Scuba Diving club,
Southern California
Red sea urchin
'almost immortal'
By Dr
David Whitehouse
BBC News Online science editor
|
Sea Urchins have the secret
of long life |
The red sea urchin found in the shallow
waters of the Pacific Ocean is one of the Earth's longest-living animals.
The small, spiny creature can last for more
than 200 years with few signs of age-related disease, a US research team from
Oregon and California has found.
The animal, which grows to more than 15 cm
across, grazes on marine plants and uses its spines to deter predators.
"No animal lives forever, but these red
sea urchins appear to be practically immortal," said Dr Thomas Ebert.
The urchins (Strongylocentrotus
franciscanus) were once considered the scourge of the sea.
They ate plants in kelp forests and people
believed they were at least partly responsible for the decline of that marine
ecosystem - and so tried to poison them.
However, the spherical echinoderms became
valuable in the 1970s when the US sold them to Japan, where their sex organs
were considered a delicacy.
They brought high prices, and at one point in
the 1990s were one of the most valuable marine resources in California.
Now, studies indicate red sea urchins grow a
lot more slowly and live a lot longer than had been believed - certainly longer
than the seven to 15 years previously assumed.
Steady growth
The latest work on sea urchin growth rates
uses measures of the isotope carbon-14, which has increased in all living
organisms following the atmospheric testing of atomic weapons in the 1950s.
"Radiocarbon testing in this type of
situation provided a very strong test of growth rates and ages," says Dr
Ebert, from Oregon State University.
"Some of the largest and we believe
oldest red sea urchins up to 19 centimetres in size have been found in waters
off British Columbia, between Vancouver Island and the mainland.
"By our calculations, they are probably
200 or more years old.
"They can die from attacks by predators,
specific diseases or being harvested by fishermen. But even then they show very
few signs of age. The evidence suggests that a 100-year-old red sea urchin is
just as apt to live another year, or reproduce, as a 10-year-old sea
urchin."
In fact, the indications are that the more
mature red sea urchins are the most prolific producers of sperm and eggs, and
are perfectly capable of breeding even when incredibly old.
"Among other things, [the radiocarbon
data] confirmed that in older sea urchins, there is a very steady, very
consistent growth that's quite independent of ocean conditions or other
variables, and once they near adult size our research indicates they do not
have growth spurts."
The research is published in the US Fishery
Bulletin, by scientists from Oregon State University and the Lawrence Livermore
National Laboratory.
(Home) (Boat Dives) (Buddy List) (Campouts) (Diving Links) (Dive Spots & Dive Boats) (Diving Time Line) (Email) (Meetings) (Membership) (Recipes) (Safety & Education) (News Letters AKA Snorkel Talk) (Non Sequitur) (Updates)
Posted January 30, 2004