Covering Harmful Algal Blooms

Why Cover Harmful Algal Blooms?

Incidents of harmful algal bloom (HABs) along America’s coasts
appear to be increasing, and impacts on local economics and health -- 
let alone tourism and recreation -- can be substantial. For some, it’s
primarily a public health concern, for others it’s the economic impact,
and for practically everyone, there are issues of aesthetics.
Coastal areas are not only magnets for tourism, they accommodate
the nearly two-thirds of the world’s population that lives 10km of
the coasts. With a heads up on what to expect, people living near or
visiting the shore and those planning to enjoy a seafood meal can
take precautions without becoming unduly alarmed. Individuals also
can play a pivotal role in early detection and reporting if they know
what to look for and what authorities to contact.

A growing body of evidence suggests harmful algal bloom incidents
are increasing around the globe. Opinions differ on why: Heightened
awareness and surveillance may be a factor, but natural
phenomena like storms and currents change or "all of the above," to
varying degrees.

HAB events can have serious consequences for human health, the
environment, and local economies. Some species release extremely potent
natural poisons known as biotoxins that can cause illness and even
death in humans. Others can result in massive mortality to wild and farmed
fish, marine mammals, seabirds, and protected species. Some produce
massive "blooms" of cells that discolor large of water, such as Florida’s
toxic "red tides." Certain species threaten marine life and human health
even when they are not visible in the water. Some nontoxic HABs cause
harm by irritating of damaging fish gills, causing murky water that shades
of other marine plants, or reducing dissolved oxygen levels when they
die off and decay.

Local economies suffer when these events disrupt seafood harvest-ing,
and depress recreation and tourism. Perceptions -- and sometimes
misperceptions -- about risk can further magnify economic losses, in what
is known as the "halo effect." Consumers opt to switch to other foods or
other recreational activities because of concerns about possible contamination.
In Maryland’s 1999 Pfiesteria case, the economic impacts were
substantial. Good reporting can help avoid unwanted fears and help citizens
and experts focus on actual concerns.

Story Ideas

1. Where public advisories on harvesting and eating shellfish are common,
media can monitor regional Web sites and other sources for advisories.
Offer readers and viewers counsel on safe seafood handling and
consumption. Cite hotline telephone numbers, e-mail addresses, Web
sites, and other ways for visitors and residents to report problems and get
current information on beach closures and shellfish beds.
2. Find out what HAB events affect your region, how often and when
they have occurred. Which blooms are hazardous to public health in
your area? What local industries could potentially be affected and at what
cost? From national and regional Web sites, stay apprised of research
progress on early detection and prediction. Establish contacts with state
and local officials and, in particular, shellfish sanitation programs.
3. TV and newspaper kids’ features can present the HAB issue in a
way that reinforces biology class lessons. Encourage volunteer field
monitoring as an individual or classroom-related activity. California,
Maine, and Rhode Island have had successes with these volunteer
monitoring networks. Other states have efforts underway. FDA
offers technical assistance at the national level and has plans to develop
formalized observation manuals and other training materials.
For a list of equipment needed for field observation and related fact
sheets, contact Sherwood Hall. (202) 205-4818.

Background and Context

Only a few dozen among the thousands species of microscopic algae
are known to be harmful. Among these, dinoflagellates, are the
most well-known group. Within this group are species that form
"red tides." Less common groups include diatoms (Pseudonitzschia),
organisms associated with brown tides (Aureococcus and
Aureoumbra), and bacterial-like blue-green algae (cyanobacteria).
Historically, the term "red tide" has been applied to all types of harmful
blooms. Because blooms come in many colors and can vary in toxicity
by species, the scientific community now uses the term "harmful
algal bloom" or HAB to describe them. (Broadcasters note: The "g" in
algal is pronounced hard as in "big" and not soft as in "large.")

Human health consequences of eating tainted seafood have been
recognized since ancient times. As they filter water for food, shellfish
such as clams, mussels, and oysters can accumulate toxins in
their tissues. A single clam can harbor enough toxin to kill a human
or large marine mammal. Moreover, certain of the more lethal HAB
toxins are not affected by cooking or preserving methods and have
few effective antidotes.

Paralytic Shellfish Poisoning (PSP) is a significant problem on
the East and West Coasts of the United States. It is caused by toxins
from a species of dinoflagellates in the genus Alexandrium that are
accumulated by filter-feeding shellfish and other grazers. Ingestion
of contaminated shellfish can be fatal to humans. There is no known
antidote. Health risks are controlled by monitoring and closing areas
to harvesting once toxins are detected.

Amnesic Shellfish Poisoning (ASP) known as Domoic Acid Poisoning
(DAP), affects mostly the West Coast. It is caused by diatoms
in the genus Pseudonitzschia, which produce a potent toxin
called domoic acid. Asp is associated with permanent loss of short
term memory and can be fatal to humans, marine animals, and birds.

Neurotoxic Shellfish Poisoning (NSP) is prevalent in HAB events
in waters of the eastern Gulf of Mexico. Toxic substances produced
by the dinoflagellate Gymnodinium breve are harmful to humans
and marine mammals. Risks to humans include respiratory irritation
and severe gastrointestinal and neurological reactions when consumed.
However, full recovery usually occurs within several days.

Ciguatera Fish Poisoning (CFP) cases have been documented in
tropical and subtropical waters of Florida, the Caribbean, and Hawaiian
islands. It is associated with dinoflagellate toxins that accumulate in fish,
with the highest concentrations in the flesh of top predators. Human consumption
can result in long-term nonlethal but debilitating illness. CFP is
the most frequently reported nonbacterial illness associated with fish
consumption in the United States and its territories.

Pfiesteria-related illness has been reported in connection with fish
kills and contaminated waters in North Carolina and Maryland’s Eastern
Shore. Lab workers exposed to lab cultures of P. p i scicida cite respiratory
irritation and problems with concentration and memory. Federally
sponsored research is underway to confirm whether this species causes
illness in humans.

Harmful cyanbacterial blooms in freshwater systems throughout the
United States have been linked with poisoning and death in humans,
birds, fish and other animals.

Other major regional HAB events include macroalgae blooms in
Florida, brown tides in Texas, Southern New England, and the mid-Atlantic,
and massive HAB-related fish kills.

Players and Sources

NOAA, EPA, CDC, FDA, USGS, and USDA support research, analysis,
and policy guidance nationally. Responsibility for implementation
rests largely with state and local environmental, public health,
and coastal management programs.

The Harmful Algal Page (www.redtide.whoi.edu/hab/), cosponsored
by NSF and NOAA grants to the Woods Hole Oceanographic
Institution, is a useful launching point for further research by region
or subtopic. It includes background about the national scope of the
problem, maps showing regional distribution, illustrative graphics
and pictures, and other pertinent information.

See also the National Assessment of Harmful Algal Blooms in U.S.
Waters, October 2000, a report jointly sponsored by NOAA and the National
Science and Technology Council (www.habhrca.noaa.gov).

There are many regional sites affiliated with universities, health
departments, and various coastal programs. The Washington State
Department of Health Biotoxin site (http://www.doh.wa.gov/ehp/
sf/BiotoxinProgram.htm) is an example of a regional site offering
practical advise on seafood safety, much of which could be adapted
to other regions. Here is what that site has to say about the commonly
held view that "R" months are safe for harvesting shellfish:

"This is a common misconception. The fact is, shellfish can be toxic
(or safe) at any time of the year. This misconception was actually law at
one, enacted by the New Jersey legislature in 1719, in an attempt to
address a spoilage issue. In the warm summer months (those without an
"R" in them), shellfish would spoil on the way to market due to a lack of
refrigeration during transport. (Imagine horse-drawn oyster wagons heading
to town on a hot summer day!) Although modern refrigeration methods
make this law obsolete, the misconception remains to this day."

HAB Contacts

Paul E. Hargraves, Professor of Oceanography, Graduate School of Oceanography,
University of Rhode Island, Narragansett, RI 02882-1197, pharg@gso.uri.edu

Stephanie Balian, NOAA National Centers for Coastal and Ocean Science,
(301) 713-3066, stephanie.balin@noaa.gov