The environmental impacts of the recent boom in marijuana growing operations have prompted calls for stronger regulation of the business of cultivating marijuana. At stake is the protection of multiple species of salmon, which has dwindled to the brink of extinction along the North Coast of California. “As many as a half-million Chinook salmon once spawned in the Eel River each year. By the 1950s, the fish were almost gone. Since then, the population has slightly rebounded, and several thousand Chinook now return to the Eel annually,” reports Alastair Brand. Dave Bitts, a Humboldt County commercial fisherman and the president of the Pacific Coast Federation of Fishermen's Associations is quoted describing the importance of maintaining watersheds as habitat for salmon: "There is no salmon-bearing watershed at this point that we can afford to sacrifice."
The impacts of marijuana cultivation on watersheds are at least twofold. First, there is the process’s water supply requirements. According to Brand, “Growers of marijuana often withdraw water directly from small streams and use up to six gallons per day per plant during the summer growing season.” Growers might be cultivating as many as 20,000 or 30,000 plants in one watershed.
The effluents produced by marijuana growers poses another risk: “Fertilizers that drain into rivers can cause floating carpets of algae to grow in the water. When these mats begin to decay, the breakdown process steals oxygen from the water, suffocating fish."