Sunday, March 11, 2012

Good news: we somehow killed just the right blue whales

From Bits of Science: Good news: we somehow killed just the right blue whales
Earth is a bit over 4.5 billion years old. Life on it is only about one billion years younger.

And let´s say Homo smartphonensis is a mere three years old.

That means we [not really ‘we’ – some of us resist symbols of stupidity] are actually privileged to be swimming in geological time accompanied by the largest organism Earth’s evolution over all these millions of years of dinosaurs and yetis has managed to produce: the blue whale.

And then we decided to kill over 99 percent of them.

[It is something we decided we could do over much of the 20th century. So that’s still fairly recently in geological history, if you think H. smartphonensis would perhaps not be directly to blame. (If however you are a scientist and you found evidence that does suggest a direct link, please do let us now. We do have email – indeed, we must be guilty of something else there.) The killing by western whalers ended in 1966, the Soviets continued until 1972. By that time only 400 individuals remained of a natural population of 250,000 Antarctic blue whales.]

New research by a group of American scientists – from the University of Oregon, NOAA and the University of Washington published in PLoS ONE – however shows the massive whale killings could have been a lucky shot. Somehow we must have killed each whale that still had at least one close relative swimming somewhere else across Earth’s Ocean.

The researchers have at least found that the remaining population of 2,200 blue whales still harbours very large genetic diversity – which is of course wonderful news.

For their research they have examined 218 biopsy samples collected from living [the trick is to use a smaller harpoon] Antarctic blue whales throughout the Southern Ocean from 1990 to 2009, through a project coordinated by the International Whaling Commission.

As the researchers also found prove that some of the whales actually swim in circles around Antarctica (at least 6,650 kilometers) within a couple of years, there is likely also decent mixing occurring between the different subpopulations of blue whales. All in all this would seem to suggest that the endangered marine mammals are genetically healthy and – if we allow them – could have a chance to recover to larger numbers and a stable, unthreatened population, which would be a good thing for the health of marine ecosystems in general.

Blue whales can grow to a length of more than 30 meters (100 feet) and can weigh an absolutely incredible 150,000 kilos (330,000 pounds) or more.

Under normal circumstances individuals live to an age of 70 to 100 years. This makes the species vulnerable after a large collapse, as it must have evolved around a slow reproduction rate. It also means some of the whales alive today are the same whales that swam through the whalers’ net to safety, now forty years ago. It is good to know sometimes we are lucky. Because let’s reassure ourselves this is no human feat. Smartphones or not, we are still none the wiser when it comes to hunting down large marine predators and by chance even unwittingly dumber when it comes to Antarctica itself.

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