Invasive Pacific red lionfish and the Big Bad Wolf have something in common: Both huff and puff to nab their prey. New observations show that these predators, which have invaded the Atlantic Ocean, confuse their prey by spitting eddies of water at them. This deadly weapon, not seen before in fish, could help explain the lionfish’s success in its new world.
The lionfish Pterois volitans (pictured), which typically swims in reefs near Japan and Australia, first arrived in the Atlantic off the coast of Florida in the mid-1980s. Since then, the tiger-striped animal has slipped throughout the Gulf of Mexico and into the Caribbean. It’s a formidable foe for native fish, gobbling down nearly every reef animal in sight, from small guppies to bigger parrotfish. But the lionfish is no ordinary predator. While scuba diving, Mark Albins of Oregon State University in Corvalis and Patrick Lyons of the State University of New York at Stony Brook noticed something strange: When hunting, the lionfish seemed to “cough” right at their soon-to-be-victims.
To understand this underwater hiccup, the team took some lionfish to the lab. There, they plopped them into tanks–laced with food dye to make any water motion easier to see–and taped the predators sneaking up on unsuspecting guppies. Sure enough, before pouncing, the lionfish blew, Albins and Lyons report in Marine Ecology Progress Series. First, the fish slowly paddled toward the guppies, protected behind clear plastic, then they let loose a big gulp of water. The resulting jets extended as much as 10 centimeters and moved at speeds around 20 centimeters per second. These vortices potentially throw prey fish for a loop, the researchers argue, hiding the lionfish’s approach. Although other fish similarly cough to empty their stomachs, no other predator is known to spit their way to a quick kill.
In the wild, however, not every lionfish employs this strategy. During their scuba sessions, Albins and Lyons observed lionfish living in their native ranges blowing at prey fish nearly half the time. But in the Atlantic, that number dipped to just over 17%. Pacific reef animals, they suggest, have learned to expect lionfish attacks, forcing the predators to adopt extreme hunting ploys. Atlantic fish, on the other hand, don’t see the invaders coming. And for those unfortunate fish, that’s a house made out of straw. – Daniel Strain | February 26, 2012
Source: Albina MA and Lyons PJ. (2012) Invasive red lionfish Pterois volitans blow directed jets of water at prey fish. Marine Ecology Progress Series. http://www.int-res.com/abstracts/meps/v448/p1-5/. DOI: 10.3354/meps09580.
Image Jens Petersen/Wikimedia