underwater cave, watching Victor slowly approach the motionless lionfish, flashlight in one hand and a modern trident in the other. With impressive aim, he speared it from about four feet away.

Kind of cool in a childish sense, maybe. But I didn’t take up diving to watch people kill fish, and while the lions are undoubtedly a major threat in an ecosystem that doesn’t need more problems, watching that stunning animal slowly die in front of me was a strange and very sad experience.