PERIODICITIES IN THE ANNUAL MUSKRAT POPULATION FIGURES FOR THE PROVINCE OF SASKATCHEWAN

Abstract

The yearly production of muskrat pelts in Saskatchewan for the period 1915–60 exhibits a 6-year periodicity instead of the expected 10-year cycle. To check the synchrony of these periodicities, the province is divided into thirds: the southern prairie section, the middle aspen grove section, and the northern Canadian Shield section. In the prairie section there are two main peaks, one in 1923 and the other in 1955. The remainder of the peaks, which are at 6-year intervals, vary greatly in magnitude. The aspen grove section has peaks which are also 6 years apart but are of similar magnitude. The northern section has peaks of equal magnitude which are 30 years apart. The environmental control exercised on the conservation blocks in the Cumberland House area tends to disrupt the cycle.Some of the population changes are correlated with precipitation data. In the prairie section, the highest catches occur after 2 wet years. In the other sections, the muskrat population is not correlated with the precipitation. In the aspen grove section there is a slight correlation between snowfall and the muskrat catch the next spring.