Thinning the Aishihik wood bison herd to 1,000 animals is among the primary objectives of the new bison management plan officially adopted Tuesday.

Ensuring the herd remains free from contact with plains bison to the west in Alaska and south in Alberta and B.C. to maintain genetic purity is also among the recommendations contained in the 24-page document.

Hunting, says the plan, is to be the primary tool for population control.

The management plan was developed last year by the wood bison technical team through a series of public and internal meetings. It was put out for review and delivered to the government earlier this year.

Environment Minister Currie Dixon announced the plan's acceptance.

"A co-operatively developed management plan for the Aishihik wood bison herd ensures that the varied interests in the conservation and management of the population are heard and addressed,” Dixon said in a press release.

Environment Yukon biologist Tom Jung said now that the general principles of the plan have been adopted, it will be left to the technical team to chart a course to fulfill the objectives.

The team is made up of representatives from the Yukon and several First Nation governments, along with representation from different groups and organizations, such as the Yukon Fish and Wildlife Management Board.

Exactly how the estimated population of 1,300 will be reduced by 300 and maintained at 1,000 bison is a task the team will have to address, Jung explained.

He said however it decides to approach the reduction, the intent is to have it completed within the five-year life of the management plan, using annual harvest opportunities.

There have already been several changes to strengthen hunting pressure since the initial test hunt in 1998, explained Jung.

The government, he added, just announced the tag fee for bison has been dropped from $50 to $10 as another measure to encourage more hunting.

Jung said the technical team will also develop the guidelines regarding what action should be taken if bison are seen inside the bison-free zones established to the west and south to prevent contact with plains bison.

Most likely, it will mean providing hunters with an opportunity to take the animal or animals, or it would be left to conservation officers, he said.

From 1988 to 1992, 170 wood bison were introduced in southwest Yukon as part of a national wood bison recovery effort.

Despite original intentions to maintain the herd at no more than 500 animals, the population took off.

Predation by wolves and bears was non-existent up until recently, and the annual harvest has not been able to keep the herd in check.

Once listed internationally as endangered, the status of the wood bison has been upgraded to threatened.

During the last hunting season, from the late fall of 2011 to last March 31, hunters harvested 132 Aishihik bison.

As the herd swelled in size, concerns were raised about the impact the growth was having on the moose and caribou populations, and their habitat.

There were also concerns about more conflicts with highway motorists, and the impact the large roaming animals were having on fencing and other personal property.

The draft management plan proposed maintaining the population at below 500 animals, at 500, at 1,000, or between 1,000 and 1,250.

It was the stated desire of the Champagne and Aishihik First Nations to reduce and maintain the herd at the original management goal of 500.

The national recovery plan, on the other hand, recommends individual herds be maintained at no fewer than 1,000 animals to ensure vitality.

An aerial census in the summer of 2011 put the herd at an estimated 1,230 bison.

Another count is scheduled for next summer, subject to budget approvals, Jung explained.

The management biologist said last year's count estimated 20 per cent of the population were calves, which is well above what would be expected in an average year.