Published Date: 2005-02-05 23:50:00
Subject: PRO/AH/EDR> Red tide - USA (FL): alert
Archive Number: 20050205.0400
RED TIDE - USA (FLORIDA): ALERT
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 5 Feb 2004
From: George Robertson <email@example.com>
Source: The Daytona Beach News-Journal [edited]
Large red tide outbreak may threaten manatees
An unseasonable outbreak of red tide has scientists worried migrating
manatees may swim into the potentially deadly algae.
The red tide, which formed in the Gulf of Mexico about 30 miles off Tampa
Bay in early January 2005, has moved nearer shore and south. It stretches
from north of Anna Maria Isle south to Venice.
Red tide normally occurs from August through September. A winter bloom
spells peril for manatees, which start moving out of warm water in rivers
and estuaries in late February and early March, said Elsa Haubold,
administrator for marine mammal research at the Fish and Wildlife Research
Institute. Haubold said there is a danger of a repeat of 2002 and 2003,
when red tide killed 34 and 96 manatees, respectively.
A bloom forming in winter on the southwest coast likely will remain along
the manatee migration routes as they move north from the Caloosahatchee
River. The animals congregate there during the winter to be near the warm
waters around the Florida Power & Light power plant near Fort Myers.
Haubold said the public should look out for manatees that seem to be in
distress. Of the manatees reported to the institute as affected by red
tide, scientists have been able to save every manatee but one.
Although they have no data to support their contention, scientists are
speculating that nutrients flushed into coastal waters by 2004's 4
hurricanes could be responsible for the January red tide, said Cynthia Heil
of the Fish and Wildlife Research Institute.
Red tide is formed when _Karenia brevis_, microscopic algae, reproduces at
an explosive rate, forming a bloom. Nutrients such as phosphorus and
nitrogen are known to fuel that explosion.
Minor fish kills have been reported from the tide, but there have been no
incidents of massive numbers of dead fish being washed up on Gulf beaches,
Heil said. A fisherman alerted the institute about the red tide when his
bait started dying.
Red tide is known to cause breathing problems in people when the algae's
toxic spores become airborne. The effects can be serious for people with
breathing problems such as asthma.
[Red tide is caused by several toxic algae. Depending upon the toxin, it
is also known as paralytic shellfish poisoning (PSP), because it causes
shellfish to be toxic for consumption.
PSP is a significant problem in several geographic areas, especially on
both the east and west coasts of the U.S. Produced by several closely
related species in the genus _Alexandrium_, PSP toxins are responsible for
persistent problems due to their accumulation in filter-feeding shellfish,
but they also move through the food chain, affecting zooplankton, fish
larvae, adult fish, and even birds and marine mammals.
_Alexandrium_ blooms generally do not involve large-cell accumulations that
discolor the water and may instead be invisible below the water surface.
Low-density populations can cause severe problems due to the high potency
of the toxins produced. Furthermore, _Alexandrium_ spp. can grow in
relatively pristine waters, and it is difficult to argue that anthropogenic
nutrient inputs are stimulating the blooms. These characteristics are
important when considering mitigation and control strategies.
Often PSP is associated with red tides or algal blooms. Red tide is caused
by an organism called _Karenia brevis_, which in high concentration can
make the water look red. The organism releases a toxin that paralyzes the
respiratory system of fish and other marine life.
Airborne toxins, water spray, and splashes in an outbreak have kept people
from beaches while leaving others with irritated eyes and throats. Red tide
irritates the skin of people exposed to it and can cause itchy eyes,
scratchy throats, and coughs. Harvesting from affected areas for personal
consumption is discouraged. Red tide poisoning symptoms include nausea and
dizziness and may last for several days.
Previously the organism causing red tide was known as _Gymnodinium breve_,
but it has been reclassified in the taxonomy of dinoflagellates. Its new
name is _Karenia brevis_, or _K. brevis_. Karenia was chosen in honor of
Dr. Karen Steidinger, a prominent red tide scientist from the Florida
Marine Research Institute in St. Petersburg, FL.
<http://www.marinelab.sarasota.fl.us/~mhenry/rtupdate.phtml> - Mod.TG]