California authorities are investigating the fatal shooting of a protected southern sea otter that had been rescued and returned to the ocean last year.
The state Department of Fish and Wildlife said Tuesday that the dead otter was found floating in Morro Bay in September and a necropsy determined it was killed with a pellet gun.
A numbered tag identified the animal as an otter that had previously been found tangled in a fishing line. It was rehabilitated and returned to the wild in July 2016.
"The senseless shooting of any sea otter is concerning," said Mike Harris, a Fish and Wildlife senior environmental scientist who helped with the initial rescue, "but to discover a case such as this, where a team of conservation organizations had already successfully treated the animal for a life-threatening entanglement, is exceptionally troubling and frustrating."
The department says the killing was the latest in a rash of crimes targeting sea otters along the stretch of coastline between San Francisco and Los Angeles.
A skinned otter was found in September. Three otters were shot to death in August 2016.
Southern sea otters are a protected species under the Endangered Species Act, the Marine Mammal Protection Act and California law. Harming or harassing a sea otter, as well as removing or possessing a sea otter pelt or parts without a permit, are all illegal. Penalties include fines up to $100,000 and possible imprisonment.
12:20 p.m.: This article was updated with comments from state scientist Mike Harris and information about sea otter protections.