Man-Made Noise Pollution is Seriously Harshing Blue Whales' Mellow

Blue whales, the largest mammals on Earth, have long been revered as gentle giants roaming their way through the world's oceans, sucking back krill by the ton and serenading each other with their majestic songs. It sounds like a peaceful existence...

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Feb 29 2012, 9:59pm

Blue whales, the largest mammals on Earth, have long been revered as gentle giants roaming their way through the world’s oceans, sucking back krill by the ton and serenading each other with their majestic songs. It sounds like a peaceful existence, right? Well, new research says the blue whales’ lives aren’t too chill any more.

You see, oceans these days are noisy as hell. A paper published today in PLoS ONE from a team led by Marian Melcon at UC San Diego finds that man-made noise that’s filling the oceans is screwing with blue whale vocal behavior, which is key for just about everything they do, including eating and mating. The results suggest that noise pollution could have large-ranging effects on not only the whales themselves, but also all marine creatures in general.

Melcon’s team followed blue whales off the coast of Southern California, tracking their vocalization frequencies in various sound environments. They recorded ocean noise into four groups: sonar, ship noise, explosions, and non-anthropogenic (not man-made) sources. The team found that sonar dramatically decreased the number of whale calls, while ship noise increased vocalizations.

It’s important to note that the disruptive noises weren’t necessarily in the same frequency as the whales’ calls. In other words, it’s not simply the case that the whales aren’t vocalizing because the ocean is already full of noises that mimic their own. Instead, it seems that a number of noise sources are having an effect.

It’s obvious, as the authors admit, that more research is needed to get a better idea of why the whales are responding how they are –Are they alarmed? Warning? Aroused? – but noise pollution is certainly having an effect. However, in light of past studies that have shown noise is harmful to whales (as well as research showing that ocean noise caused squids’ heads to explode), it’s tough to imagine that the changes to whales’ behavior is indicative of anything positive.

Artwork by the author. Follow Derek Mead on Twitter.

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