PACIFIC RED LIONFISHES (PTEROIS VOLITANS) ARE PROBABLY BETTER KNOWN TODAY as destructive invaders of the Atlantic/Caribbean basin than as the strikingly dramatic, even exotic, fishes they have always been in their native Indo-Pacific basins. Since their introduction into Florida waters in the 1980s, P. volitans has spread throughout the western Atlantic and Caribbean, in some locations achieving more dense populations than in their native Pacific habitats – and affecting fish population of their new homes.
One reason is that they’re formidable predators, stalking species unaccustomed to their modus operandi. Another is that they’re equipped with a wealth of venomous spines, superb camouflage in colorings and body shape and an ability to herd and corner prey, sometimes working in teams.
TECHNIQUES OF CONFUSION Turns out they’re sneaky little devils as well, according to a study, which found that P. volitans often utilizes a technique of blowing jets of water toward their prey to confuse or distract them and cause them to turn to face the predator – and present an easier target.
PREDATORY MOVES While bony fishes have long been known to have the ability to produce pulses of water, this behavior by lionfishes appears to be the first time it’s ever been observed in use to capture other fishes as prey, say Mark A. Albins of Oregon State University and Patrick J. Lyons of SUNY at Stony Brook in research published in the journal Marine Ecology Progress Series.
Albins and Lyons observed the behavior in lionfishes in both aquaria and open ocean waters in the Bahamas, noting it in 100 percent of aquarium feeding trials and 23.2 percent of field observations of actively hunting lionfishes. Smaller lionfishes appear to use the technique more often than larger ones, and Pacific lionfishes more often than Atlantic ones, the authors say, suggesting that the metabolic energy costs involved are more valuable for dealing with prey who have otherwise learned to evade or defend against lionfish predation.
DOUBLE EFFECTS The use of water jets directed against prey fish may produce two results, Albins and Lyons note. They may overwhelm the prey fishes’ lateral lines, masking detection of vibration signals associated with the predator’s strikes. And they may cause the prey to turn to face the predator, enabling an easier, faster head-first capture.
Source: Invasive red lionfish Pterois volitans blow directed jets of water at prey fish, Marine Ecology Progess Series, published February 23, 2012, Vol. 448: 1–5, 2012. Link: http://www.int-res.com/articles/feature/m448p001.pdf