Some coral reefs are thriving and scientists say they may guide efforts to curb threats such as overfishing and climate change, which are blamed for widespread global declines.

A major study identified 15 "bright spots" among more than 2,500 coral reefs in 46 nations, including off Indonesia, the Solomon islands and Kiribati where given local stresses there were far more fish than predicted.

And the Great Barrier Reef off Australia, the world's biggest, was performing in line with expectations given its remoteness and high level of protection, lead author Joshua Cinner, a professor at James Cook University in Australia, told Reuters of the study published on Wednesday in Nature.