Toke This: The Unexpected Effect of California’s Pot Farm Explosion on Wildlife

Your weed habit may be killing more than just your motivation.

pot farm
Pot farming methods cause trouble for native animals, from salmon to bears. (Photo: Kevin Miller/Getty)
has an ASME Award, edits for Backpacker Magazine and writes for Outside, Skiing, and more.

Medical marijuana may be California’s next gold rush, with farmers tending to valuable plants worthy of sale by real-life Nancy Botwins. In just one remote 37-square-mile patch of forest in Northern California, for instance, researchers conducting aerial surveys recently counted 281 outdoor pot farms and 286 greenhouses, containing an estimated 20,000 pot plants. The crop, say proponents, helps patients suffering with everything from arthritis to leukemia (and multiple self-diagnosed ADD-sufferers this writer knows to “focus better to clean the house”).

But recently, several California wildlife researchers reported that pot farms are wreaking havoc on wildlife ranging from endangered salmon to black bears to a rare Northern California weasel called the Pacific fisher. 

“There are [growers] that care,” Scott Bauer told TakePart, “who are doing things like capturing winter flows [to offset their need for siphoned water]. But this activity is so large that it’s not enough. There are people coming from all over America to grow marijuana. They’re here to get in on the action—the so-called Green Rush. But when it’s legalized and the bottom drops out, they’ll be gone and we’ll be left with the problem.” 

In a recent L.A. Times story, scientists said that grow ops near just one small tributary of the Eel River were siphoning up to 18 million gallons of water from the river’s watershed. That water is crucial for species like the endangered Coho salmon as well as Chinook Salmon and steelhead, all of which swim up the Eel tributaries to spawn. According to Scott Bauer, the state scientist in charge of the Coho salmon recovery on California's North Coast for the Department of Fish and Game, both juvenile Coho and Chinook spend a year or two in a stream before beginning their long swims back to the Pacific Ocean. California is currently in a drought, says Bauer, which is already contributing to stream dry-up. Add in pot farm siphoning, and Bauer says, he is “getting reports, almost daily, that fish are dying.” 

Yet water siphoning is just one impact of the California cannabis boom. The L.A. Times also reports that growers are guilty of several other infractions normally associated with logging, mining, or drilling. “With little or no oversight, farmers have illegally mowed down timber, graded hilltops flat for sprawling greenhouses, dispersed poisons and pesticides, drained streams and polluted watersheds,” reports the paper. “Growers are pumping pollutants like fertilizers, soil amendments, miticides, rodenticides, fungicides, plant hormones, diesel fuel, human waste into the watershed.” 

Mark Higley, a wildlife biologist on the Hoopa Indian Reservation, told the Times that growers have been using a particularly lethal form of pesticide, called Carbuforan, to kill bears and other animals that raid their camps. Deadly to humans in small doses, the pesticide requires a special permit from the EPA. “But [the growers] are mixing it up with tuna or sardines and the bears eat that and they die,” Higley said. 

TakePart was unable to find the exact number of bears that have succumbed to the poison. But we’ve learned that the Pacific fisher, a rare forest carnivore and smaller cousin of the wolverine, may have been hit even harder. 

Researchers from the University of California, Davis, told the L.A. Times that the weasel-like animals were probably eating rodenticides that marijuana growers use to keep animals from gnawing on their plants. They reported that 46 of 58 fisher carcasses they analyzed had rat poison in their systems. Mourad W. Gabriel, a scientist at the University of California, Davis, told The New York Times that the contamination began when marijuana growers in deep forests spread d-Con to protect their plants from wood rats. Scientists have also found d-Con in at least two endangered spotted owls

From the sound of it, there’s no end in sight to the assault on the environment and wildlife by the new agribusiness. Which is ironic given many pot smokers’ (and growers’) professed love of all things wild. 

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