A group of tiger sharks tearing into a bobbing whale carcass is a sight that would keep most people out of the water, but for biologist Neil Hammerschlag, it’s just the kind of rarely seen feeding frenzy that had him slipping on a wetsuit and jumping in. Hammerschlag – a shark specialist at the University of Miami – received news recently that a whale carcass had been sighted in the Gulf Stream off Florida’s Key Largo. Certain that the meaty treat would attract a bevy of ocean predators, he rallied together team members Alex Anstett and Stephen Cain, and sought out a dive company to take them to the action.
Subtropical Storm Alberto made for a rough approach, and it took the group a few hours to hunt down the floating whale buffet. Eventually, another boat attracted them to the action and as they approached the carcass, they spotted fins carving the water around the massive blob of fat and tissue.
At least five tiger sharks were ripping into what remained of the whale. "We could see the sharks would swim up and take a big bite and shake their heads back and forth to cut into the flesh," Hammerschlag told the Sun Sentinel.
Taking a dip with the ocean’s apex predators is not something to be taken lightly, but Hammerschlag was confident that his experience and knowledge would keep him safe. A second diver kept a close eye on any approaching sharks and the divers remained near enough to the boat to be able to jump back in if things took a turn for the terrifying.
"They would come close and turn, showing me the length of their body, and make a wide turn out and do the same thing, and then the next one would do it," Hammerschlag explains. "Maybe they were trying to push me off or intimidate me. They're not territorial. But you got a sense they were guarding this carcass. Maybe they saw me as a competitor."
So why take such a risk? For science! It’s rare to witness sharks feeding, and the team were hoping to glean some interesting insights from the sighting. Surprising was that only one shark species showed up for the feast, and they seemed to take turns approaching the carcass. "One would go in and then leave and then the next one would come in,” notes Hamerschlag who has published articles on sharks feedings on whales, but had never witnessed the behaviour firsthand.
Dead whales play an important role in the marine ecosystem and when one of these behemoths sinks to the ocean floor it can be provide nourishment for a huge diversity of species. Sharks are usually among the first to scavenge on the soft tissue before the carcass sinks and is devoured by deeper-dwelling creatures on the ocean floor.
"You see what an important role these sharks play in the ecosystem. They're recycling this whale back into the food web,” says Hamerschlag.
Hammerschlag admits that it was a bit nerve-racking diving into sharky waters. "It was just unnerving when they starting coming into my peripheral vision and surprising me. They were interested in the carcass, not in me. It was only when I got too close,” he told the Sun Sentinel. The experienced biologist stresses that he assessed the risks and was not trying to be a daredevil. "I was very cautious in the way I did it," he said. "I wouldn't recommend that anyone try this."
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