Scientists have demonstrated a new method for counting whales from space.

科学家展示了一种从太空中计算鲸鱼数量的新方法。

It uses very high-resolution satellite pictures and image-processing software to automatically detect the great mammals at or near the ocean surface.

A test count, reported in the journal Plos One, was conducted on southern right whales in the Golfo Nuevo on the coast of Argentina.

The automated system found about 90% of creatures pinpointed in a manual search of the imagery.

This is a huge improvement on previous attempts at space-borne assessment, and could now revolutionise the way whale populations are estimated. 

Currently, such work is done through counts conducted from a shore position, from the deck of a ship or from a plane. But these are necessarily narrow in scope. 

An automated satellite search could cover a much larger area of ocean and at a fraction of the cost.

"Our study is a proof of principle," said Peter Fretwell from the British Antarctic Survey.

"But as the resolution of the satellites increases and our image analysis improves, we should be able to monitor many more species and in other types of location. 

"It should be possible to do total population counts and in the future track the trajectory of those populations," he told the Inside Science programme on BBC Radio 4.