ASSESSING AGE OF HARVESTED MOOSE PRIOR TO POPULATION DECLINES IN BRITISH COLUMBIA

Abstract

Moose populations in parts of British Columbia, Canada have been declining since about the mid-2000s with the licensed harvest dropping by more than half from 1987 to 2014. A tooth reporting program for harvested moose from 1982 to 2003 enabled us to assess the relationship between age of harvested moose and 1) time (1982–2003), 2) level of licensed harvest of bulls and cows, and 3) estimated populations prior to declines with age data collected after decline in the province. We used age data determined from cementum annuli of teeth collected from hunter returns from 72,888 moose (n = 57,376 bulls and n = 15,512 cows). We found average age of harvested bulls and cows to be 3.32 ± 0.02 and 4.99 ± 0.06 years, respectively, similar to ranges reported elsewhere in western North America. Age of bulls declined linearly by year, whereas age of cows declined in the latter half of the study period. The average age of cows harvested from 1983 to 2003 prior to the population decline (n = 2,016; mean = 3.84 years, SD = 3.03) was 7 years younger than that of a small sample of cows dying of multiple causes (harvest and natural) during the decline (n = 47; mean = 10.93 years, SD = 3.72). We acknowledge the logistical and financial constraints required to gather a representative sample of teeth from harvested moose, but recommend reimplementation of a tooth collection program to provide continuous information on the age structure of moose populations to help guide management decisions.