Wednesday, March 28, 2007
Another reason I don't surf in red tide
Sea mammal deaths sound alarm
Experts investigate new dolphin die-offs
By Juliet Eilperin
The Washington Post
March 27, 2007
SARASOTA, Fla. -- In the summer of 2005 marine animals suddenly started dying off Florida's southwest coast, with scores of bottlenose dolphins, manatees and turtles washing up on shore. In October alone, 22 dolphins became stranded and died, compared with the usual monthly average of three.
Hoping to unravel the mystery, nearly 50 researchers, part of the Working Group on Marine Mammal Unusual Mortality Events, commissioned a study of the deaths. After taking samples from 130 stranded dolphins, they concluded that red tide -- an algae bloom that creates a neurotoxin, brevetoxin -- caused the massive die-off.
The working group, formed 16 years ago under the auspices of the National Oceanographic and Atmospheric Administration, has investigated scores of such events. At present, the panel is handling eight such cases simultaneously, an unprecedented high.
Experts believe a range of factors are contributing to the algae blooms and viruses linked to the die-offs, including nutrient runoff from farming, rising ocean temperatures and discarded waste such as cat litter.
The group, now with 12 permanent members and a shifting array of volunteers, has evolved into the federal government's top detective team for these events.
Randall Wells, who heads the Sarasota Dolphin Research Program at the private Mote Marine Laboratory and studied the 2005 red tide, said he and his colleagues are still struggling to figure out whether environmental contaminants or other factors might have weakened the mammals that fell prey to the 2005 algae bloom.
"It is so hard ... to pick all those things apart," he said.
This month the rapid-response team sprang into action again after 64 dead bottlenose dolphins and numerous fish washed ashore on the Texas and Louisiana coasts.
Teri Rowles, senior scientist for NOAA's marine mammal mortality program, said the dolphin deaths have spurred a major response.
Typically, marine scientists first try to determine whether a virus or an algae bloom is to blame. Rowles said she is concerned that the morbilli virus, which is similar to distemper in dogs and killed tens of thousands of European animals in 2004, may be responsible for the recent dolphin deaths.
Frances Gulland, who directs veterinary science at the Marine Mammal Center in Sausalito, Calif., said that marine mammals dying in waves can serve as indicators for human health.
"They can be early messengers, really, for broader changes," she said.