Press Release 29 June 2003 from the Center for Whale Research, Friday Harbor, WA 98250 Contact Ken Balcomb, (360) 378-5835
A useful diagnostic technique for examining for such pressure trauma and injuries, or other cause of death prior to necropsy, is computerized tomography (CT) which reveals internal structure and fine scale damage before dissection; but, CT is expensive and difficult to arrange due to human patient backlog for health diagnosis at imaging laboratories. Federal officials have been trying for six weeks to arrange CT imaging for some or all of the porpoise specimens prior to necropsy, because of concerns that dissection could destroy difficult to detect hemorrhagic evidence of pressure trauma, particularly around the ears and brain encased in bone. These officials say they have located a facility that might be able to scan these specimens, including larger specimens, beginning in August; but, that is after the scheduled necropsies. (Note: As of July 1, the porpoise specimens are now scheduled to be scanned in the third week of July, prior to the necropsies, according to Brent Norberg of NOAA FIsheries.)
Hearing of the need for urgency, a private diagnostic imaging facility and technician in Seattle generously donated time and equipment availability to the Center for Whale Research to CT scan the porpoise we had in our freezer prior to delivering the specimen to the National Marine Mammal Laboratory (NMML) on Saturday. The facility also CT scanned two frozen beaked whale earbones from a stranding of a Baird's beaked whale at La Push, WA on 22 January 2003, following a naval exercise near the W237 operating area in the Olympic National Marine Sanctuary.
Both the porpoise and the Baird's whale showed evidence on CT scan consistent with hemorrhagic trauma that could be due to a sonic pressure insult that would disorient and incapacitate the animals (or a human). The necropsies at NMML and subsequent histology and laboratory work on these specimens, including the other porpoises (and other whale specimens from other strandings), may very well reveal that naval sonar is killing marine mammals here in the Pacific Northwest, and that sonar-killing could be a factor in the resident killer whale population decline since 1996. That would not be all that surprising a finding, considering it is now well established that these powerful sonars are killing whales, dolphins and porpoises elsewhere in the world where naval exercises are conducted. There is no reason to believe that isn't happening near Seattle, as well.
We consider it important for the federal government (perhaps with Navy funding) to CT scan at least some of the remaining sonar incident porpoises prior to necropsy at the National Marine Mammal Laboratory; and, we encourage the US Congress to continue to refrain from exempting the military from the Marine Mammal Protection Act and other environmental laws meant to protect wildlife and the environment from abuse and injury.