Sonar and satellites reveal the fish and other creatures that live far below the surface.

The depths of the ocean still hold great mysteries. At depths between 200 and 1,000 metres live creatures that, taken altogether, weigh as much as 10 billion tonnes.

Rudy Kloser, an expert on echo sounding and deep-sea ecosystems at CSIRO in Hobart, says these creatures are vital but poorly understood. Continue reading Spying on the denizens of the Southern Ocean →