Two more sea lions have been killed amid a spat of slayings that are suspected to have been perpetrated by fishermen in the Seattle area.

In total, some 18 sea lions have been found after they were killed recently. "We found these sea lions both washed up in the West Seattle area on December 4 and December 5. One we believe was reported across the waterway previously, so that animal just washed to the West Seattle area after about a day," Casey McIean of the local marine wildlife protection nonprofit SR told local media.

The sea lions have been found in Puget Sound, an area across an inlet from Seattle. Eighteen sea lions that have been stranded in the area have died since late September. That's an "exceptionally high number," KIRO 7 reported, as only "one to four" strandings occured at around this time of year previously.

Twelve sea lions have been found after being shot in the head.

McIean said that the newly-discovered carcasses are severely decomposed and that they were likely killed around the same time as the others.

In November, one local told the station off camera that "he witnessed fishermen on Alki [Point] shooting the animals, which is against federal law."

"We are concerned about a number of recent reports of marine mammal deaths caused by gunshots in the greater Seattle area. All marine mammals are protected by the Marine Mammal Protection Act, and Office of Law Enforcement (OLE) investigates all reported unlawful takes of sea lions," Greg Busch, assistant director of the National Oceanic and Atmospheric Administration Fisheries' OLE, said in a statement in November.

According to local reports, sea lion assassinations may be linked to bad memories of visitations from sea lions who decimated trout populations. In the 1930s, residents in the Pacific Northwest could win bounties for shooting seals and sea lions.