Researchers have recorded the first-ever video of a shark being struck by a boat, revealing how the animals respond to traumatic interactions with human maritime activities. In this case, a 7-meter-long (23-foot) basking shark was hit by the keel of a boat just behind its dorsal fin, resulting in “flight behavior” and a drastic change in temperament.
Describing the incident in a new study, the researchers explain that theirs is the first known footage of any large marine animal colliding with a vessel. The event occurred off the coast of County Kerry, Ireland, roughly six hours after the study authors had fitted the shark with a camera that was designed to automatically detach following a set period of time.
After retrieving the device and viewing the recording, the researchers noted that the shark spent the first six hours feeding along the surface in shallow coastal waters. However, the animal was then seen to suddenly “make a large and quick evasive movement,” write the study authors.
“Within a second, a large boat keel cut across the back of the shark, just behind the dorsal fin, and the shark was tumbled through the water,” they continue. Commenting on the incident in a statement, study author Taylor Chapple explained that “the shark was struck while feeding on the surface of the water and it immediately swam to the seafloor into deeper, offshore waters, a stark contrast to its behavior prior to the strike.”
While the collision left the shark with paint marks and a red abrasion on its back, no bleeding or open wounds were visible in the video. Despite this, the animal drastically reduced its activity levels and did not return to shallow waters or resume feeding for the remaining 7.5 hours of recording, sometimes appearing to rest on the seafloor.
Because the device then stopped filming and released itself from the shark, the researchers have no idea if the animal ever resumed its previous behavior, or indeed if it suffered any long-term consequences. Nonetheless, Chapple says that the shark’s worrying reactions “demonstrate the risk and impact of vessel strikes and the need for measures to reduce this risk.”
The basking shark seen shortly after it was tagged.
Image credit: Big Fish Lab, OSU
The second largest fish in the world – behind whale sharks – basking sharks are a globally endangered species, although their numbers do appear to be increasing in the waters around Ireland. To help protect the species, a new National Marine Park has been established in County Kerry.
Ironically, it was here that the collision occurred, and the study authors are keen to point out that conservation gains within the region may impact on maritime activities, requiring greater care when navigating through the reserve.
“With the increasing numbers of sightings in the region, and throughout Ireland, …] it is very likely that [basking shark]–vessel interactions will continue to increase with the recovery of the population,” they write.
The study is published in the journal Frontiers in Marine Science.
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