A Steller sea lion died w hen it became entangled between two traps at Bonneville Dam.  The Oregon Department of Fish and Wildlife says there were no witnesses to the incident, which occurred sometime Monday night.  Biologists believe the animal got between the two cage traps onto a narrow area where the wooden floors of each trap extended beyond the cages, coming together to create a makeshift platform.  It appears that as the animal tried to back out of the narrow area, it became entangled in the tethering cables holding the traps together.  A veterinarian on site determined the animal drowned, and a complete necropsy will be performed.  ODFW spokesman Rick Hargrave says the agency’s focus now is to prevent this from happening again.  Trapping operations at Bonneville Dam have been suspended while ODFW consults with NOAA.  In the meantime, cage trap doors will be closed and locked, and a temporary barricade will be installed between the two cage traps to prevent access.