Sunday, March 21, 2010

Science Sunday: It's All One Big World

Critters don't get much gaudier than the lionfish.

This native of the Southeast Pacific is popular with aquarium owners, but apparently enough have been released or escaped into waters off Florida that they are now spreading through the Bahamas like weeds. This would not necessarily be a bad thing, but as Chet Raymo notes, lionfish have no natural predators in the Atlantic. They do have voracious appetites for other reef denizens, notably the young of local food fish, and their spines are venomous to humans.

Lionfish (genera Pterois, Parapterois, Brachypterois, Ebosia or Dendrochirus) grow to be about 12 inches in length while dwarf species are about the size of tennis balls.

"It's all one big world now," writes Raymo. "Viruses and tropical birds wing around the globe at nearly the speed of sound. The lionfish may have made it to the Atlantic on a jet liner from Auckland, via a aquarium in Boca Raton. Oh, it's pretty, all right. I'd love to see one on the reef. But beauty is not always benevolent. 'Beauty is the beginning of terror,' wrote the poet Rainer Maria Rilke. I'm not quite sure what he had in mind, but the lionfish fits the bill."

Bite marks on the skeleton of a now-extinct dolphin reveal that it was killed by an enormous shark that bit, shook and bled its victim to death 4 million years ago. The shark measured over 13 feet long.

The dolphin skeleton had laid unstudied in a Turin museum for more than a century, but when Giovanni Bianucci of the University of Pisa examined it as part of a larger study of fossil dolphins, he noticed bite marks on the ribs, vertebrae and jaws.

Identifying the victim of the attack was the easy part -- it's an extinct species of dolphin known as
Astadelphis gastaldii, but working out the identity of the killer called for some serious detective work, as the only evidence to go on was the bite marks.

Bianucci called in fossil shark expert Walter Landini, who simulated the bite marks of the potential culprits and narrowed it down to Cosmopolitodus hastalis."

A proposal to ban the export of Atlantic bluefin tuna prized in sushi has been rejected by a U.N. wildlife meeting.

Thursday's decision occurred after Japan, Canada and scores of poor nations opposed the measure on the grounds that it would devastate their fishing economies. Monaco had introduced the proposal at the 175-nation Convention on International Trade in Endangered Species, arguing that extreme measures are necessary because the stocks have fallen by 75 percent and current managing agencies have done nothing to rebuild the stocks.

Only the United States, Norway and Kenya supported the proposal outright.

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