Sharks disappear from home waters

Reef sharks have vanished from vast swaths of the planet’s coastal waters, according to a study.

An Australian grey reef shark. Picture: AFP

Reef sharks have vanished from vast swaths of the planet’s coastal waters, according to a study that drew on surveillance footage from thousands of underwater cameras.

The researchers saw no sharks in about a fifth of their expected habitats. Only three were seen in footage from reefs in the waters of the Dominican Republic, the French West Indies, the Windward Islands, Kenya and Vietnam.

However, they found signs that conservation measures had succeeded in boosting reef shark populations. Reefs off Australia, the Bahamas, Micronesia, French Polynesia and the US appeared to have healthy shark populations.

Each of these nations had ­either banned shark fishing or had a “strong, science-based” policy governing sharks catches.

Reef shark numbers were known to have been devastated by overfishing, the researchers said in a paper published in ­Nature, but much of what was known of their population was inferred from fishing industry catch records.

Marine biology organisation Global FinPrint put 15,000 cameras on 371 reefs in the coastal ­waters of 58 nations in 2015 and shot footage over four years.

“We observed no sharks on ­almost 20 per cent of the surveyed reefs,” the researchers said. “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.”

Biologist Demian Chapman from Florida International University said: “We found that robust shark populations can exist alongside people when those people have the will, the means, and a plan to take conservation action.”

The Times