Chris Avila, of Canadian Marine Aquaculture, described how he was trying to collect a 3mm DNA sample from each of the fins of a new shipment of sharks, a species of bamboo shark (Hemiscyllium halmahera). They had showed no signs of distress when handled and had not reacted to having their fins pinched lightly, which is a stress test done prior to the clipping. Nevertheless, Avila had lightly sedated them for the procedure.

But when he attempted to take a fin clipping—just 2mm off the edge of the second dorsal fin—the shark had a violent reaction and nearly succeeded in jumping out of the box. Avila said that there was no doubt that it had reacted to the tiny cut he had made.

So he anesthetized the animals before continuing with the procedure, as shown in the video. Yet in spite of the anesthesia, it is clear to see from the delicate motions of the shark's fin, how sensitive it still is.