Friday, July 24, 2020

Sharks are now "functionally extinct" from reefs. That's bad news for our oceans

As "sentinel species" that predict ecosystem health, sharks' disappearance from reefs doesn't bode well.

Gray Reef Shark (Getty Images)

By Matthew Rozsa

Sharks are renowned as some of the most robust creatures on Earth. Not only have they existed in a similar form for over 300 million years and survived multiple planet-wide extinction events, but sharks have evolved to be able to repair their own DNA — making them extremely resistant to cancers. 

Yet humankind may finally fell these ancient predators that have become a symbol of ferocity in our culture. As a result of human intervention, the iconic fish is "functionally extinct" in roughly one out of five of the reefs analyzed throughout the world in a recent study.

"We observed no sharks on almost 20% of the surveyed reefs," write the authors, who conducted the study as part of the Global FinPrint organization and published their article in Nature. "Reef sharks were almost completely absent from reefs in several nations, and shark depletion was strongly related to socio-economic conditions such as the size and proximity of the nearest market, poor governance and the density of the human population."  Read more >>