THE USE OF SCHAEFER'S AND FOX'S SURPLUS-YIELD MODELS TO ESTIMATE OPTIMAL MOOSE HARVEST AND HUNTING EFFORT

Abstract

We studied changes in moose harvest-per-unit effort (CUE) in Québec wildlife reserves to estimate maximum sustainable yield. Using data from the beginning of controlled moose hunts in 1962, we examined 5 parameters used to express the hunting effort. Since all 5 were significantly correlated with each other (P<0.01), we selected the simplest and most intuitive one, number of hunting-days, to calculate surplus-yield models. Hunting effort, expressed as the number of hunting-days, grew exponentially over the last 30 years, but harvest did not, resulting in a progressive decline of CUE. Among the 6 biological indices used to manage moose populations in wildlife reserves, only the yearling (1.5 year) percentage, which had risen gradually from 1962, seemed sensitive to harvest rate modifications. Both Schaefer’s and Fox’s surplus-yield models produced significant equations thus permitting the application of surplus-yield models. Hunting effort explained 60% of CUE variances in 8 of the 10 wildlife reserves where sufficient data were available. Schaefer’s and Fox’s models were also tested in zecs (controlled harvest zones), territories managed by hunter’s associations since the late seventies, using hunting effort parameters. Explained variance (0.36 < r² < 0.74) was generally lower in zecs than in wildlife reserves probably because hunting effort was not recorded as precisely in zecs as in wildlife reserves. Model applied to reserves suggest maintaining harvest at around 0.45 moose/10 km² in the central part of Québec. In eastern Québec, south of the St. Lawrence River, moose populations can sustain a greater harvest (0.5-0.9 moose/10 km²) probably due to a very low predation rate. Where predation is present and in northern parts of the province, the harvest must be less than 0.3 moose/10 km². Models suggest maintaining effort between 3 and 19 hunting-days/10 km² depending on the reserve. Optimal harvest and effort given by the models are generally greater in zecs than in reserves.