Fight for Survival

Researchers say there could be serious impacts to other species including martens, spotted owls and Sierra Nevada red foxes because they feed on the same prey as the fisher. Some flavored rodent poisons could also attract the fisher leading to first generation ingestion. / Photo courtesy of the Hoopa Wildlife Department.

Study Finds Pesticides on Pot Farms Poisoning Rare Mammal

By ALLIE HOSTLER, Two Rivers Tribune

A rare carnivorous mammal, studied intensively in some Northwest public forests, including Hoopa, is being inadvertently poisoned by illegal marijuana grows according to a study released Friday in PlosOne, a scientific journal.

Fishers, candidates for protection under the Endangered Species Act, are an elusive member of the weasel family, so elusive in fact, that many woodsmen in the area may never see one in their lifetime.

According to Mark Higley, director of the Hoopa Tribe’s Wildlife Department, there are about 28 Fishers that now call Hoopa forests home, down from 52 in 1998. The population was beginning to strengthen between 1999 and 2011. As more dead fishers turn up, Higley worries about their ability to make a significant population recovery.

A male fisher that goes by the number 102305 was found dead in May. He tested positive for Brodifacoum, a second-generation rodenticide intended to kill rodents by causing blood coagulation problems. Anti-coagulant poisons inhibit the ability of fishers and other mammals to recycle vitamin K. This creates a series of clotting and coagulation problems, which can cause the animal to bleed to death.

Lead researcher and author of the study, Mourad Gabriel did much of his graduate degree work  in Hoopa working closely with Higley and his crew at the Tribe’s Forestry/Wildlife Department. He is now a UC Davis Veterinary Genetics Laboratory researcher.

“Our findings were very surprising since non-target poisoning from these chemicals is typically seen in wildfire in urban or agricultural settings,” Gabriel said. “In California, fishers inhabit mature forests within the national forest, national parks, private industrial and tribal community lands—nowhere near urban or agricultural areas.”

Exposure to the poison was high throughout the fisher populations studied, complicating efforts to pinpoint direct sources. The fishers, many of which had been radio-tracked their whole lives, did not wander into urban or agricultural environments. However, their habitat did overlap with illegal marijuana grows.

The study describes a recent example in which more than 2,000 marijuana plants were removed less than seven-and-a-half miles from one of the project areas, where large amounts of rodenticides were used around the marijuana plants and along plastic irrigation lines were observed. This area was in the Pine Creek Watershed.

Rodent poison has been found in nearly 80 percent of all fisher carcasses used in the recent study by UC Davis Veterinary Genetics Laboratory Researcher and others. The study relied heavily on data gathered in the Hoopa area by the Tribe’s Forestry and Wildlife department. “It’s not just Hoopa, though,” Wildlife director, Mark Higley said. “We’re finding fishers poisoned in Hoopa because we study fishers in Hoopa.” / Photo courtesy of Hoopa Tribal Wildlife Department.

Researchers say the deaths occur during a concentrated time of year—between mid-April and mid-May. They suspect that is the optimal time for planting young marijuana plants outdoors and when seedlings are especially vulnerable to pests. This is also when fishers are breeding and raising their young.

Fishers likely become exposed when eating animals that have ingested the rodenticides. The study says that they also may be drawn to rodenticide dispersed around or near the plants by bacon, cheese and peanut butter “flavorizers” manufacturers add to attract rodents.

Because they share similar diets, other species such as martens, spotted owls and Sierra Nevada red foxes may be at risk from the poison too.

“If fishers are at risk, these other species are most likely at risk because they share the same prey and the same habitat,” Gabriel said. “Our next steps are to examine whether toxicants used at illegal marijuana grow sites on public lands are also indirectly impacting fisher populations and other forest carnivores through prey depletion.”

Higley is excited about the highly anticipated publication of the study. He believes it could be a turning point in the protection of wildlife against unregulated marijuana plantations. Something he and his department deal with on a regular basis.

“The Tribe is starting to take this much more seriously [illegal marijuana plantations],” Higley said. “There were small-scale local grows before, but over the last 10 years and especially over the past few years cartels have really taken hold in our area. Some of the grows are really large, in excess of 10,000 plants, or even 120,000 plants.”

The Office of National Drug Control Policy published statistics as evidence that large-scale marijuana growers and cartels are targeting public lands.

“During calendar year 2010, nearly 10 million plants were removed from illegal outdoor grow sites in seven states: California, Hawaii, Washington, Oregon, Kentucky, Tennessee, and West Virginia. More than 46 percent of the marijuana plants eradicated in 2010 were eradicated from public and tribal lands. The U.S. Forest Service reports that nearly 88 percent of the 3,531,443 plants eradicated from National Forests were eradicated in California. Marijuana grow sites are typically in excess of 1,000 plants per site and sometimes more than 200,000 plants,” the ONDCP wrote in a report. “Law enforcement officials are also increasingly encountering dumpsites of highly toxic insecticides, chemical repellants, and poisons purchased by drug trafficking organizations, and transported into the country.”

Pot farms get the blame for poisoning the elusive fisher, a carnivorous forest mammal, and candidate for protection under the Endangered Species Act, in a recent study conducted in the Hoopa region as well as the Sierra Nevada. / Photo courtesy of Hoopa Tribal Wildlife Department

It is also believed that cartels target Indian lands due to complex and shaky jurisdictional quandaries.

Higley’s employees and many more Hoopa Tribal employees who work in the forested areas have come into contact with large-scale marijuana grows, some of them have even been shot at. They call the police and are often told they can’t do anything about it.

“I’ve been working here for more than 21 years,” Higley said. “And I’ve seen the police in the woods four times—four times. Two of those times I saw the former resource officer, Joseph LeMieux, one time it was a Humboldt County Sheriff’s Deputy and the other time it was a Tribal Police officer. I don’t know why law enforcement takes a back seat in the woods.”

Frustrated with the damage to wildlife habitat, Higley says the study gives some hope that something can be done.

“I’m not necessarily attached to each individual animal,” Higley said as he showed a video of an ill Fisher in the throes of death. “But the idea of poisoning an entire population is really horrific.”

The fisher study—which  goes a step further than simply identifying the cause of death by the linking the death to illegal marijuana grows—analyzed 58 fisher carcasses in Humboldt County in and around Hoopa,  and Southern Sierra Nevada near and within Yosemite Park. An alarming 79 percent of them had been exposed to anticoagulant rodenticides.

Higley is awaiting necropsy results for three more recently discovered fisher carcasses. He suspects they’ll too test positive for rodenticides.

For more information visit Scientific Journal and watch a video on YouTube at


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July 18th, 2012


1 to “Fight for Survival”

  1. David James says:

    If cannabis could be grown legally on the farms in America that need a profitable crop, these problems the author speaks of would be nearly eliminated. The prohibition of cannabis is the ultimate cause of these problems.

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