Scientists on Monday urged Arctic rim nations to set fishing regulations for the Arctic Ocean, and order a moratorium on fishing until stocks are assessed, before trawlers soon start dropping nets in the pristine waters.

"A commercial fishery in the central Arctic Ocean is now possible and feasible," said more than 2,000 scientists from 67 countries in an open letter released by the Pew Environment Group to Canada, Denmark, Norway, Russia and the United States.

A team of Russian scientists say they will embark on a quest next week to observe the only all-white, adult killer whale ever spotted -- a majestic and elusive bull they have named Iceberg.

The researchers from the universities of Moscow and Saint Petersburg first spotted the orca's towering, two-meter dorsal fin break the surface near the Commander Islands in the North Pacific in August 2010.

The space shuttle Enterprise's scheduled arrival in New York City has been pushed back because of possible bad weather.

NASA says Monday's planned arrival of the shuttle has been postponed "until further notice."

Peruvian authorities are still trying to unravel the mystery of why hundreds of dolphins ended up dead on beaches in the country over the past 2 1/2 months.

Deputy Environment Minister Gabriel Quijandria told The Associated Press in an interview on Friday that studies are incomplete but officials hope to complete their research on the likely causes next week.

A startup evidently devoted to mining asteroids for metals is to make its public debut Tuesday in the U.S. northwest city of Seattle, seeking to redefine the term "natural resources."

X Prize founder Peter Diamandis and a former NASA astronaut are slated to unveil Planetary Resources, which boasts an impressive list of backers including Google co-founder Larry Page and famed film maker James Cameron.

Four new species of freshwater crab, bright purple in color, have been discovered in the biologically diverse Philippines, according to a scientific paper.

The tiny crustaceans were found in streams in remote areas of the Palawan island group, according to a team led by Hendrik Freitag, of Germany's Senckenberg Museum of Zoology.

Kenyan rangers shot dead five suspected elephant poachers in a night-time firefight in the north of the country, the Kenya Wildlife Service (KWS) said on Saturday.

"Five suspected poachers were last night gunned down and one escaped during a fierce exchange of fire with Kenya Wildlife Service rangers at Chepareria in West Pokot County," it said.

Polar bears diverged from their closest relatives 600,000 years ago, far earlier than previously thought, suggesting more challenges in the face of climate change, scientists said Thursday.

Previous genetic analysis of polar bears had determined the species was only about 150,000 years old. But in fact, it took them five times longer for the polar bear to adapt to arctic conditions, according to the study by Frank Hailer and colleagues.

The acceleration of climate change is stressing mountain plants in Europe and driving them to migrate to higher altitudes, according to a study released Thursday by U.S. researchers.

The plant migration is also decreasing species diversity, the study's authors said in the April 20 edition of the journal Science.

Seismologists say last week's powerful earthquake off western Indonesia increased pressure on the source of the devastating 2004 tsunami: a fault that could unleash another monster wave sometime in the next few decades.

"The spring was pushed a little bit tighter," said Kerry Sieh, director of the Earth Observatory of Singapore.