2 Sea Lions Crushed to Death at
by Kelly House
Two sea lions died at Bonneville Dam this week after a trap used to remove the aquatic mammals from the dam malfunctioned, leaving nine of them stuck in the confined space for hours.
An Oregon Department of Fish and Wildlife veterinarian concluded the two dead California sea lions were crushed under the weight of a much larger Stellar sea lion also stuck in the cage. The large sea lion weighed 1,500 pounds - about four times the weight of each dead sea lion.
In addition to the two dead sea lions and the one that crushed them, the cage held two more Stellar sea lions and four more California sea lions. All were released.
ODFW submitted an incident report to NOAA Fisheries and has temporarily suspended trapping at Bonneville.
The state fish and wildlife department operates four traps at the dam as part of a program to deter sea lions from preying on endangered salmon and steelhead. The dam poses an obstacle for spawning fish, making them an easy target for the massive carnivores. During the height of the spring Chinook runs, which are happening now, hordes of sea lions congregate at the dam in search of a meal.
The electromagnetically operated doors are typically left open at night, agency spokesman Richard Hargrave said. Sometime between early Tuesday night and 3:45 a.m. on Wednesday, a wire came loose from the battery that operates one of the traps, causing the door to close and locking the animals inside.
According to ODFW's incident report, an exam on the two dead sea lions revealed, "diffuse hemorrhage, very pale organs, and consolidation of the lungs."
"These findings are consistent with asphyxiation and severe internal bleeding, and suggest the sea lions were crushed by one or more of the larger animals," the report states.
ODFW and NOAA officials believe the wire may have loosened as a result of rocking caused by the sea lions' movement.
"We're going to look at it more and see if there's anything we need to do so this doesn't happen again," Hargrave said.
Roaming Bonneville security staff check the traps several times throughout the night and cameras transmit a constant view of the traps into the Bonneville control center. Hargrave said ODFW staff received no word that anything was wrong until agency workers found the dead sea lions in the morning.
"We'll review the tapes and go through to see if anything was remiss," Hargrave said.
Agency workers will inspect all trap doors and test battery wires and connections before resuming trapping next week, according to the incident report. In the future, all battery connections will be tightened before the traps are set.
When the sea lion traps are operating normally, workers must press a button to close the door. Sea lions that have not been trapped at the dams before are branded, allowing workers to identify them in the future. Sea lions that have already been branded are monitored. If they are seen eating salmon and attempts to haze them fail, state workers can kill them or send them to zoos or aquariums.
Since the program began, 74 animals have received lethal injections while 13 have gone to zoos and aquariums.
This isn't the first time malfunctioning traps at Bonneville have killed sea lions. Six sea lions died of dehydration in 2008 after becoming trapped in a faulty cage. The incident fueled uproar among some animal advocacy groups and ODFW responded by installing the electromagnetic doors.
Death of Sea Lions in Trap Determined to be Accidental by Pete Springer, Oregon Public Broadcasting, 2/6/9
Sea Lions' Death: Humans in the Clear by Lynda Mapes, Seattle Times, 2/6/9
No Evidence People Shut Trap on Dead Sea Lions by Staff, Seattle Times, 2/5/9
Oregon: Heat Killed Sea Lions by William Yardley, New York Times, 5/16/8
Another Presumption: Sea Lions Died of Overheating by Ted Moore, eNews 2.0, 5/15/8
Heat Killed Six Sea Lions at Bonneville Dam by Michael Milstein, The Oregonian, 5/14/8
Heat Killed 6 Sea Lions Trapped at Bonneville Dam by King5 Staff, NWCN, 5/14/8
Heat may have Killed 6 Caged Sea Lions by Associated Press, Seattle Post-Intelligencer, 5/14/8
U.S. Sea Lions Died of Overheating, Not Gunshots by Teresa Carson, Reuters, 5/14/8
Who Killed the Sea Lions? by Winston Ross, Newsweek, 5/10/8
6 Sea Lions Found Dead in Traps on Columbia by William McCall, Seattle Times, 5/5/8
Sea Lion Dies During Veterinary Exam by UPI, United Press Intl., 4/30/8
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