John Fryxell, J. Bruce Falls, E. Ann Falls, Ronald J. Brooks, Linda Dix, Marjorie Strickland†
Wildlife Biology 7 (3), 151-159, (1 September 2001) https://doi.org/10.2981/wlb.2001.019
KEYWORDS: Canada, cohort, dynamics, harvesting, marten, Martes americana, model
Virtual population analysis (cohort analysis) was used to reconstruct past dynamics of a harvested population of martens Martes americana in the Bracebridge District of southern Ontario. Harvests in the Bracebridge District were managed using a quota system set by regional authorities. Quotas changed from year to year, apparently on the basis of past trapping success and variation in the proportion of young-of-the-year among harvested animals. The proportion of young in the harvest was a sensitive indicator of the annual rate of increase, whereas trapping success tended to be linked most strongly, in inverse fashion, with marten harvesting quotas. The proportion of martens harvested each year was constant, averaging 34%, despite 3-fold variation in marten abundance. This proportion was very close to the maximum sustainable yield (36%) for the population, suggesting that the management policy in the administrative unit was effective in the past in sustaining the source population as well as yielding high trapping returns. Monte Carlo simulation showed that proportionate harvesting, such as the policy in the Bracebridge District during 1972–1991, should be considerably less likely to lead to overharvesting than a constant quota policy, particularly at high average yields.