January 11, 2009
Tests Find Algae-Toxin May Have Sickened Pelicans
Wildlife experts reported Friday that a toxic chemical produced by algae has been found in some sick California brown pelicans. The birds have been found in record numbers along the West Coast in recent weeks.
Preliminary laboratory results from the University of Southern California found that half of the blood samples obtained from ailing pelicans tested positive for domoic acid. Meanwhile, five of 14 water samples taken from waters off the Southern California coast also suggested low concentrations of domoic acid in the phytoplankton.
"We believe these results are significant but do not explain all the signs we are seeing in the pelicans," Dr. Heather Nevill, a veterinarian at the Fairfield-based International Bird Rescue Research Center, which provided the samples, told the Associated Press.
"We are seeing a number of conditions that are not typical of domoic acid toxicity or a domoic acid event."
Although the majority of the hundreds of sick pelicans are thin, birds poisoned by domoic acid are usually of normal body weight, leading researchers to believe that domoic acid is probably playing an ancillary role to a bigger problem.
The neurotoxin domoic acid is made by microscopic algae. Birds and sea mammals consume the acid by eating fish and shellfish that ingest the algae. Jay Holcomb, the center's executive director, said two of the pelican samples showed relatively high levels of domoic acid and one was fairly mild.
Additional results are expected in the next two weeks as more blood and tissue samples are tested, the center said.
The ailing, disoriented pelicans have been discovered on roads, alleys, farm fields and backyards --unusual places far from their homes. During the past week, the sick birds have been reported staggering across Culver Boulevard in Playa del Rey and on a Los Angeles International Airport runway, and one bird reportedly struck a vehicle.
According to the center, there are now 265 reports of sick or dead pelicans from Baja California, Mexico, to Washington state. More than 100 pelicans are being treated with a combination of IV fluids, medications and a diet of smelt and squid at the center's two facilities in Fairfield and San Pedro.
The California brown pelican is a subspecies of the common brown pelican. Its habitat stretches from the Sinaloa and Nayarit coast of Mexico to the Channel Islands off the Southern California coast. The birds were nearly wiped out during the 1960s and 1970s as a result of the pesticide DDT, which had infiltrated their food in nesting grounds such as Southern California's Anacapa Island. The species began recovering in 1972 when the U.S. banned the pesticide.
On the Net:
- University of Southern California
- International Bird Rescue Research Center
- Image Courtesy Wikipedia