Towards the end of the Dive 07 of Windows to the Deep 2019, after searching for a potential shipwreck target approximately 80 miles off the coast of South Carolina and instead finding a series of rocky outcrops, the expedition team had a rare encounter — a group of sharks in what looked to be a feeding frenzy appeared in the dim reaches of remotely operated vehicle Deep Discoverer's lights.
Upon closer approach, the lights revealed a dead swordfish, approximately 2.5 meters (8 feet) in length, lying on the seafloor with at least 11 sharks circling and feeding “vigorously” on the swordfish's skin and muscle tissue. The sharks represent two species of deep-sea dogfish from the family Squalidae. The smaller and more numerous animals are now known as Genie’s dogfish and at least two of the larger sharks are roughskin dogfish.
At one point while the team was watching the sharks feed, a wreckfish (not a grouper as stated in the video) was observed capturing and eating a shark in the foreground of the swordfish.
The sighting was rare because normally we don’t see deep-sea sharks in a group or aggregation, unless there is some nearby patch of food. As relatively small apex predators, they spend a great deal of time searching for prey. When a large food fall occurs, like a 250-plus pound swordfish, the ability to detect and locate the food, and then maximize food intake, is the key to growth and survival — yet remains poorly understood.
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Video courtesy of NOAA Ocean Exploration, Windows to the Deep 2019.