Study: Pot Killing Rare Fishers in the Sierra Nevada

Tracked animals with radio collars

Adam Roy

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Poisons meant to keep grazing animals away from pot grows in California’s Sierra National Forest are wreaking havoc on the fisher, a rare weasel-like animal, researchers say. In a paper published this week in Conservation Letters, a team of veterinary scientists for the University of California-Davis measured the survival rates of 46 adult female fishers and compared them against the location of poison-laden growing sites that had been discovered throughout the area.

The researchers found that illegal grows were the most likely cause of poisoning, as very few of the radio-collared animals were observed venturing into cities or agricultural areas where they would have been likely to encounter the chemicals.

“By increasing the number of animals that die from supposedly natural causes, these pesticides may be tipping the balance of recovery for fishers,” lead author Craig Thompson said in a statement. The animals are candidates for listing under the federal Endangered Species act, as well as under California and Oregon state statutes.

Read Damon Tabor’s feature story on the pot wars in Mendocino County

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