Captive Shark Has "Virgin Birth"!

From the BBC:

Female hammerhead sharks can reproduce without having sex, scientists confirm.

The evidence comes from a shark at Henry Doorly Zoo in Nebraska which gave birth to a pup in 2001 despite having had no contact with a male.

Genetic tests by a team from Belfast, Nebraska and Florida prove conclusively the young animal possessed no paternal DNA, Biology Letters journal reports.

The type of reproduction exhibited had been seen before in bony fish but never in cartilaginous fish such as sharks.

Parthenogenesis, as this type of reproduction is known, occurs when an egg cell is triggered to develop as an embryo without the addition of any genetic material from a male sperm cell.

The puzzle over the hammerhead birth was reported widely in 2001, but it is only with the emergence of new DNA profiling techniques that scientists have now been able to show irrefutably what happened.

Unfortunately, there is a dark side to this tale of wonder. Read on:

Dr Paulo Prodohl, a co-author on the Biology Letters paper from Queen's School of Biological Sciences, said: "Vertebrates in general have evolved away from parthenogenesis to boost genetic diversity and enhance evolutionary potential.

"The concern for sharks is that not only could we be reducing their numbers but we could be making them less fit as well."

"Our findings will now have to be taken into consideration for any conservation management strategy, especially for overexploited species."

The birth of the hammerhead (of the bonnethead species, Sphyrna tiburo) at Henry Doorly was as tragic as it was puzzling.

The new pup was soon killed by a stingray before keepers could remove it from its tank.

But at the end of the day, I can't help but think this lady hammerhead won this particular round of Science vs. Creature:

At the time, some theorised that a male tiger shark kept at the zoo could have been the father - but the institution's three bonnethead females had none of the bite marks that are usually inflicted on their gender during shark sex.

Some even suggested that one of the females could have had sex in the wild and stored the sperm in her body - but the three-year period in captivity made this explanation highly unlikely.

The new tests on the dead pup's tissues now show the newborn's DNA only matched up with one of the females - and there was none of any male origin.

Although extremely rare in vertebrates, parthenogenesis (out of the Greek for "virgin birth") occurs in a number of lower animals. Insects such as bees and ants use it to produce their drones, for example.

Also from the BBC, this helpful diagram:



Discuss.

Arts 'n' Crafts time.

How does a LEVIATHAN chase away the blues of knowing we live in a world where tea clippers and Russian subs are imperiled by the nefarious doings of villains and vandals? How, I say?


Well, the arts & crafts table always cheered me up in nursery school.

I admit that I clicked on the link to WikiHow's How To Make A Sea Creature Mobile expecting to be instructed in various methods of conferring mobility to our deep-sea friends. But this is still pretty good, because it involves "glitter glue," "shiny stickers," and "goggle eyes."

CUTTY SARK BURNS!

Was the sinking of Providence's Russian sub only the beginning of a nefarious crime spree? A "suspicious" fire in London has seriously damaged the 19th-century wooden ship, apparently "the world's oldest surviving tea clipper." What's next? The Intrepid capsized? The Constitution teepeed? Who will save the world's maritime monuments from ignominious vandalism?

http://news.bbc.co.uk/2/hi/uk_news/england/london/6675381.stm

RUSSIAN SUB SINKS!

And now for a sea story that hits close to home (or, for many of you, a former home)
Yes, a few weeks ago, during a spring nor'easter, the RUSSIAN SUB MUSEUM SANK into the Providence bay! I would have posted this sooner, except that it has only just come to my attention. For some reason, this event did not receive much publicity...if you ask me, such lack of interest in the local Soviet-era sea-themed tourism industry does not reflect well on the Providence citizenry.

Meanwhile, the lovely staff at the Russian Sub Museum seems to be taking it all in stride. I like their snappy "Nothing can keep a Russian Sub down" attitude.

Loose lips may sink ships, but seasoned submarine docents can certainly warm one's heart.

Soviet-era submarine sinks in Providence
By Michelle R. Smith, Associated Press Writer April 18, 2007
PROVIDENCE, R.I. --An old Soviet submarine now used as a floating museum sank and was completely submerged in the Providence River after being battered by a powerful nor'easter earlier this week.
All that could be seen of the Russian Sub Museum Wednesday was about two feet of its periscope, and workers said it could be months before it's open again.
"We got hit with a freak storm with astronomical high tides," ship's engineer Damon Ise said.
A tidal surge paired with direct and powerful easterly winds from the storm on Sunday and Monday pushed the sub up onto a shoal adjacent to where it's anchored along the western bank of the river, Ise said. Then water began seeping into the inoperable sub, which is not watertight.
The sub was listing to its left, or port, side Monday. Late Tuesday night, Ise said, the sub tipped further and sank.
Museum officials believe the sub is filled with water, though they don't think the instruments are damaged because they are water tight.
Ise said the sub, alternately designated as K-77 or Juliett 484, is the only submarine of its kind in the United States.
"For those of us who put a lot of time into this, it's heartbreaking," he said.
K-77, launched in 1965 as part of the Soviet Northern Fleet, is about 282 feet long and 31 feet wide, and was diesel powered. The Juliett class was initially planned as a nuclear missile platform for strikes against the United States and carried four nuclear cruise missiles. Later, it began tracking U.S. aircraft carriers.
The sub was used in the 1990s as a restaurant and vodka bar in Helsinki, Finland, and later as a set for the Harrison Ford movie "K-19: The Widowmaker" before being acquired by the USS Saratoga Foundation, a private, nonprofit group.
It opened as a museum in 2002 and has since had tens of thousands of visitors from all over the world. It's also a popular place for birthday parties and even hosted a wedding in 2005, volunteers at the museum said Wednesday.
Laurie Prete and her 14-year-old son Louis, of North Providence, have been volunteers at the museum for four years, and the two spent part of Wednesday in the sub's ticket office with other workers peering out the window at the empty space where the sub once floated.
Louis is a docent and leads tours of the sub, he said.
"He got so into history, World War II, everything, because of this sub," Laurie Prete said. "I feel like I lost a family member."
A salvage company was working on a plan to bring the sub off the river floor and pump out the water, Ise said. The sub is insured, and he said that should pay the tab for the work.
"I assume it's going to cost a huge amount of money," he said. "This is going to be a huge salvage operation."
It was too early to know how long it might take to raise the sub and clean it out, but Ise said it took workers three months to get it ready for visitors before the museum opened in 2002. This time around, they'll be contending with what he termed "a slime line" left by the water.
Still, workers were taking the news with a sense of humor Wednesday.
Ise was calling it the "Russian Sunken Sub Museum."
Riffing off the museum's motto of "Our museum can sink your museum," volunteer Ken Johnson came up with a new one: "Our museum can sink. Your museum?"