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Monday, September 1, 2008

Nemo Sniffs His Way Home

Tiny orange clownfish, made famous by the Disney character Nemo, use the smell of leaves and anemones in the water to find their way home on the coral reef.

That's the finding of a new study using a clever apparatus to measure the fishes' preference for water carrying different odors.

A team led by Geoffrey Jones of James Cook University in Townsville, Australia surveyed waters around Papua New Guinea for clownfish populations.

"The boat captain said, 'If you want to find the orange clownfish, you have to find islands. The fish need to see trees,'" said study lead author Danielle Dixson. The survey confirmed this observation: "There's a huge statistical difference [in the numbers of clownfish] between where there are islands and where there are not islands."

For reasons that are unknown, the two types of anemones that the region's clownfish call home only live near islands with trees and beaches and are not found on "islands" made only of reefs.

But the fish have to search for these anemones, because after eggs hatch near the parents' home anemone, the larvae are carried away by ocean currents. About 11 days later, the juvenile fish settle back into a new anemone, somehow having found their way to their favored abodes.

The researchers set out to figure out how.

They used a chamber with two sources of water flowing side by side. At the top, a wall divides the chamber, separating the water sources. Lower down, the wall disappears, but the water remains unmixed, with the two types of water flowing parallel to each other.

The researchers introduced clownfish into the chambers and measured how much time they spent on either side. This allowed the researchers to test the fishes' preference for water from different sources.

First they compared beach water from near vegetated islands with water from reef islands.

"It was ridiculously high how attracted they were to the beach water," said Dixson. The fish spent more than 99 percent of their time on the side of the chamber with beach water flowing by.

"The next step was to figure out what is in the beach water that is making them able to discriminate beach water from the other," she said.

Researchers have previously shown that clownfish are attracted to a chemical cue from anemones, and the team found that the fish strongly preferred water that had been exposed to anemones versus water that had not.

But the signal from anemones is unlikely to travel very far, so the team wondered whether there were other cues that could draw the fish back to the islands.

"The islands are loaded with trees," Dixson explained, and the water nearby has large numbers of leaves floating on the surface. So, the team exposed ocean water to five different kinds of leaves from the islands, and to a mixture of the leaves, and compared those to ocean water with no leaf exposure. "They were attracted to all of them."

But they were not attracted to the tea tree plant, which grows in swamps nowhere near the islands, so the fish have specific preferences for the "right" kind of trees.

Finally, the team showed that even fish bred in aquariums in synthetic seawater were attracted to beach water and to anemone and leaf cues, suggesting that this attraction is innate.

"The results are just spectacular," said Jelle Atema of Boston University who developed the testing chamber for his own research and shared one with the Jones group. "As humans we don't take very seriously the notion of odor in water. It's very foreign to people: How can you smell in water?"

Jelle agrees with the researchers that the abundance of leaves in the water near these islands serves to bring the fish into the right vicinity, after which they can search out the anemones.

Beyond providing an example of animal abilities, the research also has a broader message.

"It shows that there is a connection between the marine and the terrestrial environment," Dixson said. "It shows that the two can't be treated separately, especially in terms of management."

"If you're trying to protect the reef, but you're not protecting the shoreline that calls these 'Nemos' home, it's not going to work," she said.

Pedophile Nervous For First Day Of School

Worried about meeting new children and making friends, area pedophile Howard Dengal admitted Monday that he was feeling "pretty nervous" for the first day of school.

"I hope the kids at Hampstead Elementary like me," said Dengal, who spent the summer reading comic books, watching early morning cartoons, and hanging around the entrance of a local swimming pool. "It'd be nice to have someone to play with during recess."

Enlarge Image Pedophile

An anxious Dengal hopes some of the kids he knows from Little League will be there.

In preparation for Tuesday's start to the school year, Dengal picked out his favorite Batman shirt, Yankees baseball cap, and knee-length trench coat to wear. The 37-year-old then carefully packed a blue knapsack with two peanut butter and jelly sandwiches and some toys.

A change of shorts was also added to the knapsack.

"Maybe someone will see me in the morning and come up and say hello," said Dengal, who claimed that he's always a bit shy at first. "And maybe if we both like the same kind of stuff, and he has dark-brown hair, we could be friends."

After finishing his dinner and practicing a few funny jokes in front of the mirror, Dengal reportedly got ready for bed around 9 p.m. Though he tried to fall right asleep, the twice-convicted pedophile said he began to get "all excited" just thinking about school.

"I bet there's going to be a big playground, and a jungle gym, and some really tall bushes that go all the way around everything," Dengal said while tossing and turning in anticipation. "Yeah, I shouldn't be nervous. I'm going to really like this new school."

The middle-aged man went on to tell himself that it's perfectly natural to feel a little nervous on the first day of class, and that there would probably be lots of kids also feeling scared that morning. According to Dengal, he plans to just be himself, learn the names of as many children as he can, and avoid getting into trouble with any of the teachers at Hampstead Elementary.

"After I get to know some of the kids, I could ask them if they like video games, and if they say yes, I could invite them over after school to play my Nintendo Wii," Dengal said. "And then later that week we could have a sleepover, and we could all watch scary movies, and try out the new camera I just got, and eat pizza until we pass out."

Added Dengal, "We could make it a secret club that no one ever has to know about."

Despite "really looking forward" to the first day of school, Dengal said he hasn't always had an easy time making new friends. The sexual predator claimed that he's been repeatedly ignored in the past, told several times to "go away" and "stop talking to us," and once had a group of third-graders call him hurtful names.

In addition, Dengal said the fact that he's always moving around from town to town hasn't helped when it comes to keeping friendships.

"It seems like every time I meet a kid I really like, something bad happens, and I suddenly have to change schools," Dengal said. "That's what happened with my friend Joshua. I still talk to him online sometimes, but it's not the same."

While Dengal said he hopes his luck will finally change this year, the registered sex offender admitted that there was one thing that still worried him.

"There better not be too many girls at school this year," Dengal said. "Last year there was, like, a hundred of them, and they were all so stupid and gross."

"Yuck," Dengal added. "Girls!"

Bush Lets War Widow Punch His Arm Once

In an unprecedented gesture of apology, President Bush allowed widow Mary Holt, 32, to punch him once on the left arm Monday as retribution for the death of her husband, Marine Pfc. David Holt, who was killed in a 2007 roadside bomb explosion outside Fallujah. "President Bush cares very deeply about the families of our fallen heroes," said White House Press Secretary Dana Perino, who later explained the stipulations of the punch, which included no monkey bubbles or taking a running start. "The president gladly would have let Mrs. Holt punch his favored right arm if it didn't still sting from when little Abigail Pritchard give him a five-second Indian burn for her grandmother being killed in the aftermath of Hurricane Katrina." After delivering the blow, Holt reportedly sustained massive internal hemorrhaging when five Secret Service agents tackled the grieving widow to the ground.