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DNA reveals hooded seals have wanderlust

Researchers have discovered a new fact about hooded seals, a mysterious 200 to 400 kilogram mammal that spends all but a few days each year in the ocean.

An international team of researchers led by Dr. David Coltman, an evolutionary geneticist at the University of Alberta, have learned that all the hooded seal populations in the world share the same genetic diversity. The researchers reached their conclusions after analysis of more than 20 years of DNA samples taken from hundreds of hooded seals from around the world.

"These results mean that if you brought me a DNA sample of a hooded seal, I wouldn't be able to tell you where in the world you got that sample because of the genetic similarity between populations," Coltman said.

"This is important information because it helps shed light on an animal that we know very little about," he added.

Female hooded seals give birth (whelp) and wean their pups on ice floes over a period of three to four days once every year in the spring. Male seals wait until the females finish weaning for the one time of year when they will mate. The researchers believe the genetic similarities among the seals indicate these seals intermingle and mate among populations.

The research is published this month in the journal Molecular Ecology.

There are four places in the world where hooded seals go to whelp: Davis Straight in northern Canada, the Gulf of St. Lawrence, the eastern coast off of Greenland, and the coast off of Labrador. Ninety per cent of the estimated 600,000 hooded seals in the world whelp off the coast of Labrador.

Hooded seals are often harvested—especially juveniles—for their meat, blubber and light blue coats. Hooded seals are slightly larger than their cousins, harp seals, which are more famously harvested and often amidst controversy. Much less is known about the behavior of hooded seals compared to what is known about harp seals, which is a much more social breed of seal.

"Any little bit of information we can learn about hooded seals is really beneficial," Coltman said. "And now that we know hooded seals are panmictic, that is, that they interbreed worldwide, it can help us shape the way that we try to preserve and manage them."

University of Alberta. May 10, 2007.