JawsFest on Martha’s Vineyard was a sure sell to “finaddicts” – serious fans of the 1975 shark attack movie. Organizers wanted to appeal to film buffs thrilled by the ferocity of the Great White. But they also threw out some chum to shark enthusiasts trying to save the the big fish.

So, this weekend, Samantha Whitcraft—a member of the Miami–based group Shark Savers — found herself on the island where Jaws was filmed. Standing at a literature-covered table in what was once an Oak Bluffs oyster bar, she said the group’s goal is to protect the shrinking populations of at-risk sharks

About one–third of all shark species are threatened with extinction, Whitcraft said. One major culprit – Chinese chefs who offer shark fin soup. She noted that scientists estimate there are about 3,500 white sharks left on the planet — fewer than that other endangered ferocious creature, the tiger.

But, she noted that solid scientific data on sharks is lacking.

“For many species, we don’t’ even know where they pup or mate,” Whitcraft said. “No one has ever seen the birth of a white shark.”