AL.com reviews all the reasons why the invasive lionfish have taken over in the Gulf of Mexico and the Caribbean; here are excerpts:
[. . .] Lionfish are king
When lionfish take over a reef structure, it’s easy to tell who’s boss. Scuba divers don’t have to poke their heads below rock ledges or approach slowly or quietly to catch a glimpse of one. Dozens of them can be seen lazing about the reef structure, their billowing white spines almost looking like anemonies, as seen in this photo by AL.com’s Ben Raines [below].
‘They’re always eating’
Albins’ Ph.D thesis dealt with the impacts of lionfish predation on local fish populations in the Bahamas, and those impacts can be significant. Albins said the lionfish stomachs can expand to 30 times their usual size to accommodate a big meal, and they also eat more frequently than some fish.
Albins said that while doing diet analysis of many different kinds of fish, he’s noticed that lionfish stomachs are rarely ever empty, unlike many other species.
“For most predators, you usually get 30 or 40 percent of the fish you collect have some analyzable stomach content,” he said. “When we do the same kind of study with lionfish we find that rate is more like 80 or 90 percent. They’re just always mowing down these little fish, they’re always eating.”
But they can survive lean times
Lionfish will eat constantly when food is available, but they can also survive for long periods of time when prey is not readily available. The lionfish is good at storing fat from its frequent meals in the summer and has been known to survive for 12 weeks without feeding.
Lionfish blow jets of water at their prey… for some reason
Being the new kid in town, lionfish use techniques when hunting their prey that are unique in the Gulf. Those big white, billowing fins aren’t just used for defense. Albins said the lionfish will use them to herd small prey fish into a corner and prevent them from escaping before it strikes.
“They’ve got a couple of characteristics that are just completely unique in the Atlantic,” Albins said. “They blow jets of water at their prey before they strike in a lot of cases.
“Nobody’s 100 percent certain why that happens, but we think it might confer some advantages in terms of capture success.”
Snapper on the menu
Lionfish are not picky eaters, and have been known to gobble most species they encounter, basically anything smaller than about two thirds of their own body length. They eat crustaceans and fish, both the young of larger reef fish like snapper and grouper, or full-grown smaller reef fish like blennies, beneficial species that graze on algae to keep it under control.
Albins pointed out a recent study from the University of Florida that found vermilion snapper in particular made up a large percentage of the diets of speared lionfish off the Panhandle. [. . .]