The sounds of the sea

Quick - when you think of ocean animals making sounds, what comes to mind?

Chances are, you immediately think of whales. After all, some whales make beautiful music. So beautiful, in fact, that some of the more enlightened among us even make whale music an integral part of their relaxation rituals.

The sounds of the sea are not limited to whales, however. There is a growing body of evidence to suggest that sound is very important to a variety of living things in the ocean - including the very, very tiny. A few months ago, back when Water Blogged was just a wee little blog polyp itself, we featured an amazing story about coral larvae using the sounds of coral reefs to choose their settlement location. That still blows my mind.

Well, today, we present to you more evidence that the sounds of the living ocean may be far more important than we've realized in the past: in a new study of crustaceans in the Great Barrier Reef region, researchers report that many species of tiny crustaceans, which previously had been assumed to be functionally deaf, display marked avoidance or preference for the sounds of a coral reef. Basically, the researchers found that the young of those crustacean species that live on reefs showed preference for the the sounds of the reef, while those that don't settle on reefs showed a definite avoidance of the sounds - which makes sense, given that those things that are making the sounds also have mouths that like to eat little crustaceans.

One of the obvious implications of this and similar findings is that the noise generated by human activities on the water is likely causing far more havoc than we even realize. We're doing a pretty lousy job of taking noise into consideration when we manage activities, but the tide may be turning - for example, the Federal Court's recent judgment regarding DFO's responsibilities for protecting killer whale critical habitat found that the acoustic environment of the whales is one of the pieces of their habitat that must be protected.

So, the take home message? The sounds made by the oceans' living things are important - important to them, and important to other species. This is why we need to do a better job at protecting the acoustic habitat of the oceans.

Curious about some of the noises that are made by ocean creatures? Then I strongly suggest going to this awesomely powerful time-waster: the audio gallery of the Discovery of Sound in the Sea website. Here, you'll find that:

• Harbor seals, despite their relatively tiny size and big-eyed adorableness, sound exactly like the devil coming to collect your soul.
  
• The black drum is the original beatboxer.

• Weddell seals are aliens.

And, on a more poignant note, you can hear the whistle of the baiji, or Yangtze River dolphin. It's not terribly impressive by itself, but take a good listen, because that's a sound that will never be heard again on earth. It's become extinct over the past several years - on our watch.