It's known as the cell from hell--a voracious, microscopic predator that stalks and kills fish by the millions and produces potent toxins linked to human skin sores and neurological disorders, including memory loss. To scientists, the organism, discovered just a few years ago, is a thing of dark, wondrous beauty: Part animal, part plant, it quietly produces energy from sunlight until prey appear, when it transforms into a skilled and efficient hunter, leaving fish scarred with gaping, bloody lesions.
Pfiesteria piscicida, as it's called, can also poison entire industries--as fishermen, poultry farmers, and jittery government officials are finding in the states around the Chesapeake Bay. Dead fish have been appearing on riverbanks since August, when the red tide of pfiesteria first roiled the waters of Maryland's Pocomoke River. And the epidemic continues. Last week, Virginia officials reported finding symptoms of pfiesteria poisoning in five people, following similar reports in Maryland several weeks ago.
RED TIDES RISING. When the epidemic began, Maryland Governor Parris N. Glendening immediately closed part of the Pocomoke. He blamed poultry farmers, arguing that contaminated farm runoff might have caused the outbreak. When farmers protested they were being unfairly singled out, some scientists agreed. Although farm runoff is a suspect, researchers don't know precisely what causes pfiesteria epidemics.
The Chesapeake Bay outbreak of pfiesteria (it rhymes with hysteria) is only the latest in a series of increasingly destructive "red tides" and "brown tides" that are striking more often and in more places around the country and around the world. Virtually the entire coastline of the U.S. is now affected. Technically known as harmful algal blooms (habs), and caused by a variety of organisms--not just pfiesteria--the red and brown tides are disrupting tourism and fishing around the country.
No precise determination of the cost of the outbreaks has been made. But "factor in tourism loss and the cost of monitoring for these blooms," says Donald Scavia, director of the Coastal Ocean Program of the National Oceanic & Atmospheric Administration in Washington, and he arrives at "a very conservative estimate of about $1 billion a year." That figure could rise, says Scavia. "Prior to 1972, if you were to plot these on a map, you would show 10 or so places" where they had occurred. "We're now looking at 20 or 30 places where it's a regular occurrence or where we've had the first-ever" appearance.
BEACH BLOOMS. North Carolina, where pfiesteria was discovered in 1988, has suffered repeated episodes for nearly a decade. (Evidence suggests that runoff from hog farms there is at least partly responsible, which is why poultry runoff is a suspect in the Chesapeake Bay outbreak.) On Sept. 29, Texas officials extended a ban on shellfishing to South Padre Island, where a red tide that has already killed millions of fish is spreading. Florida suffered an 18-month red tide in 1995 and 1996 that had a particularly nasty feature: The algal toxin generated a toxic, airborne fog that produced a temporary asthma-like syndrome in beachcombers and swimmers along the southern portion of Florida's Gulf Coast. "A friend of mine who has three restaurants along here told me he lost $1 million in revenue himself," says Rob Haglund, president and ceo of the nonprofit Solutions To Avoid Red Tide (start) on Longboat Key.
Florida officials say they have no official estimate of the economic impact of red tides but are confident that it is significant. "When dead fish wash up on the beach, and when respiratory irritation occurs along the beaches, people don't want to go," says David Heil of the state Environmental Protection Dept.
In Maryland, the epidemic led to the closing of three rivers. (The Pocomoke was reopened last week.) The National Institute of Environmental Health Sciences just announced a $400,000 pfiesteria research program. But short of a scientific breakthrough, the waters will likely be muddied for some time to come.