The fourth and final year in the attempt to turn around the decline of the Chisana caribou herd is set to get underway March 20.

Caribou biologist Rick Farnell of the Department of the Environment said in an interview last Thursday the goal is to capture 50 pregnant cows, the same as last year.

The first three years of the project have not only slowed down the decline of the Yukon-Alaska herd, but have helped to even-out the composition of young and old, male and female caribou, Farnell pointed out.

He noted that before the first capture took place in 2003, the herd was shrinking at a rate of approximately six per cent a year, while the composition was somewhere around 25 bulls for every 100 cows.

The decline, said Farnell, has slowed to two per cent a year, and there are now 45 bulls for every 100 cows.

By balancing the composition, the herd will be in a much better position to rebound successfully if and when it does bottom out, he said.

The capture of pregnant cows began with the belief that keeping the cows in a large enclosure situated on the Chisanas' home range until after the calves are born, and strong enough to escape predation, would help boost the population, and stunt the decline.

Concerns about the state of the trans-boundary herd were first raised in the late 1980s, and in the mid-1990s it was put under protection by the Yukon government.

Although biologists estimated the population at somewhere around 350 animals before the capture program began, it has since readjusted that pre-capture estimate to 700 caribou, given the additional information it has gathered with a more intense look at the herd.

Farnell said the size is currently estimated at 694.

In addition to boosting the number of calves added to the herd over last three years 96 in all biologists are witnessing the beginning of a natural rebound in the survival rate of calves, he said.

In the first year of the project, the calf survival rate among the free ranging Chisana caribou was about 13 per cent, compared to the 74 per survival rate among the first 17 calves released from the wilderness pen.

In 2004, the free-ranging survival rate was up slightly to 14 per cent, while the rate among the 29 calves released in the capture program remained relatively constant at 76 per cent.

But last year, the free-ranging survival rate jumped to 24 per cent, while the survival of the 50 calves released from the pen at Big Boundary Lake southwest of Beaver Creek remained at 74 per cent, Farnell pointed out.

This estimated cost of this year's capture program is $325,000. Alaskans are also expected to spend an additional $150,000 monitoring the herd once it moves from the winter range in the Yukon across to the border onto the summer range in the St. Elias-Wrangell National Park.

There will be approximately 16 people involved in the capture program, from netgunners flying in helicopters to veterinarians performing ultrasounds on the captured cows to see if they're pregnant.

A total of 57 cows were netted and sedated last year to get the desired 50 pregnant cows.

An essential part of the program is the annual collection of lichen by elementary school students. The lichen is needed as an essential part of the diet for the cows in captivity.

Farnell said students collected an additional 200 bags this year, which were shipped to Alberta. That province is embarking on a capture program in an attempt to save one of its threatened herds, using the same capture model developed by Yukon and Alaska for the Chisana project.

The homegrown captive rearing program, Farnell said, is drawing the attention of other jurisdictions, and is looking like a viable method to save threatened woodland herds across North America.

He pointed out the Yukon, northern B.C. and Newfoundland have the only woodland herds in North America that are not threatened.