Moose Alces alces hunting in Finland - an ecological risk analysis

The moose Alces alces population in Finland has been managed for sustained harvest since 1970 by regulating annual hunting quotas. However, against al l expectations the population size declined in the 1990s. An ecological ris k analysis approach was used to build a growth model with annual harvest fo r the moose population. In the model there is stochasticity in the paramete rs representing population dynamics. We shall address: 1) whether the popul ation decline could be due to a mismatch between harvest and anticipated po pulation growth rate, and 2) to what extent hunting the moose population do wn to a much lower target size succeeds. A central element in this is the a ssumption that the estimate of the pre-hunting population size errs. First, the probability of a population decline due to hunting increases from valu es close to 0% up to 100% in a very narrow range (15-25%) of harvest rates. Even with high birth rates the risk of a population decline was substantia l when the hunting rate exceeded 25% for cows and 37.5% for calves and bull s. The 1974-1994 moose harvest rate was, on average, ca 45% of the populati on size in autumn. The high rate suggests that the harvest might have been too intense in that period to keep the population stable. Second, we set th e target to reduce the moose population drastically (to say 50% of the exis ting population size). Assuming that the estimates of the population size m ay err, our analysis shows that the achieved population size after the seve re harvest is far below the size we aimed at.