Micro-Chip Tracking Tags to reveal walrus migration
Pastor Dale Morgan
*Micro-Chip Tracking Tags to reveal walrus migration*
By Rebecca Morelle
Science reporter, BBC News, Greenland
Scientists want to find out where walruses are migrating
Scientists are closer to solving the mystery of where walruses head to
in the summer months after attaching satellite tracking tags to eight of
the beasts.
Until now, the Arctic animals' migration route and destination have
remained a mystery to researchers.
A Danish-Greenlandic team had to spend five days off the west Greenland
coast in harsh conditions to tag the mammals.
They also hope the devices will shed light on how hunting, oil
exploration and climate change affect walruses.
The tags were deployed over a period of two days by the expedition's
field leader Mikkel Villum Jensen.
"I think it went well and I'm very happy with eight tags," he told the
BBC News website.
"We lost two to the big blue shelf, which was a pity - if you have 10
tags in your pocket, you are aiming to get 10 in, but, in general, I'm
happy."
The Atlantic walruses of west Greenland are one of at least eight
separate sub-populations of the animals.
The creatures were scoped out from a 70-tonne trawler as it ploughed
through the ice-covered waters of the Davis Strait, which lies between
the west coast of Greenland and Baffin Island, Canada.
'A lot of ice'
The conditions were a lot tougher than the team expected.
Mr Villum Jensen said: "It took five days to finally get to them - there
was a lot of ice making it difficult for us to navigate to their habitat.
Tagging walruses in Greenland
In pictures
"The icy conditions also made it difficult to stealth-in on the animals
using the boat, and it was very cold and extremely windy at times, too."
The walruses were eventually located in an area called the Hellefiske
Bank, where the creatures dive for clams and other molluscs about 70m
(230ft) down. Many of the tusked animals could be seen resting on the
ice, often in groups of two or three.
Two different types of tags - one about the size of an ice hockey puck,
the other about the size of a cigarette lighter - were used on the walruses.
They were deployed from a few metres away using a crossbow, a carbon
dioxide (CO2)-powered gun, and a harpoon that had been crafted by the
boat's skipper.
"Most of the animals we tagged were between six and 10 years of age, but
we tagged a couple that were 20 years-plus. We tagged an even amount of
males and females," Mr Villum Jensen explained.
Walrus watch
The tags will now begin relaying the walruses' co-ordinates via the
Argos satellite system. The BBC News website will be following the
creatures' movements on its "Walrus Watch" map.
"Previously these tags have lasted between two and three months," said
Mr Villum Jensen.
"But I have modified the anchor, so they could hopefully stay on for
longer than that."
The team is hopeful the tags will last longer than three months
Erik Born, from the Greenland Institute of Natural Resources, and Rune
Dietz, from the Danish National Environmental Research Institute (Neri),
will study the data to find out more about the animals' movements. The
Technical University of Denmark is also a collaborator on the project.
Mr Villum Jensen said: "The tags will tell us about the walruses'
migration; we are not certain where this sub-population in west
Greenland spends the summer.
"And they will tell us about their haul-out patterns, meaning how long
they spend on ice or land compared to their time in water."
The scientists will also use the tags to find out whether oil
exploration is altering the creatures' movements, and they will also
help to establish whether the number of walruses being hunted in west
Greenland at present is sustainable.
In the longer term, the tagging information could also help to assess
how climate change is affecting these Arctic animals.
Mr Villum Jensen observed: "Tags are a godsend to marine mammal research
- there is no other way you can find out about where these animals are
going."