2011年2月3日 星期四

Japan team finds 1st eel eggs at sea


BY TOMOYUKI YAMAMOTO STAFF WRITER

2011/02/03


photoAn eel egg just before hatching, found off the Mariana Islands, is 1.6 millimeters in diameter. (Provided by the University of Tokyo's Atmosphere and Ocean Research Institute and the Fisheries Research Agency)

A team of researchers in Japan has found naturally spawned eel eggs in the ocean for the first time, a discovery they say will contribute to the aqua-farming of eels from eggs.

The researchers, led by Katsumi Tsukamoto, a professor of marine life science at the University of Tokyo's Atmosphere and Ocean Research Institute, collected the eggs in May 2009 off the Mariana Islands in the western Pacific.

The team included researchers from the Fisheries Research Agency, an independent administrative institution. The finding was reported in the Feb. 1 online edition of the British journal Nature Communications.

The researchers collected the eggs in a trawling survey using plankton nets.

DNA analyses found that 31 eggs, all fertilized, were those of the freshwater eel Anguilla japonica, or Japanese eel. They measured an average 1.6 millimeters in diameter.

The team said their success was the world's first in collecting naturally spawned eggs of any of the 19 eel species and subspecies.

The team focused their survey on dark new-moon nights, when they expected eels to spawn in the ocean area based on their past research.

Fertilized eggs float in seawater for only a day and a half before hatching.

The sea area, near the West Mariana Ridge, is about 3,000 to 4,000 meters deep and dotted with seamounts. The eel eggs were collected in relatively shallow waters of about 200 meters.

"We used to think eels lay eggs on the deep-sea bottom, but in fact spawning takes place in rather shallow waters," Tsukamoto said.

Japanese researchers have been probing the mystery of eel spawning for about four decades. In 2005, they succeeded in locating spawning areas by capturing just-hatched eel larvae off the Mariana Islands. But eggs were never found.

Because it's common for Japanese to eat eel to stave off fatigue from the summer heat, the fish are raised in aqua farms using nearly 100 million glass eels caught in the wild annually.

But the annual catch of young Japanese eels has dropped in recent years to only 10 to 20 percent of levels from around 1970, increasing the need to develop ways to mass-cultivate them.

The Fisheries Research Agency in spring 2010 successfully raised eels from eggs, but the rate of survival for young eels was very low, making commercial farming impractical.

The researchers say the data on water depth, temperature and salt density in the area where the eggs were found will prove valuable in attempts to efficiently raise eels from eggs.

2011年2月1日 星期二

Web Running Out of Addresses


Internet Sites, Carriers Are Laying the Groundwork for a New Routing System

By BEN WORTHEN And CARI TUNA

The Internet is about to run out of new addresses, a milestone that is spurring Web giants like Facebook Inc. and Google Inc. to develop new versions of their sites and prompting carriers like AT&T Inc. and others to upgrade networks.

This week, the last batch of existing Internet protocol addresses is set to run out. The solution to the dilemma? A new addressing scheme that tech companies like Facebook and Google are planning to test. WSJ's Ben Worthen reports.

This week, the organization that oversees Internet addresses is expected to dole out its last batch of existing Internet protocol addresses, a step akin to telephone companies running out of numbers to give customers.

Internet protocol addresses are numerical labels that direct online traffic to the right location, similar to the way a letter makes its way through the postal system. Such routing is generally invisible to users—when they type in www.facebook.com, for instance, they are actually connected to a computer located at the numerical address 66.220.149.32. It is those numbers that are in dwindling supply.

While there is a new Internet addressing system ready to go that greatly expands the number of addresses, it isn't compatible with the existing system. So in June, Google, Facebook, Yahoo Inc. and others will switch over to the new addresses for one day in the first wide-scale test of the new network, dubbed IP version six, or IPv6.

A permanent shift to a new Internet addressing system is still years off. But it is now inevitable, said Lorenzo Colitti, an engineer at Google who is helping to oversee the search company's transition to IPv6. Switching to the new network, "is critical to preserving the Internet as we know it," he said, adding it's the only way that Google will be able to be accessible to future users of the Internet.

The shift—similar to the move to 10-digit telephone dialing—is necessary because of a quirk in the way the Internet is designed. The Web is made up of networking equipment like routers and servers that decode electronic signals using an addressing system developed more than 30 years ago.

That addressing system is called IP version four, or IPv4, which allows for about 4.3 billion possible addresses. In the 1970s, that number of IP addresses was more than enough as the Internet only connected a small number of government and university researchers.

But now all sorts of devices connect to the Internet as does an ever-growing percentage of the world's population. That has caused the number of available addresses to drop from more than 1 billion in June 2006 to just 117 million in December 2010, according to the American Registry for Internet Numbers.

More than a decade ago, the Internet's founding fathers developed the much longer IPv6 addressing system that allows for a near-infinite number of websites and devices. Still, less than 0.25% of people currently access the Internet with IPv6 connections, Google says.

If the changeover to IPv6 goes well, the transition—likely to happen gradually over a number of years—won't have a big impact on consumers. Some older operating systems and home routers won't work with the new addresses, but ones bought in the last couple of years should, according to networking experts.

Bloomberg News

Businesses need to install networking gear compatible with the new addresses and build connections to their websites for people using the new addresses. Above, an Asustek Eee Slate EP121 tablet computer.

Telecommunications companies such as AT&T Inc. and Verizon Communications Inc. have been upgrading their Internet and cellular networks. For instance, over the past few years, AT&T has spent "hundreds of millions" of dollars retooling its Internet network for large companies, in addition to regularly buying networking equipment that's compatible with the new addressing system, said Dale McHenry, vice president of enterprise network services.

When Verizon Wireless begins adding cellphones to its new 4G network later this year, every device will be given one of the new breed of addresses, though the phones will work with websites addressed under the old system, too."It's part of our device requirements," said Chris Neisinger, executive director of technology at Verizon Wireless. "It has to be IPv6 compatible to be on the network."

Businesses, however, need to install networking gear compatible with the new addresses and build connections to their websites for people using the new addresses.

Last year the federal government's chief information officer said all new technology purchases made by government agencies must be compatible with the new addressing scheme and ordered the agencies to upgrade websites amd equipment.

Companies like Cisco Systems Inc., which makes routers and switches, stand to benefit. "It's a gold mine because everybody eventually has to upgrade" to equipment that is compatible with IPv6, which Cisco began selling several years ago, said Joel Conover, a Cisco senior marketing manager.

At Facebook, the company said it began planning for a transition to IPv6 three years ago, steadily upgrading its equipment with gear that supports both the new and the old addressing scheme. It launched its IPv6 website last summer, though it is rarely visited.

That site, www.v6.facebook.com, needs to be typed in manually and can only be viewed by people with an IPv6 connection, meaning that more than 99% of Facebook visitors who use the old addresses would get an error message.

Facebook, Google and others announced the June test last month along with the Internet Society, a nonprofit focused on Internet policy, in order to test how well their IPv6 sites work.

Up to now, the new addressing scheme has been stuck in a chicken-and-egg problem: No one wants to develop services using the new scheme until there's a network for accessing them; no one wants to build the network until there are services to drive demand.

One of the reasons Facebook is participating in the June test, dubbed World IPv6 Day, is to try to break that standoff, says Jonathan Hellinger, Facebook's vice president of technical operations.

Other companies haven't yet begun revamping their websites. Bryan Panovich, manager of network services for Eaton Corp., said the Cleveland maker of electrical and hydraulic partsis in the process of securing IPv6 addresses, but isn't planning to update its websites until more customers and other visitors to the sites are using IPv6 connections.

Running out of the old addresses should help hasten the switchover. "The handing out of the last space is irreversible," said Leslie Daigle, chief internet technology officer for the Internet Society, adding that it should show "those who have to move that this is not a hypothetical."

Write to Ben Worthen at ben.worthen@wsj.com and Cari Tuna at cari.tuna@wsj.com