Researchers hung baited cameras off a boat and identified 50 different oceanic whitetip sharks using only their fins

Researchers using baited GoPro cameras off Cat Island in The Bahamas say they were able to identify 50 oceanic whitetip sharks across two seasons using only dorsal fin markings. A Florida International University (FIU) team began in late April 2023, dropping cameras about 43 feet (13 meters) deep with roughly 2 pounds (1 kilogram) of bonito. They repeated the survey in 2024 and counted 50 distinct individuals, each distinguished by notches, fin shape, and pigmentation patterns. Candace Fields, who earned her PhD in marine biology at FIU in 2025, led the work. The study notes fin-based counting can overestimate versus typical methods, and it was limited to one island area and two field periods amid deep water. The species is listed as Critically Endangered by the IUCN.