Early laboratory results suggest that whatever killed sea gulls along the Tacoma waterfront last month likely isn’t harmful to people, but more tests are underway to determine the source of the die-off of upward of 80 seagulls.
“Based on what we know so far, water pollution or contamination is highly unlikely and there is little or no risk to human health,” said Dr. Katie Haman, a veterinarian for the Washington Department of Fish and Wildlife, which is investigating the incident.
Haman reported that initial results showed inflammation of the intestine and liver, but bacteria could not be cultured from those lesions, making it difficult to determine the cause. Initial lab work further ruled out avian influenza virus and avian cholera, and standard screening at wildlife rehabilitation centers ruled out lead poisoning. She also said that additional lab tests are looking for botulism toxin, even though the gulls’ symptoms don’t perfectly match what would be expected from such toxicity. Given the scavenging nature of gulls, they may have been exposed to the bacterial toxin from contaminated food sources. Testing is also underway for heavy metals and viruses.
Port of Tacoma workers and beach watchers first reported on Jan. 22 that at least 30 gulls were found dead or dying in and around Commencement Bay. That number then grew to between 60 and 80 after initial reports, when 31 sick sea gulls were taken to rehabilitation centers for treatment. The dead and dying birds were all the same species of gull, the glaucous-winged gulls or glaucous-winged/western gull hybrids, some of the most common gulls on the West Coast. No other birds are apparently affected by whatever killed or paralyzed the sea gulls. No additional sea gulls have been reported in the area since the first few days of the initial report.
WDFW biologist Emily Butler noted that since crows, waterfowl and other birds in the area were not affected, water pollution or contamination is highly unlikely. Marine algal toxins are also an unlikely cause because no other affected animals were found, but testing for them is underway at a National Oceanic and Atmospheric Administration lab.
State biologists collected six of the dead gulls and sent them to the Washington Animal Disease Diagnostic Laboratory at Washington State University in Pullman for testing. Another nine gull carcasses were sent to the U.S. Geological Survey’s National Wildlife Health Center in Madison, Wisconsin.
About two-dozen of the 31 sick gulls were taken to the Progressive Animal Welfare Society in Lynnwood. Other gulls went to Puget Sound WildCare, Fair Isle Animal Clinic, and West Sound Wildlife Shelter. At last report, 20 of the gulls were still alive and showing signs of improvement.
All final lab results are expected later this month.
As a happenstance, volunteers with the South Sound Chapter of the Surfrider Foundation, were cleaning the shoreline along Commencement Bay this weekend. They didn’t spot any new dead birds but collected a half dozen bags of trash – mostly plastic bottles and shards of glass and pieces of tires and car bumpers that had likely washed down the hillside and into the bay during the recent rainfall. The group last cleaned the beach in the fall.
“I’m encouraged that this is no longer on the beach,” organizer Ken Campbell said, noting that while the beach cleanups are still gathering more trash than he would like, the beaches are generally cleaner than when he first moved to the area in 1987. “You have to kind of take the long view of it. The overall arch is better.”