Since September, at least eight dead sea lions that washed up on the shores of Washington state were shot and killed with guns, according to the National Oceanic and Atmospheric Association.
Several other California sea lions are suspected to have died from "acute trauma" caused by humans, says Seal Sitters Marine Mammal Stranding Network, which responds to reports of stranded or dead sea lions. The group reported that a carcass of a sea lion with its head chopped off was found last week along the shores of Seattle.
It's illegal under the 1972 Marine Mammal Protection Act (MMPA) to shoot marine life, such as sea lions and dolphins. Those who violate the act can face up to $28,520 in fines and up to a year in prison.
But that hasn't stopped some fishermen from shooting sea lions anyway. For decades, fishermen and sea lions have been locked in a fierce battle for dominance over one of the region's hottest commodities: salmon.
"It's kind of a feeding frenzy at times," says Michael Milstein, a spokesperson for NOAA Fisheries, which is investigating the recent sea lion shootings. He tells Here & Now's Lisa Mullins that the number of sea lions found shot dead is unusually high for this time of year.
The fight for salmon in the Puget Sound has grown increasingly tense in recent years, Milstein says. Puget Sound Chinook salmon have been listed under the Endangered Species Act since 1999, due to climate change and habitat loss.
Sea lions often scoop up thousands of dollars' worth of salmon that fishermen have hooked on their lines, Milstein says. They are "smart, effective predators" with a history of aggravating fishermen, who say sea lions threaten their livelihood.
"We know that seals and sea lions ... now in Puget Sound probably consume around six times the amount of salmon that people are catching," Milstein says. "So they have a big appetite, and the challenge is to balance that against the needs of everyone else that depends on these resources."
Between 1998 and 2017, nearly 700 California sea lions were found with gunshot and stab wounds in California, Oregon and Washington, according to a National Geographic report citing NOAA Fisheries data.
Milstein says prior to the MMPA, states placed bounties on sea lions to reduce pressure on fisheries. The sea lion population made a huge recovery as a result of that law, increasing from less than 90,000 in 1975 to more than 250,000 in 2014.
The MMPA also prohibits the harassment of marine mammals, but NOAA Fisheries has outlined a list of potential methods for deterring marine mammals, including creating barriers, using noise makers and visual repellents.
Milstein says NOAA has authorized some states to remove sea lions in areas where they are significantly impacting endangered salmon stocks. An amendment to the MMPA passed the House of Representatives this year that would allow fisheries to kill up to 100 sea lions each year to help protect salmon.
Marine mammal shootings are difficult to prosecute because carcasses often decompose before investigators can examine them, Milstein says. Since 1998, only a handful of perpetrators have been charged, according to National Geographic. All of them were fishermen.
"One of the disconcerting things about these recent shootings is that they've been close to populated areas in Seattle, and that's disturbing from a public safety standpoint," Milstein says. "But we're hoping that somebody will hear or see something that will give us some leads to go on."