Pot goes the weasel: Surprising new victims of illegal marijuana farms
Illegal marijuana fields in California are killing the fisher, a cat-sized relative of the weasel found in the Pacific Northwest.
Researchers found that in Northern and Southern California, fisher deaths from pesticides increased more than 200 percent since 2012. The toxic chemicals were found to be coming from illegal marijuana farms on public and tribal lands where the forest-dwelling fishers make their homes.
The study, published this week in the journal PLOS One, found that poisoning accounted for 10 percent of all documented fisher deaths between 2012 and 2014.
Though they live out in the wilderness, far from most agriculture, autopsy tests found that more than 85 percent of the dead fishers tested had a particular type of rodenticide in their systems. The poison is often flavored to taste like bacon, fish or peanut butter and is used to deter pests from clandestine pot crops.
More than two-thirds of the poisoning cases took place in the spring, which is both the fishers' mating season and the peak time for marijuana cultivation, when pesticide use is high.
The U.S. Fish and Wildlife Service proposed listing fishers in California, Washington and Oregon as threatened under the Endangered Species Act late last year, and in 2015, the Sierra Nevada population was listed as threatened under the California Endangered Species Act. But they are not the only animal in possible danger.
"We're showing that it's not getting better," said lead author Mourad Gabriel, head of the Integral Ecology Research Center in Blue Lake, Calif. Gabriel began the research as a doctoral student with the UC Davis Veterinary Genetics Laboratory and published the first results in 2012. "Fishers are the flagship species. We have to think of so many species, like Sierra Nevada red foxes, spotted owls, martens -- they all are potentially at risk. This is essentially going to get worse unless we do something to rectify this threat."