How sluggish and regular lionfish win the race towards quick prey
Lionfish actually aren’t the quickest predators on the reef, however new analysis means that they’ll catch swift prey by way of pure tenacity, gliding slowly in pursuit till the right second to strike.
The discovering could assist clarify a part of the lionfish’s influence as an invasive species, and reveal a key looking technique that different comparatively sluggish 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 towards a coral reef backdrop lengthy sufficient to stalk and ambush small fish. However the predators additionally feed in open water the place they’re extra seen.
Interested by how the predators hunt in plain view, Ashley Peterson, a comparative biomechanist on the College of California, Irvine, and her colleagues positioned pink 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. Additionally they had a excessive price of strike success, capturing the chromis in 74 % of the trials the place the lionfish made a strike try.
On common, the chromis swam about twice as quick because the lionfish. However many nonetheless fell sufferer to what Peterson and biomechanist Matthew McHenry, additionally on the College 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 workforce discovered.
“In the event that they’re focused on one thing and so they wish to attempt to eat it, they only appear to not hand over,” Peterson says.
In distinction, the prey fish does bursts of quick swimming together with brief pauses.
“Over time, all these pauses add up and permit this lionfish to get nearer and nearer and nearer,” Peterson says. Then the slightest mistake or little bit of distraction can doom the prey to the lionfish’s suction-creating jaws.
“It is a good instance of ‘sluggish and regular wins the race,’” says Bridie Allan, a marine ecologist on the College of Otago in Dunedin, New Zealand who was not concerned within the analysis. It might be attention-grabbing 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 attainable 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). However different components, such because the lionfish’s big urge for food or prolific copy, could possibly be extra influential on invasiveness.
The persistent-predation technique is probably not unique to lionfish, Peterson says. Different predatory fish teams with sluggish swimmers — like straw-shaped trumpetfish (Aulostomus spp.) — might additionally use it.
In a pure setting, prey which can be dodging lionfish and different sluggish swimmers could have extra locations to cover, Peterson says. However there are inherent dangers in a busy, distracting setting too. “Should you’re close to a reef or up towards the coral, you might get pinned in case you aren’t actually paying consideration,” she says. That’s when decided and hungry slowpokes could have the higher hand.
