The sequence was filmed off Pescador Island in the Philippines and analysed frame by frame. The shark approaches a school, pitches its body down, and throws the tail over the head in an overhead strike lasting a fraction of a second. Measured tail-tip speeds averaged about fourteen metres per second, roughly fifty kilometres per hour, with the fastest single strike near eighty. Stunned or killed sardines then drift while the shark turns to collect them.
The strike does more than hit. The acceleration can drive dissolved gas out of solution, producing visible cavitation bubbles, and a successful strike disabled a mean of about three and a half sardines, which is why the tactic pays.
The filmed work was on the pelagic thresher, Alopias pelagicus, and the behaviour is inferred rather than filmed in equal detail for the common thresher, though tail-hooking in longline fisheries has long implied it. Threshers are Vulnerable globally, hurt by finning and by high post-release mortality after tail-hooking.