Beaver age structure analysis of Colchester and Digby counties, Nova Scotia

Mandibles from a total of 3136 beaver collected from Colchester and Digby County trappers every season since 1964 to 1976 in Colchester and 1975 in Digby were aged by root closure and number of cemental annuli. Age structures were analyzed for stability and productivity, and differences between beaver populations in the two counties were related to differences in habitat. It was determined that the age structure of the Colchester County beaver population remained fairly stable throughout the study period due to a high productivity level which is probably a result of the good beaver habitat of the area. The age structure of the Digby County beaver population appeared to be greatly affected by trapping pressure due to a low productivity level as a result of the poor beaver habitat of the area. A double log exponential equation for the total age structure of each county was proposed as a useful management tool for the purpose of indicating changes in age structure from year to year. The equation for Colchester was y=16.6(X⁻.⁹³) and y=14.1(X⁻.⁶⁹) for Digby.