Bill and tag’s excellent adventure: A year in the life of one southern right whale

A satellite tag which unexpectedly kept working for a year has followed one whale's 15,000km journey across three oceans

A loud bang shatters the winter calm of Port Ross, in New Zealand's remote Auckland Islands, and the small inflatable boat is rocked by the swirl of a 40-ton whale being swallowed up by the cold, dark water.

When it resurfaces, the team of scientists are happy to see their US$3,200 satellite tag securely fixed to his side. The whale, whom they have nicknamed Bill", slips away into the ocean, the tag transmitting his movements. A few days later, researchers watch as he starts heading west towards Australia.