Northeastern Minnesota's moose population continues to decline
An aerial survey conducted in January estimates that the number of moose in northeastern Minnesota increased from 6,600 in 2007 to 7,600 in 2008.
However, the long-term trend suggests that Minnesota's moose herd remains in decline, according to the Minnesota Department of Natural Resources.
"At first glance, the raw numbers appear to suggest that the population has increased," said Dr. Mark Lenarz, DNR wildlife researcher. "The margin of error, however, overlapped between years which means that there was no significant change in the number of moose this year."
"Based solely on the survey results, I would be hesitant to infer a declining population," he said. "But the long-term population trend suggests otherwise, and there are other factors that significantly impact moose population."
Aerial surveys to estimate the moose population have been conducted every year since 1960. But wildlife researchers implemented a new methodology in 2005.
Lenarz said statistical comparisons of data collected from 2005 to 2008 indicate that the population increase was not as significant as it appears.
When non hunting factors such as disease, bull and cow pairings, cow pregnancy rates, calf survival and predation are considered, indexes used to estimate herd viability drop below the levels at which researchers would like to see them.
Lenarz said a study of radio-collared moose in northeastern Minnesota shows that non-hunting mortality has averaged 21 percent during the last six years. Elsewhere in North America, that rate generally falls between 8 and 12 percent.
"Biologically, issuing 200-250 permits a year for a bull-only hunt doesn't negatively impact Minnesota's moose population," said Lou Cornicelli, DNR big game program coordinator. "What directly impacts moose population is the cow and calf survival rates."
Minnesota is the only state in the central region of the lower 48 states with a significant moose population. The moose is the largest member of the deer family.