EFFECTS OF SELECTIVE HARVEST ON MOOSE POPULATIONS OF THE BAS-SAINT-LAURENT REGION, QUÉBEC

Abstract

Selective hunting, based on the protection of a portion of cows, was implemented beginning in 1994 in Hunting Zone 2 located in the Bas-Saint-Laurent region of Québec. Using an aerial survey carried out in the winter of 1997, the impacts of this management measure on the moose population and its harvest hunting were evaluated. Contrary to expectation, the winter moose density, estimated at 1.8 ± 0.3 moose / 10 km² (α = 0.10), has remained unchanged since the precious survey carried out in 1991. However the structure of this population has changed. Bulls, which had represented 28.0% of the winter population in 1991 only represented 15.8% in 1997. In sharp contrast, the percentage of cows in winter increased from 41.4% to 51.8% between 1991 and 1997; this difference is significant (1-tailed Z­ test, P < 0.001). The percentage of bulls among adults fell from 40.3% to 23.4%, which is below the target value of 30%. Despite this imbalance in the sex ratio, the productivity of this population was excellent, with a winter ratio of 62 calves per 100 cows. Moreover, this ratio was not statistically different from that observed in  1991 (74 calves: 100 cows; P > 0.05). productivity in the fall, prior to the hunting season, has remained stable since the introduction of selective hunting, with a ratio of 73 calves per 100 cows as comparted to 68 calves per 100 cows. It was hypothesized that the better survival of cows allowed a greater number of them to achieve their full reproductive potential. The overall harvest rate seemed higher in the fall of 1996 (27%) than it was in the fall of 1990 (25%) even though the harvest of cows was cut in half. This increase in the harvest rate was not due to selective hunting, but rather to a 2-day extension of the hunting season which resulted in an additional harvest of 2.6%. the harvest rate for bulls, estimated at 57.5%, was very high and exceeded the initial forecasts in the management plan, which set this rate at 35%. This situation was attributed to the fact that the quotas placed on cows have resulted in a transfer of hunting pressure, mainly towards bills and, to a lesser extent, towards calves. Nevertheless, selective harvest has improved the recruitment of calves and the population now has a growth rate that is superior to what it was prior to 1994 (λ = 1.053). however, sport hunting largely offsets this clear growth in the fall population. In conclusion, it is expected that the winter population of this hunting zone will increase more slowly than forecasted in the management plan. Moreover, the effects of selective hunting will be positive provided that the firearm-hunting season continues to be after the main rutting period of moose.