Report: Caribbean lionfish showing signs of cannibalism

Lionfish off the coast of the Florida Keys appear to be displaying signs of cannibalistic behavior, according to a recent National Geographic article. 

The first indication of cannibalism in lionfish was found in both Mexico and the Bahamas, according to a study published in a Public Library of Science journal in 2012. Cannibalism is a rare behavior in fish, so the increase in this activity has piqued the interest of marine scientists in the region. 

Although it may sound like a blessing, this type of activity may not necessarily be a good sign, according to Stephen Broadbelt, co-founder and partner of Ocean Frontiers dive shop in Grand Cayman. 

“This is believed to only happen when they have eaten all other fish populations,” Mr. Broadbelt said. “When they have eaten everything in sight, then they start to eat themselves.” 

Mr. Broadbelt is not yet concerned about the possibility of this behavior spreading to Cayman waters. “They have not yet reached that point here,” he said. “I would be surprised to hear any cases of anyone witnessing lionfish cannibalism in the Cayman Islands.” 

Mr. Broadbelt said Ocean Frontiers alone has culled more than 10,000 lionfish in the past two years. “They’re still a problem, and if left unchecked they will rebound back to the scale they were at a couple years ago,” he said. “It’s a matter of staying on top of the problem.” 

Jason Washington, operator of Ambassador Divers and a member of Cayman United Lionfish League, said he is not surprised to hear of the cannibalism occurring in other countries, although he has not observed any indication of it in Cayman. 

“Through the 15 [lionfish culling] tournaments that we’ve had, we’ve seen the inside of a lot of lionfish and I’ve seen stingrays, reef fish … They’ll eat anything [up to] half their size,” he said. 

Mr. Washington said in any case, it is important to stay informed and to keep up conservation efforts. 

In April, the first confirmed lionfish was found off the coast of Brazil, and lionfish continue to be a problem throughout the Caribbean. 

Mr. Washington said the spread of lionfish is difficult to manage or contain because of the way they breed. “They fertilize eggs that can drift for miles and miles on ocean currents,” Mr. Washington said, “so wherever mother ocean takes them they’re going to wind up.” 

Lionfish can lay upward of 30,000 eggs per spawn and can spawn every four days in the right conditions. This equates to a potential of each lionfish laying more than 2 million eggs per year. 

Stacy Frank is one of the founders of Lionfish University, a non-profit that seeks to raise awareness about lionfish. 

“So far I haven’t seen any evidence [of lionfish cannibalism] in the Cayman Islands, but this of course doesn’t mean it’s not happening or could not happen,” Ms. Frank said. “It’s kind of like the video we shot of the grouper eating the lionfish – that also doesn’t usually happen.” 

Members of Lionfish University caught on video a grouper seemingly hunting and eating a lionfish in Little Cayman earlier this year. 

Ms. Frank said that it would be impossible to know for certain what potential implications the cannibalistic behavior could have with so little knowledge of the phenomenon. It could be that lionfish resort to this behavior after depleting their other food sources, she said, but she noted that there are respected voices in the marine biology field who believe otherwise and say that the cannibalistic behavior has other causes. 

“What it would mean – I don’t think anybody really knows. It’s a very controversial topic,” she said. 

Ambassadors Divers’ Jason Washington, left, and Mark Orr from the Department of Environment, measure a large lionfish caught in a recent lionfish culling tournament in Cayman.
Ambassadors Divers’ Jason Washington, left, and Mark Orr from the Department of Environment, measure a large lionfish caught in a recent lionfish culling tournament in Cayman. – PHOTO: COURTNEY PLATT