OLYMPIA, Wash. -- Washington state biologists are trying to determine what killed a sea lion that was captured and released after it was strangely found in the driveway of a cattle ranch about 50 miles from the ocean.
The male California sea lion was released into Puget Sound on April 15 after it apparently swam and waddled its way to the ranch, The News Tribune reported.
On Friday, the sea lion was found dead under a bridge in Olympia, ending its unusual journey from the ocean to a small creek and then to Puget Sound.
Dyanna Lambourn, a Washington Department of Fish and Wildlife biologist, examined the sea lion Sunday and found no immediate cause of death. Samples from the necropsy were sent out Tuesday to test for possible causes.
The animal's wayward journey to Soggy Bottom Farm began sometime before April 15.
Rancher Ken Shively found his gate open and the 350-pound animal in his driveway. He initially thought it was a deer or elk. The sea lion was about 200 yards from a tributary of the Chehalis River, and roughly 50 miles of river, creek and drainage ditch travel from Washington's coast.
He called state wildlife officials. "They didn't believe us," Shively told The News Tribune. "They were like, 'A what? Can you describe that to us?'"
Sgt. Bob Weaver with the agency's enforcement division said it was the most unusual call he's gotten in years.
"I've dealt with sea lions before, but never in a cattle farm," he said.
He estimates the animal traveled about 5 miles up a creek, which is only a foot deep in some places.
It's not unusual for a sea lion to travel far up rivers in the pursuit of salmon and other fish. "The unusual part is that it went up that little creek," said Steve Jeffries, a research scientist with the state wildlife department.
Agency personnel corralled the sea lion into a cage on a flatbed trailer, and released it that evening into Puget Sound near DuPont.
"All our cows came running over to see what all the excitement was about," Shively said.
Lambourn, who examined the sea lion at the ranch, found no obvious injuries or illnesses. The animal weighed between 350 and 400 pounds, half the normal weight of an adult male sea lion.
Biologists are investigating what role domoic acid, a neurotoxin produced by algae blooms, played in the sea lion's death. Domoic acid can affect a sea lion's neurological functioning and cause seizures.
In California, where all sea lions originate, the population has been hit by low birth rates and high mortality.
Despite challenges sea lions face, Lambourn say the overall population of about 300,000 animals is in good shape.