Researchers have discovered evidence suggesting that a pregnant porbeagle shark was eaten by a larger shark. The incident was uncovered during a satellite tracking project in the Northwestern Atlantic aimed at understanding shark species’ behaviors and environmental preferences. The victim, nicknamed Penelope, was one of 11 sharks tagged off the coast of Cape Cod in 2020 and 2022.
Tracking tags were placed on the sharks’ dorsal fins to collect data on water depth and temperature. The tags were designed to stay on for a year, but Penelope’s data came in after just five months. Dr.
Brooke Anderson, the lead author and a marine biologist for the North Carolina Department of Environmental Quality, noticed something unusual in the data. A few days before Penelope’s tag popped off near Bermuda, the water temperature suddenly spiked and remained high, even at depths of 600 meters.
Porbeagle shark’s predator encounter
Anderson and her colleagues concluded that the porbeagle had been hunted and eaten by another large shark. “The only explanation for that data is that this tag is now in the stomach of a predator,” Anderson said. While the exact predator is unknown, the diving pattern tracked by the tag was similar to that of white sharks monitored in the past.
“Based on that, it was likely, I’d guess, a mature female white shark,” Anderson said. Jon Dodd, executive director of the Atlantic Shark Institute, which helped lead the study, noted that larger sharks eating smaller sharks is common, but cases of large sharks eating other large sharks are rare. The loss of pregnant females and their babies could be devastating to the already vulnerable porbeagle population, which has been overfished historically.
Sharks play a critical role in maintaining the balance of the underwater ecosystem, and healthy shark populations are essential for the oceans. The study, published in the journal Frontiers in Marine Science, presents the first evidence of a porbeagle being preyed upon by a larger animal. The findings highlight the importance of continued tagging and tracking to understand the impact of such predation events on the species’ recovery.
