Harmful Algal Blooms in US Waters

The National Science and Technology Council

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Order on November 23, 1993. This cabinet-level council is the principal means for the President

to coordinate science, space, and technology policies across the federal government. The

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secretaries and agency heads with significant science and technology responsibilities, and

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under the NSTC. It is charged with improving coordination among federal agencies involved in

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To obtain additional information regarding the CENR, contact the CENR executive secretariat at

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OCTOBER 2000

National Science and Technology Council

Committee on Environment and Natural Resources

NATIONAL ASSESSMENT

 of harmful algal blooms in US waters
Harmful Algal Blooms in US Waters

Coordinating Committee for the National Assessment on Harmful Algal Blooms

Don Scavia, Chair

National Oceanic and

Atmospheric Administration

Robert McKenna

U.S. Department of Defense

Joan Cleveland

Office of Naval Research

Allen Dearry

U.S. Department of Health

and Human Services

Sherwood Hall

Food and Drug Administration

Howard Hankin

U.S. Department of Agriculture

Richard Miller

National Aeronautics

and Space Administration

Michael Mac

U.S. Geological Survey

Scott Siff

U.S. Department of Justice

Robert Menzer

U.S. Environmental Protection

Agency

Dave Garrision

National Science Foundation

White House Office of Science

and Technology Policy

Mark Anderson

CENR Task Force on Harmful Algal Blooms and Hypoxia

D. James Baker, Co-Chair

National Oceanic and

Atmospheric Administration

Rosina Bierbaum, Co-Chair

White House Office of Science

and Technology Policy

Ghassem Asrar

National Aeronautics and

Space Administration

James Decker

U.S. Department of Energy

Roland G. Droitsch

U.S. Department of Labor

Albert Eisenberg

U.S. Department of Transportation

Delores M. Etter

U.S. Department of Defense

Terrance J. Flannery

Central Intelligence Agency

George Frampton

Council on Environmental Quality

Timothy Gerrity

U.S. Department of Veteran’s Affairs

Charles Groat

U.S. Department of the Interior

Len Hirsch

Smithsonian Institution

Kathryn Jackson

Tennessee Valley Authority

Eileen Kennedy

U.S. Department of Agriculture

Margaret Leinen

National Science Foundation

Committee on Environment and Natural Resources

Paul Leonard

Department of Housing

and Urban Development

Norine Noonan

U.S. Environmental Protection Agency

Kenneth Olden

U.S. Department of Health

and Human Services

David Sandalow

U.S. Department of State

Wesley Warren

Office of Management and Budget

Michael Armstrong

Federal Emergency Management

Agency

Samuel Williamson

Office of the Federal

Coordinator for Meteorology

Nancy Foster, Chair

National Oceanic and

Atmospheric Administration

Mary Clutter

National Science Foundation

Michael Davis

U.S. Department of Army

Allen Dearry

U.S. Department of Health

and Human Services

Harold Guard

U.S. Department of the

Navy

George Hoskin

Food and Drug

Administration

Glenda Humiston

U.S. Department of

Agriculture

Eric Lundstrom

National Aeronautics

and Space Administration

Daniel Sakura

Council on Environmental

Quality

Mark Schaefer

U.S. Department of Interior

Lois Schiffer

U.S. Department of Justice

Mark Anderson

Office of Science and

Technology Policy

Harold Zenick

U.S. Environmental

Protection Agency
Kay Austin

U.S. Environmental Protection Agency

Lorraine Backer

Centers for Disease Control and Prevention

JoAnn Burkholder

North Carolina State University

Gary Fahnenstiel

National Oceanic and Atmospheric Administration

Judith Kleindinst

Woods Hole Oceanographic Institution

Sherwood Hall

Food and Drug Administration

Danielle Luttenberg

National Oceanic and Atmospheric Administration

Donald Anderson

Woods Hole Oceanographic Institution

John Heisler

U.S. Environmental Protection Agency

Doug Lipton

University of Maryland

Helen Schurz-Rogers

Centers for Disease Control and Prevention

Alison Sipe

National Science Foundation

Karen Steidinger

Florida Marine Research Institute

Richard Stumpf

National Oceanic and Atmospheric Administration

Patricia Tester

National Oceanic and Atmospheric Administration

Acknowledgments

Many scientists and managers from federal and state agencies and research institutions contributed to the

knowledge base upon which this assessment depends. Production of this assessment report was managed by the

National Centers for Coastal Ocean Science and the Office of the Senior Scientist of the National Ocean Service.

Special thanks to Denise Yver of the National Ocean Service Special ProjectsOffice for cover design and overall

design support and Emily Meyer for layout assistance.

Primary Authors

Contributors

Kevin Sellner

National Oceanic and Atmospheric Administration

Donna Turgeon

National Oceanic and Atmospheric Administration
Harmful Algal Blooms in US Waters
Harmful algal blooms (HABs) are found in the waters

of almost every US coastal state. Virtually every US

coastal state has experienced the environmental, human

health, and economic impacts of HABs. HAB events

regularly threaten living marine resources, restrict local

harvests of fish and shellfish, divert public funds to monitoring programs, burden medical facilities, and depress

local recreational and service industries. Some HABs

produce toxins and make their presence known as massive “blooms” of cells that are so dense and extensive

that they discolor large areas of water, such as Florida’s

toxic red tides. Still others can threaten human health

and marine life even when they are not visible in the

water. The algae responsible for HABs are a very diverse group of organisms. Some are single-celled

microalgae or phytoplankton, while others are large, leafy

seaweed-like macroalgae.

The Harmful Algal Bloom and Hypoxia Research and

Control Act (P.L. 105-383) calls for “an assessment which

examines the ecological and alternatives for reducing,

mitigating, and controlling harmful algal blooms, and

the social and economic costs and benefits of such alternatives.” This report, A National Assessment of Harmful Algal Blooms in US Waters, presents a synthesis of

current research and management expertise on the causes,

consequences, and current status of harmful algal blooms

(HABs) nationwide and presents alternatives and recommendations for addressing HABs and their impacts.

This assessment was developed by the Task Force

on Harmful Bloom and

Hypoxia under the National Science and Technology Council (NSTC)

Committee on Environment and Natural Resources

(CENR). It was a multi-agency, multi-disciplinary effort that included input from States, Indian tribes, industry, nonprofit organizations, and other stakeholders.

Problem and Causes of HABs

A growing body of evidence suggests that HABs are increasing worldwide. There are more HAB species, more

HAB events, more algal toxins, more areas affected, more

fisheries impacted, and higher economic losses today

compared to twenty-five years ago. There are different

opinions about the reasons for this expansion of HABs.

Some “new” HAB events may simply reflect better detection methods and more observers rather than new species introductions or dispersal events—today, more researchers and managers are surveying more waterways

for the presence of HAB species using more sensitive

and accurate tools than ever before. Natural events may

also play a role in the expansion of HABs. Alexandrium,

a HAB species which contaminates shellfish beds in the

Gulf of Maine almost annually, was introduced to those

waters by a massive hurricane in 1972. Excess nutrients

delivered to coastal waters may act as fertilizers and

stimulate populations of micro- and macroalgae to increase to bloom proportions. The abundance of Pfiesteria

piscicida, which has been found in tributaries with high

levels of anthropogenic nutrients and organic matter, appears to be linked to nutrient loads. Blooms of Pseudonitzschia in the Gulf of Mexico and California also appear to be stimulated by nutrients. This potentially toxic

diatom is a dominant species in the nutrient-rich plume

of the Mississippi River. Humans may have contributed

by transporting toxic species to new areas in the ballast

water of ships.

Impacts of HABs

HAB impacts include human illness and death from ingesting toxins from contaminated seafood, mass mortalities of wild and farmed fish, mortalities of marine

mammals, seabirds, and other protected species, and disturbances of marine food webs and ecosystems. Paralytic, neurotoxic, and amnesic shellfish poisoning (PSP,

NSP, and ASP) syndromes occur when humans ingest

fish and shellfish that have accumulated HAB toxins.

These syndromes have severe

effects, some of which are fatal. Some HABs release toxins

and other compounds into the

water that can kill marine fauna.

Mass mortalities of wild and

farmed fish, death and illness of marine mammals, sea

turtles, seabirds, and other protected species, and alterations of coastal food webs through adverse effects on

seagrasses, and young and adult marine organisms are

common. Nontoxic HABs can cause harm by irritating

or damaging fish gills, shading out other marine plants,

or causing low oxygen conditions. These impacts can

affect commercial, recreational, and subsistence fisheries, tourism, and coastal recreation. A recently completed

study of the economic impact of HABs in the United

States estimated that the average annual impact of HABs

is $49 million. Individual HAB outbreaks can cause economic damage that exceed the annual average—outbreaks of Pfiesteria piscicida in the summer of 1997

and the consumer panic that ensued is estimated to have

Harmful algal blooms threaten

human health and natural resources

throughout US coastal waters, from

Alaska to the Gulf of Maine.

Harmful Algal

 Blooms in US waters Executive Summary

Executive Summary
Harmful Algal Blooms in US Waters

cost the Maryland seafood and

recreational fishing industries almost $50 million in just a few

months.

Management of HABs

Management options for dealing

with the impacts of HABs include

reducing their incidence and extent (prevention), stopping or containing blooms (control), and

minimizing their impacts (mitigation). Where possible,

it is preferable to prevent HABs rather than to treat their

symptoms. Controlling pollution inputs is one approach

that may reduce the incidence of those HAB species that

are stimulated by nutrient enrichment. Potential approaches to control HABs are similar to those used to

control pests on land. However, more research is needed

before these means are used to control HABs in US waters. The most effective mitigation tools are monitoring

programs that detect toxins in shellfish and/or monitor

the environment for evidence of HAB events. These programs can provide advance warnings of outbreaks and/

or indicate areas that should be closed to harvesting.

Some states supplement their monitoring programs with

rapid response teams that are deployed during suspected

HAB events to assess the blooms’ extent and impacts.

Recent technological advances, such as remote-sensing

and molecular techniques, have increased detection and

characterization of HAB blooms, and are playing an increasing role in monitoring programs nationwide. A longterm goal of these HAB monitoring programs and tools

is to develop the ability to forecast bloom development

and movement.

Recommendations to Address HABs

Over the past decade there has been an ongoing effort

by Federal agencies working with state public health and

fisheries managers, the science community, and coastal

industries and constituencies to identify uncertainties and

data gaps and the research needed to address the problem of HABs in US coastal waters. This has been furthered through hearings, workshops, scientific conferences, and town hall meetings. The general consensus

of these discussions is that a long-term commitment and

significant support are needed for research on the ecology of HABs and their causes and consequences, and

for development of ways to manage the problems caused

by increasing HABs nationwide.

The objective of much of the research on HABs has focused on the fundamental biological, chemical, and

physical processes underlying blooms and their impacts.

Such understanding is essential if we are ever to manage

or mitigate blooms. The key to understanding of the influence of human activities on HABs is understanding the

influence of environmental factors on

harmful algal species and their competitors. This will help determine

whether such activities are likely to

lead to more frequent and severe HABs

and if the means can be developed to

mitigate HAB impacts. To fully understand the impacts of HABs, greater emphasis must be placed on estimating the economic impacts of HAB events.

The epidemiology of the human health impact of exposure to HAB toxins is in its infancy. Studies are needed

on the effects of chronic exposure and how HAB toxins

move through the body and how they are metabolized.

These gaps in understanding prevent researchers from

developing antidotes or effective treatments for HAB

poisoning syndromes. Improved disease reporting and

surveillance is also needed as well as education to alert

public health providers to the symptoms and dangers of

HAB-related illness.

As HABs continue to increase, we must focus our goals

and research expertise toward developing techniques for

detecting and reducing the impacts of these events. Reduction of nutrient pollution to coastal waters may reduce the incidence of those HABs that are stimulated by

over-enrichment. Research into control methods may

lead to ways to limit and even terminate blooms in

progress. Monitoring and event response programs can

be the most effective means to mitigate HAB impacts

on human health. Research and development of new technologies can help make these programs more efficient,

reliable, and cost-effective.

Federal Efforts to Address HABs

A recent General Accounting Office (GAO) report concluded that coordinated Federal efforts are being undertaken to learn about, manage, and protect the public from

the effects of harmful algae. These include the interagency Ecology and Oceanography of Harmful Algal

Blooms (ECOHAB) research program, which has initiated regional studies and targeted projects to investigate

and model the growth and toxin dynamics of the major

toxic species along the entire US coast. Individual agencies are also working together and with stakeholders to

improve water quality, monitor shellfish toxins, and examine the linkages between runoff and water quality.

These programs and others contribute to understanding

and managing HABs and their impacts.

This bloom of Noctiluca stretched for

20 miles along the California coast

(Photo: P.J.S. Franks).
Figure 1. Global increase in reported algal toxins. Circles

indicate where outbreaks have occurred or toxin has been

detected at levels sufficient to impact human or environmental health. (Van Dolah, 2000).

1970's

PSP

NSP

DSP

ASP

ciguatera

Pfiesteria

1999

(Aureococcus and Aureoumbra), and the bacteria- like

blue-green algae (cyanobacteria). Blooms of toxic algae

were commonly called “red tides,” since, in the case of

some dinoflagellates, the tiny organisms increased in

abundance until they dominated the planktonic community and tinted the water reddish with their pigments.

Because other blooms may tint the water green or brown

and adverse effects can occur when algal concentrations

are low and the water is clear, the scientific community

now uses the term “harmful algal bloom” or HAB.

In October 1998, Congress passed the Harmful Algal Bloom and Hypoxia Research and

Control Act, which the

President signed into law

as P. L. 105-383 on November 13, 1998. This

law calls for an interagency Task Force to

complete and submit to

the Congress “an assessment which examines the

ecological and economic

consequences of harmful

algal blooms, alternatives for reducing, mitigating, and controlling

harmful algal blooms,

and the social and economic costs and benefits

of such alternatives.”

This report, A National

Assessment of Harmful

Algal Blooms in US Waters, presents a synthesis

of current research and

management expertise

on the causes, consequences, and current status of HABs nationwide.

It examines alternatives

for preventing, controlling, and mitigating

HABs and their impacts and presents recommendations

for addressing the growing problem of harmful algal

blooms in US waters.

Some of these harmful species produce toxins and make

their presence known as massive “blooms” of cells that

discolor the water. Other species are noticed even in dilute, inconspicuous concentrations of cells because they

produce highly potent toxins that can kill marine organisms directly or can travel through the food chain and

cause harm at multiple levels.

Many coastal communities

have experienced the environmental, human health,

and economic impacts of

harmful algal blooms

(HABs). HAB events regularly threaten living marine

resources, restrict local harvests of fish and shellfish,

divert public funds to monitoring programs, burden

medical facilities, and depress local recreational and

service industries. Blooms

of familiar and previously

unknown species are occurring in new coastal areas

with increasing frequency,

and HABs are now found

throughout US coastal waters, from the Gulf of Maine

through the Gulf of Mexico

and north to Alaska.

The algae responsible for

HABs are a very diverse

group of organisms; some

are microalgae or

phytoplantkon, while others

are large, leafy seaweed-like

macroalgae. The most well

known group responsible

for HABs worldwide is the dinoflagellates, which include those that form red tides as well as the toxic

Pfiesteria species. Less common groups include diatoms

(Pseudo-nitzschia), the brown tide organisms

Among the thousands of species of

microscopic algae at the base of the

marine food web, only a few dozen are

considered “harmful.”

Harmful Algal

 Blooms in US waters

The Problem

The Problem
Harmful Algal Blooms in US Waters

Increasing Trends: Expansions of

Harmful Algal Blooms

Harmful algal blooms are natural phenomena that have

occurred throughout recorded history and such blooms

were familiar events to the native peoples who lived along

affected coasts. In 1530, Spanish explorers to Florida’s

coast noted that tribes of the

Tampa Bay area knew the

onsets of certain seasons by

events such as red tides and

fish kills. However, given

the increased attention being paid to HAB phenomena, a question that scientists, managers, and the affected public ask is, “Are

HABs spreading and is the

problem getting worse?” A

growing body of evidence

suggests that HABs are increasing around the globe.1-

3 In the past, HABs impacted only a few scattered

coastal areas in the US; today, virtually every US

coastal state is affected. In

the last three decades, there

appears to have been a major worldwide expansion in

the frequency, geographic

extent, and magnitude of

HAB events and in the number of HAB species involved [Figure 1]. A map of

current US HAB events also

shows more HAB species, more algal toxins, more affected areas, more impacted fisheries, and higher economic losses, compared to 25 years ago [Figure 2].

A National Assessment of Harmful Algal Blooms was

developed by the Task Force on Harmful Bloom and

Hypoxia under the National Science and Technology

Council (NSTC) Committee on Environment and Natural Resources (CENR). The development of this assessment was a multi-agency, multi-disciplinary effort. States,

Indian tribes, local governments, industry, academic institutions, nongovernmental organizations, and other stakeholders were involved in

the development of this

assessment through the

World Wide Web, town

meetings, email updates,

and direct editing opportunities. The assessment

builds upon important

federal, state, and academic HAB reports issued over the last 5-10

years which also had extensive stakeholder input.

This assessment summarizes the most up-to-date

information available on

the growing national

problem of HABs. It

should form the basis for

further research, monitoring, and detailed assessments of regional HAB

issues, and inform management decisions regarding HAB problems in US coastal waters.

Figure 2. Since 1972, the number and distribution of harmful

algal bloom species and events in U.S. waters have increased.

(NOAA and WHOI).
Although few would argue that the number of toxic

blooms events, toxins, and toxic species have increased

over the last thirty years in the United States and around

the world, there are different opinions about the reasons for this expansion. 1,2 Possible explanations include:

1) heightened scientific awareness and surveillance, 2)

dispersal of HAB organisms through currents, storms,

or other natural mechanisms, 3) nutrient enrichment,

and 4) introduction/transport of cysts via ballast water

transfers.

Heightened scientific awareness

and surveillance

Some “new” HAB events may simply reflect better detection methods and more observers rather than new

species introductions or dispersal events—today, more

researchers are surveying more waterways for the presence of HAB species using more sensitive and accurate tools than ever before. Dramatically expanded aquaculture

activities and reliance on fisheries resources, which have led

to a concomitant increase in

monitoring for product quality

and safety, may now be “revealing” indigenous toxic algae. For

example, the detection of amnesic shellfish poisoning (ASP)

along the West Coast after 1991

may have been a result of improved detection methods that

allowed the identification of

domoic acid, produced by an

organism that was initially

thought to be a benign species.

While Pfiesteria piscicida has

only been associated with fish

kills in North Carolina, Maryland, and possibly Delaware, testing of estuarine waters with sensitive molecular probes has revealed the presence of this organism

in waters of numerous states along the mid-Atlantic and

Gulf coasts.

Resolution of this issue is difficult because of lack of

long-term data sets.4 Among those data suitable for

analysis, however, there is evidence to support an increase in HABs in US waters and worldwide. 1-3,5

Species dispersal through unusual

currents or storms

Natural events may also play a role in the expansion of

HABs. Regional circulation patterns can be a very important determinant of which algae are present in an

area. The distribution and occurrence of Gymnodinium

breve, the organism responsible for neurotoxic shellfish poisoning (NSP) in the Gulf of Mexico, are largely

due to the regional circulation of the eastern Gulf of

Mexico. The complex winds and currents of the eastern

Gulf are thought to deliver sparse, offshore populations

of G. breve to the shelf break on Florida’s western coast,

allowing for growth, accumulation, and bloom formation. In 1987-1988, blooms of G. breve were transported

to North Carolina’s Outer Banks via the Gulf stream.

The blooms moved onshore through a Gulf Stream eddy

and persisted in NC waters for 3.5 months.6 This mass

transport, or advection, of the red tide has been documented through examination of remote sensing images collected during the

period.7

Alexandrium, the organism responsible for paralytic shellfish poisoning

(PSP), is common along the

Canadian coast. In 1972, a

massive hurricane was responsible for introducing

dormant cysts of this species to southern New England waters, where it has

persisted to this day.

Alexandrium species distribution and the patterns of

PSP that are seen in the region are closely linked to large- and small-scale circulation of the Gulf of Maine [Figure 5]. Because of the

organism’s unique life cycle, which includes a resting

cyst stage, resident populations of Alexandrium are now

entrenched in Maine’s river mouths and shelf sediments.

These excyst or “hatch” each spring to give rise to new

toxic populations that are transported to the south and

west.

This kind of expansion has raised the possibility that

HABs may be affected by global climate change. Some

researchers suggest that recent increases in the emerThe West and East Maine Coastal Currents (WMCC

and EMCC) appear to determine the distribution

and dynamics of Alexandrium bloooms in the Gulf

of Maine. (WHOI).

Harmful Algal

 Blooms in US waters

The Causes

The Causes
Harmful Algal Blooms in US Waters

-

gence and frequency of diseases affecting marine organisms, such as coral bleaching, are linked to climate

change and that HABs could respond to global change

in much the same way.8 Increases in the number of storm

events or changes in circulation patterns could effect

the distribution and transport of HAB species. However, in the absence of long-term data sets, it has been

difficult to assess the impacts, if any, of global change

on HAB events.

Regional circulation patterns that carry nutrient-rich

deeper waters into shallow coastal zones can also result in HABs. Classic examples are the massive dinoflagellate and ciliate blooms that occur near upwelling

zones off coastal Peru, but similar coastal circulation

patterns have been suggested as the cause of toxic

blooms of ASP-producing Pseudo-nitzschia off southern California. The coincidence of high levels of domoic

acid in shellfish in the Northwest and seasonal upwelling

also suggests that the delivery of deep nutrients to near

surface waters in these regions may be potentially responsible for the annual occurrences of ASP. The response of Pseudo-nitzschia to this nutrient pulse has

supported previous observations of an association between nutrient loading from rivers and the development

of blooms of this organism.

Nutrient enrichment

Nutrient enrichment has also been suggested as the cause

for the increasing frequency of HAB events worldwide.2-

4

 Manipulation of coastal watersheds for agriculture, industry, housing, and recreation has drastically increased

nutrient loadings to coastal waters. Just as the application of fertilizer to lawns can enhance plant growth,

marine plants (algae) may grow in response to the input

of nutrients to our nation’s coastal areas.

Shallow and restricted coastal waters that are poorly

flushed appear to be most susceptible to nutrient-related

algal problems. Nutrient enrichment of such systems

often leads to excessive production of organic matter, a

process known as eutrophication,9 and increased frequencies and magnitudes of phytoplankton blooms, including HABs. 2,3,10 The National Estuarine Eutrophication Assessment, which surveyed 300 scientists and

managers about 138 US estuaries, found

blooms of macroalgae and other nuisance and

toxic algae to be common symptoms of

eutrophication.11 Of the 44 US estuaries surveyed that exhibited highly eutrophic conditions, 20 experienced high incidence of nuisance and/or toxic algal blooms [Figure 3]. A

recent National Research Council report nutrient pollution concluded that, while not all

HABs are caused by nutrient loading, many

are at least in part associated with the ecological changes that accompany eutrophication.12

Two classic studies from Asia support the links

between coastal development, eutrophication,

and HABs. Tolo Harbor in Hong Kong experienced an increasing incidence of red tide as

a result of increased urban development of the

surrounding watershed, which increased nutrient inputs to the adjacent coastal waters.

From 1976 to 1986, as the population of the

watershed increased sixfold, nutrient loadings

Figure 3. U.S. estuaries with reported moderate to high levels of

nuisance or toxic blooms, cited as symptoms of high eutrophic conditions (Bricker et al., 1999).11

The Role of Nutrients in

Outbreaks of Pfiesteria piscicida

Pfiesteria piscicida, the organism

associated with fish kills and fish lesion

events in Maryland in 1997 and North

Carolina for much of the present decade,

has been found in tributaries with high ambient levels of

nutrient and dissolved organic matter (sugars and amino acids)

relative to similar waterways.15 Elevated populations of this

HAB species have been found immediately downstream of

sewage outfalls and discharges from hog farms and other

animal feeding operations. Excessive nutrient loading appears

to create an environment rich in the microbial prey and organic

material that Pfiesteria and their fish prey feed upon. These

observations, coupled with laboratory results, suggest a

linkage between high nutrient load and abundance of this

potentially toxic dinoflagellate. This conclusion was

supported by the forum of scientists that was asked to advise

the State of Maryland in the wake of the 1997 outbreaks on

Maryland’s Eastern Shore.16 However, the presence of excess

nutrients is only one of many factors that appear to be involved

in Pfiesteria outbreaks.

Nuisance and/or

Toxic Algal

Bloom Problems
Potentially toxic diatoms

Pseudo-nitzschia is a potentially toxic

diatom that may also be stimulated by

nutrients. Nutrient inputs to the Gulf

of Mexico from the Mississippi have

increased significantly since the 1950’s and historical data

show large increases in the abundance of this organism in the

same time period. Non-toxic Pseudo-nitzschia species are

among the dominant species of phytoplankton in the nutrientrich plume of the Mississippi River and reach peak abundance

in the spring when river flow and nutrient levels are highest.17,18 Along California’s coast, nutrients delivered to surface

waters from natural coastal upwelling have stimulated Pseudonitzschia blooms.19 In 1998, the Pseudo-nitzschia blooms that

killed hundreds of sea lions followed upwelling and record

levels of river discharge that carried high nutrient loads into

Monterey Bay.

increased more than twofold, and red tide incidents increased more than eightfold (69 red tide incidents were

recorded from 1980 to 1986, compared with only 4 in the

preceding decade). Multiple fish kills were the red tides’

major impact.13 In the Seto Inland Sea of Japan, coastal

pollution was also responsible for an increase in HAB

events. From 1965, visible red tides increased steadily from

44 per year to over 300 per year a decade later, matching a

concurrent pattern of increased nutrient loadings from pollution. Effluent controls to curb pollution inputs were initiated in the mid-1970’s and between 1976 and 1985 red

tide outbreaks decreased by 50% and remain at this level

to the present day.14

Some scientists hypothesize that increased nutrient loads

to coastal waters stimulate low-level ambient populations

of microscopic and macroscopic algae to initiate a bloom.

Others suggest that changing nutrient inputs may be affecting the fundamental structure of coastal ecosystems.

Phytoplankton species have widely different nutrient requirements and tolerances. Species that are adapted to lownutrient conditions may be intolerant of high nutrient conditions or unable to compete with those species that thrive

when nutrient concentrations are high. Different

phytoplantkon species may also require different ratios of

nutrients for growth. Some experts argue that the nutrients

that humans are introducing to coastal waters are delivered in proportions that differ from those found in nature,

thereby favoring certain groups of algae, among them

HABs.3

While some data are compelling, it has been difficult to

determine conclusively if nutrients have played a role in

the overall expansion of HABs because of the lack of historical data on nutrients and abundance of HAB organisms, especially in the U.S. Gymnodinium blooms, which

are responsible for NSP, are initiated in nutrient-poor waters 40-80 miles offshore in the Gulf of Mexico. Therefore, the initiation of G. breve blooms does not appear

to be nutrient-mediated. However, it is possible that

the blooms that get into nearshore waters can benefit

from the nutrients of the West Florida Shelf. For other

HABs, there is may be no direct cause and effect relationship between nutrient pollution and the occurrence

of blooms, such as those of PSP-causing Alexandrium,

which impact more U.S. coastline than any other HAB.

Transport of HABs via ballast

water

Still other researchers hypothesize that humans may

have contributed to the global HAB expansion by transporting toxic species in ship ballast water.20 Ballast

water is used to stabilize cargo ships. When ships take

on ballast water, they also take on the millions of microscopic organisms that are present in that water.

Ballast water transfer has been responsible for the transfer of non-indigenous and invasive species among marine ecosystems.21 While the planktonic stages of phytoplankton show limited survival in ballast water tanks,

the cysts of these organisms may remain viable under

such conditions. Some researchers suggest that ballast

water transfer may have been responsible for the recent appearance of PSP-producing HABs in Australian waters in the 1980’s. 5,22

The environmental conditions that trigger, maintain,

and terminate algal blooms are not well understood,

and the diversity of HABs makes it likely that these

factors will differ among species and therefore difficult to generalize about the causes of these trends.

Blooms of some HAB species such as Alexandrium

appear to occur independent of human activities, in

relatively pristine or isolated offshore waters. Other

HABs, such as Pfiesteria, appear to be strongly influenced by human activities such as nutrient over-enrichment of coastal waters. The role of nutrients in the

initiation of Pseudo-nitzschia blooms, or in the maintenance of Gymnodinium blooms, is still unclear.

The Causes
Harmful Algal Blooms in US Waters

HAB impacts include human illness and death from ingesting contaminated shellfish or fish; mass mortalities

of wild and farmed fish; death and illness of marine

mammals, sea turtles, seabirds, and other protected species; and alterations of coastal food webs through adverse effects on seagrasses, and young and adult marine

organisms. Impacts from some HABs occur when marine fauna are killed by algal species that release toxins

and other compounds into the water. Nontoxic HABs

can cause harm by irritating or damaging fish gills, shading out other marine plants, or causing low oxygen conditions. These impacts can affect commercial, recreational, and subsistence fisheries, tourism, and coastal

recreation.

Public Health Impacts

Human illnesses caused by marine toxins in seafood have

been recognized for over 200 years. When Captain

George Vancouver landed in British Columbia in 1793, he observed

that among the local Indian tribes

it was taboo to eat shellfish during phosphorescent algal blooms. In one of the earliest

recorded cases of human fatalities from HABs, two members of members of Vancouver’s crew died from paralytic shellfish poisoning (PSP) after eating toxin-contaminated shellfish. In 1799 PSP claimed the lives of

more than 100 Aleuts in the region that is now Alaska.

Shellfish poisoning syndromes have been given names

that reflect some of their dominant and dangerous symptoms: paralytic, neurotoxic, and amnesic shellfish poisoning (PSP, NSP, and ASP). These syndromes have

severe effects, some of which are fatal. These syndromes

are caused by biotoxins synthesized by marine dinoflagellates,

or in the case of

ASP, by marine

diatoms. When

toxic algae are

filtered from

the water as

food by shellfish such as

clams, mussels,

oysters, and

scallops, their

toxins accumulate in the shellfish tissues.23,24Typically, the shellfish are only marginally affected. However, a single clam can accumulate sufficient toxin to kill a human or large marine mammal.

Humans can also become ill from ingesting fish that have

accumulated HAB toxins. Ciguatera Fish Poisoning

(CFP), common in subtropical regions, accounts for more

than half the food poisonings associated with fish in the

United States and is the most common food-borne illness caused by a chemical toxin.25

HAB toxins pose serious threats to human health because

they cannot be destroyed by cooking or storage (e.g.,

freezing, drying, or salting), and there are few effective

antidotes. Historically, marine seafood poisonings were

limited to geographic areas where specific algae and host

organisms (clams, mussels, reef fishes) thrived, i.e., temperate to tropical coastlines and coral reefs. However,

given the global distribution of marine seafood products,

the growth of aquaculture, tourism, and the increased frequency of

HABs, much of the

world’s population could potentially be at risk for these

diseases.

Epidemiological data on marine seafood toxin syndromes

primarily consist of case reports presented in the scientific literature or popular press, or present as part of local history. Seafood poisonings are less likely to be recognized by physicians outside of areas where poisonings

have historically occurred, and poisonings are often not

reported to physicians in areas where the disease is endemic and symptoms are therefore commonplace, e.g.,

CFP in Hawaii. Thus, documented cases of illness from

marine seafood toxins may represent only a fraction of

true exposures.

Humans can also become ill from direct environmental

exposure to HAB toxins and these exposures may be

equally important in terms of public health impact. For

example, in Florida and Texas elderly people, asthmatics, and otherwise healthy adults have experienced eye

and nose irritation and respiratory distress during red tide

events. The extent of health effects from environmental

exposure to these toxins when they become aerosolized

during HAB events are currently undocumented, although

respiratory irritation is so common that it is used as a

sentinel of red tide.

A single clam can accumulate

enough HAB toxin to kill a human

or a large marine mammal.

Harmful Algal

 Blooms in US waters The Impacts
As we identify new toxic species and toxins, the nature

and extent of the problem is shown to be larger than

previously thought. Unknown and newly identified microorganisms, such as P. piscicida, may produce toxins

harmful to people and marine life. The increasing frequency, intensity, and distribution of HAB events increases the likelihood that people will become ill from

exposure to these toxins, and their presence has implications not only for public health, but also for nutrition,

medical care, resource development, and tourism. There

is an urgent need for multifaceted public health action,

particularly in the areas of disease surveillance, health

care provider education, epidemiologic studies, and

emerging issues. This is especially critical given the

large-scale under-reporting, the apparent increase in the

incidence and geographic distribution of HABs, and the

evidence that public health impacts of HABs are not

limited to food poisonings.

HAB-related Illness in the US

Paralytic Shellfish Poisoning (PSP). PSP is a worldwide problem that affects more US coastline than any

other HAB.26 PSP is caused by several closely related

species of dinoflagellates in the genus Alexandrium.

These organisms produce saxotoins and gonyautoxin,

which are accumulated by filter-feeding shellfish and

other grazers, and can affect higher levels of the food

web, including lobsters, fish, and marine mammals,27,

28 as well as humans. Ingestion of contaminated shellfish can lead to illness, incapacitation, and even death.

There is no antidote and health risks are controlled

primarily through monitoring shellfish and rapidly

closing affected regions to harvest once toxins have

been detected.

Amnesic Shellfish Poisoning (ASP), also known as

Domoic Acid Poisoning (DAP). ASP, so named because one of its severe symptoms of the permanent

loss of short-term memory, has been fatal to humans,

marine mammals, and birds. Domoic acid, the ASP

toxin, is produced by diatoms in the genus

Pseudonitzschia. ASP was discovered in 1987 when

more than one hundred people became ill and three

died from eating contaminated mussels harvested on

Prince Edward Island. ASP became a concern along

the West Coast of North America in September, 1991

when more than one hundred brown pelicans and cormorants were found dead or suffering from unusual

neurological symptoms in Monterey Bay, CA.29-

31Domoic acid has been detected in shellfish almost

annually for the last decade and presents potential

health risks to commercial, recreational, and subsistence harvesters all along the West Coast.

Neurotoxic Shellfish Poisoning (NSP). NSP is caused

by the dinoflagellate Gymnodinium breve, which forms

red tides in waters of the eastern Gulf of Mexico. G.

breve produces neurotoxins and hemolytic substances

called brevetoxins that can harm human and marine

mammal populations. When humans eat shellfish that

have fed on G. breve, they may suffer severe gastrointestinal and neurological symptoms. While there

is no antidote for NSP, full recovery usually occurs

within several days. The substances produced by G.

breve can also cause human respiratory irritation.

Ciguatera Fish Poisoning (CFP). CFP is a malady

associated with dinoflagellate toxins that accumulate

in the flesh of tropical fish. CFP toxins (ciguatoxins)

are produced primarily by epiphytic dinoflagellates

(Gamberdiscus toxicus, Amphidinium carterae, Coolia

monotis, and several species in the genera

Prorocentrum, Ostreopsis, and Thecadinum) that grow

on the surface of red and brown macroalgae in virtually all subtropical and tropical waters. Ciguatoxins

accumulate in fish tissues, persist over extended periods and often become concentrated in the flesh of top

predators. When these contaminated fish are eaten by

humans, these toxins can cause long-term nonlethal

but debilitating illness.32,33CFP is the most frequently

reported nonbacterial illness associated with eating fish

in the United States and its territories, with Southern

Florida, the Caribbean, and Hawaiian islands accounting for the majority of documented CFP incidents. CFP

was once restricted to tropical coastal areas but reports of CFP intoxications from temperate “inland”

locations have been increasing as a result of the widespread commercial distribution of subtropical and

tropical fish.

Pfiesteria-related illness. Laboratory workers working with cultures of P. piscicida have reported respiratory irritation and problems with concentration and

memory and a recent report suggests that people experienced learning and memory difficulties following

exposure to waterways containing P. piscicida.

34 However, the toxins produced by this organism have not

been identified and characterized. Therefore, there is

no biological marker of exposure, and it is currently

not possible to verify environmental exposures to either the organism or its toxins. CDC, in collaboration

with other federal, state, and local government agencies and academic institutions, is conducting multistate

surveillance, epidemiologic studies, and laboratory research for possible Pfiesteria-related human illness.35,36

The Impacts
Harmful Algal Blooms in US Waters

Impacts on Marine Life

HABs impacts on marine life range

from subtle to the dramatic, from almost invisible effects on microscopic

plankton organisms to the deaths of the

world’s largest animals, whales. Although deaths of endangered marine

animals often focus public attention on

these harmful algal species, many of

the consequences of HABs are seen

at every trophic level and stage of development.

Fish mortalities are the most frequent animal impact of

HAB events. In the winters of 1997 and 1998, millions

of fish washed up onto the Texas shore, with more than

21 million reported in 1997 alone. The red tide dinoflagellate G. breve was found to be the cause. The

accumulation of dead fish along beaches of the Gulf is

not unusual and coastal communities and counties on

Florida’s western coast have had to maintain active

beach-cleaning activities to dispose of rotting fish for

the last forty years. In North Carolina waters alone, fish

kills of millions of fish have been associated with P.

piscicida in the last decade. This dinoflagellate is also

implicated as the likely agent for smaller fish kills in

Maryland’s Eastern Shore tributaries in 1997.

Catastrophic losses of cultured and wild fish not only

occur from many toxic algal species but also from others that do not cause illness in humans. Nontoxic HABs

can kill fish and shellfish through physical damage, disruption of coastal ecosystems, or creation of low oxygen conditions. Blooms of the flagellate Heterosigma

akashiwo and the diatoms, Chaetoceros convolutus and

C. cavicornis, do not produce toxins but have caused

massive kills of pen-reared fish in the Pacific Northwest.

Chains of these diatoms, which are armed with long setae and short spines, become lodged in fish gills and

cause irritation, mucus production, and eventually suffocation. These species which do not appear to harm

wild fish that can avoid blooms and swim to safety, can

cause near instantaneous

mass mortalities of the

densely aggregated populations associated with fish

pen mariculture operations. The

problems

caused by these species are so damaging that the mere knowledge that

they have been detected locally can

foreclose any possibility of fish pen

mariculture as a viable industry in

an area.

Algal toxins also affect many bird

and mammal species. There have

been a number of documented occurrences of HAB-related mortalities in marine and freshwater

aquatic species. Brevetoxin has

been documented as the cause of mortality in manatees

and, most recently, bottlenose dolphins, and is suspected

as the cause of mortality in lesser scaup and other bird

species on the Gulf Coast for a number of years.37,38 In

1996, a Florida red tide (G. breve) was responsible for

the deaths of 149 of these endangered animals. Many

of the deaths appeared to result from the inhalation of

brevetoxin released into the air just above the highly

concentrated bloom.39 A red tide bloom that persisted

off the Florida coast from August 1999 to January 2000

killed over 100 bottlenose dolphins. Saxitoxin, produced

by Alexandrium species, has been strongly suspected

as the cause of mortality in sea birds (common terns,

shags, great cormorants, northern fulmars, herring gulls,

common murres, Pacific loons, and sooty shearwaters).40-42 Domoic acid has caused mortality in brown

pelicans and Brandt’s cormorants as well as sea lions

on the central California coast, and is recently suspected

to be affecting southern sea otters. In 1998, over 400

California sea lions died and many others were sickened during a bloom of Pseudo-nitzschia australis along

the California coast. The animals died as a result of ingesting anchovies contaminated with domoic acid, demonstrating that this toxin can be transferred through the

food web and affect marine mammals.43 Cyanobacterial

toxins have been suspected as the cause of mortalities

of free-ranging ducks, geese, eared grebes, gulls, songbirds, and have been fatal when ingested by domestic

animals such as cattle and dogs.40,44

Affected wildlife may serve as suitable models for the

study of physiologic and pathologic changes produced

by algal toxins and may also provide insights into toxic

effects on humans and domestic mammals. Because of

their position in the food web, sickness and death in

these higher-level aquatic animals may serve as early

indicators of toxin-producing algal blooms. Little is

known about the toxicity of algal toxins in fish and wildlife, including the induced physiologic changes, toxin

exposure levels, and subacute or chronic effects. In addition, field signs of illness or tissue lesions caused by

Fish farms in the Pacific Northwest

lose many fish to nontoxic blooms of

Chaetoceros and Heterosigma.

(Photo: WHOI)

This California sea lion was treated

for DAP during a 1998 Pseudonitzschia bloom off Monterey–over sea

lions 400 died. (Marine Mammal

Center, Sausalito, CA).
HABs are not well known or described for wildlife species. There are generally poor baselines for comparison

or laboratory studies that have established concentrations of toxins required to produce sickness or death in

wildlife species. Thus, even when levels of particular

toxins can be measured in animals from mass mortality

events, it may be difficult to assess their significance.

Little work has been done to document the effects of

acute or chronic exposure of algal toxins on wildlife

specie. Exposure to sublethal levels of toxin may reduce

productivity, decrease resistance to other diseases, and

alter an animal’s behavior thereby predisposing it to predation. Toxic algal blooms might also disrupt food chains

in marine ecosystems, thereby indirectly affecting animal health by reducing food supplies.

Large, prolonged blooms of nontoxic brown tide species and macroalgae can reduce light penetration to the

bottom, decreasing densities of valuable submerged

aquatic vegetation (SAV) in coastal areas.45,46 Loss of

SAV can have dramatic impacts on coastal ecosystems

as these grass beds serve as nurseries for the food and

the young of commercially important fish and shellfish

populations. These impacts can result in long-term damage to local shellfish and aquaculture fish stocks, sometimes leading to the collapse of fisheries.

Macroalgae (seaweeds) cause problems throughout the

coastal waters of the United States and its territories.

Over the past several decades, blooms of macroalgae

have been increasing along many of the world’s developed coastlines in response to coastal eutrophication.

Macroalgal blooms occur in nutrient-enriched estuaries

and nearshore areas that are shallow enough for light to

penetrate to the sea floor. Macroalgal blooms have a

broad range of ecological effects, and often last longer

than “typical” phytoplankton HABs. They can have significant negative effects, pervasively and fundamentally

altering coastal ecosystems.47,48 Once they are established, macroalgal blooms may remain in an environment for years unless the nutrient supply decreases.

Macroalgal blooms can be particularly harmful to coral

reefs, which are fragile, highly diverse ecosystems that

are adapted to stable oligotrophic (low nutrient) conditions. Under high nutrient conditions, opportunistic

macroalgal species out-compete, overgrow, and replace

coral reefs. Studies of coral reefs from around the Caribbean49 -55 and around the world56 -59 have confirmed the

link between nutrient enrichment and increased dominance of reefs by macroalgae. Seagrass ecosystems can

also be shaded out and destroyed by macroalgal blooms.

The over-accumulation of plant life, primarily

macroalgae and phytoplankton, can lead to high rates of

plant decomposition. Bacterial decay of this excess plant

matter can strip much of the oxygen from local waters,

causing conditions of low or no oxygen (hypoxia and

anoxia). These HAB events need not produce toxins to

cause detrimental impacts. Some of those HABs that

result in visible water discoloration, e.g., the mahogany

tides of the Chesapeake, the red sea slicks off southern

California, often produce hypoxia during the night. This

reduction of oxygen can be severe enough that the area

may not be suitable for normal fish, shellfish, and other

animals that require oxygen.

Economic Impacts

HABs result in wide-ranging impacts, many of which

involve some degree of economic loss. Overall, the economic impacts from HABs are diverse and large. Perhaps more important, these impacts are recurrent, and

show signs of increasing as the number of toxic and harmful algal species grows and our reliance on the coastal

zone for aquaculture, commerce, and recreation expands.

Most coastal states have neither conducted economic

analyses of HAB impacts nor collected data that can be

used to generate reliable quantitative estimates of economic impacts. In many cases, the complex physical and

ecological characteristics of the coastal environment

make it difficult to determine whether an algal bloom is

the immediate and relevant cause of a fish kill, low oxygen event, or seagrass die-off. Moreover, local experts

often differ substantially in their opinions about the magnitude of economic impacts from HABs. There may also

be indirect or hidden costs such as constrained development and lost opportunities for marine recreation.

Summaries of two of the few recent studies that have

been conducted on the economic impacts of HABs are

included below. The first, from the Woods Hole Oceanographic Institution, looks at the impacts from HABs nationwide. The second study focused on the economic

impacts of the 1997 outbreaks of Pfiesteria on

Maryland’s Eastern Shore.

The Impacts
Harmful Algal Blooms in US Waters

A Recent Study of the Economic Impacts of HABs in the United States

Researchers at the Woods Hole Oceanographic

Institution (WHOI) conducted a study of the estimated average annual economic impacts resulting

from HABs in the United States.60 This study

represents the first attempt to develop a coherent

estimate of the economic impacts of HABs in the

nation. The analysis is based primarily on a survey of

experts and literature, covering the period from 1987

to 1992. The most reliable data was available for this

period, from which the most consistent estimates

could be made.

Economic impacts were classified as those affecting:

(1) public health, (2) commercial fishery, (3) recreation and tourism, and (4) monitoring and management costs. The annual economic impacts from HABs

for each of these categories are provided in Table 1.

The average total annual impact was approximately

$49 million, ranging from $34 to $82 million over the

six-year interval.

Individual blooms have been known to cause economic impacts equal to or greater than the annual

averages for this study interval. For example, in 1976,

a red tide in New Jersey caused more than $1 billion

in losses to commercial shellfish harvesting and

processing sectors. The 1997 outbreaks of Pfiesteria

piscicida in the Chesapeake Bay were estimated to

have cost the Maryland seafood and recreational

fishing industries more than $40 million. Each of

these events exceeded the annual average of HAB

impacts for the entire nation during the study period.

(1) Public Health. Human sickness and death from

eating tainted seafood resulted in lost wages and

workdays. Costs of medical treatment and investigation were also an important part of the economic

impact. Estimates of total public health impacts from

HABs from 1987 to 1992 ranged from $18-$25

million, averaging $22 million per year over the six

year interval.

Cases of sickness and death from shellfish toxins are

probably the most clearly documented impact of

HABs, in part because they are recorded by public

health agencies in individual states as well as at the

federal level. Average annual public health impacts

due to shellfish poisoning from HABs from 1987 to

1992 were estimated at $1 million (caused by PSP,

NSP, and ASP).

Ciguatera fish poisoning (CFP) predominantly affects

residents of and visitors to tropical and subtropical

areas, such as Florida, Hawaii, Puerto Rico, and

Guam. Over the study interval, the economic impact

of ciguatera poisoning alone varied from $18 million

to over $24 million per year, averaging $21 million.

These estimates were probably low, because any CFP

that may have occurred from exports of tropical fish

may not have been diagnosed or reported.

(2) Commercial Fisheries. Commercial fishery

impacts from HABs include wild harvest and aquaculture losses of fish and shellfish resources due to NSP,

PSP, ASP, ciguatera, and brown tides. Annual

impacts varied from $14-$26 million with average

Table 1: Estimated Annual Economic Impacts from Harmful Algal Blooms*60

* Estimates are for 1987-1992, reported in 1999 dollars

% of 

Low High Average Total

Public Health $ 24,912,544 18,493,825 $ 22,202,597 $ 45%

Commercial Fishery $ 25,265,896 13,400,691 $ 18,407,948 $ 37%

Recreation/Tourism $ 29,304,357 - $ 6,630,415 $ 13%

Monitoring/Management $ 2,124,307 2,029,955 $ 2,088,885 $ 4%

TOTAL $ 33,924,471 81,607,104 $ 49,329,845 $ 100%

15 Year Capitalized Impacts

(discounted at 7%) $308,981,162 $743,270,485 $449,291,987
annual impacts of $19 million. Some currently

untapped fishery resources may have had economic

value that could have been realized in the absence of

HAB threats. Because such values are difficult to

estimate they were not included. A prominent

example was the shellfish resource of coastal Alaska,

which is permanently closed due to persistent PSP

toxicity, and the difficulty of monitoring such a vast

coastline. The potential gross revenues of this

presently untapped resource have been estimated at

$6 million per year.

(3) Tourism and Recreation. Estimates of economic

impacts on recreation and tourism during the 1987-

1992 period ranged from zero to $29 million with an

annual average of $7 million. In Florida, recurrent red

tides have been estimated to cause over $20 million

in tourism-related losses every year. Unfortunately,

these impacts, as well as similar losses in Texas and

other areas, were not well documented and thus

impact estimates were not included. Although many

experts argue that the impacts of HABs on recreation

and tourism are important and potentially large, there

is little available data describing the size of the

impacts.

(4) Monitoring and Management. Annual average

costs for monitoring and management of HABs were

estimated to total $2 million, distributed among

twelve states: Alaska, California, Connecticut,

Florida, Maine, Massachusetts, New Hampshire,

North Carolina, New Jersey, New York, Oregon, and

Washington. These costs included the routine

operation of shellfish toxin monitoring programs,

plankton monitoring, and other management activities. It is important to note that expenditures made to

improve monitoring and management are likely to

result in decreases in the other categories.

The Impacts
Harmful Algal Blooms in US Waters

During the summer of 1997, several fish kills associated with blooms of Pfiesteria piscicida occurred on

Maryland’s Eastern Shore. Approximately 30,000 fish

died and many others showed lesions which were

thought to be related to P. piscicida. These blooms were

confined to small areas; only a few commercially and

recreationally important fish species were affected, and

only a few commercial fishermen complained of health

effects. Despite this limited impact, and the fact that

there was no evidence that P. piscicida toxins would

affect consumers of seafood, the economic impact of P.

piscicida was extraordinary.

The Maryland Sea Grant Extension Program, in conjunction with the Maryland Department of Agriculture’s

Office of Seafood Marketing, attempted to measure declines in Maryland seafood sales that may have resulted

from the public’s concern about the safety of Chesapeake Bay seafood during these outbreaks. A survey

was mailed to retail and wholesale seafood businesses

in the state.

Seafood sales in 1997, prior to the P. piscicida outbreak, were running ahead of the 1996 baseline by about

7.4% and would have totaled $253 million. Actual 1997

seafood sales were $210 million, a loss in revenues of

$43 million. Firms that specialized in Chesapeake Bay

products had a greater reduction in sales (12.8%) than

those that sold products from other areas (9.4%), but

both types of firms were greatly affected.

The recreational fishing industry also felt the far-reaching impacts of P. piscicida. The loss of roughly 28,000

party/charter boat trips, presumably due to concerns regarding P. piscicida, translated into lost revenues for

party/charter boat captains of approximately $2.2 million. Total expenditures of party/charter boat fishermen

were reduced a total of $4.3 million. The lost benefit to

the fishermen on the party/charter boats due to the loss

of a fishing opportunity was approximately $1.9 million.

Overall, the aggregate impact of the P. piscicida outbreak for just a four-month period in 1997 approached

$50 million in Maryland.

Economic Impact of Pfiesteria on the Seafood and Recreational Fishing

Industries 61

A supermarket sign displayed to ease

consumer fears about Pfiesteria.

Photo: J.A. Purcell, the Washington Post.

The “Halo Effect”. The consumer panic caused by the

P. piscicida outbreaks is a good example of what has

become known as the halo effect. In general terms, the

halo effect refers to a situation in which seafood consumers switch to substitute foods because of concerns

about the possible contamination of seafood due to one

or more HAB events. A halo effect typically affects

producers of seafood or providers of recreation and

tourist services. Because consumers can switch to other

foods or to other recreational activities, the halo effect

may not be serious for consumers, but it can be detrimental for producers. Tourists may choose an alternative vacation destination because of the risk of a HAB

event. Because the public may be unsure of the public

health risks of a HAB event, a halo effect may occur

for seafood that is not even contaminated. As in the

Maryland Pfiesteria case, the economic impacts associated with a halo effect can be substantial. The halo

effect can be reduced through monitoring, management,

and risk communication.
HAB events were previously confined to a few

coastal areas in the U.S.; today, they are common

throughout U.S. coastal waters, from the Gulf of

Maine, through the Gulf of Mexico to Alaska,

Hawaii and the tropical islands and territories.

Northeast: Gulf of Maine

Paralytic Shellfish Poisoning. PSP has recurred every year over large areas of the northeastern United

States for more than two decades. Prior to 1972, shellfish toxicity was known only in eastern Maine. That

year, a massive bloom introduced Alexandrium

tamarense to more southern waters, and now the entire New England coastline experiences PSP outbreaks almost annually, with extensive shellfish bed

closures and economic losses. In 1989, the rich beds

of Georges Bank were contaminated, closing the surf

clam fishery to this day.

Although blooms have not occurred in all regions, the detection of A. tamarense cells and cysts in Connecticut and

Long Island small embayments, and as far south as New

Jersey, suggests a gradual southward dispersion of these

toxic Alexandrium species.62-64

Southern New England and the MidAtlantic

Brown Tide Blooms. Brown tides, which occur in shallow, poorly-mixed waters during the late spring and summer, can persist up to four months. The first U.S. outbreaks

of brown tides occurred concurrently in New York and

Rhode Island in 1985; blooms have occurred in New York

many times since. Brown tide algae have been detected in

aquatic systems ranging from Massachusetts to Virginia,

although many of these areas have no previous history of

visible or destructive blooms.65 Blooms of the brown tide

species Aureococcus anophagefferens have been confirmed in Narragansett Bay, Rhode Island, Barnegat Bay,

New Jersey, Maryland’s inland bays, and the PeconicGardiners Bay estuary and south shores of Long Island,

New York.66

The initial notable impacts of brown tides were on the

eelgrass and bay scallops in Long Island bays54-56 and mussels in Narragansett Bay. Brown tides reduce the penetration of sunlight and thus destroy eelgrass beds, important

habitats for scallops and other marine organisms.45,67These

brown tide blooms are so dense and the cells so small that

shellfish either stop filter feeding or retain very little food

and starve to death. During brown tide events, the hatching success of important estuarine fish species, such as

red and black drum and spotted seatrout is reduced and

the larvae die from lack of food. Brown tides also cause

mortality, recruitment failure, and growth inhibition of

numerous commercially important bivalves, including

blue mussels in Rhode Island68 and bay scallops in New

York.69, 70

Pfiesteria piscicida and Pfiesteria-like organisms. In

1991, Pfiesteria piscicida, an ichthyotoxic dinoflagellate, was found at a fish kill in the Pamlico River, a

large estuary in North Carolina.71,72 Since then, fish kills

associated with this organism have become an almost

yearly event in North Carolina, with an estimated 1

billion fish dead over the last decade. In 1997, toxic P.

piscicida was associated with fish kills in three tributaries on Maryland’s Eastern Shore. P. piscicida is one

of several newly-discovered species of dinoflagellates

that have multiple life stages, making them difficult to

detect and study. Laboratory studies suggest that P.

piscicida is stimulated to transform from benthic cysts,

amoebae, or nontoxic flagellated stages to icthyotoxic

zoospores by some unknown substances freshly secreted by finfish and shellfish.72 A second icthyotoxic

species has been discovered in the same genus

(Pfiesteria shumwayae sp. nov.) but it does not appear

to be as toxic as P. piscicida.73

Pfiesteria-like organisms (PLOs) have also been detected in estuarine waters. PLOs are dinoflagellates that

are morphologically similar to Pfiesteria species and

Harmful Algal

 Blooms in US waters Regional Effects

Regional Effects
Harmful Algal Blooms in US Waters

can easily be confused with them under a light microscope. Since they can co-occur with Pfiesteria species

in the same habitat and may have similar niches, they

may be present during fish kills and fish lesion events.

Whether they produce neurotoxic or bioactive compounds that can be icthyotoxic has not been demonstrated.

Southeast and the Gulf of Mexico

Neurotoxic Shellfish Poisoning. The toxic dinoflagellate Gymnodinium breve forms red tides in waters from

the Gulf of Mexico to the South Atlantic Bight (off the

Southeastern United States). Gymnodinium breve

blooms are usually seasonal, starting in late summer or

early fall and many occur over three to four months.

Extensive blooms can cover areas as large as 30,000

km2 and persist for up to eighteen months. Bloom events

significantly impact fishing and tourist industries and

alter population levels or recruitment potential of affected

marine animals.7,74 Toxic blooms of G. breve are generally identified by visual confirmation (water discoloration and fish kills), illnesses in people who have consumed contaminated shellfish, and human respiratory

ailments.47,75,76 Other detection strategies include timeintensive chemical assays for the presence of brevetoxins

within shellfish tissue samples as well as mouse bioassays.77-79

G. breve is primarily a problem along Florida’s shoreline coasts but occasionally blooms can be transported

to the Texas coast. In 1987, a red tide bloom was transported from Florida waters to the coast of North Carolina, where it persisted for 3.5 months. During this time

there were 48 cases of NSP and 1,480 km2 of shellfish

harvesting waters closed.6

Macroalgae. Seagrass ecosystems in Florida waters have

been disrupted and destroyed by macroalgal blooms.80

Dramatic evidence of this impact is visible in South

Florida where macroalgae blooms have contributed to

the marked decline in extent and vigor of coral reef and

seagrass

ecosystems

that provide

a vital nursery habitat

for pink

shrimp,

spiny lobster, and

many species of finfish.

Brown Tide Blooms. A second brown tide population,

Aureoumbra lagunensis, first created an extensive bloom

in Laguna Madre, Texas in 1990, persisted for many

years, and has bloomed several times since. These

blooms have had substantial ecological impacts including decreased light penetration levels, loss of seagrass

beds, and reduced zooplankton grazing rates.46, 81 Recent investigations have focused on whether hypersaline conditions in the Laguna Madre are selecting for A.

lagunensis which may have an adaptive tolerance to such

extreme conditions.82 It is possible that significant ecosystem changes will result from the long-term dominance

of the Laguna Madre system by these brown tide blooms.

Subtropical Regions: Florida, the

Caribbean, and the Pacific Islands

Ciguatera Fish Poisoning. CFP is the most frequently

reported nonbacterial illness associated with eating fish

in the United States and its territories, with Southern

Florida, the Caribbean, and Hawaiian islands accounting for the majority of documented CFP incidents. An

estimated 50% of the adults in the U.S. Virgin Islands

have likely been poisoned at least once. Presently, no

coordinated, systematic monitoring program exist for

CFP in the United States and its territories.

West Coast: California

Paralytic Shellfish Poisoning. Since PSP was made a

reportable disease in California 1927, there have been

over 500 reported incidents, with more than 30 deaths.

From the 1960’s through the 1980’s, there were toxic

events most years along the California coast.83 Today,

most toxic events occur in the summer and fall, and the

state imposes an annual mussel quarantine of sport-harvested mussels from May 1 to October 31 along the entire California coastline.84

Amnesic Shellfish Poisoning. ASP, also known as

Domoic Acid Poisoning (DAP), became a concern along

the California coast in September 1991 when more than

one hundred cormorants and brown pelicans were found

dead or suffering from unusual neurological symptoms

in Monterey Bay, CA.29-31 This event was attributed to

poisoning by domoic acid, a toxin produced blooms of

the diatom Pseudo-nitzschia australis. In 1998, over 400

California sea lions died as a result of ingesting fish contaminated with domoic acid during a bloom in the same

area.85-87 In both cases, the blooms of Pseudo-nitzschia

appeared to originate offshore and then get transported

to the coast.

Figure 14. Enrichment of nutrient-poor

tropical waters stimulates macroalgae

that can overgrow coral reefs.

(Photo: B.A. LaPointe)
Blooms of the golden-brown alga, Heterosigma

akashiwo, have been associated with kills of farmed fish

in U.S. and Canadian waters of the Pacific Northwest.

In 1986, H. akashiwo was responsible for the loss of

$2.5 million worth of farmed salmon (about 1/3 of the

stock) in British Columbia’s Sechelt Inlet. In 1989, Washington State and Canada each lost $4 million worth of

penned salmon from such blooms. Since then, commercial salmon aquaculturists in both countries have experienced substantial economic losses from these blooms.

H. akashiwo has also recently been linked to mortalities

of salmon in the wild.92

Nationwide

Harmful cyanobacterial blooms. Cyanobacterial

blooms are common in freshwater systems throughout

the world and can be fatal to humans. Excessive growths

of Anabaena, Aphanizomenon, and Microcystis species

lead to blooms that can cause severe neuro-, cyto-, and

hepatotoxicity in humans, domestic animals, birds, and

fish. Such blooms are often associated with excessive

nutrient loading in low-salinity systems and have occurred in the Chesapeake Bay, Albemarle-Pamlico

Sound, Florida Bay, and the Great Lakes. In 1991, an

algal bloom, dominated by the species Synechococcus

elongatus, appeared in mid-north central Florida Bay. It

spread to central and western areas, and persists to this

day. This bloom and the resultant turbid waters and reduced light penetration have been linked to large-scale

mortalities of seagrass and sponge beds and even the

degradation of coral reefs in the Florida Keys. Large

blooms of Microcystis occurred in Lake Erie during the

summers in the mid- and late 1990’s, despite recent improvements in the lake’s water quality. These blooms

may be related to the infestation of zebra mussels, which

selectively graze on other planktonic species. Harmful

cyanobacterial blooms often terminate rapidly (“crash”)

in response to sudden physical changes (e.g., rapid drop

in temperature, reduced light associated with poor

weather). When crashes occur, oxygen consumption from

the decaying biomass can lead to anoxia. This chain of

events has been responsible for major estuarine

fish and shellfish kills and

loss of benthic habitat .93 94

Northwest: Oregon,

Washington, and Alaska

Paralytic Shellfish Poisoning. Native American tribes

and early European explorers on the West Coast reported

illness and mortalities from eating shellfish over 200

years ago.88, 89 In 1942, PSP resulted in the deaths of

three people as well as mass mortalities of seabirds in

this region.90 Since then, the Washington coast from the

Strait of Juan de Fuca to the mouth of the Columbia River

has been closed to bivalve harvesting each year from

April through October. In Alaska, PSP is so widespread

that all beaches and waters are closed to recreational

shellfish harvesting; commercial harvesting is strictly

limited. In 1917, five million pounds of shellfish were

harvested from Alaskan waters, but today the state’s commercial bivalve industry is virtually nonexistent. The destruction of the clam industry, estimated at 25-50 million pounds per year, is in large part a result of product

contamination by PSP.91 Other commercially valuable

species, such as Dungeness crabs, are also affected by

PSP.

Amnesic Shellfish Poisoning. When ASP was first found

in razor clams on the Oregon and Washington coasts in

October 1991, both commercial and recreational harvests were halted. This event caused a combined $15-

$20 million in damages to the Oregon and Washington

coastal economies. Since then, the fall and spring recreational harvesting seasons in these states have been delayed, shortened, or not opened at all due to domoic acid

contamination almost annually.92 Coastal tribes that have

traditionally depended upon these shellfish for food and

income are particularly hard hit by these closures. Contaminated razorclam beds, which often must be closed

with less than 24 hours notice to visitors, can remain

closed for over a year due to residual toxins. In 1998,

when record levels of domoic acid were detected in Oregon and Washington razor clams, the coastal tourism

industry experienced an estimated $15 million loss. Repeated closures have, in fact, reduced tourist visits to

the WA coast.

HAB-related Fish Kills. Blooms of

the diatom Chaetoceros convolutus

do not produce a toxin but have

caused massive fish kills. Chains of

these spiny cells become lodged in

fish gills and cause irritation, mucous production, and eventually

suffocation. C. convolutus and C.

concavicornis have been repeatedly

implicated in the death of penreared salmon, especially in the Pacific Northwest.

Cyanobacterial blooms, often caused by

nutrient over-enrichment, are a problem for

many states (NOS Image Library).

Regional Effects
Harmful Algal Blooms in US Waters

Harmful Algal Blooms (ECOHAB) program would contribute basic information on the causes and behavior of

HABs and ultimately lead to the development of prevention, control, and mitigation strategies. To complement this program, federal and state agencies with responsibilities for resource management, environmental

protection, and public health should support research

addressing prevention, control, and mitigation (PCM).

Prevention

Prevention refers to environmental management options

for reducing the incidence and extent of harmful algal

blooms before they begin. It is preferable to prevent

HABs in the first place rather than to treat their symptoms; therefore, where possible and practical, prevention is the preferred management option. Since increased

pollution and nutrient loading may cause an increased

incidence of outbreaks of some HAB species (e.g.,

Pfiesteria, Pseudo-nitzschia, cyanobacteria), these

events may be prevented by reducing pollution inputs

to coastal waters, particularly those industrial, agricultural, and domestic effluents high in plant nutrients. This

is especially important in shallow, restricted, poorly

flushed coastal waters that appear to be most susceptible to nutrient-related algal problems. For such

waterbodies, preventive reduction of nutrient inputs

would be the preferred management strategy.

Other strategies that may prevent HAB events include:

regulating the siting of aquaculture facilities to avoid

areas where HAB species are present (e.g. Heterosigma,

Chaetoceros), modifying water circulation for those

HABs where restricted water exchange is a factor in

bloom development (cyanobacteria), and restricting species introductions, e.g. through regulations on ballast

water discharges or shellfish and finfish transfers for

aquaculture.

Control

Human efforts to control insects, diseases, and weed

species are common on land. There are many reasons

for the lack of similar efforts to control marine pests,

but in general, they reflect concerns about costs, effectiveness, and environmental impacts.95 There are numerous success stories in agriculture where biological

control or integrated pest management have eliminated

problem weeds or insect pests, often over millions of

acres and without significant adverse impacts on the

environment.96 Another factor is that no federal agency

has been given the mandate for marine pest manageManagement options for specific HABs vary, depending on the species, the region, and the impacts. In general, however, management options for dealing with

the impact of HABs include reducing their incidence

and extent (prevention), stopping or containing blooms

(control), and minimizing human health risks and reducing the losses of resources or economic values (mitigation). 26,95 In 1996, the National Oceanic and Atmospheric Administration (NOAA) and the Department

of the Interior (DOI) requested an assessment on the

status of HABs in the U.S. and options for their prevention, control, and mitigation (PCM). Representatives from NOAA, DOI, the National Fish and Wildlife Foundation, and academic scientists worked in partnership to produce the report Harmful Algal Blooms

in Coastal Waters: Options for Prevention, Control and

Mitigation.

26 Regional meetings were convened in

Texas, Washington, and Florida to bring together scientific experts, managers, and user constituencies to

provide input to the assessment report.

The report offered numerous specific

recommendations and generally concluded that the

following

were needed:

1) improved

precautions

for the protection of human

health, 2)

more concerted efforts

to manage activities which

may cause

HABs, and 3)

renewed consideration of strategies to control blooms once they occur. The assessment focused attention on the control

of HABs and the evaluation of control techniques in

the context of risk assessments (i.e., similar to those

applied in the agricultural industry).

The report also noted that research being initiated by

federal agencies on the Ecology and Oceanography of

Harmful Algal

 Blooms in US waters Management Options
ment in the way the U.S. Department of Agriculture has

been assigned this responsibility for the terrestrial pests

that threaten agriculture. Approaches to direct bloom

control include chemicals, flocculants, and biological

control agents.

Attempts to use chemicals to directly control HAB cells

in blooms encounter many logistical problems and environmental objections. The dispersion of copper sulfate

over 16 square miles using crop dusting planes in a 1957

Florida red tide control effort highlights several of these

problems, the most significant being that the chemicals

are likely to be nonspecific and thus kill co-occurring

algae and other organisms indiscriminately.97 Efforts to

find a magic chemical bullet that would somehow kill

only a specific, targeted HAB species may be futile, as

it is difficult to develop a chemical that would only be

lethal to a single phytoplankton species. Even if such a

chemical were found, objections on environmental

grounds are likely to be significant. Each candidate

chemical will require extensive testing for lethality, specificity, and general safety, and each must surmount regulatory hurdles such as those imposed on industrial discharges to coastal waters. Although direct chemical control of red tides may not be a strategy of choice given

other more benign alternatives, the use of this approach

in terrestrial systems (e.g., application of herbicides and

pesticides) suggests that it should not be completely ruled

out.

A flocculant is a material that, when added to water, scavenges particles as it falls to the sediments below. One

natural mineral flocculant that shows considerable potential for HAB control in coastal waters is clay. When

added to seawater, clay particles absorb inorganic and

organic materials, including algae and other particles to

form a floc that falls to the sediments. In field trials,

In South Korea, clay has been used in attempts to

control HABs and protect fish ponds. (Photo: WHOI)

Asian scientists have used clay to treat natural red tide

blooms on several occasions, including major blooms

in Korea covering 100 square miles. Studies are needed

that examine the effectiveness of this strategy on U.S.

HAB species and the environmental effects of the treatment, especially the potential release of toxin during flocculation and the impact of sedimented cells and clay on

bottom-dwelling organisms. Some of these studies are

presently underway, but it will be several years before

scientific results are sufficient to justify pilot studies and

field tests.

Biological control of HABs is another option. There are

a variety of organisms that could conceivably be used to

control HABs. However, in reality, this approach has

many logistical problems and is far from the application

stage. Introductions of non-indigenous species or strains

pose unknown risks and may be irreversible. Biological

control is used extensively in agriculture, but there is

still considerable opposition to the concept of releasing

one organism to control another. Concern is likely to be

greater regarding the marine environment, as there is

little precedence for such activities. Despite examples

where such an approach has had negative long-term consequences on land, there are cases where the approach

has been both effective and environmentally benign (e.g.,

sterile male releases for control of the Mediterranean

fruit fly). The concept deserves some consideration in

marine systems, focusing on control agents such as zooplankton, bacteria, parasites, and viruses, and several studies are in progress. Viruses, for example, have the potential to be highly specific and effective control agents.

They are abundant in coastal seawater and are recognized as being significant in the dynamics of phytoplankton blooms. They replicate rapidly, releasing hundreds

of viral particles when a host cell is disrupted. Another

important feature is that viruses tend to be host-specific.

This means that a single algal species could be targeted,

leaving closely related, co-occurring organisms unaffected. In reality, however, viruses are sometimes so hostspecific that they are unable to infect different genetic

strains of the same host species.

With respect to future research, studies are needed to

determine if viruses, bacteria, or parasites exist that can

be effective pathogens to targeted HAB species. Once

pathogenic isolates are established, they must be tested

for specificity and efforts made to understand the dynamics of infection and replication. The environmental

implications of the release of non-indigenous organisms

will need to be fully understood before this strategy could

be tested in the field.

Management
Harmful Algal Blooms in US Waters

Mitigation

Mitigation involves steps taken to minimize human

health risks, ecosystem damage, or fisheries losses from

HABs that are otherwise not prevented or controlled.

Many different types of actions can be taken to mitigate

the impacts of HABs, including forecasting the development and movement of HABs, and responding rapidly to HAB events.

Monitoring HAB Cells and Toxins. To prevent human

illness from shellfish poisoning syndromes, the most

effective mitigation tools are monitoring programs that

detect toxins in different fisheries species to provide either advance warning of outbreaks or to delineate areas

that require harvest restrictions. This is predominantly a

state activity, coordinated with the Food and Drug Administration (FDA) through the Interstate Shellfish Sanitation Conference (ISSC). States differ in their monitoring strategies. Some, such as Maine, Massachusetts,

Florida, Oregon, and Washington, monitor their shellfish seasonally at sites along the coast and then close

specific areas to harvesting when toxins approach dangerous levels.98 Other states (e.g., Alaska) maintain permanent shellfish closures due to persistent toxicity or

the logistical difficulties of monitoring remote stretches

of coastline.

Another aspect mitigating HAB impacts is monitoring

the environment for blooms and forecasting their development and movement. Many coastal states have developed monitoring programs for plankton and fish in

coastal estuaries and bays that

provide early warning of

blooms. The state of Florida

has been monitoring G. breve

blooms in some form since the

1950’s and effective monitoring programs have prevented

most human exposure to contaminated shellfish, except

when blooms have occurred in

previously unaffected areas.99

The Gulf of Maine states have

been monitoring Alexandrium

since the 1970’s. Recent outbreaks of Pfiesteria have encouraged mid-Atlantic states to

develop or expand monitoring

for this organism. On the West

Coast, increasingly frequent

Pseudo-nitzschia blooms have

led those coastal states to expand their monitoring programs and improve detection of Pseudo-nitzschia toxins and cells.

Monitoring programs are expensive, but they do provide an important measure of safety to consumers and to

the fisheries industries. However, one important result

of the HAB expansion over the last several decades is

that the monitoring programs of many states are under

severe financial pressures, due to flat or declining budgets and the need to monitor for more toxins in more

organisms over larger areas. Programs that formerly

monitored only a single toxin in one or two shellfish species now must assay for several toxins in multiple shellfish species, as well as crabs, snails, and other wildlife.

One improvement in this area has been the development

of networks of observers under the SEAPORT (Signal

Environmental And Plankton Observations in Real Time)

program. Volunteers are trained to use field microscopes

to do real-time observations of plankton in coastal waters. These observations, when combined with other environmental signals, help states focus their toxicity monitoring efforts. SEAPORT programs are now active in

California and most New England states. In addition to

helping states expand their monitoring coverage, these

programs have proven to be effective for establishing

long-term baseline databases on coastal plankton populations and for engaging the public in marine resource

management.

Technological Advances in HAB Detection and Monitoring. Recent technological advances, such as remotesensing methods, have increased detection and characterization of HAB blooms, and are playing an increasing role in monitoring programs nationwide.100-107 Computer-based instrumentation

has enabled the use of bio-optical techniques for identifying

and characterizing HAB

blooms.108 Various algal

blooms can be detected and

monitored using satellite remote sensing data. Integration

of satellite imagery with field

data from state monitoring programs is providing an improved method for warning of

blooms, tracking them, and

characterizing their source.

Satellite imagery can serve

several purposes; while the

goal is direct detection, imagery can provide a means of

identifying blooms that should

be sampled allowing investigators to focus their efforts. Imagery can also provide an

estimate of the extent of a bloom, particularly in areas of

low chlorophyll.

The concentrated regions of chlorophyll visible in

this satellite photo are large blooms of G. breve

off the coast of Florida. (Photo: P. Tester).
The SeaWiFS (Sea Wide Field-of-view Sensor), the current operational ocean color sensor, became operational

in September 1997, and other sensors are expected to

appear over the next year (including MODIS, the Moderate Resolution Imaging Spectrometer, which is in orbit but not yet fully operational). These color satellite

sensors have the capability of determining chlorophyll

and some optical properties of materials in the water.

HABs are caused by several organisms, each with different characteristics and life histories—these factors influence the potential effectiveness of remote sensing for

monitoring. For remote sensing to be effective, the HAB

organism must be either detectable directly through its

effect on the water color, indirectly by correlation with

other algal blooms, or through association with a water

mass that can be monitoring by several means, such as

sea surface temperature (SST). Of

the HAB species of critical concern

in the US, G. breve, which causes

NSP in the Gulf of Mexico, is the

most amenable to remote sensing.

New investigations on Pseudonitzschia in the Northwest will provide information on the effectiveness of remote sensing to detect

these blooms.

Rapid progress has also been made

in the development and use of molecular techniques to detect the

presence of harmful algal bloom

cells.109-111 Many harmful algal

bloom species are virtually impossible to distinguish from similar

nontoxic species based solely on

morphology (shape and size). Therefore, identifying

when species of public health concern are present is difficult, particularly when they are present at low prebloom levels. To overcome this problem, sensitive molecular techniques, called assays, are being designed that

can identify HAB species based on their unique DNA or

surface composition, not their morphology. The goal is

to develop accurate molecular assays that are sensitive,

rapid, and cost effective. Using unique cellular characteristics of each HAB species, field detection of individual species is now possible for several HABs, including species of Pseudo-nitzschia, Heterosigma, and

Alexandrium.

Many of the current molecular assays being developed

focus on a unique DNA or RNA sequence from the harmful algal species of interest. First, the species of interest

is isolated and grown in a pure culture. DNA is then

extracted from these cells and cloned. These DNA clones

can be of either known genes or of random non-coding

DNA segments. These clones are subsequently sequenced and compared to other species to identify sections of DNA that are unique to the harmful species of

interest. Unique sections of DNA, if expressed, will produce unique sequences of RNA, which can also be used

in molecular assays. Once the species-specific DNA sequences have been identified, various molecular assays

can be developed. Two of the most common assay methods under development are polymerase chain reaction

(PCR) and in situ hybridization techniques. PCR allows

minuscule amounts of a species-specific DNA found in

a cell extract to be amplified over one million times.

This amplified DNA can be stained with a fluorescent

dye that specifically binds DNA and glows when viewed

under a fluorescent microscope. Modified versions of

this technique, known as competitive

PCR and quantitative PCR, have also

been developed that allow the numbers of HAB cells present in the

sample to be estimated (quantified)

in addition to confirming the presence

or absence of a particular HAB.

These techniques have proven useful

in identifying toxic dinoflagellates including Alexandrium, Gonyaulax,

and Pfiesteria species.112-122

In situ hybridization involves

fluorescently labeling a short piece of

DNA that binds a specific RNA molecule that is present in the HAB of

interest. The cells are then viewed under a fluorescent microscope and the

number of brightly glowing cells indicates how many harmful algal cells are present. In a

modified version of this technique, sandwich hybridization, RNA extracted from the cell is trapped on a special

membrane and fluorescently labeling it with a complementary piece of DNA. Both systems have proven particularly successful at identifying species that release

domoic acid, the toxin responsible for recent sea lion

deaths in California.43 Other molecular techniques being developed to identify and understand the biology of

HABs include antibody detection and electrochemical

detection of HAB DNA or RNA. These ‘molecular techniques’ are likely to be the primary detection methods

for many HABs in the future.

Response to HAB Events. Harmful algal blooms can

endanger human health and cause major impacts to

aquatic living resources. When reports of potential HAB

activity, such as marine mammal strandings, erratic fish

behavior or fish kills, are made to state authorities, it is

A fluorescently-labeled Alexandrium cell

(red) from a bloom near Casco Bay, ME

in 1998. (Photo: K. Gribble WHOI)

Management
Harmful Algal Blooms in US Waters

critical that trained and equipped personnel respond and

assess the situation quickly. HABs have the potential to

develop rapidly and, as in the case of Pfiesteria outbreaks, the observable event may be short-lived. Rapid

response is essential to ensuring that the appropriate sampling is conducted to determine if a HAB event is in

progress.

Many states supplement their HAB monitoring programs

with rapid response teams that are deployed to assess

suspected HAB events. To determine if aquatic disease

or mortality events are caused by HABs, and whether

there are human health risks, an event must be thoroughly

investigated following scientific protocols and procedures. Such a response can help answer critical questions about the event: is it related to other events, e.g.,

chemical spills, that are dangerous or threatening? Should

beaches or shellfish beds be closed to protect public

health? Can aquatic resources be saved?

Communication among researchers, managers, and the

public is also critical to HAB event management response. Citizens in coastal communities often play a pivotal role in noticing and reporting HAB events. Many

coastal states have established and maintain efficient and

accessible systems for allowing citizens to report aquatic

disease and mortality events to agencies responsible for

HAB rapid response. Risk communication, both longterm and during a bloom event, is another important

mitigation activity. Many regions have programs to inform the public, the media, and the medical community

about the risks (and misconceptions) of HABs and their

toxins. Doctors and hospitals should be well informed

and prepared to recognize and treat individuals suffering HAB toxicity. Public education and communication

should be increased in areas that are subject to HAB

events so that those visiting or living on the shore or

consuming seafood are informed about the risks and can

be cautious, but not unduly alarmed. Accurate and timely

information about HAB risks, can also help to limit the

Federal/State Workshops to Standardize Pfiesteria Monitoring Protocols

In 1998, NOAA, EPA, and involved states and researchers agreed there was a need to standardize monitoring

protocols among the many agencies that collect information on water quality, fish health, plankton, and environmental conditions associated with suspected Pfiesteria

events. NOAA held two workshops to gain consensus

among State and Federal agency representatives and scientific experts: the Workshop to Standardize Pfiesteria

Monitoring Protocols, 14-15 December 1998, and the

Workshop to Standardize Fish Health Monitoring Protocols, held 22-23 June 1999. They had three goals: (1)

to reach agreement on protocols for rapid-response assessments of toxic Pfiesteria outbreaks, (2) to recommend a suite of standard parameters that should be measured (e.g., water quality, fish health, and phytoplankton) when responding to potential HAB events, and (3)

to discuss the integration of state and federal agency data

sets into regional and national assessments.

Coastal states from New Jersey

through Texas sent experts on water quality, fish health, and phytoplankton. Representatives from

several Federal agencies also attended: the Environmental Protection Agency (EPA), the Centers for

Disease Control and Prevention

(CDC), the Food and Drug Administration (FDA), the U.S. Department of Agriculture (USDA), and the U.S. Geological Survey (USGS). Both workshops were conducted by the Center for Coastal Monitoring and Assessment (CCMA) of

National Ocean Service’s (NOS) National Centers for

Coastal Ocean Science (NCCOS) in Silver Spring, MD.

The more than 60 managers and scientists who participated

in the two workshops reached consensus on the need for

consistency in the parameters measured, the methods of

analysis for samples collected, quality control and quality

assurance, and the need to share monitoring data with other

state and federal agencies. The group proposed a threetiered monitoring program: (1) rapid response to fish kill

events, assisted by appropriate experts, (2) comprehensive

surveys and assessments in areas that have experienced or

are at risk for toxic Pfiesteria outbreaks (as well as other

harmful algal blooms), and (3) routine monitoring at sites

that might support toxic strains of toxic Pfiesteria species.

Attendees called for concurrent collection of phytoplankton, fish health, and water quality samples for each tier of

their program. The draft report, “Standardized Protocols

for Monitoring Suspected Pfiesteria

Events,” presents the deliberations

and recommendations of participants

from both workshops. These recommendations provide a valuable foundation to state and federal agencies

that are refining and improving rapid

response and assessment at sites of

suspected toxic Pfiesteria outbreaks,

as well as to those states that are developing such monitoring programs

for the first time.
impacts of the “halo effect” on resources and regions

that are not directly affected by HAB events.

HAB Modelling, Forecasting, and Prediction. The ultimate goal of many HAB monitoring programs is to

eventually be able to forecast bloom development and

movement. HAB events result from a combination of

physical, chemical, and biological

mechanisms and interactions that

are, for the most part, poorly understood. A workshop cosponsored

by NOAA and NSF in 1994 focused on developing a research

agenda to increase our understanding of the fundamental processes

underlying the impacts and population dynamics of HABs. Participants identified the physical, biological, and chemical oceanographic questions critical to scientifically based management of fisheries resources, public health, and

ecosystem health in regions threatened by toxic and harmful algae.

The findings of this workshop were

published in Ecology and Oceanography of Harmful Algal Blooms

(ECOHAB): A National Research Agenda,

123 which became the multi-agency research program of the same

name. The overall goal of the ECOHAB program is to

develop forecasting capabilities for HABs in all US

coastal waters (e.g., HAB predictions like weather forecasts).

To accomplish this, ECOHAB research rigorously investigates and models the growth and toxin dynamics of

the eight major toxic species along the entire US coast.

Five-year ECOHAB research projects have been implemented on four of these harmful species: Alexandrium

in the Gulf of Maine, Gymnodinium in the Gulf of

Mexico, the brown tide organism Aureococcus in eastern Long Island, and Pfiesteria in the

mid-Atlantic states. Research has

just begun on Pseudo-nitzschia in

southern California waters. The rest

of the U.S. coastline and other HAB

species need investigation: Pseudonitzschia blooms in the waters of the

Pacific Northwest, brown tide and

Gymnodinium populations in Texas,

macroalgal blooms on Florida’s and

Hawaii’s coral reefs, ciguatera dinoflagellates in the subtropical and

tropical US, developing populations

of Dinophysis in the Northeast and

on the West Coast, and several species, including Chaetoceros and

Heterosigma, that jeopardize fish

pen mariculture in the Northwest.

Future efforts must also focus on development of management strategies to prevent, control, and mitigate the blooms and

their impacts, ensuring reduction of HAB-generated

problems to coastal resources, local economies, and public health as well as guaranteeing that the intervention

techniques do not cause negative impacts themselves.

Expansion of research into these critical unfunded areas is needed.

In 1997, when outbreaks of Pfiesteria piscicida in the

mid-Atlantic threatened public health and local economies, a strong Federal-State response effort was initiated to ensure public and environmental safety. Public

health and seafood safety teams were mobilized to ensure public safety, document potential illnesses associated with the events, and assay seafood for toxicity.

A number of Federal agencies participated in these response activities, which included medical diagnoses,

epidemiology, fish toxicity, and assessments of water

quality, fish lesions and mortality, watershed land use,

and nutrient and pollution loads.

While this response was rapid and effective, these

events clearly demonstrated the need for a formal

mechanism to coordinate and efficiently focus Federal and State response capabilities. The Federal Event

Response Plan for Harmful Algal Blooms identifies

Federal capabilities and resources that could be mobilized

to supplement existing State rapid response programs and

to assist those States who have not yet implemented a rapid

response plan for suspected outbreaks of toxic Pfiesteria

species. The HAB Response Plan describes the basic

mechanisms by which the participating Federal agencies

can: (1) work with States to identify and communicate State

response needs; (2) mobilize resources and conduct activities to augment State and local response efforts; and (3)

communicate and coordinate Federal response efforts to

avoid duplication. This Plan was developed by the National

Oceanic and Atmospheric Administration (NOAA) National Ocean Service with the Environmental Protection

Agency (EPA) and the cooperation and support of participating Federal agencies and offices (Centers for Disease

Control Prevention, Food and Drug Administration), the

States, and the academic community.

Federal Event Response Plan for Harmful Algal Blooms

Management
Harmful Algal Blooms in US Waters

Over the past decade there has been an ongoing effort

by Federal agencies working with state public health and

fisheries managers, the science community, coastal industries and constituencies, to identify uncertainties and

data gaps and the research needed to address the problem of HABs in US coastal waters. These are detailed

other important HAB reports such as Marine Biotoxins

and Harmful Algae: A National Plan;

124 and National

Harmful Algal Bloom Research and Monitoring Strategy: An Initial Focus on Pfiesteria, Fish Lesions, Fish

Kills and Public Health.

125 The general consensus of

these reports and more recent discussions and forums is

that a long-term commitment and significant support are

needed particularly in the areas of research on the ecology of HABs and the causes and consequences of these

blooms, and developing ways to manage the problem of

increasing HABs nationwide.

The PROBLEM of HABs:

furthering our understanding

The objective of past and ongoing research on HABs in

the United States has generally been to seek an understanding of the fundamental biological, chemical, and

physical processes underlying blooms and their impacts.

Such understanding is essential if we are ever to manage

or mitigate blooms

Studies at the organismal level. To understand the population dynamics of HABs and their toxic and/or harmful

effects, studies at the level of a single HAB cell are essential. The goals of such studies are to determine the

biological factors that influence HAB bloom dynamics,

general ecology, and negative impacts.

Studies at the community and ecosystem level. Studies

that focus on the interactions between HABs and other

members of coastal ecosystems are essential if we are to

understand the ecology of harmful algal blooms. The

goals of such studies are: 1) to determine the impacts of

interactions among organisms in the coastal food web

on the dynamics of HABs and 2) to determine the impacts of HABs on food web structure and processes.

Studies of HAB toxins. HAB toxins represent a significant and expanding threat to human health, fisheries, and

coastal ecosystems. However, information is lacking

about toxins, their public health risks, and their impacts

on fisheries. The key to this knowledge is an understanding of HAB toxin pharmacology and toxicology. This

includes studies to: 1) determine the structure and chemical properties of HAB toxins, 2) develop means to extract, purify and synthesize them, and 3) develop rapid

and cost-effective methods for detecting and quantifying HAB toxins in water and tissues.

The CAUSES of HABs:

identifying the triggers

The number of toxic HAB events, toxins, and toxic species have increased over the last thirty years in the United

States and around the world. The key to understanding

of the influence of human activities on HABs is understanding the influence of environmental factors on harmful algal species and their competitors. This will help

determine whether such activities are likely to lead to

more frequent and severe HABs and if the means can be

developed to mitigate HAB impacts. The goals of studies focused on environmental factors are: 1) to determine the environmental factors that govern the initiation, growth, maintenance, termination, and impacts of

HABs, and 2) to identify ecosystems that are susceptible to HABs and understand why the types of blooms

occur in the systems they do. Such studies will require

both large-scale field studies and smaller-scale experimentation in the laboratory. Shipboard observations, field

programs, satellite remote sensing, and moored instrument arrays are all potential strategies for identifying

the mechanisms underlying HAB outbreaks. Research

efforts focusing on environmental factors influencing

bloom dynamics would complement studies at the

organismal level and are necessary to foster a greater

understanding of HAB dynamics.

The potential influence of human nutrient inputs on

HABs is generally unknown and will require a focused

commitment of resource and effort including time-series analysis of existing databases for phytoplankton communities These should be tied to data about contaminants and other environmental variables and require longterm monitoring programs of at least ten-years duration

in coastal areas where anthropogenic changes are of concern. Laboratory studies on the stimulatory effects of

chemicals contained in effluents or terrestrial runoff are

also needed.

The IMPACTS of HABs:

assessing the damage and counting

the costs

Public Health. The epidemiology of the human health

impact of exposure to HAB toxins is still in its infancy.

Harmful Algal

 Blooms in US waters

Recommendations
4) develop improved diagnostic techniques to identify

symptoms of biotoxin poisoning in marine fish and wildlife.

The difficulties encountered in generating a national estimate of HAB economic impacts underscores the need

to formalize the reporting practice and format for HAB

events. At present, information about HAB events is

fragmentary and inconsistent. Local and state governments and federal agencies should place much higher

emphasis on the quantification of economic impacts.

Discussions of economic impacts should include the

causes of the impacts and the degree of their uncertainty.

The following specific actions are recommended:

• Hold a national workshop to agree on procedures

and methods for the economic analysis of HAB

impacts.

• Include the causes of economic impacts and the

degree of their uncertainty in discussions of economic impacts and report economic factors affecting the impact estimates.

• Undertake another national compilation of the economic impacts of HABs for the years following

1992.

MANAGING HABs: reducing occurrence and impacts

Reducing HAB impacts is a major emphasis for national

HAB efforts. As HABs continue to increase, we must

refocus our goals and research expertise toward developing techniques for detecting and ameliorating the

impacts of these natural disasters.

Reduction of nutrient pollution to coastal waters may

reduce the incidence of those HABs that are stimulated

by over-enrichment. Implementing best management

practices (BMPs) on agriculture lands can help reduce

overall nutrient loads. New mechanisms to encourage

the implementation of BMPs are needed with monitoring to assess the effectiveness of the BMPs after they

are implemented. This kind of monitoring will not only

aid in evaluation but can also contribute to continuing

development and improvement. The Environmental Protection Agency and the American Society of Civil Engineers are developing a National Stormwater BMP

Database (http://www. bmpdatabase.org). The long-term

goal of this project is to promote technical design improvements for BMPs. The cost of implementing BMPs

is also an important planning consideration and economic data is needed to help determine the most costeffective means.

First, there is a need for basic analytic studies. While

the acute effects of HAB toxins have been studied in the

laboratory, little is known about chronic and/or repeated

exposure in humans, which may be a more common experience. There is also a lack of understanding about

how HAB toxins move through the body and how they

are metabolized. These gaps in understanding prevent

researchers from developing antidotes or effective treatments for HAB poisoning syndromes. There is a definite need for improved disease reporting and surveillance. The current passive systems (e.g., reportable disease status, calls to poison information centers) are inadequate to allow more than an estimation of the magnitude of the problem. Active surveillance in appropriate

counties or states would allow the public health community to determine appropriate public health response

activities. Health care professionals are not likely to recognize these illnesses in their patients. Health care providers should be made aware of the symptoms of these

illnesses so they can be included in diagnostic procedures.

Newly identified diatoms and dinoflagellates from US

estuaries are currently being characterized. These populations (e.g., Chattonella verruculosa, Pfiesteria

piscicida) may pose unexpected health risks and epidemiologic studies will be needed to determine whether

there are associations between exposure to these organisms or their toxins and subsequent adverse human health

effects.

Early warnings of HABs and the presence of toxins in

coastal waters and shellfish are required to adequately

protect public health. Risk of human illness and fatalities from seafood poisonings have been significantly

reduced through seafood sampling programs. However,

current sampling programs are not sufficient for early

bloom detection or characterization, and in many areas

do not adequately protect subsistence fishers or harvesters.

Impacts on Marine Life. Marine biotoxins can move

throughout marine food webs and cause impacts for organisms at various levels in the food web. Little is known

about the impacts of HABs on shellfish, fish, and other

marine species. Studies are needed to: 1) identify the

mechanisms of biotoxin uptake and metabolism in shellfish, fish, and other marine animals, 2) determine the

long-term effects of biotoxins on growth of fish including commercially valuable species, as well as marine

mammals, birds, and other protected species, 3) develop

rapid field assays for fish and shellfish and analytical

methods for detecting biotoxins in animal tissues, and

Recommendations
Harmful Algal Blooms in US Waters

Monitoring and event response programs are among the most

effective means to mitigate HAB impacts on human health.

Research on how to make monitoring programs more efficient while providing better coverage in time and space is

sorely needed. Research should be encouraged on technologies such as: 1) remote sensing (to detect and track blooms),

2) molecular probes (to identify and quantify cells and toxins in a rapid or even automated fashion), 3) improved toxin

assay methods (to provide fast, accurate, and inexpensive

methods for use by agencies, industry, and consumers), and

4) moored or automated sampling arrays that can detect cells

or toxins and telemeter the information to shore. These are

but a few examples of areas where funding will provide practical benefits to consumers and to the fisheries industry.

Although the significance and recurrence of HAB phenomena would seem to justify bloom control as a high-priority

research topic, virtually no focused research has been undertaken on this topic in the United States.26, 96 In fact, there are

currently no national research initiatives to promote efforts

in prevention, control, and mitigation (PCM) of HABs and

their impacts. Targeted funding is needed for a program focused on prevention, control, and mitigation and should be

separate from, and complement, funding for ECOHAB or

other ecology programs.

The following steps should be taken to ensure progress on

HAB PCM:

• Convene a workshop to define the specific science

agenda for the prevention, control, and mitigation of

HABs.

• Develop partnerships with the private sector, perhaps

through cooperative research with industry, since it is

private industry that will be focused on practical aspects of HAB research and development.

• Involve others outside the HAB community in the effort, e.g., the Agricultural Research Service (ARS) or

engineering companies. The ARS in particular may have

much to offer given its long involvement in pest control.

• Provide sustained funding specifically for PCM programs. These funds for PCM should not come at the

expense of fundamental studies on the biology, ecology, and toxicology of HAB species, but should be

supplemental.

• Take steps to ensure the program includes efforts to

transition research and application activities from federal-sponsored research development to implementation where States and industries take on the burden and

responsibilities to reduce HAB impacts.
Clean Water Action Plan (CWAP)

The President’s CWAP, announced on February 19, 1998,

created a partnership between Federal, State, and local

officials to increase the protection of public health and

restore our nation’s precious waterways. The CWAP emphasizes collaborative strategies to coordinate existing

programs and develop new means to protect watersheds

and benefit the communities they sustain. For the past

two years, nine agencies have been working with states

and local groups to carry out over one hundred key actions called for in the CWAP to improve watersheds. A

complete listing of these key actions and an electronic

copy of the CWAP can be found at http://

www.cleanwater.gov/.

The CWAP focuses attention on the need to continue

support for coordinated efforts to understand harmful algal species and to prevent, control, and mitigate the impact of HAB outbreaks. The CWAP also highlights the

need for a coordinated Federal response system to assist

state and local governments during major HAB outbreaks. An interagency Federal Event Response Plan

[p.24], put in place in August 1998, continues to guide

Federal, state and local authorities in dealing with the

consequences from HAB outbreaks.

The second major concern affecting coastal waters is polluted runoff and nutrient enrichment. The CWAP recognizes the potential benefits of non-point source and other

pollution controls to reduce eutrophication and limit HAB

outbreaks in coastal waters. CWAP partners are working

on a number of fronts to reduce excess nutrients entering

our nation’s watersheds. State non-point source controls

are being strengthened on farm and urban lands to reduce excess nutrients entering our watersheds. The regulation of concentrated animal feeding operations is being updated to reflect modern practices and problems.

Programs to control stormwater and combined sewer

overflows are being improved. Efforts to improve the

control of airborne nutrients and better monitor the impacts of air deposition are also being undertaken. In addition to coordinating federal efforts to reduce polluted

runoff, the CWAP also supports efforts at the local level

such as “Smart Growth” that can help plan for less runoff of nutrients in the future, even as populations grow.

The combination of federal and local nutrient reduction

efforts supported by the CWAP have the potential to prevent or limit the environmental problems associated with

eutrophication and HAB outbreaks.

National Oceanic and Atmospheric

Administration (NOAA)

National Centers for Coastal Ocean Science (NCCOS).

NCCOS has established expertise and programs that focus on harmful algal blooms. NCCOS's HAB activities

include research, monitoring and assessment, and event

response components. NCCOS's research components

include the Marine Biotoxins Program at Charleston and

the Harmful Algal Bloom Program at Beaufort. The

Marine Biotoxins Program was established in 1992 to

address research impediments identified in the National

Plan for Marie Biotoxins and Harmful Algae. The Program is national in perspective and multi-disciplinary in

approach. The Marine Biotoxins Program has developed

rapid, specific detection methods for all classes of algal

toxins that impact human and environmental health and

state of the art analytical methods for elucidation of toxin

chemistry. The Program serves as a national analytical

response facility, and has employed this suite of suite of

detection methods to provide identification of toxins involved in novel human toxic outbreaks and marine mortality events throughout the past decade. The Marine

Biotoxins Program also encompasses research on genetic and biological control measures to terminate harmful algal blooms. The Harmful Algal Bloom Program at

Beaufort has focused on mechanisms that control development and distribution of HABs since the 1987 red tide

occurrence in North Carolina. Current research focuses

on the application of remote sensing for monitoring and

predicting blooms, and the transfer of toxins through the

food web. NCCOS also coordinates the interagency Ecology and Oceanography of Harmful Algal Blooms

(ECOHAB) research program, overseeing an intensive

modeling effort to examine linkages between the ecology, physiology, toxicity, and behavior of the HAB species, their planktonic and pelagic neighbors, their chemical environment, and physical movements of particles

and water. The models developed through this activity

will be transferrable between different physical environments and bloom species. These research and modeling

foci will draw upon NCCOS’ recognized expertise in

marine biotoxins and fish lesion characterization, HAB

ecology, photobiology, physical transport mechanisms,

and remote sensing as well as involve other Federal agencies, States, and academia in new partnerships to address some of these issues.

NCCOS developed the Federal Event Response Plan

for Harmful Algal Blooms with the Environmental ProHarmful Algal

 Blooms in US waters

Federal Efforts

Federal Efforts
Harmful Algal Blooms in US Waters

tection Agency and other Federal agencies. NCCOS is

responsible for coordinating with EPA all Federal HAB

event response efforts initiated under the plan. NCCOS

has also identified existing internal scientific and technical capabilities that can be mobilized to support State

efforts to respond to HABs and other unusual biological

events. NCCOS recently initiated an intensive monitoring program that focuses on the environmental conditions believed to be conducive to occurrences of HABs.

Small teams of Federal, State, and academic experts coordinate the planning, implementation, and analytical

phases of the monitoring studies. Where appropriate,

these studies incorporate emerging monitoring methods

and technologies, such as remote sensing and identification methods for individual species, to encourage their

development and to provide opportunities for field testing. Monitoring studies have been developed that focus

Pfiesteria and Pfiesteria-like organisms in Maryland, and

Florida, and on Pseudo-nitzschia in Washington State.

Retrospective analyses of existing databases will also

be carried out to identify the magnitude and duration of

the US HAB problems through time and possible linkages with anthropogenic activities in coastal waters. Results from these analyses will be used to develop and

further refine research hypotheses.

National Environmental Satellite, Data, and Information Service, National Oceanographic Data Center

(NODC). The NODC is developing a system which will

provide access to physical, chemical, and biological information acquired from various sources, to assist in

harmful algal bloom (HAB) management and research.

Initially, a prototype system will be developed for the

Gulf of Maine and the Gulf of Mexico in coordination

with the Ecology and Oceanography of Harmful Algal

Bloom (ECOHAB) program. This system will be expanded to include data from other US coastal areas where

HABs occur. Sources of data include routine monitoring efforts, event driven monitoring, topical research initiatives (ECOHAB), and the NODC archives.

National Marine Fisheries Service, Northwest Fisheries Science Center (NWFSC). The NWFSC Biotoxin

Program focuses on and integrates methodology, food

web interactions, species susceptibility, and coastal ecosystem health. Recent highlights include the development of new receptor binding and DNA probes for toxin

and toxic algae detection, studies of toxin transfer through

the food web, and culture studies to determine effects of

nutrients on toxin production.

The NWFSC’s Biotoxin Program has formed several productive research and monitoring partnerships with Federal, state, and private institutions. The NWFSC Biotoxin

program and the Olympic Coast National Marine Sanctuary (OCNMS) have an ongoing partnership to study

offshore and inshore HAB events within the Sanctuary.

The NWFSC Biotoxin program has also established a

partnership with the Quileute tribe whose lands abut the

Sanctuary. This project includes research, monitoring,

and assessing the severity and spatial distribution of

domoic acid in both shellfish and local waters where the

tribal fisheries occur. This pilot project is a model for

creating partnerships between Indian Tribes, other

coastal communities, Federal agencies, and scientific research institutions. Plans are underway to expand this

project to include other tribes along the northern coast

of Washington State.

Office of Ocean and Atmospheric Research, Sea Grant.

With its role in marine research, education, advisory services and public outreach, Sea Grant’s expertise and its

network of local experts play major roles during HAB

events. Sea Grant has long supported individual investigators studying local HAB problems (e.g., research first

identifying Pfiesteria in North Carolina) and this support has built the foundation for several of the large regional HAB field projects. A series of articles published

by Maryland Sea Grant (e.g., In Harm’s Way? The Threat

of Toxic Algae; Harmful Algal Blooms on the Move; and

The Trouble with Toxics in the Bay) explained to readers the latest information on algal blooms, particularly

those in the Chesapeake Bay region and the role of the

complex of Pfiesteria-like organisms in fish mortalities

in the Pocomoke River. Sea Grant programs in Maine,

Massachusetts, New York, Florida, Texas, Washington,

North Carolina, and Alaska have released similar materials on HABs from those areas of the country. In 1999,

the National Sea Grant Program contributed funds to

ECOHAB to support research on prevention, control,

and mitigation of HAB impacts on commercially important fisheries, mariculture, public health, and focused

economic assessments of HABs in the U.S.

Environmental Protection Agency (EPA)

EPA’s Office of Water and Office of Research and Development are working to support State rapid response

and monitoring activities, HAB research, and public outreach. The Office of Water (OW) is supporting efforts

in State governments to establish and maintain rapid response and monitoring programs for toxic Pfiesteria

outbreaks. Additionally, OW has supported a pilot monitoring project in the Neuse River estuary which has provided information on the role of nutrient pollution in

toxic Pfiesteria outbreaks. Many other monitoring efforts supported by EPA, largely conducted by States to

determine water quality overall, can serve to provide information on HABs. EPA’s water quality database,
The 1992 NOAA-sponsored workshop brought scientists and regulatory officials together to address the

problems of harmful algae. This workshop resulted

in the 1993 publication of a national plan—Marine

Biotoxins and Harmful Algae: A National Plan—for

conducting basic research and developing management and mitigation strategies to protect the public

and the environment from problems associated with

harmful algae. In the plan, representatives from federal and state government, academia, and industry

stated that the US research, monitoring, and regulatory infrastructure is not adequate to meet the expanding threats from harmful algae and established the goal

of effectively managing fisheries, public health, and

ecosystem problems. According to the plan, the following eight specific research objectives must be addressed to comprehensively evaluate, model, and manage harmful algae and its impacts:

• Isolating algae toxins and characterizing their

chemical and pharmacological actions,

• Developing tests to identify individual toxins

based on their unique chemistry,

• Developing the capability to predict the occurrence and assess the impacts of harmful algae,

• Determining the source and consequences of algae toxins in the marine food web,

• Developing management and mitigation strategies to minimize the impacts of harmful algae,

• Identifying and improving access to databases

on toxic algae occurrences and impacts,

• Developing programs to communicate educational and public health information, and

• Providing rapid response programs for harmful

algae outbreaks.

The national plan set in place an interagency process

for addressing these objectives. A December 1995

report—The Ecology and Oceanography of Harmful

Algal Blooms: A National Research Agenda —serves

as a blueprint for carrying out the federal research

program on the ecology and oceanography of harmful algae. This report resulted in the establishment of

the ECOHAB program, the first federally coordinated

effort dedicated to conducting the basic research necessary to understand the nature of harmful algae, the

reasons they occur, and the steps that can be taken to

control them. Under the auspices of the ECOHAB

program, five federal agencies—NOAA, the Environmental Protection Agency (EPA), the National Science

Foundation (NSF), the Office of Naval Research

(ONR), and the National Aeronautics and Space Administration (NASA)—have funded research projects

that are carried out in-house or by universities and other

organizations. Other agencies, including the Centers

for Disease Control and Prevention (CDC), the National

Institute of Environmental Health Sciences (NIEHS),

and the Food and Drug Administration (FDA), are involved in conducting research and disseminating information to the public on harmful algae. Research supported by CDC and NIEHS primarily focuses on the

human health effects that result from exposure to water or aerosols containing harmful algae, while FDA’s

research focuses on the human health effects from exposure to toxins from consuming seafood. Collectively,

these agencies spent more than $40 million in 1997

and 1998 on these efforts.

Before the ECOHAB program, research on the effects

of harmful algae was typically isolated and uncoordinated. Often, the research was carried out by individual

scientists and was not sustained over time. Before the

program, there was essentially no overall federal coordination of the work to ensure that important national

priorities were being addressed. A second report was

issued in February 1997. Developed on the basis of the

objectives in the national plan—Harmful Algal Blooms

in Coastal Waters: Options for Prevention, Control and

Mitigation—describes the processes and mechanisms

that need to be employed to control harmful algae and

their impacts. According to NOAA officials, this report is the basis for new initiatives for intervention strategies to deal with harmful algae to minimize human

health, ecological, and economic impacts. The National

Harmful Algal Bloom Research and Monitoring Strategy, published in November 1997, presents a national

strategy for federally-supported research and monitoring for problems associated with harmful algae, particularly Pfiesteria and Pfiesteria-like organisms. The

report is intended to serve as an action plan for

Pfiesteria research and monitoring within the framework of the broader objectives identified in the National Plan.

Coordinated Efforts to Learn About and Manage the Effects of Harmful Algae.

The following is excerpted from a General Accounting Office report.126

Federal Efforts
Harmful Algal Blooms in US Waters

STORET, may also house valuable information that can

be correlated to outbreaks of HABs.

Beyond monitoring, many EPA and EPA-supported programs can play a primary role in reduction of excess nutrients. Programs addressing non-point source pollution,

including agricultural and urban runoff, stormwater and

combined sewer overflows, concentrated animal feeding

operations, and air deposition, are critical to addressing

all the problems generated by excess nutrients. In addition, voluntary partnerships, such as support of local Smart

Growth efforts, can reduce the areas of water with excess

nutrients. These programs all have excellent potential for

HAB prevention, as well as the benefit of producing other

environmental improvements in the affected waters.

OW is also working with the academic community, States,

and our Federal partners to produce public fact sheets on

HABs. The EPA Regions and OW have conducted national conferences on Pfiesteria that have served as forums for information exchange among State and Federal

resource managers and the academic community. Other

methods of information exchange include a web-site and

monthly conference calls with States, other Federal agencies, and academics, the later coordinated by the EPA

Chesapeake Bay Program.

The Office of Research and Development (ORD) is supporting research to identify the effects of Pfiesteria and

other HABs on the fresh water and marine environment

through a multi-investigator research program supported

and conducted at the Gulf Ecology Division (GED) in Gulf

Breeze, Florida. GED research concentrates on HABs in

the Gulf of Mexico, primarily Gymnodinium breve. This

research includes:

• Determining the critical environmental and genetic

factors regulating population growth, life cycle transitions, and toxin production of HAB species;

• Determining the effects of HAB toxins on water quality, higher trophic level species, and ecosystem condition;

• Developing and implementing a real-time coastal

ecosystem monitoring system with early warning capabilities for HABs;

• Investigating and evaluating potential strategies to

control, mitigate, and prevent HABs in coastal ecosystems; and

• Developing and implementing a national coastal

mortality monitoring network to investigate and report coastal mortalities and their most likely cause(s),

including the occurrence of harmful algal blooms.

Pfiesteria piscicida has not been reported in the Gulf of

Mexico to date. However, GED is developing methodologies, based on electron microscopy, to identify

Pfiesteria-like species and other potential HABs in the

marine and estuarine environment.

An Interagency Agreement has been approved between

EPA/GED and NOAA/Charleston Laboratory to coordinate research on causes and impacts of marine

HABs. Additionally, a Memorandum of Understanding has been approved between EPA/GED and the US

Geological Survey/Columbia Laboratory that includes

coordinating research on HABs, particularly freshwater cyanobacteria

The EPA Advanced Measurement Initiative, Application of the SeaWiFS for Coastal Monitoring of Harmful Algal Blooms, seeks to identify unique spectral absorption, scattering, and reflectance properties of the

red tide organism Gymnodinium breve, which can be

applied to the SeaWiFS ocean color satellite sensor,

thus allowing for the remote sensing of this organism

from space.

Specific EPA-sponsored research projects include

ECOHAB: Control of Harmful Algal Blooms Using

Clay; ECOHAB: Florida, a multi-agency/investigator

project that addresses HAB in Florida; and the Environmental Consequences of the Use of Veterinary Pharmaceuticals in Concentrated Animal Feedlot Operations which will investigate the relationship between

these operations and HABs. Finally, the US Office of

Coastal Global Ocean Observation Systems and

LABNET have approved a pilot project on HAB monitoring in the Gulf of Mexico. This project will be coordinated through a partnership with EPA/GED,

NOAA/NODC, and NASA.

Centers for Disease Control and

Prevention (CDC)

CDC is in a unique position to lead the public health

response to the issue of marine seafood poisonings related to HABs. CDC has the crucial epidemiologic expertise required to address marine toxin syndromes in

a timely manner. CDC’s mandate is to respond to the

needs of the state public health agencies and thus has a

history of successful collaborations with these agencies. CDC has the ability to initiate and oversee the

multi-state activities necessary to critically examine the

public health problems from HABs as demonstrated

by our long history of surveillance activities and specifically in 1997, by our multifaceted and timely response to the public health issues associated with

blooms Pfiesteria piscicida.
Food and Drug Administration (FDA)

FDA’s ongoing marine biotoxin research program continues to progress in characterizing the various seafood

toxins, developing methods for detecting them, and culturing the organisms that produce them. The FDA also

routinely supplies reference standards of saxitoxin and

domoic acid to other laboratories for regulatory and research purposes.

A major function of the FDA’s research program is to

provide technical support to state and other regulatory

agencies when there are management questions or HAB

outbreaks. For example, FDA provided technical support in working out a management strategy regarding

giant clams (geoducks) in Washington State, and in dealing with an outbreak of PSP due to shellfish from Burley

Lagoon, in southern Puget Sound in October of 1998.

The latter case involved three mild illnesses from eating

mussels that had been harvested and sold in a local market.

Over the past two years the FDA’s research labs have

investigated five outbreaks of ciguatera, all in the continental United States. One of these, in Chicago, involved

21 victims who had eaten amberjack from South Florida.

The FDA, the states, and the shellfish industry continue

to work together, through the structure of the Interstate

Shellfish Sanitation Conference (ISSC), to ensure the

safety of bivalve molluscs. Components of the FDA contributing to this effort include research laboratories, regional shellfish specialists that maintain close ties with

each producing state, the Shellfish Program Implementation Branch which provides overall coordination and

technical standardization, and the Office of Seafood,

which provides policy guidance. The ISSC and its regional components (such as New England and Pacific

Rim) also hold annual meetings.

With assistance from FDA, Signal Environmental And

Plankton Observations in Real Time (SEAPORT) networks of volunteer observers are well established in

California, Maine, and Massachusetts and are being developed in Connecticut, Rhode Island, and New Hampshire. The FDA encourages their development in other

coastal states that have HAB problems, particularly

Alaska, Washington, and Oregon. The FDA assists the

states with technical support and in conducting training

and refresher workshops for the volunteer observers. In

addition to providing advance warning of toxicity outbreaks, these networks are accumulating an important

and unprecedented body of baseline data on plankton

populations along our coasts.

The FDA is a participant in the Gulf of Mexico program

and, from the FDA research laboratory in Dauphin Island, Alabama, continues to provide direct lab support

of marine biotoxin management programs in the Gulf

coast states.

US Geological Survey (USGS)

USGS is conducting research and monitoring the delivery of nutrients to coastal waters in an effort to provide

information on linkages between eutrophication and algal blooms. USGS research includes the evaluation of

strategies to reduce nutrient runoff, including the use of

wetlands and riparian areas, particularly in the Mississippi River basin. In the Chesapeake Bay watershed,

USGS is looking at modeling nutrient delivery and examining the effectiveness of buffer strips to reduce runoff. Other sources of nutrient enrichment, such as groundwater, are being examined as well. USGS conducted preliminary health assessments of fish potentially affected

by Pfiesteria and found an invasive fungus to be associated with the lesions detected on fish in the Chesapeake

Bay. Therefore, further research is underway to determine the relation between the invasive fungus, Pfiesteria,

and other environmental factors that may weaken the

immune systems of the fish.

In the Gulf of Maine, a collaborative ECOHAB project

is examining the source population dynamics of “red

tide” dinoflagellates. Researchers on this project have

determined how physical transport mechanisms have

affected the distribution and fate of toxic Alexandrium

cells and how physical dynamics and the nutrient environment affect their growth. A physical/biological model

is being created for the Gulf of Maine to potentially be

used for evaluating resource management strategies. In

the Laguna Madre, Texas, USGS continues to research

the linkage between changes in the seagrass community

and brown tide. Seagrass habitat is critical to a number

of wildlife species and the long lasting brown tide has

caused significant changes in the structure and composition of this habitat.

USGS scientists are working to improve the assessment

of toxic algae by developing immuno- and bioassays for

the detection of cyanobacterial toxins. The most potent

cyanobacterial toxins produced by HABs can cause paralysis and even death making them a serious public

health issue. The technologies developed will allow for

the exact identification of toxins present in water samples

and specifically the isolation of the lethal anatoxin-a

neurotoxin. Additionally, researchers are working to

determine which water quality parameters appear to favor cyanobacterial production.

Federal Efforts
Harmful Algal Blooms in US Waters

US Department of Agriculture (USDA)

USDA agencies work with landowners and land users

to reduce runoff from farms, ranches, and private lands

to improve water quality in adjacent streams and water

bodies. USDA’s actions are based on sound scientific

research that takes into account the linkages between

land use and the conditions of natural resources in watersheds. Through management programs that focus on

improving and protecting water quality, the USDA encourages farmers, ranchers, and other private landowners to include conservation practices in their operations.

Researchers in USDA’s Agricultural Research Service

(ARS) are investigating the environmental effects of

farming. Scientists from various disciplines are engaged

in evaluating agricultural activities. Research includes

pathogens such as Crytosporidium and Pfiesteria, livestock feed efficiencies, animal waste management, ammonia source and delivery, sustainable agricultural,

composting wastes, and erosion control. ARS scientists

are continually evaluating new agricultural technologies

to help land managers enhance and protect their natural

resources.

The Natural Resources Conservation Service (NRCS)

provides technical and financial assistance to private

landowners and land users to reduce polluted runoff and

enhance natural resources. NRCS utilizes authorities to

help local groups tackle community resource concerns.

Tools include natural resource inventories, soil surveys,

conservation practice specifications, funding, and a comprehensive knowledge of resources conservation.

The agency, as an active participant in the President’s

Clean Water Action Plan, has agreed to increase technical and financial assistance to reduce polluted runoff and

enhance natural resources. NRCS utilizes authorities provided through the 1996 and other farm bills, offering a

wide range of conservation options that can be tailored

to fit special situations. Some important programs offered by NRCS and Farm Services Agency (FSA) include the Environmental Quality Incentives Program

(EQIP) which targets assistance to high priority areas,

the Wetland Reserve Program (WRP) which offers 30-

year easements or restoration cost-share agreements, the

Conservation Reserve Program (CRP), which allows

landowners to take environmentally sensitive areas out

of production, and the Wildlife Habitat Incentives Program (WHIP), which allows landowners to improve habitat for wildlife.
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Proper citation of this document is as follows:

CENR. 2000. National Assessment of Harmful Algal Blooms in US Waters.

National Science and Technology Council Committee on Environment and

Natural Resources, Washington, DC.

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