Sharks 'functionally extinct' at 20% of world's coral reefs as fishing drives global decline

Worldwide study finds Australia among nations with highest shark numbers, but 34 out of 58 nations have half what was expected

Destructive and unsustainable fishing has caused a crash in shark numbers across many of the world's coral reefs, upsetting the ecological balance of the critical marine ecosystems, a major study has found.

A network of remote underwater cameras across 58 countries found sharks were functionally extinct" at almost one in five of the 371 reefs studied over four years.