Officials say a sea lion trapped below Oregon's Bonneville Dam is the first to die in a campaign to protect the salmon the animals feed on.
The Oregon Department of Fish and Wildlife said Thursday the sea lion had a viral lesion that indicated it had cancer, which could have spread to other animals if it had been kept captive.
The sea lion was identified as a repeat visitor to the dam, eligible to be killed or removed under an amendment to the 1972 Marine Mammal Protection Act.
The trapping operation began this week.
Veterinarians are awaiting test results for a second sea lion captured Wednesday. If healthy, it will go to Shedd Aquarium in Chicago.
