As early as 2013, local officials in Japan’s Fukushima prefecture were beginning to express concern because hunters had become far less interested in bagging wild boar in the area around the disabled power plant out of fear that the meat would be irradiated.

Officials responded by setting boar traps and electric fences. They also began offering subsidies and prize money to the region’s generally older hunters, according to The Japan Times. These tactics were ineffective.

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“It is a cat-and-mouse game because they reproduce quickly,” conservation official Hiroshi Sakai said, according to the Times.

One seemingly intractable issue is that the area near the reactor is not being cleared, which allows the wild boars ample space to hide — and proliferate. Prior to the meltdown, the ares was frequently cleared.