The Yukon government today announced the territory's bison population is much higher than wildlife officials had estimated.

In late June, biologists with the Department of the Environment estimated the population to be about 700 animals.

Now, senior biologists have measured the results of recent collaring programs and aerial counting trips to arrive at an estimated Aishihik Wood Bison population size of 1,089.

'This is higher than what was obtained in any other census,' said biologist Thomas Jung. 'Most biologists or conservationists deal with lower population numbers, but with us the tables are turned.'

This estimate work provides a 90 per cent likelihood that the true bison herd population is somewhere between 970 and 1,309 animals.

Researchers, including Jung, found 48 groups of wood bison with groups size ranging from one lone bison to 96 during helicopter trips over bison habitat. As this is the first reliable estimate of the herd's size in many years, a subsequent census will be performed in July 2008 to confirm this year's results.

When 170 wood bison were introduced to the territory in the mid-1980s and early 1990s, they were a species facing extinction in most parts of the world. Now, the Yukon herd is the second largest in the world.

'Even though the numbers are larger than we had expected ... the bison still have to be managed very carefully,' said Jung. In the two decades that the bison have roamed the Yukon, they have not attracted any consistent predators.

'There is little natural predation. Here in the Yukon, I suspect grizzly bears will be the bigger predator, and that's probably happening at a very low level,' said Jung. The primary way to control the bison herd size has been through organized hunts.

The first harvest was introduced in 1998, and in the last few years, the regulations surrounding the hunt have expanded.

'We've opened up the zones, so there's no north or south hunting; you can hunt anywhere in the zone,' said Jung. 'We've also added an extra month to the hunt and put out more permits then ever.'

The bison herd is also spread out across the territory and they roam in smaller, isolated groups. This has bolstered the population numbers because it decreases the ability for disease or weak genetics to spread throughout the entire bison population, said Jung.

Now that the department has its first solid grasp on the population size, it can create a more guided management strategy.

'Now we can better plan our direction for the herd, in studying its population, predators, its impacts on the land and with other species,' he said. 'With population modeling, we can now answer more of the what-ifs.'

Before bison were brought here artificially, they had naturally roamed the Yukon as recently as 100 years ago, according to first nation oral tradition. Jung said bison bones had also been discovered and dated to 300 years ago.