Copyright 1998 Sun-Sentinel Company
Sun-Sentinel (Fort Lauderdale, FL)
March 19, 1998, Thursday, Final EDITION
SECTION: NATIONAL, Pg. 1A
LENGTH: 1285 words
HEADLINE: A FISH KILL MYSTERY;
MICRO-ORGANISM SUSPECTED IN OUTBREAKS FROM FLORIDA TO S. AMERICA
BYLINE: ROBERT McCLURE; Staff Writer
BODY:
A weird new fish disease that is causing a grotesque wasting
away of fish near Stuart is only the latest in a string of unexplained
fish kills stretching from Florida to South America.
A suspect in the latest outbreak is a microscopic life form,
a close cousin of a chameleon-like, single-cell animal that masquerades
as a plant.
The masquerading cousin, Pfiesteria piscicida, has been blamed
for killing millions of fish in the Mid-Atlantic region. Both
organisms are thought to thrive in polluted waters.
In the last two weeks, state scientists have launched an intensive
investigation of the outbreak in the Indian River and St. Lucie
River near Stuart, about 30 miles north of West Palm Beach.
Meanwhile, they remain mystified about another series of fish
kills, including one last year stretching from the coral reefs
off Broward and Palm Beach counties to the Caribbean Sea and Venezuela.
In each incident, fish turned up with ugly sores. Most sores
are red, like a skinned knee, though the ones in the latest outbreak
are white, rotting, ulcerated lesions.
''We're seeing more and more fish with lesions,'' said Leigh
Demateis, a spokeswoman for the Florida Department of Environmental
Protection.
A state task force convened to investigate sudden ''blooms''
of algae and microscopic, algae-like microbes possibly at fault
in the kills meets today in Miami.
The discovery of diseased mullet, snook and other fish in the
Indian River near Stuart has not been tied to any micro-organism.
But state scientists, who played a major role in the discovery
of toxic marine microbes in the last decade, are looking closely
at them as a possible cause.
''The problem is much more widespread than you might have thought
a few years ago,'' said Donald Anderson, director of the National
Office for Marine Biotoxins and Harmful Algae.
The tiny toxic creatures, a subset of a group of organisms
known as dinoflagellates, are worrisome because they have caused
serious health problems in fishermen, scientists and others who
were exposed in North Carolina and Chesapeake Bay. Do sores harm
people?
Yet it remains unclear whether the sores on the fish near Stuart
could harm people, said Steven Wiersma, deputy state epidemiologist.
At least 55 toxic, microscopic creatures are known to reside
in Florida waters, but scientists still are working to understand
what makes them bloom into fish-killing numbers, said Ed Conklin,
director of the DEP's division of marine resources.
Only in the last year or so have researchers even known about
the existence of the microbe found near Stuart, Cryptoperidiniopsis.
But they quickly figured out it is very similar to Pfiesteria
piscicida, a somewhat better-known creature discovered a decade
ago by North Carolina and Florida researchers.
Dubbed ''the cell from hell'' by some scientists, Pfiesteria
can assume more than 20 forms.
Pfiesteria, a master of disguises, can lurk in the sediment
as a benign cyst until conditions are right for it to emerge in
its toxic form.
It looks and usually acts like a plant, appearing to live by
photosynthesis, the process by which plants create food from
sunlight. But in fact, Pfiesteria steals chloroplasts, plants'
food-making apparatuses, from algae.
Pfiesteria propels itself with wavy, armlike appendages known
as flagella, a component of the name dinoflagellate. When conditions
are right, Pfiesteria emerges in its animal form and releases
a still-unidentified toxin. This attacks fish, causing sores
to develop where the fish's protective, mucus-like coating sloughs
off. Pfiesteria eats the sloughed-off skin, then metamorphoses
into another form that allows it to feast on fish carcasses once
the fish die. Millions of fish killed In North Carolina and
the Chesapeake Bay areas, the micro-organism has been blamed for
killing millions of fish over the past decade.
Pfiesteria's toxic stage is thought to be stimulated by the
presence of large amounts of algae, another of its food sources.
These algae tend to grow explosively in polluted waters.
The current outbreak in Florida's Indian River comes after
state and federal water managers disgorged billions of gallons
of polluted floodwater from Lake Okeechobee. The water carries
a heavy load of pollutants from agricultural sources, including
cattle manure washing into the rain-swollen lake.
Although researchers have detected Pfiesteria's cousin, Cryptoperidiniopsis,
in waters where the Stuart-area outbreak is happening, much work
remains to be done examining the diseased fish. The cause could
turn out to be something else.
Resarchers theorize that the Cryptoperidiniopsis acts like
its cousin, causing fish to slough off their protective mucus
coatings. That may allow bacteria and fungus to attack the fish,
causing the sores.
''We really don't know that much about this organism,'' said
Ann Forstchen, a state researcher.
It's the first time Cryptoperidiniopsis has been associated
with a fish kill in Florida. But the fish in the Indian River
look ''strikingly similar,'' Forstchen said, to another fish kill
in the same location in 1980.
That year also marked the beginning of a series of at least four fish kills affecting angelfish, rock beauties and other species on South Florida's coral reefs. Similar outbreaks occurred in 1993, 1994 and 1997.
Fish affected in these outbreaks had fin and tail rot and were
infested by parasites, including one named Brooklynella hostilis.
They had a white slimy or fluffy coating and blotchy lesions,
leading to scientists' description: ''slime-blotch disease.''
In the 1997 outbreak, researchers soon began hearing reports
of similar fish kills in the Caribbean and Venezuela, and similar
but apparently non-lethal maladies among fish in the Bahamas and
Puerto Rico. Some of those areas also were affected in the 1980
outbreak.
But researchers have yet to pinpoint a cause. They think some
agent weakens the fishes' immune systems, leaving them vulnerable
to the parasites. If true, it would be like a fish version of
AIDS.
A leading scientist from Florida, Jan Landsberg of the DEP,
said in a paper on the 1993-94 reef fish kills that it appeared
a toxin might be at work. She speculated that a number of health
conditions among sealife, including coral diseases and tumors
on turtles, could be related to biological toxins transferred
through the marine food chain.
The DEP's Forstchen said she doubts the fish kills along the
reefs are related to the outbreak at the Indian River. But Anderson,
head of the national marine biotoxins office, said it's quite
possible that a third organism with similarities to Crypto and
Pfiesteria was at work.
''It wouldn't surprise me,'' Anderson said. ''There's no reason
( Pfiesteria's method) can't work elsewhere in the oceans as
a way of life.''
It's still possible, researchers say, that all of these events
could be explained by some natural cycle. But there is another
explanation, too: While toxic dinoflagellates have been around
for a long time, people are now doing something that encourages
their growth beyond natural limits.
Could sewage and similar pollution be at work? Some researchers
think so, Forstchen said. Perhaps the microscopic bugs are like
roaches _ they've been around forever, but their population explodes
when food is left around.
Wade Aycock of Stuart, one of the first to report the Indian
River fish disease, thinks the problem is related to pollution.
''Our river is so sick that it may never recover unless something
is done right,'' Aycock said. ''It doesn't take a rocket scientist
to see that something is long past due to be done about it.''
GRAPHIC: PHOTO MAP, Stuart News photo/JIM URICH; (color) Fish
caught about 30 miles north of West Palm Beach show various stages
of decay. Staff graphic/CHRIS JOHNSON; Map: North Ameirca and
South America - Southern tip of U.S. and Norhtern portion of South
America (Venezuela).
LOAD-DATE: March 20, 1998