5 Shark Species See 'Frightening' Losses

In a comprehensive survey of shark and manta ray populations in nearly 400 coral reefs on Earth, scientists made an alarming discovery, reports the Washington Post: Five shark species known to call those reefs home have declined at a devastating rate of between 60% and 73% in the last 50 years, according to the study in Science. Some species weren't found at all in up to 47% of the surveyed areas. According to New Scientist, the surveys were conducted using 200,000 hours of footage from reef-focused cameras within the territorial boundaries of 67 countries. They focused on the Caribbean reef shark, nurse shark, grey reef shark, blacktip reef shark, and whitetip reef shark.

New Scientist notes that Australia-based study lead Colin Simpfendorfer pointed to overfishing for sharks as the likely culprit (think: the ever-popular shark-fin soup). Marine biologist David Shiffman of Arizona State University wasn't involved in the study, but told the Post the results were "absolutely jaw-dropping." Study co-author Mario Espinoza of the University of Costa Rica termed it a "really frightening" discovery for anyone who studies sharks. The oft-mythologized creatures are typically the apex predators in any area they frequent, and when they are gone, the food chain begins to break down. Rays assume top-dog position but do not consume as much as their cousin species—they basically can't handle the same workload.

This isn't the first study to note such a big loss. In 2020, Nature published the results of the Global FinPrint study, which had made its own survey of 371 reefs in 58 countries. No sharks were found at all in reefs that fell within the boundaries of the Dominican Republic, the West Indies, Kenya, Vietnam, the Dutch Antilles, or Qatar. In that study, the authors reached a similar conclusion, finding years "of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status." Humans lose if the sharks go away, according to the 2023 study. The authors conclude that shark loss causes species "diversity deficits," and the "loss of ecological function and ecosystem services" extending from that deficit will have an ever larger impact on nearby communities. (More sharks stories.)