The nation's deer, which have been blamed for causing huge damage to crops and forests, could number 5 million by fiscal 2025 — nearly double the figure in fiscal 2011 — if the capture rate remains unchanged, estimates by the Environment Ministry show.
The first projections of their kind, reported Wednesday at a ministry panel meeting, showed that the number of wild deer in fiscal 2011 stood at some 2.61 million.
Around 270,000 of the animals were caught that year, and the ministry used these figures to conduct simulations.
The projections indicate that if the capture rate remains at the 2011 level, the deer population will increase to 5 million in 2025. But if the rate increases 2.2-fold, the population will drop to 1.71 million, and if it rises 2.9-fold, deer numbers will fall to 840,000.
Behind the rapid increase in wild deer is a declining number of hunters amid Japan's aging society. The number of licensed hunters, which stood at around 290,000 in fiscal 1989, had dropped to 190,000 by 2010. To alleviate the damage, the ministry is considering introducing a new system under which registered groups could conduct large-scale hunts.
Financial losses from deer-related damage to agriculture amounted to ¥8.3 billion in fiscal 2011, more than double the ¥3.9 billion reported in 2005.
In addition to the shrinking number of hunters, a ministry official explained that the changing environment that deer inhabit may also be a factor.
"Deer have a high reproductive capacity and live in areas where there are now no natural enemies such as wolves. Mild winters in recent years could have further reduced deer deaths due to food shortages," the official said.