(Image: Hawaiian Islands Humpback Whale National Marine Sanctuary)

If you want to give a whale a check-up, have a look at the bacteria that live on it. That’s the message from the world’s first study of bacteria piggybacking on whales.

This unfortunate humpback travelled all the way from the Bering Sea off Alaska to Hawaii tangled in fishing gear. By the end of what was no doubt a stressful experience, the mix of bacterial species on its skin was different to that coating healthy whales. The same proved true of other stressed, injured and dead whales, found a team led by Amy Apprill of the Woods Hole Oceanographic Institution in Massachusetts.

Her team isn’t yet sure how the bacteria interact with the whales, but one possibility is that in healthy animals, as in humans, beneficial species predominate and exclude the bad guys.


“There’s a spectrum of things they could be doing, such as keeping the whale clean of fouling organisms, or producing antibiotics to fend off potential pathogens,” says Apprill.

Her team took 56 skin samples from humpbacks in the Pacific and North Atlantic oceans. They collected them either with darts that bounced harmlessly off the whales, or by netting skin that had sloughed off the whales into the sea.

The analysis provides a baseline pattern of bacterial species for healthy whales, and a non-invasive way of monitoring whale health.

Journal reference: PLoS One, DOI: 10.1371/journal.pone.0090785