Lionfish actually aren’t the quickest predators on the reef, however new analysis means that they will catch swift prey by way of pure tenacity, gliding slowly in pursuit till the right second to strike.
The discovering might assist clarify a part of the lionfish’s impression as an invasive species, and reveal a key looking technique that different comparatively gradual predators use, researchers report August 2 in Proceedings of the Royal Society B.
Festooned with lengthy striped spines, lionfish could make their surreal silhouettes disappear in opposition to a coral reef backdrop lengthy sufficient to stalk and ambush small fish. But the predators additionally feed in open water the place they’re extra seen.
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Curious about how the predators hunt in plain view, Ashley Peterson, a comparative biomechanist on the University of California, Irvine, and her colleagues positioned purple lionfish (Pterois volitans) in a tank and recorded them as they chased down a inexperienced chromis (Chromis viridis), a small reef fish.
In 14 of the 23 trials, the lionfish efficiently gulped down their prey. They additionally had a excessive price of strike success, capturing the chromis in 74 p.c of the trials the place the lionfish made a strike try.
On common, the chromis swam about twice as quick because the lionfish. But many nonetheless fell sufferer to what Peterson and biomechanist Matthew McHenry, additionally on the University of California, Irvine, name a persistent-predation technique — the lionfish swim towards a chromis, aiming for its present place, not the path to intercept its path. And the lionfish’s pursuit is regular and relentless, the group discovered.
“If they’re interested in something and they want to try to eat it, they just seem to not give up,” Peterson says.
In distinction, the prey fish does bursts of quick swimming together with quick pauses.
“Over time, all those pauses add up and allow this lionfish to get closer and closer and closer,” Peterson says. Then the slightest mistake or little bit of distraction can doom the prey to the lionfish’s suction-creating jaws.
“This is a good example of ‘slow and steady wins the race,’” says Bridie Allan, a marine ecologist on the University of Otago in Dunedin, New Zealand who was not concerned within the analysis. It could be fascinating to see how the unwavering chase performs out within the wild, the place there are not any spatial restrictions like in a tank, she says.
If lionfish do use the technique within the wild and prey react equally, it’s doable that the tactic might contribute to the damaging potential of their invasion within the Caribbean, Western Atlantic and the Mediterranean, the place the fish are devouring native ocean animals and disrupting meals webs (SN: 7/6/16). But different elements, such because the lionfish’s large urge for food or prolific replica, may very well be extra influential on invasiveness.
The persistent-predation technique might not be unique to lionfish, Peterson says. Other predatory fish teams with sluggish swimmers — like straw-shaped trumpetfish (Aulostomus spp.) — might additionally use it.
In a pure setting, prey which are dodging lionfish and different gradual swimmers might have extra locations to cover, Peterson says. But there are inherent dangers in a busy, distracting surroundings too. “If you’re near a reef or up against the coral, you could get pinned if you aren’t really paying attention,” she says. That’s when decided and hungry slowpokes might have the higher hand.
