NUNAVUT - Pond Inlet hunter Jayko Peterloosie says Nunavut's narwhals are choosing different migration routes, which is part of the reason why it's been hard to determine how many of the animals there are.

"Sometimes there are less in certain years and sometimes there are more," Peterloosie said through an interpreter.

But new methods to estimate narwhal populations has boosted the estimated number of animals in the High Arctic, the Department of Fisheries and Oceans' lead research scientist recently told Nunavut News/North.

Pierre Richard said the current mean number of narwhals in the High Arctic is approximately 66,000.

Former surveys estimated the population at between 30,000 to 40,000 whales.

Traditionally, surveys were done by flying over water and counting the number of animals, Richard said.

"People used to count everything that was five or six hundred metres from the aircraft as they were encountering them as the aircraft moved over the water, so that's called a 'strip,'" he said. "But it's been recognized over the years that actually animals are not detected equally over that strip. There is a decline in detection with distance."

Richard said the new survey methods involve mathematically calculating the margin for error involved in surveying, including calculating the number of whales researchers might not see due to the distance from the aircraft to the water.

"You can say, 'What would be the number of animals if the probability of detection was 100 per cent throughout the whole strip?'" he said. "It's a mathematical model that allows you to correct for that declining detection with distance."

New methods also include a mathematical formula to correct observers' errors that might occur.

"We're trying to estimate how many animals are missed by observers and correct for that in our estimation process," he said.

Richard said the formula factors in distractions faced by observers that might make them miss seeing whales, such as taking time to record previous sightings or scanning a different area in his or her field of vision.

"What we do is we use two observers and we determined the number of times one observer would see something and the other didn't, and the number of time they both saw it and so on and so forth," he said. "This way we're able to correct for, the error of observers."

Estimates also involve expanding the surface estimate to accommodate whales that might be underwater during the observation, said Richard.

"With dive information we estimated that they spent about a third of their time at the surface and two thirds of their time below," he said. "So (for) every animal that we estimate above the surface, there are two more below the surface."

Richard said the information gathered will allow the Nunavut Wildlife Management Board to determine the total allowable harvest of narwhals with more accurate numbers.

Peterloosie said he has noticed narwhals moving farther North where there is more food and fewer ships.

He has also heard from other hunters that the whales are now heading towards Greenland, which used to typically host beluga whales.

Another survey using the new survey methods is scheduled to take place this summer in Admiralty Inlet on the northwest coast of Baffin Island, Richard said.