(CNN)Animal control in the western United States just got more extreme.
A new law allows some Native American tribes to kill sea lions that have been devouring the region's endangered salmon and steelhead -- as long as they first get a permit.
The law, passed by Congress and signed by President Trump last month, amends the Marine Mammal Protection Act of 1972 to ease protections on California and Steller sea lions in the Columbia River, the Willamette River and their tributaries.
It authorizes the National Oceanic and Atmospheric Administration (NOAA) to issue the permits to the Nez Perce Tribe, the Confederated Tribes of the Umatilla Indian Reservation, the Confederated Tribes of the Warm Springs Reservation of Oregon and the Confederated Tribes and Bands of the Yakama Nation.
The new law also gives state officials more flexibility in removing sea lions from the designated areas.
Government authorities in Washington, Oregon, and Idaho already were permitted to kill a limited number of threatening sea lions, according to NOAA. But under the new law, state officials will no longer have to identify individual sea lions by their markings or document the animals feeding on salmon and steelhead before removing them. It also expands the areas in which sea lions can be legally removed.
"Many salmon and steelhead populations in the Northwest are threatened and endangered, and the last few years have been particularly hard as ocean conditions have turned and fewer salmon have returned to the rivers," NOAA spokesman Michael Milstein told CNN.
"That leaves fewer fishing opportunities and fewer salmon to feed other predators such as sea lions and killer whales."
Up to 920 sea lions could be removed each year under the new law.
But it's not a free for all -- the law specifies the mammals must be killed humanely and with a permit. It also says the policy must be suspended in five years if the salmon and steelhead populations no longer need extreme protection.
Killing the mammals might seem like a drastic step, but Oregon wildlife officials say attempts to scare off sea lions with pyrotechnics and rubber bullets only helped temporarily.
The migratory salmon and steelhead are protected by the Endangered Species Act, and the NOAA says fish populations cannot sustain themselves without government protections.
What's more, the fish are vital to the West Coast's ecosystems and economy.
"They help sustain the ecosystem by bringing nutrients back to rivers from the ocean, they provide food for many predator species, and they support the economy through commercial and recreational fishing," Milstein said. "So the recovery of salmon and steelhead supports the ecosystem as well as communities in the region."
In recent months at least eight sea lions have been fatally shot in and around Puget Sound in Washington. Experts suspect commercial and tribal fishermen who blame the sea lions for decreasing the salmon population.
CORRECTION: This story has been updated to say that under the new law only state officials and certain Native American tribes are eligible for a permit to kill sea lions.