In the ocean food chain, larger sharks generally only have to worry about securing their own meals. Orcas But a new study suggests that apex predators need to look out for themselves, too.
Researchers have discovered evidence pointing to the first known case of the porbeagle shark — which can grow up to 100 feet (30 meters). 12 feet long and weighs 500 pounds — being killed by a larger shark predator. The conclusions were Published in the journal Biology on Tuesday Front Lines in Marine Science,
This is not the first case “Shark cannibalism.” John Dodd, executive director of the Atlantic Shark Institute, who led the study, said it’s common for bigger sharks to eat smaller ones. “Size does matter in the open ocean, but there’s always something bigger,” he said.
In some cases— Bull sharkMako Sharks and Baby sand tiger sharkFor example, sharks eat creatures of their own species.
But lead author Dr. Brooke Anderson, a marine biologist with North Carolina’s Department of Environmental Quality, said cases of big sharks eating other big sharks, which is the subject of this study, are few and far between.
Anderson said the female porbeagle’s death raises questions about whether the phenomenon represents a widespread trend among large predators. “With advances in technology, it’s possible this is happening more often than we’ve seen,” Anderson said.
Dodd said it’s impossible to know the number of sharks eaten by other sharks, “but if our experiences at the Atlantic Shark Institute are any indication, it may be more than we thought.”
A group of scientific researchers from across the US discovered the porbeagle’s death while conducting a satellite tracking project in the northwest Atlantic to better understand the whereabouts, behavior and environmental preferences of shark species. They were particularly curious about female porbeagles, which are known to cross long stretches of ocean to give birth to their cubs.
“We were really trying to understand the habitats that pregnant females use, and where they would give birth,” Anderson said.
The attack victim, named Penelope by researchers, was one of 11 sharks tagged off the coast of Cape Cod in 2020 and 2022. Tracking tags were attached to the sharks’ dorsal fins and used to collect information about water depth and temperature. The tags stored data until they eventually fell off the shark, after which the data was transmitted back to researchers via satellite.
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The tracking devices were designed to stay on for a year, but Penelope’s data came in just five months after the experiment began. “As soon as I got the data from that tag, I immediately knew something strange had happened,” Anderson said.
Penelope’s tag A few days before it erupted off the coast of Bermuda, water temperatures Suddenly, it rose. It remained relatively high even when it reached 600 meters below sea level, which is “very unusual,” Anderson said.
Anderson and his colleagues came to a horrifying conclusion: The porbeagle had been hunted and eaten by another giant ocean creature. “The only explanation for this data is that this tab is now in the stomach of a predator,” Anderson told CBS News.
The researchers don’t know with 100% certainty who the culprit was, but the predator’s diving pattern, which the researchers tracked by looking at depth data collected by the tags, was similar to that of white sharks they’ve tracked in the past. “Based on that, my guess is that it was probably a mature female white shark,” Anderson said.
porbeagles, which have historically been overhunted, It is considered endangered in some parts of the worldBecause they are already endangered, the deaths of pregnant females and their babies could be devastating to the population, Anderson said.
And sharks aren’t the only fish that could feel the effects of this change. The rulers of the deep sea maintain the balance of the underwater ecosystem. keeping populations of smaller predators in check and adding vital nutrients to shallow water,
“Humans depend heavily on the oceans for food and many other things, and the oceans need healthy shark populations,” Anderson said.