Scientific Assessment 

of Marine

Harmful Algal Blooms

Interagency Working Group on

 Harmful Algal Blooms, Hypoxia, and Human Health

December 2008
This document should be cited as follows:

Lopez, C.B., Dortch, Q., Jewett, E.B., Garrison, D. 2008. Scientific Assessment of Marine 

Harmful Algal Blooms. Interagency Working Group on Harmful Algal Blooms, Hypoxia, and 

Human Health of the Joint Subcommittee on Ocean Science and Technology. Washington, 

D.C.

Acknowledgements:

Many scientists and managers from Federal and state agencies, universities, and research 

institutions contributed to the knowledge base upon which this assessment depends. Thank 

you to all those who contributed to this report, including Lynn Dancy of NOAA National 

Centers for Coastal Ocean Science who provided a thorough copy editing.

Cover and Sidebar Photo Credits: 

Cover: A bloom of the nontoxic dinoflagellate Lingulodinium polyedrum along the coast of La 

Jolla, San Diego County, Kai Schumann (see p. 2 for the entire photo).

Sidebars: Red drift algae on Sanibel Island, Florida, Mike Valiquette (see p. 17 for entire 

photo).
Scientific Assessment of Marine Harmful Algal Blooms i

Council on Environmental Quality 

Office of Science and Technology Policy 

Executive Office of the President 

November 13, 2008 

Dear Members of Congress: 

We are pleased to transmit this report, a Scientific Assessment of Marine Harmful Algal 

Blooms. This document assesses the problem of harmful algal blooms (HABs) in our Nation’s 

coastal ocean and estuarine waters and describes recent advances made by Federal agencies to 

improve scientific understanding of HABs and our ability to manage them. 

In December 2004, Congress reauthorized the Harmful Algal Bloom and Hypoxia Research and 

Control Act (HABHRCA) by passing the Harmful Algal Bloom and Hypoxia Amendments Act 

of 2004 (HABHRCA 2004). The reauthorization of HABHRCA acknowledged that HABs are 

one of the most scientifically complex and economically damaging issues challenging our ability 

to safeguard the health of our Nation’s aquatic and marine ecosystems. The Administration 

further recognized the importance of HABs as a high priority national issue by specifically 

calling for the implementation of HABHRCA in the President’s U.S. Ocean Action Plan. 

This report is the last of four reports required by HABHRCA 2004 to address various aspects of 

HABs in U.S. waters. It was prepared by the Interagency Working Group on Harmful Algal 

Blooms, Hypoxia, and Human Health, which was chartered through the Joint Subcommittee on 

Ocean Science and Technology of the National Science and Technology Council and the 

Interagency Committee on Ocean Science and Resource Management Integration. This report 

highlights a number of research advances relevant to the HAB-related priorities identified in 

Charting the Course for Ocean Science in the United States for the Next Decade: An Ocean 

Research Priorities Plan and Implementation Strategy, recently released by the Joint 

Subcommittee on Ocean Science and Technology. The assessment draws from direct 

contributions of Federal agencies as well as previous reporting efforts that involved numerous 

experts and stakeholders from Federal, state, and local governments, and academia, industry, and 

non-governmental organizations. 

As the U.S. Commission on Ocean Policy points out, our Nation’s coastal ocean, estuaries, and 

inland waters are vital to our quality of life, our culture, and the economy. This report is an 

effort to assess the problem of HABs, specifically in our coastal ocean and estuarine waters, and 

to highlight research advances over the last decade. Activities highlighted here have improved 

our ability to minimize human health, economic, and environmental impacts from marine HABs. 

We hope it will be useful to the Congress and a broad range of interested parties. 

Sincerely,

James L. Connaughton John H. Marburger III 

Chair, Committee on Ocean Policy Director 

Chair, Council on Environmental Quality Office of Science and Technology Policy 
ii Scientific Assessment of Marine Harmful Algal Blooms

Arctic Research Commission 

John Farrell

Department of Agriculture 

Louie Tupas 

Department of Commerce 

National Oceanic and Atmospheric 

Administration 

Richard Spinrad

Steve Murawski 

Marie Colton 

Department of Defense 

U.S. Army Corps of Engineers 

Charles Chesnutt 

Joan Pope 

Department of Defense 

Office of Naval Research 

Linwood Vincent

James Eckman 

Department of Energy 

Office of Science 

Julie Carruthers 

James Ahlgrimm 

Department of Health and Human Services 

Centers for Disease Control and Prevention 

Lorraine Backer 

G. David Williamson 

Department of Health and Human Services 

Food and Drug Administration 

Robert Dickey

William Jones 

Department of Health and Human Services 

National Institutes of Health 

Allen Dearry 

Department of Homeland Security 

U.S. Coast Guard 

Jonathan Berkson 

Department of the Interior

Kameran Onley

Tim Petty

Department of the Interior 

Minerals Management Service 

James Kendall 

Walter Johnson

Department of the Interior 

United States Geological Survey 

Linda Gunderson

John Haines

Department of Justice 

Bradford McLane 

Department of State 

David Balton 

Liz Tirpak 

Department of Transportation 

Maritime Administration 

Richard Corley

U.S. Environmental Protection Agency 

George Gray 

Steven Hedtke 

Executive Office of the President 

Council on Environmental Quality 

Gerhard Kuska 

Executive Office of the President 

Domestic Policy Council 

Paul Skoczylas

Executive Office of the President 

Office of Management and Budget 

Stuart Levenbach

Kimberly Miller

Executive Office of the President 

Office of Science and Technology Policy 

Dan Walker 

Joint Chiefs of Staff 

Robert Winokur 

James Kraska

Nadeem Ahmad

National Aeronautics and Space 

Administration 

Jack Kaye 

Eric Lindstrom 

National Science Foundation 

Margaret Leinen

Julie Morris 

Marine Mammal Commission 

Robert Gisiner

Smithsonian Institution 

Leonard Hirsch 

Joint Subcommittee on Ocean Science and Technology 

(JSOST)

Richard Spinrad, DOC/NOAA, Co-Chair

Dan Walker, OSTP, Co-Chair

Julie Morris, NSF, Acting Co-Chair
Scientific Assessment of Marine Harmful Algal Blooms iii

Lorraine C. Backer (Co-Chair)

Centers for Disease Control and Prevention

Paul A. Sandifer (Co-Chair)

National Oceanic and Atmospheric Administration

Paula Bontempi

Alternate: John A. Haynes

National Aeronautics and Space Administration

Herbert T. Buxton

United States Geological Survey

Stacey M. Etheridge

U.S. Food and Drug Administration

David Garrison

National Science Foundation

Sherwood Hall

U.S. Food and Drug Administration

Rob Magnien

Alternate: Quay Dortch

National Oceanic and Atmospheric Administration

Tim Ragen

Alternate: Mike Simpkins

Marine Mammal Commission

Teri Rowles

National Oceanic and Atmospheric Administration

Juli Trtanj

National Oceanic and Atmospheric Administration

Frederick L. Tyson

National Institute of Environmental Health 

Sciences

Usha Varanasi

Alternate: Walton Dickhoff

National Oceanic and Atmospheric Administration

William Russo

U.S. Environmental Protection Agency

Mark Weltz

Alternate: Mike O’Neill

Department of Agriculture

Scientific support staff:

Elizabeth B. Jewett

Cary B. Lopez

Carolyn Sotka

Virginia Fay

National Oceanic and Atmospheric Administration

Cheryl L. Fossani

National Science Foundation

JSOST Interagency Working Group on 

Harmful Algal Blooms, Hypoxia and Human Health (IWG-4H)

Primary Authors 

Cary B. Lopez

National Oceanic and Atmospheric Administration

Elizabeth B. Jewett

National Oceanic and Atmospheric Administration

Quay Dortch

National Oceanic and Atmospheric Administration

David Garrison

National Science Foundation

Other Contributors

Rachel Jakuba

Environmental Protection Agency

Tiffany Moisan

National Aeronautics and Space Administration 

John Schwab

National Institute of General Medical Sciences

Kevin Chu, Kelly Goodwin, Greg Doucette, 

Steve Morton, John Ramsdell, Marc 

Suddleson, Pat Tester, Michelle Tomlinson, 

Vera Trainer, Dwight Trublood, Frances 

VanDolah, Gary Wikfors

National Oceanic and Atmospheric Administration

Mark Poli

United States Army Medical Research Institute of 

Infectious Diseases

Scientific Assessment of Marine Harmful Algal Blooms v

Table of Contents

vi List of Boxes

vii List of Figures

vii List of Tables

viii List of Acronyms

1 Executive Summary

7 Chapter 1. Legislative Background and Report Process

7 1.1 Legislative Background

7 1.2 Report Process

9 Chapter 2. State of the Marine HAB Problem in the United States

 9 2.1 Causes

 11 2.2 Consequences

21 Chapter 3. Federal Research on Marine HABs in the United States

21 3.1. Program and Agency Research Focus Areas 

30 3.2. Research and Accomplishments

49 Chapter 4. Coordination and Communication for Marine HAB Research and 

Response

49 4.1. National Coordination and Communication

52 4.2. International Coordination and Communication

54 References

60 Appendix: Marine HAB Research and Response by State, Local, and Tribal 

Governments
vi Scientific Assessment of Marine Harmful Algal Blooms

Page #

 7 Box 1.1. HABHRCA 2004 Reports and Assessments

 8 Box 1.2. Oceans and Human Health Act 2004

 8 Box 1.3. Harmful Algal Bloom Management and Response: Assessment and Plan

11 Box 2.1. Human Poisonings in 2007 Highlight Importance of Monitoring and Outreach Programs

13 Box 2.2. HABs and HAB Impacts in the Northeastern United States 

14 Box 2.3 HABs and HAB Impacts along the Mid- and South-Atlantic Coast

16 Box 2.4 HABs and HAB Impacts in the Gulf of Mexico

18	 Box 2.5 HABs and HAB Impacts along the Pacific Coast

19 Box 2.6 HABs and HAB Impacts in Alaska

19	 Box 2.7 HABs and HAB Impacts in Hawaii and the Pacific Territories

31 Box 3.1. Highlights of Major Advances in the Northeastern United States

33 Box 3.2. Highlights of Major Advances along the Mid- and South-Atlantic Coasts

36 Box 3.3. Highlights of Major Advances in the Gulf of Mexico

39	 Box 3.4. Highlights of Major Advances along the Pacific Coast

41	 Box 3.5. Highlights of Major Advances in Hawaii and the Pacific Territories

43 Box 3.6. Highlights of Major Advances Applicable in Multiple Regions of the United States

List of Boxes
Scientific Assessment of Marine Harmful Algal Blooms vii

Page #

9 Figure 2.1 HAB events in the United States.

21 Figure 3.1. Marine HAB ECOHAB projects and the funding amounts supported by the ECOHAB Partners.

21 Figure 3.2. Marine HAB ECOHAB targeted and regional projects categorized by the revised HARRNESS 

research categories.

24 Figure 3.3. Marine HAB ECOHAB targeted and regional projects categorized by HAB organism.

24 Figure 3.3. Marine HAB MERHAB projects categorized by the revised HARRNESS research categories.

List of Figures

List of Tables

Page #

10 Table 2.1. Major HAB organisms causing problems in U.S. marine systems, their major toxins (if 

characterized), their direct acute impacts, and U.S. regions that have been impacted by these HAB 

organisms.

22 Table 3.1. Federal agencies involved in marine HAB research and response.

23 Table 3.2. Regional ECOHAB projects on marine HABs and the grant and research partners.

25 Table 3.3. NOAA MERHAB regional projects on marine HABs.
viii Scientific Assessment of Marine Harmful Algal Blooms

AOAC Association of Analytical Communities

ASP amnesic shellfish poisoning

CCEHBR NCCOS Center for Coastal Environmental 

Health and Biomolecular Research, NOAA

CCFHR NCCOS Center for Coastal Fisheries and 

Habitat Research, NOAA

CCMA NCCOS Center for Coastal Monitoring and 

Assessment, NOAA 

CDC Centers for Disease Control and Prevention, 

Department of Human and Health Services

CFP ciguatera fish poisoning

CICEET Cooperative Institute for Coastal and Estuarine 

Environmental Technology

COHH Centers for Oceans and Human Health, NSF/

NIEHS

CSCOR NCCOS Center for Sponsored Coastal Ocean 

Research, NOAA

DSP diarrhetic shellfish poisoning

ECOHAB Ecology and Oceanography of Harmful Algal 

Blooms Program

ELISA enzyme-linked immunosorbent assay

EMCC Eastern Maine Coastal Current

EPA U.S. Environmental Protection Agency

FDA U.S. Food and Drug Administration, Department of 

Human and Health Services

GEOHAB Global Ecology and Oceanography of Harmful 

Algal Bloom Program

GEOSS Global Earth Observation System of Systems

GLERL Great Lakes Environmental Research 

Laboratory, NOAA

GOOS Global Ocean Observing System

HAB harmful algal bloom

HABHRCA Harmful Algal Bloom and Hypoxia Research 

and Control Act 

HABISS Harmful Algal Bloom-related Illness 

Surveillance System

HARR-HD Harmful Algal Research and Response: A 

Human Dimensions Strategy

HARRNESS Harmful Algal Research and Response: A 

National Environmental Science Strategy 2005–2015

HPLC high performance liquid chromatography

IEOS U.S. Integrated Earth Observing System

IOC Intergovernmental Oceanographic Commission

IOOS Integrated Ocean Observing System

ISSC Interstate Shellfish Sanitation Conference

ISSHA International Society for the Study of Harmful 

Algae

IWG-4H Interagency Working Group on Harmful Algal 

Blooms, Hypoxia, and Human Health

JSOST Joint Subcommittee on Ocean Science and 

Technology

LCMS liquid chromatography mass spectrometry 

MERHAB Monitoring and Event Response for Harmful 

Algal Blooms Program, NOAA

MMC Marine Mammal Commission

NASA National Aeronautics and Space Administration

NCCOS National Centers for Coastal Ocean Science, 

NOAA

NCEH National Center for Environmental Health, CDC

NEFSC Northeast Fisheries Science Center, NOAA

NESDIS National Environmental Satellite, Data, and 

Information Service, NOAA

NERRS National Estuarine Research Reserve System

NHC National HAB Committee

NIEHS National Institute of Environmental Health 

Sciences, NIH

NIGMS National Institute of General Medical Sciences, 

NIH

NIH National Institutes of Health, Department of Human 

and Health Services

NMFS National Marine Fisheries Service, NOAA

NOAA National Oceanic and Atmospheric 

Administration, Department of Commerce

NSF National Science Foundation

NSP neurotoxic shellfish poisoning

NWFSC Northwest Fisheries Science Center, NOAA

OAR Office of Oceanic and Atmospheric Research,

NOAA

OHH Oceans and Human Health

OHHI Oceans and Human Health Initiative, NOAA

ONR Office of Naval Research, U.S. Department of

Defense

ORHAB Olympic Region HAB Monitoring Program

PICES North Pacific Marine Science Organization

PSP paralytic shellfish poisoning

RDDTT Research Development Demonstration and 

Technology Transfer 

UME unusual mortality event

USAMRIID U.S. Army Medical Research Institute of 

Infectious Diseases

USDA U.S. Department of Agriculture

USFWS U.S. Fish and Wildlife Service, U.S. Department 

of the Interior

USGS U.S. Geological Survey, U.S. Department of the 

Interior

List of Acronyms
Scientific Assessment of Marine Harmful Algal Blooms 1

Algae are the most abundant photosynthetic 

organisms in marine ecosystems and 

are essential components of marine food webs. 

Harmful algal bloom or “HAB” species are a small 

subset of algal species that negatively impact 

humans or the environment. HABs can pose 

health hazards for humans or animals through 

the production of toxins or bioactive compounds. 

They also can cause deterioration of water quality 

through the buildup of high biomass, which 

degrades aesthetic, ecological, and recreational 

values. 

Humans and animals can be exposed to marine 

algal toxins through their food, the water in which 

they swim, or sea spray. Symptoms from toxin 

exposure range from neurological impairment to 

gastrointestinal upset to respiratory irritation, in 

some cases resulting in severe illness and even 

death. HABs can also result in lost revenue for 

coastal economies dependent on seafood harvest 

or tourism, disruption of subsistence activities, 

loss of community identity tied to coastal resource 

use, and disruption of social and cultural practices. 

Although economic impact assessments to date 

have been limited in scope, it has been estimated 

that the economic effects of marine HABs in 

U.S. communities amount to at least $82 million 

per year including lost income for fisheries, lost 

recreational opportunities, decreased business in 

tourism industries, public health costs of illness, 

and expenses for monitoring and management. As 

reviewed in the report, Harmful Algal Research 

and Response: A Human Dimensions Strategy1

, the 

sociocultural impacts of HABs may be significant, 

but remain mostly undocumented.

It is widely believed that the frequency and 

geographic distribution of marine HABs have been 

increasing worldwide. All U.S. coastal states have 

experienced HABs over the last decade, and new 

species have emerged in some locations that were 

not previously known to have problems. While 

marine HABs occur naturally, human actions that 

disturb ecosystems in the form of increased nutrient 

loadings and pollution, food web alterations, 

introduced species, and water flow modifications 

have been linked to the increased occurrence of 

some HAB species. 

Efforts to address the HAB problem at the 

Federal level began with the first HAB National 

Plan in 1993, followed by the Harmful Algal 

Bloom and Hypoxia Research and Control 

Act (HABHRCA) of 1998. In 2004, Congress 

reauthorized HABHRCA with the Harmful Algal 

Bloom and Hypoxia Amendments Act (HABHRCA 

2004). The 2004 legislation required the generation 

of five reports (see Box 1.1), including this 

Scientific Assessment of Marine Harmful Algal 

Blooms. HABHRCA 2004 stipulates that this 

report: 1) examine the causes, consequences, 

and economic costs of marine HABs, 2) describe 

the potential ecological and economic costs 

and benefits of possible actions for preventing, 

controlling, and mitigating HABs, 3) evaluate 

progress made by Federal research programs, and 

4) make recommendations to improve coordination 

among Federal agencies with respect to research 

on marine HABs. The primary focus of this 

report is the fundamental scientific research that 

is the basis for improving HAB management and 

response. It is based, in part, on the new national 

plan, Harmful Algal Research and Response: A 

National Environmental Science Strategy 2005-

2015 (HARRNESS)2

. 

State of the Science: 

Research Advances by 

Federal Programs

Many advances in understanding marine 

HABs have occurred in recent years in the United 

States, due in large part to Federal investments 

in marine HAB research. This research has been 

conducted through national research programs 

focused on HAB research and as part of other more 

general research programs. The two national, 

extramural HAB funding programs, Ecology 

and Oceanography of Harmful Algal Blooms 

(ECOHAB) Program and Monitoring and Event 

Response for Harmful Algal Blooms (MERHAB) 

Program, have together funded approximately $100 

million in marine HAB research since the programs 

began in 1996 and 2000, respectively. In addition, 

Executive 

 Summary
2 Scientific Assessment of Marine Harmful Algal Blooms

Executive Summary

at least 13 Federal agencies conduct significant 

marine HAB research as part of other research 

programs. 

Major accomplishments of these research 

efforts fall into the five categories discussed below. 

Research accomplishments in HAB prevention, 

control, and mitigation are discussed briefly in 

this report and are covered in more detail in HAB 

Management and Response: Assessment and Plan3

(Box 1.1).

Understanding HAB Causes and Controls 

and Developing Predictive Models 

Research on HAB causes and controls, also 

referred to as ‘bloom ecology and dynamics,’ 

encompasses research aimed at understanding 

the biological, physical, and chemical factors that 

control HAB initiation, maintenance, transport, 

and decline. The ultimate products of research on 

HAB causes and controls are models of population 

growth and mortality and, potentially, predictive 

models of bloom dynamics and impacts. Much 

research has focused on this topic and, as a result, 

significant advances have been realized. 

Cell physiology, organism life cycle, and genetic 

research has led to better understanding of how 

cells function, effective tools for detection (see next 

section), identification of known species in new 

areas, and discovery of new species. The linkages 

between cell physiology and toxicity have become 

clearer for some organisms, helping to explain why 

cells are more toxic at certain times. In addition, 

a better understanding of the role of resting stages 

in bloom initiation has improved predictive 

models. Tools have been developed for controlled 

testing of environmental factors that regulate 

growth and toxin production of the Florida red tide 

alga. Genetic research has also led to insight into 

harmful algal genes and their regulation, serving as 

a springboard for research to refine understanding 

of the biological aspects of bloom development. 

Knowledge of historical bloom patterns has 

been gained from long-term monitoring* data sets. 

These data are revealing shifts in phytoplankton 

communities and occurrence of exceptional events. 

Long-term data are also being used to explore 

natural or human-induced drivers of this change. 

Research on the role of nutrients has revealed 

relationships between increased anthropogenic 

nutrient loadings and prevalence of some species, 

such as Pfiesteria spp., some macroalgae, and 

Pseudo-nitzschia in the Gulf of Mexico. Other 

A nontoxic bloom of the dinoflagellate Lingulodinium polyedrum along the coast of La Jolla, San Diego County. 

Photo: Kai Schumann

*The term monitoring as used in this document is not meant to convey requirements under regulation unless specified.
Scientific Assessment of Marine Harmful Algal Blooms 3

Executive Summary

research has shown that changes in nutrient quality 

(e.g., organic versus inorganic nutrients), not 

quantity, may favor proliferation of some harmful 

algal species. 

As a result of years of research, models that 

incorporate biological and physical data have been 

developed for specific HAB species prevalent in 

New England, Florida, and the Pacific Northwest. 

In New England, the model has explained patterns 

and variations in shellfish toxicity and has been 

used in demonstration mode to give weekly 

predictions of bloom status to resource managers 

since 2005. These model predictions have allowed 

managers to design more precise and selective 

shellfish harvesting closures, thereby minimizing 

economic impacts on local communities while 

protecting human health. Forecasts based on 

simpler models are also now operational in the 

Chesapeake Bay and in Florida.

Developing Detection Methods for Cells 

and Toxins

Managers rely on the ability to detect HAB cells 

and toxins to mitigate bloom impacts, and multiple 

methods are often needed because no method 

fulfills all purposes. Many new technologies for 

detecting HAB cells have emerged from studies 

on HAB physiology and molecular biology. 

New molecular-based assays have been and are 

continuing to be developed. In several regions of 

the country, these tools are used routinely for HAB 

detection and have led to better understanding 

of species distributions and identification of new 

species of concern. Deployable instruments for 

real-time, in-water detection of HABs have been 

developed as well. The ‘brevebuster’ optically 

detects the Florida red tide species (Karenia 

brevis) and can be deployed on automated 

underwater vehicles or on stationary platforms. 

The ‘environmental sample processor’, another 

deployable instrument that can detect several HAB 

species, was successfully deployed in Monterey 

Bay, California, where it detected the harmful 

diatom (Pseudo-nitzschia) and its toxin, domoic 

acid, in real-time. 

A range of analytical methods for toxin 

detection—from very accurate and expensive 

laboratory analytical techniques to quick and 

easy screening methods for the field—are used to 

minimize the impacts of toxic outbreaks. Many 

agencies have been involved in improving toxin 

detection methods. As a result, there are newly 

developed methods being considered for regulatory 

testing of the toxins that cause paralytic and 

neurotoxic shellfish poisoning syndromes. These 

tests are more rapid, reliable, and efficient than the 

currently approved regulatory method. Other quick 

and easy toxin tests are being developed for rapid 

initial screening in the field. These tests reduce the 

number of samples taken for laboratory analysis, 

thereby saving time and money as components of 

tiered monitoring protocols.

Characterizing Toxins and Toxin Impacts 

New instrumental techniques have been applied 

to the determination of both toxin chemical 

structures and their metabolites, and advances in 

chemical instrumentation have enabled chemists to 

determine toxin structures on smaller quantities of 

toxins. Several new marine toxins or metabolites 

have been characterized and more are being 

investigated. Newly identified compounds include 

Applying a shellfish sample to a qualitative field test for the PSP

toxins (Jellett Rapid testing Systems, Ltd.) 

Photo: Gregg Langlois, California Department of Health Services
4 Scientific Assessment of Marine Harmful Algal Blooms

Executive Summary

the free radical-forming metal complex produced 

by Pfiesteria and the fish-killing karlotoxins. 

The primary site of action of most of the major 

toxins has been established. Animal models have 

improved understanding of acute and chronic 

effects, including developmental effects of domoic 

acid, brevetoxins, and ciguatoxins. It is now 

known, for example, that domoic acid exposure can 

cause reproductive failure in California sea lions 

as well as behavior and memory impairment in 

rats. Human and wildlife case studies have helped 

define acute impacts, such as respiratory effects 

from aerosolized brevetoxins. Knowledge of 

effects from long-term, low-level exposures is still 

being established, but research with California sea 

lions suggests chronic effects, such as epilepsy and 

behavioral changes, occur with repeated, sub-lethal 

exposure to domoic acid.

Toxin detection in clinical matrices, such as 

blood and urine, is necessary to confirm and 

investigate toxin exposure and effects during 

outbreaks. Diagnostic tests are being developed 

for ciguatera toxin exposure in humans and 

other toxins in marine mammals. More accurate 

assessments of exposures will benefit studies of 

toxin occurrence and impacts. 

Several promising therapeutic approaches 

to remediate HAB toxin exposure are also 

being explored, including the use of brevenal, 

a compound that counteracts the effects of 

brevetoxin. 

HAB impacts on food webs and fisheries

Research in this area has received less attention 

in the past than some of the other HAB-related 

issues. In addition to impacts on animal health 

(discussed in previous section), research to date has 

focused on changes in food web structure, transfer 

of toxins through the food web, and accumulation 

and elimination of toxin in food web components. 

Recent advances include identification of ‘new’ 

pathways for toxin entry into food webs, such 

as zooplankton, fish, and seagrass leaves for 

brevetoxins, which serve as additional modes of 

toxin transfer to marine mammals.

Understanding shellfish toxin accumulation 

and elimination will improve prediction and 

management of shellfish toxicity. Much of this 

work is ongoing. Some commercial bivalves 

have been shown to have saxitoxin resistance, 

which allows more rapid toxin accumulation, due 

to a genetic mutation. Genetic markers are in 

development to distinguish such toxin resistance. 

Furthermore, a model for domoic acid elimination 

in razor clams and crabs, which will be useful to 

predict how long it takes for contaminated shellfish 

to become safe for human consumption, is in 

development. 

Assessing Public Health, Economic, and 

Sociocultural Impacts 

The major acute seafood poisoning syndromes 

caused by HABs are well-defined. The geographic 

areas impacted by these syndromes are also wellknown, but recent work has identified public health 

issues emerging in new areas, such as saxitoxin 

puffer fish poisoning in Florida and, potentially, 

ciguatera-producing organisms in the Northwestern 

Gulf of Mexico. A majority of the current public 

health surveillance efforts grew from the Centers’ 

for Disease Control and Prevention initial response 

to the Pfiesteria-related outbreak in the late 1990s. 

For example, the Harmful Algal Bloom-related 

Illness Surveillance System has been developed 

Digging for clams is a tradition for many families in the Pacific 

Northwest. 

Photo: Vera Trainer, NOAA
Scientific Assessment of Marine Harmful Algal Blooms 5

Executive Summary

and is being used in some states to capture human 

and animal health data as well as environmental 

data during HAB events. 

Epidemiological studies on specific populations 

(cohort-based) have been limited, but one is 

currently underway in the Pacific Northwest with 

Native American infants, children, and adults who 

may be exposed to domoic acid through razor clam 

consumption. This research is making headway for 

identifying populations most at-risk for exposure 

and effects from toxic HABs. 

In the last decade, several thorough, yet 

conservative, assessments of the economic 

impacts of marine HABs in the United States have 

been conducted. Additionally, assessments of 

individual events have been supported by Federal 

and state agencies and illustrate well the large 

economic impact that just one event can have 

on local communities. Cost/benefit studies of 

HAB management strategies and assessments of 

sociocultural impacts are new areas that are just 

starting to be addressed.

Coordination for Future 

Progress

Research advances over the last decade 

have been considerable and the benefits have 

been observed in improved management of the 

Nation’s resources and better protection of humans 

and ecosystems. Federal involvement in and 

coordination of marine HAB research are important 

for continued progress and to meet common goals 

to protect human health, economies, communities, 

ecosystems, and fisheries. Opportunities for 

improved synergy and success of HAB research 

programs recur in a number of recent HAB reports, 

including HARRNESS 2 and the recent HABHRCA 

report, Harmful Algal Bloom Management and 

Response: Assessment and Plan3

 and can be 

categorized into the following four general themes:

1) basic research provides new understanding 

that feeds into developing strategies and tools 

for improved HAB management, 

2) coordination between programs that 

perform HAB research in the environment 

and those that study human and community 

impacts is important, 

3) programs dedicated to moving new 

information and technologies to operational 

use by managers will advance HAB response, 

and 

4) a combination of extramural and intramural 

competitive and noncompetitive research 

is best able to meet the multiple goals for 

improving management of HABs and their 

impacts. 

The Interagency Working Group on Harmful 

Algal Blooms, Hypoxia, and Human Health 

(IWG-4H), as the body fulfilling the role of the 

Interagency Task Force on HABs and Hypoxia, 

provides Federal coordination for HAB research 

and response. The IWG-4H may also cultivate 

Federal coordination through interaction with 

the HAB research and management communities 

via the U.S. National Office for HABs, the 

National HAB Committee, the Interstate Shellfish 

Sanitation Commission, the Working Group on 

Unusual Marine Mammal Mortality Events, the 

National Water Quality Monitoring Council, and 

various regional activities. Coordination at the 

international level, such as through participation 

in national and international meetings, will also 

be important for continuing progress and avoiding 

duplication of effort. 

Scientific Assessment of Marine Harmful Algal Blooms 7

1.1 Legislative Background

The Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 

(HABHRCA, Public Law 105-383) was 

reauthorized by the Harmful Algal Bloom and 

Hypoxia Amendments Act of 2004 (HABHRCA 

2004, Public Law 108-456). HABHRCA 2004 

reconstituted the Interagency Task Force on 

Harmful Algal Blooms and Hypoxia, and required 

five reports to assess and recommend research 

programs on harmful algal blooms (HABs) and 

hypoxia in U.S. waters, including this Scientific 

Assessment of Marine Harmful Algal Blooms

(Box 1.1). The Interagency Task Force on 

HABs and Hypoxia was incorporated into the 

Interagency Working Group on HABs, Hypoxia, 

and Human Health (IWG-4H, see page iii) of 

the Joint Subcommittee on Ocean Science and 

Technology (JSOST). The IWG-4H was tasked 

with implementing the requirements of both 

HABHRCA 2004 and the Interagency Oceans and 

Human Health Research Program established in 

the Oceans and Human 

Health (OHH) Act of 

2004 (Public Law 1088-

447; Box 1.2).

HABHRCA 2004 

stipulates that this 

report 1) examine the 

causes, consequences, 

and economic costs 

of marine HABs (see 

Chapter 2), 2) describe 

the potential ecological 

and economic costs 

and benefits of 

possible actions for 

preventing, controlling, 

and mitigating HABs (see Chapters 2 and 

3), 3) evaluate progress made by Federal 

research programs (see Chapter 3), and 4) make 

recommendations to improve coordination among 

Federal agencies with respect to research on marine 

HABs (see Chapter 4). The mandate to include 

information on efforts to prevent, control, and 

mitigate marine HABs (#2 above) is covered in 

more detail by the report Harmful Algal Bloom 

Management and Response: Assessment and Plan3

(Box 1.3).

1.2 Report Process

The first marine HAB assessment, the

National Assessment of Harmful Algal Blooms 

in U.S. Waters6, was completed for Congress 

in 2000 in response to the original HABHRCA 

legislation. The current report builds on the 

earlier report to assess the U.S. HAB problem, 

but also takes an extra step to provide analysis 

of major research advances made by Federal 

agencies. Research covered goes back as far as 

1996 to include projects that were precursors to the 

interagency Ecology and 

Oceanography for Harmful 

Algal Blooms (ECOHAB) 

Program, which began in 

1997. 

The primary focus 

of this report is the 

fundamental scientific 

research that is the 

basis for improving 

HAB management and 

response. Focus areas 

were derived from the 

report, Harmful Algal 

Research and Response: 

Chapter 1

Legislative Background 

and Report Process

Box 1.1. HABHRCA 2004 Reports 

and Assessments 

• Harmful Algal Bloom Management and Response: 

Assessment and Plan

• National Assessment of Efforts to Predict and 

Respond to Harmful Algal Blooms in U.S. 

Waters (Prediction and Response Report)

• National Scientific Research, Development, 

Demonstration, and Technology Transfer Plan 

for Reducing HAB Impacts (RDDTT Plan)

• Scientific Assessment of Freshwater Harmful Algal 

Blooms

• Scientific Assessment of Marine Harmful Algal 

Blooms

• Scientific Assessment of Hypoxia
8 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 1

A National Environmental Science Strategy 

2005–2015 (HARRNESS)

2

, which represents an 

intense multiyear collaboration among the HAB 

community to assess the state of HAB research 

and chart a way forward. The focus areas include 

bloom ecology and dynamics, food webs and 

fisheries, toxins and their effects, and public health 

and socioeconomic studies. However, a brief 

overview of prevention, control, and mitigation 

activities, based on the Harmful Algal Bloom 

Management and Response: Assessment and Plan3

is also given. Social science research directions 

are considered in more detail in the report, 

Harmful Algal Research and Response: A Human 

Dimensions Strategy (HARR-HD)1.

Information for this report was synthesized 

from several sources. This assessment draws 

strongly from the HARRNESS report2

, which was 

developed by the HAB research and management 

community using an open forum discussion of 

200 participants at the second U.S. National 

HAB Symposium in 2003, a detailed web-based 

questionnaire yielding more than 1000 targeted 

responses, a workshop of 50 U.S. HAB experts 

in 2004, an advisory committee with Federal 

and management representatives, and a steering 

committee to assemble and review the most current 

information available for use in developing the 

document. White papers, written by members of 

the HARRNESS Steering Committee on the state 

of the science in preparation for the HARRNESS 

workshop, along with more recent scientific 

publications and reports, were used to develop this 

assessment. In addition, Federal agencies involved 

in marine HAB research provided information, 

drawing from project progress reports, about 

current research and accomplishments. 

Box 1.3. Harmful Algal Bloom Management and 

Response: Assessment and Plan

Two reports mandated by HABHRCA 2004, the Prediction and Response 

Report5

 and the RDDTT Plan (Box 1.1), were combined into one final report that 

addresses HAB prediction and response in the United States: the Harmful Algal 

Bloom Management and Response: Assessment and Plan 3

. The Prediction 

and Response Report reviewed and evaluated existing prediction and response 

programs and activities and highlighted options for improving those efforts. This 

assessment was made available for public comment via the Federal Register in 

fall of 2006. A workshop with participants from the HAB community (both management and research 

representatives from Federal, state, local, and tribal organizations and private industry) was held in June 

2007 to address opportunities for advancement identified in the report and in the public comment period. 

The RDDTT Plan was then developed by drawing from the workshop results. The final combined report 

comprises a comprehensive evaluation and strategy developed with input by multiple stakeholders to 

improve the national and local response to HABs in U.S. waters.

Box 1.2. Oceans and Human Health Act 2004

The OHH Act requires the National Science and Technology Council to establish 

an Interagency Oceans and Human Health Research Program to improve 

understanding of the role of the oceans in human health and establishes the 

National Oceanic and Atmospheric Association (NOAA) Oceans and Human Health 

Initiative as part of this interagency program. The JSOST IWG-4H, in addition 

to serving as the Interagency Taskforce on HABs and Hypoxia as called for in 

HABHRCA, was charged with the responsibility for coordinating the interagency 

OHH program and producing both the HAB-related and OHH-related reports to 

Congress. HABs are included as part of the OHH program scope, but the OHH Act specifically states 

that “nothing in this subsection is intended to duplicate or supersede the activities of the Inter-Agency 

Task Force on Harmful Algal Blooms and Hypoxia.” The IWG-4H has prepared a 10-year Interagency 

OHH Implementation Plan4

, which was called for by the OHH Act. Coordination with HABHRCA activities 

is provided through the IWG-4H since it has responsibilities for OHH, HABs, and hypoxia.
Scientific Assessment of Marine Harmful Algal Blooms 9

Algae, in general, are beneficial because they provide the main source of energy that 

sustains marine life. However, a small percentage 

of algal species cause harm to humans, animals, 

and the environment through toxin production or 

excessive growth. The majority of these HAB 

species are phytoplankton, which are microalgae 

(microscopic, single-celled algae), that live 

suspended in the water. “Harmful algae” also 

include some microalgae that live attached to 

plants or other substrates as well as some species 

of macroalgae (i.e., seaweeds). Marine HABs 

refer to harmful blooms that occur in oceans, 

coastal waters, and estuaries. Major algal groups 

that cause problems in the United States are listed 

in Table 2.1. Freshwater and other inland HABs, 

including those that 

occur in the Great 

Lakes and upper 

reaches of estuaries, 

are covered in the 

HABHRCA report, the 

Scientific Assessment 

of Freshwater Harmful 

Algal Blooms 8 (Box 

1.1). 

Although only a 

small percentage of the 

world’s algal species 

are considered harmful, 

the geographic distribution of HAB events is broad 

with pervasive impacts. All coastal states in the 

United States have experienced HAB events over 

the last decade (Figure 2.1), and it is generally 

believed that the frequency and distribution 

of HABs and their impacts have increased 

considerably in recent years in the United States 

and globally9,10,11,12,13,14. Causes and consequences 

of HABs in the United States are discussed in 

general below. Specific HAB problems and 

impacts are discussed in more detail in the regional 

boxes throughout this chapter. 

2.1. Causes

HABs are a natural phenomenon in coastal 

ecosystems, but human activities are thought to 

contribute to the increased frequency of some 

HABs. For example, although not all HABs 

occur in high nutrient environments, increased 

nutrient loading has been acknowledged as a likely 

factor contributing to the increased occurrence 

of high biomass HABs13,14. Other humaninduced environmental changes that may foster 

development of certain HABs include changes in 

nutrient regimes14, alteration 

of food webs by overfishing15, 

introductions of nonindigenous 

species16,17, and modifications 

to water flow18. It should also 

be noted that climate change 

will almost certainly influence 

HAB dynamics in some way 

since many critical processes 

governing HAB dynamics—

such as temperature, 

stratification, upwelling and 

ocean circulation patterns, 

and freshwater and landderived nutrient inputs—are 

influenced by climate19,20. The interactive role of 

climate change with the other factors driving the 

frequency and severity of HABs is an important 

topic currently in the early stages of research.

The specific causes of HABs are complex, vary 

between species and locations, and are not all well 

understood. In general, algal species proliferate 

Chapter 2

State of the Marine HAB 

Problem in the United States

Figure 2.1. HAB events in the United States.
10 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 2

HAB Organism Toxins Acute Human 

Illness* Direct Ecosystem Impacts Impacted regions 

of the United 

States

Alexandrium spp. Saxitoxins Paralytic Shellfish 

Poisoning

Marine mammal 

mortalities 

Northeast, Pacific Coast, 

Alaska

Aureococcus 

anophagefferens

(Long Island Brown 

Tide)

Not 

characterized -- Shellfish mortality, 

seagrass die-off

Northeast, Mid-Atlantic 

Coast

Aureoumbra 

lagunensis

(Texas Brown Tide)

Not 

characterized -- Seagrass die-off Gulf of Mexico (Texas)

Dinophysis spp. Okadaic Acid Diarrhetic Shellfish 

Poisoning -- New England, Gulf of 

Mexico, Pacific Coast

Gambierdiscus spp.,

Prorocentrum spp.,

Ostreopsis spp. 

Ciguatoxin, 

Gambiertoxin, 

and Maitotoxin

Ciguatera Fish 

Poisoning --

Gulf of Mexico (Florida, 

Texas), Hawaii, Pacific 

Islands, Puerto Rico and 

U.S. Virgin Islands

High biomass bloom 

formers † -- Low dissolved oxygen, 

Food web disruption All regions

Karenia spp. Brevetoxins

Neurotoxic Shellfish 

Poisoning, Acute 

respiratory illness

Fish kills, mortalities of 

other marine animals 

Gulf of Mexico, SouthAtlantic Coast

Karlodinium spp. Karlotoxins -- Fish kills

Mid- and South- Atlantic 

Coast, Gulf of Mexico 

(Alabama, Florida)

Macroalgae ‡ --

Low dissolved oxygen, 

seagrass and coral 

overgrowth and die-off, 

beach fouling

All regions

Marine Cyanobacteria 

(CyanoHABs) 

(Lyngbya spp.) Lyngbyatoxins Dermatitis

Seagrass and coral 

overgrowth and die-off, 

beach fouling

Gulf of Mexico and 

South-Atlantic Coast 

(Florida), Hawaii and 

Pacific Territories

Pfiesteria spp.

Free radical 

toxin, 

others not 

characterized

-- Fish kills Mid- and South-Atlantic 

Coast

Pseudo-nitzschia spp. Domoic Acid Amnesic Shellfish 

Poisoning

Mortality of seabirds and 

marine mammals

Pacific Coast, Alaska, 

Gulf of Mexico, 

Northeast, Mid-Atlantic 

Coast

Pyrodinium 

bahamense Saxitoxins Puffer Fish 

Poisoning -- South-Atlantic Coast 

(Florida)

Some raphidophytes 

(e.g., Heterosigma 

akashiwo, Chattonella

spp.)

Brevetoxins 

(Chattonella), 

other 

icthyotoxins not 

characterized

-- Fish kills

Pacific Coast 

(Washington), MidAtlantic Coast

Table 2.1. Major HAB organisms causing problems in U.S. marine systems, their major 

toxins (if characterized), their direct acute impacts to humans and ecosystem health, 

and regions of the United States that have been impacted by these HAB organisms. 

‘Not characterized’ indicates that toxins have been implicated but not characterized.

*This table only captures the major acute human illnesses associated with these HAB species. Other, less severe 

acute health effects, such as skin irritation, may occur with some of these HAB groups. Chronic effects, such as 

tumor promotion, can also occur. A table of short- and long-term health effects is given in HARRNESS 2

. 

†Some high biomass bloom formers may produce toxins.

‡Some macroalgae have been shown to produce bioactive compounds, such as dopamine and 

dimethylsulfoniopropionate (DMSP), which may have direct ecosystem effects7

. 
Scientific Assessment of Marine Harmful Algal Blooms 11

The HAB Problem in U.S. Marine Waters

when environmental conditions (e.g., nutrient 

and light availability, temperature, and salinity) 

are optimal for cell growth. Other biological 

(e.g., vertical migration, grazing, viral infection, 

and parasitism) and physical (e.g., transport) 

processes determine if enhanced cell growth will 

result in biomass accumulation. The challenge 

for understanding the causes of HABs stems from 

the complexity of these biological, chemical, and 

physical interactions and their variable influence 

on growth and bloom development among different 

species21. Further, environmental control and 

genetic variation of toxin production, vertical 

migration, life cycles, and cell physiology add to 

the challenge of understanding HAB dynamics. 

The complexity of interactions between HABs, 

the environment, and other plankton complicate 

the predictions of when and where HAB events 

will occur. Knowledge of how all these factors 

control HAB initiation, maintenance, and decline 

is the subject of much research highlighted in this 

report. This knowledge is a critical precursor for 

advancing HAB management3

. 

2.2. Consequences

HAB impacts are variable in their scope and 

severity and depend on the causative species. 

Some harmful microalgae produce potent toxins 

which cause illness or death in humans and other 

organisms, including endangered species. Humans, 

wildlife, and domestic animals can be exposed 

to algal toxins via contaminated food, water, or 

aerosols, depending on the toxin. Other HAB 

species are nontoxic to humans and wildlife but 

degrade ecosystems by forming such large blooms 

that they alter habitat quality through overgrowth, 

shading, or oxygen depletion (hypoxia), thus 

adversely affecting corals, seagrasses, and bottomdwelling organisms. High biomass blooms of 

certain nontoxic harmful algae can also harm 

fish and invertebrates by damaging gills or by 

causing starvation or low reproduction due to 

poor food quality. Human health and ecosystem 

impacts of HABs can, in turn, have significant 

economic and sociocultural ramifications. Some 

economic impacts on coastal communities have 

been studied22, but assessments of sociocultural 

consequences and community vulnerabilities are 

also needed to understand the full range of HAB 

impacts and to devise strategies to mitigate them1

. 

The general impacts of HABs on human health, 

ecosystems, economies, and coastal communities 

are reviewed in the following sections. Regional 

impacts are highlighted in Boxes 2.2-2.6.

Human Health Impacts

The most severe human health impacts occur 

from consumption of shellfish or fish contaminated 

with HAB toxins. Shellfish, such as clams, 

mussels, and oysters, pose a particular threat 

to human consumers because these organisms 

filter large volumes of water as they feed and, as 

a result, can rapidly concentrate algal toxins in 

their tissues. Shellfish poisonings that are a threat 

in the United States include neurotoxic shellfish 

poisoning (NSP), paralytic shellfish poisoning 

(PSP), amnesic shellfish poisoning (ASP), and 

diarrhetic shellfish poisoning (DSP). Finfish can 

also accumulate toxins to harmful levels by feeding 

directly on toxic algae or feeding on grazers of 

toxic algae. Ciguatera fish poisoning (CFP) occurs 

in sub-tropical and tropical waters and is the most 

common finfish poisoning, with more than 400 

fish species implicated as potential vectors2

 (http://

www.whoi.edu/redtide/page.do?pid=14276). 

Saxitoxin puffer fish poisoning is a type of finfish 

poisoning posing an emerging threat in Florida23. 

In addition to the human health effects from 

eating contaminated seafood, acute human health 

impacts may occur following contact with water or 

breathing aerosolized toxin.

The effects of chronic or repeated, low-level 

HAB toxin exposure are also of concern. Cultural 

traditions, like harvesting marine mammals for 

subsistence or consuming more seafood, may place 

certain populations at increased risk for recurring 

exposure to toxins at low levels. The potential 

public health impacts of these exposures are 

unknown. 

The risk of human illness from algal toxin 

exposure can be dramatically reduced or 

prevented through harvesting closures and 

beach warnings, which are issued based on data 

provided through rigorous state monitoring 
12 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 2

Box 2.1. Human Poisonings in 2007 

Highlight Importance of Monitoring 

and Outreach Programs

In 2007, severe cases of human illness in Maine 

and Alaska occurred as a result of individuals 

harvesting shellfish from unmonitored locations. In 

Maine, four people were hospitalized within hours 

of eating saxitoxin-contaminated shellfish harvested 

from a barrel floating off the coast of Maine. The 

barrel was thought to have been transported from an 

area where the toxic alga, Alexandrium, was in high 

concentrations. In Alaska, one individual became ill 

after consuming butter clams recreationally-harvested 

from an unregulated area. Because of the difficulty 

and high cost of sampling the Alaska coastline, the 

Alaska Department of Environmental Conservation 

can only test recreational beaches on a random basis 

and discourages recreational harvesting by instructing 

that no noncommercial, recreational beaches are safe 

for clamming. These illnesses reiterate the dangers 

of harvesting shellfish from unmonitored locations and 

stress the importance of monitoring 

and outreach programs for reducing 

risks of human illness from algal 

toxin exposure. 

Saxitoxin contaminated 

mussels (right) harvested 

from a floating barrel (left) in 

the Gulf of Maine resulted 

in hospitalization of four 

individuals. 

Photos: Maine Department of 

Marine Resources

programs. Several human poisonings in 2007 

(Box 2.1) due to harvesting by individuals from 

unregulated locations highlight the necessity of 

these monitoring programs. Illnesses are likely 

underreported, especially in cases where symptoms 

are non-specific and potentially attributed to other 

causes. 

Ecosystem Impacts

Massive fish kills are perhaps the most 

commonly observed impact of HABs on wildlife, 

but HABs can detrimentally affect many aspects 

of marine ecosystems. Algal toxins have caused 

deaths of whales, sea lions, dolphins, manatees, 

sea turtles, birds, and wild and cultured fish and 

invertebrates24. An increasing number of marine 

mammal unusual mortality events (UMEs) are 

being linked to HAB toxins, which is suggested 

to be a reflection of the increasing occurrence of 

HABs in the United States25. 

The pathways by which toxins are transferred 

to higher trophic level animals are often unknown. 

Although filter-feeding fish provide one direct 

link26, other pathways are suspected—including 

inhalation of aerosolized toxin by marine mammals 

breathing at the surface in the midst of a bloom. 

Furthermore, recent manatee deaths in Florida 

have been ascribed to brevetoxin accumulation 

in layers on the outside of aquatic plants27. In 

addition, dungeness crabs on the U.S. west coast 

can accumulate domoic acid from razor clams on 

which they prey28. Sometimes a HAB toxin is 

found to be the cause of a mortality event, but there 

is no immediately obvious source of the toxin, 

suggesting that bloom impacts may be temporally 

or spatially separated from the causative bloom or 

that the pathways of exposure are unknown. 

Moreover, algal toxins can exacerbate the 

impacts of other stressors and indirectly lead to 

wildlife mortalities. Sick or dying animals are 

often the first indicators of a toxic bloom and may 

serve as sentinels for potential harmful effects 

in other species. In addition to causing acute 

mortality via toxin production, HABs can also 

release compounds or have defensive cell wall 

structures that impair normal functions of fish and 

invertebrates and lead to harm and death of these 

organisms.

Degraded habitat quality is another ecosystem 

impact of toxic and nontoxic HAB species. High 

biomass blooms are a common type of event that 

can cause hypoxia or anoxia (low or no dissolved 

oxygen), which suffocates fish and bottomdwelling organisms and can sometimes lead to 

hydrogen sulfide poisoning. High biomass blooms 

can also directly inhibit growth of beneficial 

vegetation by blocking sunlight penetration into the 

water column29. Macroalgal blooms also reduce 

sunlight penetration and can overgrow or displace 

seagrasses and corals30 as well as foul beaches. 

Finally, HAB-inflicted mortalities can degrade 

habitat quality indirectly through altered food webs 

or hypoxic events caused by the decay of dead 

animals.
Scientific Assessment of Marine Harmful Algal Blooms 13

The HAB Problem in U.S. Marine Waters

Box 2.2. HABs and HAB Impacts in the Northeastern United States

Blooms of the saxitoxin-producing alga, Alexandrium 

fundyense, are a recurrent problem in the Northeastern United 

States. Shellfish closures to protect humans from paralytic shellfish 

poisoning (caused by exposure to saxitoxin) have occurred every 

year for the past three decades with significant economic impacts 

to fishers and businesses in the region. In 2005 and 2006, A. 

fundyense blooms were the worst the region had experienced 

since 1972. Direct economic impacts on the shellfish industry from 

inshore shellfish closures in 2005 were estimated to be as high as 

$18 million in Massachusetts alone33. In addition, most molluscan 

shellfisheries on Georges Bank in the Gulf of Maine have been 

closed since 1989. Other parts of the ecosystem are affected by 

these blooms as well. For example, saxitoxins were found in fecal samples from endangered North 

Atlantic Right Whales and in their zooplankton food, leading to the hypothesis that algal toxin exposure 

via zooplankton may be a contributing factor to the population’s failure to recover34. Much has been 

learned about A. fundyense ecology and bloom dynamics over the last decade35 (see Chapter 3), which 

has been critical for improving management and lessening HAB impacts in the region. 

Harmful brown tides caused by Aureococcus anophagefferens, often called the “Long Island 

Brown Tide,” have occurred in estuaries along the East 

Coast since the mid 1980’s, resulting in significant 

ecosystem and socioeconomic impacts in the region. 

Brown tides devastated the Long Island scallop industry, 

with an estimated $3.8 million per year monetary loss (2006 

dollars)36, and caused a significant decline in eelgrass 

habitat. Blooms of A. anophagefferens have been shown 

to cause recruitment failure of other commercially important 

bivalves as well, such as mussels and hard clams. A. 

anophagefferens may also be a poor nutritional source 

for zooplankton, thus inhibiting their growth and survival 

during large blooms. A. anophagefferens brown tides 

seem to grow well in environments with high organic and 

low inorganic nutrients, so these blooms are not a direct 

response to increased nutrients, but rather may result from 

a change in the ratio of inorganic and organic nutrients37,38. 

Research has shown that mortality from grazing and viruses 

is also important.

Domoic acid-producing Pseudo-nitzschia spp. are also 

found in New England waters where managers now monitor 

shellfish for presence of the toxin. Other less-severe or lesspersistent marine HAB problems in the Northeast include 

macroalgal blooms and fish-killing raphidophyte blooms. 

Diarrhetic shellfish Poisoning (DSP) could also be a 

potential problem in the future because the species that produce the toxins associated with this illness 

occur in the Gulf of Maine39. In 1984, one shellfish sample from Narragansett Bay, Rhode Island, was 

found positive for DSP toxins at time when the Dinophysis acuminata, a known producer of DSP 

toxins, was relatively abundant40.

Long-term cycles are apparent in shellfish toxicity 

associated with Alexandrium. Following a major 

regional bloom in 1972, Massachusetts Bay had 

frequent outbreaks of toxicity for the next 20 years 

(shown here), presumably due to the introduction 

of resting cysts in the western Gulf of Maine and 

their persistence as a result of cyst deposition 

during subsequent blooms. Following a 10-year 

interval with no toxicity in the bay, another major 

bloom occurred in 2005. History would suggest 

that the region may have entered another high 

toxicity phase of the cycle, signaling a decade or 

more of frequent and intense toxicity.

Graphic: Don Anderson, WHOI
14 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 2

Box 2.3. HABs and HAB Impacts along the Mid- and South-Atlantic Coasts

As discussed in Box 2.2, harmful brown tides caused by Aureococcus 

anophagefferens occur in estuaries all along the East Coast, including 

Delaware, Maryland, and Virginia waters. Studies indicate that A. 

anophagefferens was present in Maryland and Virginia waters as early 

as 1993, but that there may be a trend of increasing frequency and 

magnitude of blooms in the region41. A reduction in growth of hard clams 

due to brown tide has been observed in Mid-Atlantic coastal bays42; other 

general impacts of east coast brown tides are discussed in more detail in 

Box 2.2. 

North Carolina was the first state to report fish kills associated with an 

outbreak of Pfiesteria spp.43. Since then, Pfiesteria has been implicated 

throughout the region and much has been learned about its ecology and 

toxicity44,45,46. Fish kills attributed to Karlodinium veneficum have also 

occurred annually since 1998 along the Atlantic Coast, and karlotoxins 

have been found in samples taken from Delaware, Maryland, North 

Carolina, South Carolina, Georgia, and Florida47. In Maryland, the Pfiesteria event in 1997 resulted 

in about $43 million (or $53 million in 2006 dollars) in lost seafood sales in just a four month period, 

primarily due to consumer fears32. 

Chattonella cf. verruculosa has been associated with fish kills and brevetoxins in Maryland 

and Delaware48. Other potentially toxic raphidophytes (Chattonella sp., Fibrocapsa sp. and 

Heterosigma sp.) have been identified in Mid-Atlantic waters, including retention ponds in South 

Carolina49 (see Box 2.6 for more about Heterosigma impacts). 

 In Maryland’s Chesapeake Bay and oastal bays, 

there has been a problem for years with high biomass 

HABs, comprising numerous algal species, due to nutrient 

over-enrichment in the region44. For example, in late 

summer of 2007, a putatively toxic, high-biomass bloom of 

Cochlodinium polykrikoides in the James River, Virginia, 

spread into the Chesapeake Bay and caused fish kills, beach 

closures, and public alarm. In addition, the Chesapeake Bay 

experiences blooms of Prorocentrum minimum annually, 

which have been associated with reduced growth of shellfish 

and seagrass declines within bloom areas50. These blooms 

can also lead to low dissolved oxygen, which can result in 

fish and shellfish kills. 

In 2002, researchers discovered that the Atlantic strain 

of Pyrodinium bahamense, found in Florida’s Indian River 

Lagoon and Banana River, produced saxitoxin and was associated with the first incidence of saxitoxin 

in puffer fish in the United States. Since 2002, 28 cases of illness associated with eating puffer fish 

from Indian River Lagoon, Florida have been reported (http://research.myfwc.com/features/view_

article.asp?id=18918), resulting in an indefinite ban on recreational fishing of all puffer fish species23.

Coral reefs in southeast Florida have been devastated by overgrowth of an invasive green 

macroalga, Codium isthmocladum, which has also been linked to increasing land-based nutrient 

pollution51 (also see Box 2.4 for more on macroalgal blooms in Florida). 

Blooms of Karenia spp. (see Box 2.4 for more on Karenia and its impacts) occur occasionally 

along the southeast Atlantic Coast52,53. Additionally, Pseudo-nitzschia spp. and domoic acid have 

been detected in North Carolina waters, and domoic acid-producing Pseudo-nitzschia spp. have been 

isolated from the Chesapeake Bay54.

Cochlodinium polykrikoides bloom in Chesapeake 

Bay tributary. 

Photo: Christy Everett, Chesapeake Bay 

Foundation
Scientific Assessment of Marine Harmful Algal Blooms 15

The HAB Problem in U.S. Marine Waters

Economic Impacts

HAB events impact a variety of economic 

sectors in a manner that can have serious and 

significant negative effects on local economies31. 

Human poisonings due to HABs can lead to lost 

wages and work days as well as costs associated 

with medical treatment. The impact of HABs 

is felt in various components of the commercial 

fishing industry from loss of product (e.g., direct 

fish mortalities, harvesting closures), higher 

processing costs, and decreased consumer demand. 

Even when parts of the commercial fishing 

industry are insulated from the biological effects 

of a HAB event, indirect or “halo” effects can 

result in losses due to public fear. For example, 

it is estimated that $43 million (which would be 

approximately $56 million in 2007 dollars) in 

seafood sales were lost in the state of Maryland as 

a result of halo effects following the 1997 Pfiesteria

bloom32. Other important economic considerations 

associated with HABs include lost revenue 

from tourism and recreation as well as expenses 

associated with monitoring and management. 

Hoagland and Scatasta22 estimated that the annual 

economic impact due to marine HAB events in 

the United States averages $82 million per year. 

Given that documentation is sparse on overall 

impacts from individual events, these estimates 

are likely conservative. Surplus losses (i.e., 

changes in economic value) and factors with 

uncertain monetary values (e.g., wild fish kills) 

were not considered. Estimates of lost revenue 

from individual events (Boxes 2.2-2.7) highlight 

that this annual average for the Nation may be too 

conservative. 

Sociocultural Impacts 

Social impacts encompass changes to “the ways 

in which people live, work, play, relate to one 

another, organize to meet their needs, and generally 

cope as members of a society”81. The public 

health, ecosystem, and economic impacts discussed 

above can all have sociocultural consequences. 

Direct sociocultural impacts of HABs, other than 

those to human health and the economy, have not 

been systematically documented but have been 

described in some cases. For example, along the 

Washington and Oregon coasts, tens of thousands 

of people visit to harvest razor clams recreationally, 

but due to high levels of the HAB toxin domoic 

acid, there have been a number of closures to the 

recreational fishery since 1991, including three 

year-long closures2

. These closures have not only 

resulted in economic losses but also in an erosion 

of community identity, community recreation, 

and the traditional way of living for native coastal 

cultures1 (Box 2.5). In Florida, aerosolized toxins 

from Karenia brevis blooms can cause respiratory 

distress and prevent susceptible individuals from 

visiting the beach or participating in nearby 

outdoor activities (Box 2.4). Prolonged harvesting 

closures or noxious HAB events can also lead local 

residents to mistrust seafood and water safety1. 

Furthermore, the HARRNESS report2

 recognized 

that there are many groups whose lifestyles can 

be affected indirectly, such as veterinarians when 

animals become ill or environmental advocates 

and community volunteers when natural resources 

are degraded. The need for better assessments 

of social impacts is highlighted in the HARRHD report1

 and in the Harmful Algal Bloom 

Management and Response: Assessment and Plan3. 

The industry vessel Misty Dawn collecting ocean quahogs 

for toxicity testing.

Photo: FDA
16 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 2

Box 2.4. HABs and HAB Impacts in the Gulf of Mexico

Karenia brevis, the Florida Red Tide and Texas Red Tide 

organism, is an alga that produces potent toxins that can cause 

human respiratory distress, toxic shellfish, animal mortality, 

and water discoloration. K. brevis was first identified in Florida 

in 1947, but anecdotal reports in the Gulf of Mexico date back 

to the 1530s. Blooms form in the Gulf of Mexico almost every 

year, most often off the west coast of Florida and generally 

beginning in the late summer and fall. They also occur, although 

less frequently, along the Texas and Mexican coasts55 and even 

less frequently off of Alabama, Mississippi, and Louisiana56. 

Blooms have recently been discovered to be a mixture of Karenia species, although K. brevis usually 

dominates57.

Several Karenia species, including K. brevis, produce brevetoxins, which can kill fish, birds, and 

marine mammals and are a threat to human health. 

Beachgoers and people working or living near the 

water can be exposed via sea spray aerosols to these 

neurotoxins, resulting in respiratory irritation in healthy 

people and potentially debilitating acute events in people 

with underlying respiratory illnesses such as asthma. The 

long-term consequences of recurrent exposure to these 

toxic aerosols are unknown. Furthermore, there have been 

dramatic impacts to the environment, including massive 

fish and invertebrate kills, sea bird die offs, and marine 

mammal unusual mortality events which have impacted 

endangered manatees as well as bottlenose dolphins. 

Steidinger et al.58 estimated economic impacts in Florida 

from K. brevis blooms to be at least $15-25 million per year 

(which would be $18-30 million per year in 2006 dollars). 

Further, economic impacts from a red tide in Texas in 

2000 were estimated to be at least $9.9 million (or $11.6 

million in 2006 dollars) in Galveston County alone due 

to commercial oyster fishery closures (to protect against 

neurotoxic shellfish poisoning), lost tourism, and costs of 

beach cleanup59.

Most cases of ciguatera fish poisoning (CFP) on the U.S. mainland are reported from Florida, but 

several recent cases of CFP have been associated with eating reef fish caught in the northwestern 

Gulf of Mexico, resulting in an advisory letter from FDA (http://www.fda.gov/bbs/topics/NEWS/2008/

NEW01790.html). In general, the soft bottom environment of northwestern Gulf of Mexico provides 

poor habitat for Gambierdiscus spp., some of which are known to produce ciguatoxin. G. toxicus, the 

dominant species of concern, has been found in the Flower Garden Banks National Marine Sanctuary 

and in the northwestern Gulf of Mexico associated with petroleum production platforms which provide 

hard substrate. It is not yet clear if the ciguatoxin in fish is coming from the local G. toxicus or if the 

fish transport the toxin in from some other place60. Ciguatera in U.S. territorial waters, including Puerto 

Rico and the U.S. Virgin Islands, account for the majority of public health costs associated with marine 

HABs31. 

Dead fish on Texas Coast caused by Karenia bloom. 

Photo: The Facts, Brazoria County, Texas.
Scientific Assessment of Marine Harmful Algal Blooms 17

The HAB Problem in U.S. Marine Waters

The Texas brown tide organism, Aureoumbra lagunensis, causes brown tides similar to 

Aureococcus anophagefferens (Boxes 2.2 and 2.3) but is unique to the Gulf of Mexico. A. lagunensis

was first documented in Laguna Madre, a hypersaline bay in Texas. It has since been found in Florida 

and Mexico. Texas brown tide resulted in the loss of over 2,000 acres of shoalgrass habitat in Laguna 

Madre, Texas due to long-term light limitation during a bloom that lasted from 1989-199729.

Species of Pseudo-nitzschia are present in coastal waters of the Gulf of Mexico, and isolates from 

the region have been shown to produce the neurotoxin, domoic acid. Domoic acid has been detected 

in plankton samples, but no human illnesses have been reported. Domoic acid has also been found 

at low levels in the urine and stomachs of dolphins during marine mammal mortality investigations in 

Florida, but the role of domoic acid in the mortalities in unclear (http://www.nmfs.noaa.gov/pr/pdfs/

health/ume_bottlenose_2004.pdf). There is evidence that Pseudo-nitzschia abundance in the Gulf has 

increased as a result of eutrophication61,62, which suggests a potential for increased risks in areas of the 

Gulf where nutrient inputs may be increasing. 

Macroalgal blooms, often comprising 

multiple species, have become a large problem 

in southwest Florida. In Lee County, Florida, 

large red drift algal blooms wash ashore, making 

beaches unsuitable for recreation. These blooms 

have been linked to land-based sources of 

nutrient inputs in the region63. Also see Box 2.3 

for information on macroalgal blooms on the east 

coast of Florida. 

Lyngbya, a filamentous, nitrogen-fixing 

cyanobacteria that can form large mats and 

overgrow coral reefs, is responsible for large 

nuisance blooms in some Florida estuaries and 

bays, including Tampa Bay, nearshore coral reef 

environments of the Florida Keys, and reefs off 

the southeastern coast of Florida. Some marine 

species of Lyngbya are a public health concern 

because they produce toxins that can cause 

dermal lesions64 and are tumor promoters65. 

Dinophysis acumita, which produces toxins that cause diarrhetic shellfish poisoning, bloomed 

along the Texas coast in March 2008 and resulted in shellfish harvesting closures to protect human 

health.

Karlodinium blooms were also associated 

with fish kills in Weeks Bay, Alabama in the 

summer of 2007 (see Box 2.3 for more about 

Karlodinium).

Violet Goby showing hemorrhaging characteristic of karlotoxin 

exposure. 

Photo: Lucie Novoveska, Dauphin Island Sea Lab

Red drift algae: Red drift algae on Sanibel Island, Florida, in 

January 2007. 

Photo: Mike Valiquette, PURRE Water Coalition
18 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 2

Box 2.5. HABs and HAB Impacts along the Pacific Coast 

Domoic acid-producing Pseudo-nitzschia blooms are a recurrent problem 

along the entire Pacific coast of the United States. In the Pacific Northwest, 

research indicates that the seasonal Juan de Fuca Eddy, a nutrient-rich, 

retentive physical feature off the Washington coast, serves as an incubator 

for growth of Pseudo-nitzschia and other algae (see Sections 3.2.3 and 3.4). 

Toxic amnesic shellfish poisoning (ASP) events along the Pacific Northwest 

coast depend on factors that control transport processes from the eddy to 

the shore66. Pseudo-nitzschia blooms have significant effects on commercial 

and recreational fisheries and local communities in Washington and Oregon. 

For example, the razor clam fishery in Washington is a significant source of 

revenue for tourism-dependent businesses, such as restaurants and motels, 

an important source of community identity, and the basis for subsistence of coastal native cultures. 

Periodic and sometimes prolonged closures of the recreational fishery have diminished the collective 

identity of surrounding communities and decreased opportunities for family and community recreatio1

 

Closures in 2002-03 resulted in an estimated $10-12 million in lost revenue67. 

In California, blooms of Pseudo-nitzschia are recurrent and have 

caused large numbers of seabird and marine mammal deaths annually 

since 1998. In fact, it was a sea lion unusual mortality event in 1998 

that brought about awareness of the threat of domoic acid to marine 

mammals in California68. Domoic acid exposure may lead to permanent 

brain damage, reproductive failure, and death in marine animals; 

commonly observed effects include seizures and head weaving68. 

Domoic acid can also have significant chronic effects, such as epilepsy 

and behavioral changes, due to repeated exposures at sub-lethal 

levels69. In 2007, domoic acid levels in water samples from southern 

California were reported as some of the highest ever recorded in natural 

samples70. 

Alexandrium catenella, which produces paralytic shellfish poisoning 

(PSP) toxins, is prevalent in Washington, Oregon, and California where 

seasonal harvesting closures are common to protect humans from 

PSP. For example, an annual quarantine on sport-harvested shellfish is 

issued for the entire coast of California, usually from May 1 to October 

31. Commercial harvesting undergoes stringent sampling to protect 

consumers from both PSP and ASP. 

Blooms of the fish-killing raphidophyte, Heterosigma akashiwo, have been documented in the 

Pacific Northwest annually since the 1960s71 with the first major bloom that killed commercial net pen 

fish in 198972. Wild fish kills are likely underreported because wild fish tend to sink when killed by 

Heterosigma. The mechanism by which Heterosigma kills fish is not well understood, but no persistent 

toxin has been characterized. Blooms of the raphidophyte, Chattonella, also cause fish kills in the 

region. Heterosigma has also formed high biomass, nuisance blooms in California73.

Macroalgal blooms are a problem in Washington’s coastal waters where they harm seagrasses, 

fish, and invertebrates due to hypoxia and potentially due to the production of bioactive compounds7,74. 

In California, Dinophysis could pose a potential threat in the future because abundance of 

Dinophysis has been correlated with low levels of diarrhetic shellflish poisoning toxins in mussel 

samples from Monterey Bay75.

Pseudo-nitzschia australis cells 

under light microscopy. This 

sample was collected off the Los 

Angeles coast during a highly toxic 

bloom in 2007.

Photo: Astrid Schnetzer, University 

of Southern California
Scientific Assessment of Marine Harmful Algal Blooms 19

The HAB Problem in U.S. Marine Waters

Box 2.6. HABs and HAB Impacts in Alaska

Alexandrium catenella is also a widespread 

problem in Alaska. There were 51 reported cases 

of paralytic shellfish poisoning (PSP) in humans 

in Alaska from 1995-2000 (http://www.pices.int/

publications/scientific_reports/Report23/HAB_US.pdf 

), and most of these cases occurred on Kodiak Island 

as a result of subsistence harvesting. More recently, 

in 2007, there was a case of PSP illness in Alaska 

associated with consumption of sport-harvested 

butter clams (http://www.dec.state.ak.us/psa/2007/

PSA_for_PSP.pdf). Because of PSP and the high cost involved in monitoring the entire Alaska 

coastline, bivalves in Alaska are an underutilized resource. 

There is a general perception that Pseudo-nitzschia spp. are causing similar problems in Alaska 

waters as in Washington, Oregon, and California. There have been incidents of amnesic shellfish 

poisoning toxins in Alaska76, but it is difficult to find data to assess the threat, possibly because most 

shellfishing is already closed in Alaska due to PSP. 

Overall, there is little information on impacts of biotoxins from Alexandrium and Pseudo-nitzschia to 

Native Alaskan populations who rely on subsistence foods such as seabird eggs and marine mammal 

tissues.

Box 2.7. HABs and HAB Impacts in Hawaii and the Pacific Territories

Ciguatera Fish Poisoning (CFP) is a problem in Hawaii, 

Guam, and other Pacific Island territories. From 1996 to 

2005, the Hawaii State Department of Health received reports 

of 250 separate incidents of CFP involving 470 individuals. 

Gambierdiscus toxicus is the primary known CFP toxin 

producer found in Hawaii, but other species of potential 

concern have also been isolated (see Section 3.2.1.6). The 

environmental factors leading to CFP outbreaks are not well 

understood, in large part due to the patchiness in time and 

space of the outbreaks. Prevention of exposure to CFP is 

also challenging because of this patchiness. 

Macroalgal blooms have been a recurring problem for the past two decades in Maui. Macroalgae 

overgrowth adversely affects corals and accumulates in odorous masses on some Maui beaches. 

These blooms are estimated to cause over $20 million a year in lost tourism revenues and decreased 

property values77,78. Evidence suggests that these blooms may be linked to anthropogenic nutrient 

inputs (see Section 3.2.6). 

Blooms of the marine cyanobacteria, Lyngbya majuscula, have also been a problem in Hawaii and 

Guam. L. majuscula was first implicated as the cause of acute contact dermatitis in Hawaii in 195979. 

In Guam, the marine cyanobacterial blooms have been linked to fish kills80.

'UAM

()

)NSULAR2EEFS

-ARIANAS

!MERICAN3AMOA

Scientific Assessment of Marine Harmful Algal Blooms 21

Major advances in understanding the 

causes and impacts of marine HABs 

have occurred in recent years, due in large part 

to Federal investments in marine HAB research. 

Research has been conducted as part of national 

research programs focused on HAB research and 

at the individual project level as a part of other 

research programs (Table 3.1). It is also important 

to recognize that state and local agencies have a 

major role in monitoring blooms and alerting the 

public to health threats posed by HABs. Some 

states either have active research programs or 

participate in Federally-funded extramural research 

programs (see Appendix I for state activities). 

Information on the state of research for 

this chapter was gathered via: 1) a request for 

information from Federal agencies involved in 

various aspects of HAB research and response, 2) 

a careful review of the HARRNESS report2

, and 

3) public information on the web. An overview 

of Federal program and agency focus areas for 

marine HAB research is given in Section 3.1. 

Programs focused solely on HABs are discussed 

in Section 3.1.1, and agencies conducting HAB 

research as part of other programs are discussed in 

Section 3.1.2. A more detailed program analysis 

is also given in Section 3.1 for the ECOHAB 

and Monitoring and Event Response for HABs 

(MERHAB) Programs, the two national extramural 

funding programs for HAB research authorized 

by HABHRCA in 1998 and 2004. Major research 

efforts and accomplishments are discussed by 

research topic in Section 3.2, with contributing 

agencies emphasized with blue font. Highlights of 

major advances and their management implications 

are provided in Boxes 3.1-3.6.

3.1. Program and Agency 

Research Focus Areas

3.1.1. Research Programs Focused on 

Marine HABs

Interagency ECOHAB Program

The ECOHAB Program, authorized by 

HABHRCA 1998 and 2004, is a multi-agency 

program comprising the National Oceanic and 

Chapter 3

Federal Research on Marine 

HABs in the United States

Figure 3.1. Marine HAB ECOHAB projects (blue) and the 

funding amounts (green) supported by the different agency 

partners in ECOHAB. Projects shown include the total 

supported (111 projects, $78 million) from fiscal years 1997 to 

2008.

Figure 3.2. Marine HAB ECOHAB targeted (blue) and regional 

(green) projects categorized by the revised HARRNESS2

research categories. Projects shown include the total 

supported from fiscal years 1997 to 2008. Projects can be 

counted in more than one research category.

0

10

20

30

40

50

60

70

80

Funding Amount

Number of Projects

NOAA

CSCOR EPA NSF NASA ONR NOAA

Sea Grant

Number of Projects or Funding Amount ($Million)

0

10

20

30

40

50

60

70

80

Regional

Targeted

Bloom Ecology

and Dynamics

Food Webs 

and Fisheries

Toxins and

Detection

 Methods

Public Health/

Socioeconomic

Studies

Prevention, 

Control,

and Mitigation

Number of Projects
22 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

Federal Programs Focused on HAB Research

Agency Program or Office Extramural Intramural

National Oceanic and Atmospheric 

Administration (NOAA) 

U.S. Environmental Protection Agency 

(EPA) 

National Science Foundation (NSF) 

National Aeronautics and Space 

Administration (NASA) 

Office of Naval Research (ONR)

Ecology and Oceanography of Harmful Algal Blooms 

(ECOHAB)

NOAA National Centers for Coastal Ocean Science (NCCOS) 

Monitoring and Event Response for Harmful Algal 

Blooms (MERHAB)

NOAA NCCOS Harmful Algal Bloom Event Response Program

NOAA NCCOS Marine Biotoxins Program

NOAA Northwest Fisheries Science Center (NWFSC) Harmful 

Algal Bloom Program

Federal Agencies Conducting HAB Research as Part of Other Programs

Agency Program or Office Extramural Intramural

Centers for Disease Control and 

Prevention (CDC)

National Center for Environmental Health (NCEH)

EPA Office of Research and Development (ORD)

Gulf of Mexico Program

Food and Drug Administration (FDA) Center for Food Safety and Applied Nutrition

Marine Mammal Commission (MMC) --

NASA Applied Sciences Program

National Institutes of Health (NIH)/ 

National Institute of Environmental 

Health Sciences (NIEHS)

NSF

Centers for Oceans and Human Health (COHH)

NIH National Institute of General Medical Sciences (NIGMS)

NIEHS

NOAA Oceans and Human Health Initiative

NOAA Various National Ocean Service Programs

NOAA Various National Marine Fisheries Service (NMFS) 

Programs 

NOAA Various Office of Oceanic and Atmospheric Research 

(OAR) Programs

NSF Biological Oceanography Program (lead)

Chemical Oceanography Program

Physical Oceanography Program

Ocean Technology and Interdisciplinary Coordination 

Program

U.S. Army Medical Research Institute of 

Infectious Diseases (USAMRIID)

--

U.S. Department of Agriculture (USDA) Agricultural Research Service

U.S. Geological Survey (USGS) Various programs contribute to marine HAB research

U.S. Fish and Wildlife Service (USFWS) Various programs contribute to marine HAB research

Table 3.1 Federal agencies involved in marine HAB research and response. 
Scientific Assessment of Marine Harmful Algal Blooms 23

Research on Marine HABs in the United States

Calendar 

Year Regional ECOHAB Project Agency Funding 

Partners

Research Partners

1996 Brown tide research initiative

NOAA CSCOR

NY Sea Grant

NSF

Academic or Private Institutions: Bigelow Laboratory 

of Ocean Sciences (BLOS), Woods Hole Oceanographic 

Institution (WHOI), University of Rhode Island (URI), State 

University of New York (SUNY) Stony Brook University, 

University of Delaware (UDel), University of Maryland 

(UMD), Old Dominion University (ODU)

Federal Government: Brookhaven National Laboratory, 

NOAA 

1997

ECOHAB Gulf of Maine: Ecology and 

oceanography of toxic Alexandrium

blooms in the Gulf of Maine

NOAA CSCOR

NSF

Academic or Private Institutions: WHOI, BLOS, 

University of New Hampshire, University of Maine (UMaine)

Federal Government: NOAA, USGS

1997

ECOHAB Florida: Ecology and 

oceanography of harmful algal 

blooms (Gulf of Mexico)*

*This project was focused on Karenia

NOAA CSCOR

EPA

Academic or Private Institutions: University of South 

Florida (USF), Mote Marine Laboratory, University of 

Southern Mississippi, North Carolina State University 

(NCSU), Rutgers University

Federal Government: EPA, USDA, NOAA

1998

Molecular approaches to Pfiesteriacomplex dinoflagellates in 

Chesapeake Bay

NOAA CSCOR Academic or Private Institutions: University of Maryland 

Biotechnology Institute

1998 Impacts of Pfiesteria piscicida on 

shellfish and the role of shellfish as 

possible toxin vectors

NOAA CSCOR

Academic or Private Institutions: NCSU, University of 

Connecticut 

Federal Government: NOAA

1998

Toward a mechanistic understanding 

of outbreaks of Pfiesteria and related 

dinoflagellates

NOAA CSCOR Academic or Private Institutions: NCSU, UDel, UMD

1999 Causes and prevention of Long 

Island brown tides NOAA CSCOR 

Academic or Private Institutions: University of Southern 

California, SUNY Stony Brook, BLOS, UMD

Federal Government: NY Sea Grant

2002

Ecology and oceanography of toxic 

Pseudo-nitzschia in the Pacific 

Northwest coastal ocean

NOAA CSCOR

NSF

Academic or Private Institutions: University of 

Washington, University of Western Ontario, San Francisco 

State University, UMaine

Federal Government: NOAA

Canadian Government: Fisheries and Oceans Canada

2002

Nuisance macroalgal blooms in 

coastal Maui: assessment and 

integration of physical factors and 

biological processes

NOAA CSCOR

Academic or Private Institutions: University of Hawaii

Federal Government: USGS

2006 Karenia nutrient dynamics in the 

eastern Gulf of Mexico NOAA CSCOR

Academic or Private Institutions: Virginia Institute of 

Marine Science, Mote Marine Laboratory, U. Miami, ODU, 

UMD, USF

State or Local Government: Florida Fish and Wildlife 

Research Institute

2006

GOMTOX: Dynamics of Alexandrium

fundyense distributions in the Gulf 

of Maine: An observational and 

modeling study of nearshore and 

offshore shellfish toxicity, vertical 

toxin flux, and bloom dynamics in a 

complex shelf sea

NOAA CSCOR

Academic or Private Institutions: WHOI, University 

of Massachusetts, UMaine, NCSU, North Atlantic Clam 

Association

State or Local Government: Maine Department of Marine 

Resources, Massachusetts Division of Marine Fisheries

Federal Government: FDA, NOAA

Canadian Government: Fisheries and Oceans Canada, 

Canadian National Research Council

Table 3.2. Regional ECOHAB projects on marine HABs and the grant and research partners 

involved.
24 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

Atmospheric Administration (NOAA) Center 

for Sponsored Coastal Ocean Research (CSCOR 

- lead), NOAA Office of Protected Resources, 

NOAA Sea Grant, U.S. Environmental Protection 

Agency (EPA), National Science Foundation 

(NSF), National Aeronautics and Space 

Administration (NASA), and the U.S. Department 

of Defense’s Office of Naval Research (ONR). 

Through extramural, competitive, peer-reviewed 

research, ECOHAB funds research to better 

understand the causes and dynamics of HABs; 

produce new detection methods for HABs and 

their toxins; develop predictions of HAB growth, 

transport, and toxicity; and understand and predict 

impacts on ecosystems and humans. Research 

results are used to guide management of coastal 

resources so that HAB impacts can be prevented or 

reduced. 

The ECOHAB program as a whole has 

supported 111 projects since it began in 1996. 

NOAA has provided the largest amount of funding 

for ECOHAB and supported the largest number 

of projects, followed by EPA and NSF (Figure 

3.1). The majority of ECOHAB projects have 

advanced knowledge in the category of ‘bloom 

ecology and dynamics’ (Figure 3.2) and have led 

to improved management in the process. Karenia

and Alexandrium, HAB taxa that are recurrent 

problems on the Gulf Coast and in New England/

on the West Coast, respectively, have been the most 

studied (Figure 3.3). 

Eleven projects have been regional studies 

(Table 3.2), which are longer-term studies 

usually focused on a particular HAB problem 

to improve understanding of multiple aspects of 

bloom dynamics in a particular region, ultimately 

leading to better monitoring and prediction. 

Accomplishments of the smaller, “targeted” 

projects have included development of new 

detection methodologies now being used in state 

monitoring programs, increased understanding of 

causes including the role of human activities in 

stimulating HABs, discovery of potential control 

methods, and improved understanding of trophic 

transfer of toxins through the food web. 

NOAA MERHAB Program 

Through extramural, competitive, peer-reviewed 

research, the MERHAB program in NOAA/

National Centers for Coastal Ocean Science 

(NCCOS)/CSCOR aims to help build sustainable 

regional partnerships that provide managers with 

information in time for critical decisions needed to 

mitigate HAB impacts. The MERHAB Program 

supports initiatives that build on basic research 

gained from programs like ECOHAB and advance 

HAB-related technologies, such as improvements 

in monitoring capabilities. The MERHAB 

Program has funded 25 projects on marine HABs 

since it began in 2000, with a total funding of $22 

million from fiscal years 2001-2008. All of these 

projects have been directly applicable to improving 

HAB prevention, control, and mitigation, and some 

0

5

10

15

20

25

Bloom Ecology

and Dynamics

Food Webs 

and Fisheries

Number of Projects

Toxins and 

Detection

 Methods

Public Health/

Socioeconomic

Studies

Prevention, 

Control, and 

Mitigation

Figure 3.3. Marine HAB ECOHAB projects, targeted in blue 

and regional in green, by HAB organism. Projects shown 

include the total supported from fiscal years 1997 to 2008. 

Projects can be counted in more than one HAB group.

Figure 3.4. Marine HAB MERHAB projects categorized by the 

revised HARRNESS research categories2

. Projects shown include 

those supported beginning fiscal year 2001 through fiscal year 

2008.

0

5

10

15

20

25

30

Regional

Targeted

Karenia

Alexandrium

Pesteria

Pseudo-nitzschia

Karlodinium

Brown Tide

Macroalgae

Raphidophytes

Marine

Cyanobacteria

Other

Number of Projects
Scientific Assessment of Marine Harmful Algal Blooms 25

Research on Marine HABs in the United States

Calendar 

Year Regional MERHAB Project Research Partners

2001 Olympic region harmful algal bloom 

(ORHAB) project

Academic or Private Institutions: University of Washington, 

Battelle, Pacific Shellfish Institute

State or Local Government: Washington Department of Fish 

and Wildlife, Washington Department of Health

Federal Government: NOAA 

Tribal: Quinalt Indian Nation

2001

Intensive monitoring for Pfiesteria

and Pfiesteria-like organisms in the 

St. John’s River

State or Local Government: Florida Fish and Wildlife 

Research Institute (FWRI)

Federal Government: NOAA

2001 Intensive monitoring for Pfiesteria

and HAB-related events in Maryland

Academic or Private Institutions: University of Maryland 

(UMD)

State or Local Government: Maryland Department of Natural 

Resources (MD DNR)

2001

Fish health, habitat quality, and 

Pfiesteria surveillance in support 

of Maryland’s response to toxic 

outbreaks of Pfiesteria and similar 

dinoflagellates

State or Local Government: MD DNR

2002 Eastern Gulf of Mexico sentinel 

program

Academic or Private Institutions: University of South Florida, 

Mote Marine Laboratory

State or Local Government: Florida FWRI

2003

California program for regional 

enhanced monitoring of phyco-toxins 

(Cal-PreEmpt)

Academic or Private Institutions: University of California 

Santa Cruz (UCSC)

State or Local Government: California Department of Health 

Services (CA DHS)

2003

Development and implementation of 

an operational harmful algal bloom 

prediction system for Chesapeake 

Bay

Academic or Private Institutions: University of Evansville, 

UMD, Chesapeake Research Consortium

State or Local Government: MD DNR

Federal Government: NOAA

2005

RAPDALERT: Rapid analysis of 

Pseudo-Nitzchia and domoic acid, 

Locating events in near real time

Academic or Private Institutions: University of Southern 

California, University of California Los Angeles, UCSC, UMD, 

Old Dominion University, Southern California Water Research 

Project

State or Local Government: CA DHS, Los Angeles Regional 

Water Quality Control Board, MD DNR, Delaware Department 

of Natural Resources and Environmental Control

Federal Government: NOAA (MD Sea Grant)

2007 Integrated HAB monitoring and event 

response for coastal Oregon

Academic or Private Institutions: Oregon State University, 

University of Oregon

State or Local Government: Oregon Department of Fish and 

Wildlife

Federal Government: NOAA

Table 3.3. NOAA MERHAB regional projects for marine HABs.

have also made advances in the topics of ‘bloom 

ecology and dynamics’ and ‘toxins and detection 

methods’ (Figure 3.4). Nine projects on marine 

HABs have been regional studies (Table 3.3), 

which are longer-term studies aimed at enhancing 

state monitoring and response capabilities. These 

have included projects in Washington State, 

Oregon, the Chesapeake Bay, the Eastern Gulf 

of Mexico, and along the central and southern 

California coast. Additional, targeted projects are 
26 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

testing or refining promising new technologies 

for routine monitoring use by coastal managers. 

Because MERHAB projects are primarily focused 

on improving mitigation, project accomplishments 

are also discussed in detail in the report, Harmful 

Algal Bloom Management and Response: 

Assessment and Plan (Box 1.3). 

NOAA Event Response Program

The NOAA Event Response Program 

administered by NCCOS/CSCOR provides 

immediate assistance, either as funding or 

expertise, for managing events and for advancing 

the understanding of HABs as they occur. The 

program focuses on rapid response whereas 

MERHAB focuses on building partnerships and 

capabilities for improved long-term response. The 

Event Response Program may provide a modest 

amount of funding to assist states or independent 

researchers to collect data, conduct training, and 

enhance or expand monitoring in coastal and 

estuarine waters, upper reaches of estuaries, and 

the Great Lakes. Since both the ECOHAB and 

MERHAB extramural funding programs are 

administered by the same office, anyone who 

requests financial assistance through the Event 

Response Program is also directed to others that 

might collaborate or assist in response efforts. 

Some examples of the types of activities funded 

over the past four years include: 1) investigation 

of linkages between animal mortalities and HAB 

events; 2) taxonomic training; 3) investigation of 

potential emerging HAB problems; 4) intensified 

sampling to protect human health; and 5) 

coordination of sampling and information flow. 

http://www.cop.noaa.gov/stressors/extremeevents/

hab/current/fact-ev_resp.html

NOAA Marine Biotoxins Program

The NOAA Marine Biotoxins Program is an 

intramural research program administered by 

NCCOS at its Center for Coastal Environmental 

Health and Biomolecular Research (CCEHBR) 

and the Hollings Marine Laboratory. The program 

targets its research and services at issues related 

to algal toxins and the organisms responsible for 

their production. Biotoxin research has focused 

on transfer of toxins through food webs, impacts 

of toxins, biomonitoring of toxins, and remote 

detection of toxins. Other HAB research has 

focused on taxonomy and distribution of HAB 

species, developing molecular tools to identify 

factors regulating HAB growth and toxicity, 

and potential avenues for bloom control. The 

Analytical Response Team, a component of the 

Marine Biotoxins Program, provides rapid and 

accurate identification and quantification of 

marine algal toxins in suspected HABs, marine 

animal mortality events, and human poisonings. 

The Phytoplankton Monitoring Network, also a 

component of this program, is an outreach program 

to unite volunteers and scientists in monitoring 

the marine phytoplankton community and HABs. 

http://www.chbr.noaa.gov/default.aspx?category=m

b&pageName=biotoxin

NOAA Harmful Algal Bloom Program

The NOAA Harmful Algal Bloom Program 

is an intramural research program coordinated 

by NOAA’s National Marine Fisheries Service 

(NMFS)/Northwest Fisheries Science Center 

(NWFSC) to gain a better understanding of the 

production, presence, and persistence of algal 

toxins in marine foodwebs and fisheries. This 

research program has focused on HABs and 

marine biotoxins in the Eastern Pacific, an area that 

stretches geographically from the Arctic Circle to 

south of the equator. The research has also focused 

on factors controlling algal growth, methods for 

the detection of marine biotoxins, toxicology, and 

analysis of past and current HAB events. In order 

to meet the challenge of monitoring thousands of 

miles of coastline, the NWFSC HAB Program has 

developed working partnerships with coastal tribes, 

universities, the shellfish industry, state agencies, 

and private companies, as well as other NOAA 

centers, and the OHH programs (see Section 3.1.2). 

http://www.nwfsc.noaa.gov/hab

3.1.2. Marine HAB Research as part of 

Other Federal Research Programs 

OHH Programs

The NSF-National Institute of Environmental 

Health Sciences (NIEHS) Centers for Oceans 

and Human Health (COHH) represent a joint 
Scientific Assessment of Marine Harmful Algal Blooms 27

Research on Marine HABs in the United States

Federal agency initiative with the overarching 

vision to promote state-of-the-art, interdisciplinary 

research that unites the oceanographic and medical 

communities, allows for cross-fertilization of 

ideas and technologies, and provides a more 

comprehensive insight of the potential risks and 

benefits to human health generated by the oceans. 

The four NSF-NIEHS Centers are located at 

the Woods Hole Oceanographic Institution, the 

University of Miami, the University of Washington, 

and the University of Hawaii. These competitively 

awarded Centers collaborate with a number of 

non-affiliated academic institutions and have 

formed working partnerships with several Federal 

agencies and state and local heath departments, 

grassroots groups, and others. Also, each of 

the NSF-NIEHS Centers has collaborated with 

international academic institutions. Research 

projects conducted by these Centers are often 

carried out in collaboration with other agency/

institutional partners, and there is considerable 

joint planning with NOAA’s Oceans and Human 

Health Initiative (OHHI) Centers. The COHH 

coordinate with the interagency ECOHAB Program 

and NOAA’s MERHAB Program through joint 

participation in the IWG-4H. A substantial amount 

of HAB-focused research is conducted within the 

NSF-NIEHS Centers. All four centers have one or 

more research projects focused on various aspects 

of the ecology and oceanography of HABs. NSF 

has provided approximately $9 million and NIEHS 

approximately $7.5 million for marine HAB 

research through the COHH since 2004. http://

www.whoi.edu/science/cohh/index.htm

NOAA’s OHHI is founded on interdisciplinary 

partnerships among marine and biomedical 

scientists, public health decisionmakers and natural 

resource managers, and works within NOAA and 

across agencies and academia. NOAA’s OHHI 

includes three competitively awarded internal 

Centers of Excellence for Oceans and Human 

Health located at NWFSC in Seattle, Washington, 

the Great Lakes Environmental Research 

Laboratory (GLERL) in Ann Arbor, Michigan, 

and the Hollings Marine Laboratory in Charleston, 

South Carolina. Each includes non-Federal partner 

institutions as integral elements of the Center. In 

addition, NOAA OHHI supports a robust external 

grant program, with some active grants on HABrelated issues, as well as distinguished scholars and 

traineeships in oceans and human health. 

NOAA OHHI has ongoing HAB-related research 

in all three OHH Centers and in five of 26 external 

grants. Research conducted at GLERL focuses on 

freshwater instead of marine HABs and is covered 

in the Scientific Assessment of Freshwater Harmful 

Algal Blooms8 (Box 1.1). NOAA OHHI research 

is focused on developing tools and technologies 

to understand, detect, track, and extract marine 

biotoxins that pose harmful health effects either 

through consumption of contaminated seafood or 

via inhalation of toxins during bloom events. For 

fiscal years 2003-2006, approximately $2.7 million 

was allocated within the external grant program 

towards marine and freshwater HAB activities and 

$3 million for center research activities. NOAA 

OHHI interacts closely with the NSF-NIEHS 

COHH, ECOHAB, MERHAB, and other agencies 

conducting OHH-related research. http://www.eol.

ucar.edu/projects/ohhi/

Centers for Disease Control and 

Prevention 

The Centers for Disease Control and Prevention 

(CDC), in general, supports research that aims to 

protect the health and safety of Americans and 

applies research and findings to improve people’s 

daily lives and responds to health emergencies. 

In response to the Pfiesteria outbreak in 1997, 

CDC’s National Center for Environmental Health 

(NCEH) established surveillance programs to 

capture reports of Pfiesteria-related human health 

effects, initiated University-based studies in three 

states to define health effects, supported six statewide monitoring programs, funded research on 

the natural history and environmental precursors 

of Pfiesteria blooms and, over the past seven 

years, established a comprehensive public health 

program to assess human health effects of all 

HABs. A majority of the current public health 

surveillance efforts grew from CDC’s initial 

response to the Pfiesteria-related outbreak in the 

late 1990s in North Carolina and Maryland. NCEH 

developed the Harmful Algal Bloom-related 
28 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

Illness Surveillance System (HABISS) to collect 

data on HAB events and their effects on human 

and animal health. NCEH is also supporting 

numerous state activities to monitor and assess 

public health impacts of HABs. CDC has given 

funding to states through the Pfiesteria-related 

Illness Surveillance and Prevention Program and, 

more recently, through the Cooperative Agreement 

to Enhance Surveillance of Risk Factors and Health 

Effects Related to Harmful Algal Blooms. CDC has 

provided approximately $26 million in extramural 

funds since 2000 to support HAB research.

 EPA 

The U.S. EPA is an independent Federal agency 

with a mission to protect human health and the 

natural environment. EPA works with state and 

local agencies, as well as volunteer and other 

citizens groups, to monitor air and water quality 

and reduce human exposure to contaminants in 

the air, land, and water, including marine waters. 

EPA has funded a significant amount of extramural 

research as an interagency partner in ECOHAB 

(see Section 3.1.1). In addition, other extramural 

regional grants have been awarded to conduct 

research on surveillance, detection, mitigation, 

restoration, and public education regarding HABs. 

EPA has also funded projects related to HABs 

through its National Estuary Program. Some 

of these partnerships with local, state, and other 

Federal organizations list HABs as a priority 

management issue and have funded research on 

topics ranging from the relative importance of 

natural versus anthropogenic nutrient sources to 

predictive models of phytoplankton abundance 

and toxin levels in mussels. The EPA has also 

performed research on marine HABs in some of its 

laboratories. 

Food and Drug Administration 

The U.S. Food and Drug Administration (FDA) 

conducts HAB-related research in support of the 

agency’s regulatory mission of protecting public 

health by assuring the safety, efficacy, and security 

of the Nation’s food supply. FDA’s knowledge and 

understanding of seafood hazards, risk assessments, 

and risk management related to HAB toxins are 

guided by scientific research provided primarily 

by the agency’s Office of Regulatory Science and 

Office of Food Safety/Division of Seafood Science 

and Technology. FDA’s objectives related to HABs 

include: 1) identify and characterize existing, 

emerging and potential health hazards in seafood, 

2) determine exposure thresholds and consumer 

health effects, and recommend guidance levels for 

health hazards in seafood, 3) develop, optimize, 

and validate surveillance/monitoring methods for 

detection of health hazards in seafood, 4) promote 

surveillance/monitoring method standardization 

and train Federal and state public health personnel 

in their applications and use, 5) evaluate strategies 

and technologies for mitigation of health hazards 

in seafood, and 6) respond to regional, national, 

and international seafood disease outbreaks and 

emergency/threat situations. In conjunction with 

Federal, state, academic, and public partners, the 

FDA is responsible for providing the scientific 

basis for agency policy, regulation, and compliance 

programs which promote and protect the public’s 

health by ensuring that the Nation’s food supply 

is safe, wholesome, sanitary, and secure. This not 

only means being prepared to deal with seafood 

toxin hazards in U.S. waters, but also potential 

biotoxin threats in seafood imported to the United 

States from other countries.

Marine Mammal Commission

The Marine Mammal Commission (MMC) was 

established under the Marine Mammal Protection 

Act to provide independent oversight of marine 

mammal conservation policies and programs being 

carried out by Federal agencies. The MMC is 

charged with developing, reviewing, and making 

recommendations on domestic and international 

actions and policies of all Federal agencies 

with respect to marine mammal protection and 

conservation and with carrying out a research 

program. With respect to HABs, the MMC focuses 

primarily on the impacts of HABs on marine 

mammals and works with other Federal agencies 

to promote prevention, control, and mitigation of 

HABs. The MMC carries out a small research 

program and, has occasionally funded research 

projects relevant to marine HABs. However, the 

MMC, with its small research budget, has not 

established a research program focusing solely 
Scientific Assessment of Marine Harmful Algal Blooms 29

Research on Marine HABs in the United States

on HAB issues. Since 2000, the MMC has 

funded HAB projects focusing on Florida red tide 

events and their impact on manatees, including 

improvement and analysis of the manatee mortality 

database and the development of liver fatty acid 

markers to identify manatees killed by red tide 

toxins.

NOAA 

Labs and Centers. In addition to CCEHBRHML (Section 3.1.3), NWFSC (Section 3.1.4), 

and the OHHI Centers of Excellence (Section 

3.2), other NOAA centers and labs with projects 

focused on HABs include NCCOS’s Center for 

Coastal Fisheries and Habitat Research (CCFHR) 

and Center for Coastal Monitoring and Assessment 

(CCMA), NMFS’s Northeast Fisheries Science 

Center (NEFSC), and the Office of Oceanic 

and Atmospheric Research (OAR)/Atlantic 

Oceanographic and Meteorological Laboratory 

(AOML). CCFHR research has focused on bloom 

ecology, methods of toxin detection, and food 

web interactions. CCMA, in collaboration with 

state agencies, NOAA’s Coastal Services Center 

(CSC), CO-OPS, and the National Environmental 

Satellite, Data, and Information Service (NESDIS), 

develops forecasting products for HABs. NEFSC 

is involved in HAB research primarily focused on 

the effects of HABs on fishery and aquaculture 

resource species, especially bivalve molluscs. 

Additionally, the NMFS Marine Mammal Health 

and Stranding Response Program provides 

marine mammal response and health assessments, 

including response to HAB events. Other NOAA 

programs that conduct research relevant to marine 

HABs as part of their larger mission include the 

National Marine Sanctuaries and the National 

Estuarine Research Reserve System (NERRS).

Extramural funding. In addition to ECOHAB 

(Sectoin 3.1.1), MERHAB (Section 3.1.2), and 

OHHI (Section 3.2), NOAA funds HAB-related 

research through the OAR National Sea Grant 

College Program, the Cooperative Institute for 

Coastal and Estuarine Environmental Technology 

(CICEET), and the NMFS Marine Mammal 

Health and Stranding Response Program. There 

is a Sea Grant program in every coastal state, and 

Sea Grant has funded an average of $700,000 

per year in HAB-related research and outreach 

projects through both the national and individual 

state programs. CICEET is a partnership between 

NOAA and the University of New Hampshire 

and it focuses on developing and applying new 

environmental technologies and techniques, 

including those for HAB detection. CICEET has 

provided approximately $1.5 million for HAB 

research since 2000. The projects funded through 

CICEET are cooperative efforts that involve 

researchers in NOAA labs, managers of NERRS 

sites, academia, and industry. The NMFS Marine 

Mammal Health and Stranding Response Program 

supports research related to marine mammal UMEs 

and for marine animal health assessments through 

the John H. Prescott Grant Program, the Marine 

Mammal Unusual Mortality Event Fund, and a 

program for research on animal health assessments. 

Grants have included support for biotoxin research, 

emergency response, and other HAB-related 

research relevant to detection or animal impacts. 

NSF 

Programs that fund research on HABs at NSF 

are largely within the Directorate of Geosciences, 

Division of Oceanography, although the 

Directorate of Biological Sciences, Division of 

Environmental Biology, and the Office of Polar 

Programs supported some work as well. The 

Biological Oceanography Program is the lead 

program for this activity, but support may also be 

provided by the Chemical Oceanography Program, 

Physical Oceanography Program, and Ocean 

Technology and Interdisciplinary Coordination 

Program. In addition, ship support for HABrelated research may be provided through the 

University-National Oceanographic Laboratory 

System. NSF-funded HAB research focuses on 

the basic science questions underlying the ecology 

and oceanography of HABs. Since 1994, NSF 

has supported a diverse portfolio of HAB studies 

submitted as unsolicited proposals to the Biological 

Oceanography Program, and several proposals 

have been supported with NSF participation in the 

Interagency ECOHAB Program (see Section 3.1.1). 

NSF has also supported international cooperative 

projects as part of a focused European 
30 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

Commission-NSF Initiative on HABs. Finally, the 

Ocean Technology Program has funded equipment 

development specifically targeted at HAB 

applications. NSF has provided approximately 

$11.3 million to support HAB research since 1994 

through these programs, which is in addition to 

funding provided by NSF through ECOHAB 

(Section 3.1.1, Table 3.1) and COHH (see above). 

Total funding through all these programs has been 

approximately $29 million since 1994. 

National Institutes of Health 

In addition to the COHH, the National 

Institutes of Health’s (NIH) NIEHS is involved 

in HAB-related work through projects at several 

universities as well as a collaborative research 

program between Florida International University 

and the University of Miami in the Advance 

Cooperation in Environmental Health Research 

Program. These NIEHS-supported projects 

account for approximately $4 million annually 

and include research on Alexandrium genomics, 

studies of toxin effects on humans, and research on 

toxin synthesis and therapeutics. NIH’s National 

Institute of General Medical Sciences (NIGMS) 

also supports HAB-related research as part of its 

larger mission.

NASA 

NASA is an interagency partner in ECOHAB 

(see Section 3.1.1) and also supports, through 

its Applied Sciences Program, a cooperative 

agreement between the Naval Research Laboratory 

and Applied Coherent Technologies, Inc. to apply 

NASA earth science observations in support of 

Gulf of Mexico coastal management activities, 

including HABs. Research has focused on optical 

physiology of HAB organisms and understanding 

remote sensing variables such as backscatter 

and absorption. In addition to funding through 

ECOHAB (Table 3.1), NASA has provided 

approximately $3 million for marine HAB research 

through the Applied Sciences Program since 2000.

United States Geological Survey

The U.S. Geological Survey (USGS) provides 

scientific information on the characteristics 

and quality of the Nation’s earth and living 

resources. A number of USGS programs 

focus on ocean-related issues. These include 

activities such as: (1) characterizing riverine and 

groundwater contributions of flow, sediment, 

and chemical constituents to coastal systems; 

(2) quantifying status and trends of critical 

biological resources and species at risk, (3) 

providing information on changes in the coastal 

land surface, connections between people and 

those changes, and the potential consequences of 

those changes; (4) documenting declines in coral 

reef, coastal, wetland, and marine habitats and 

coastal ecosystems; (5) investigating impacts of 

contaminants, invasive species, pollution, human 

use and development, climate change, and other 

human and natural stressors on marine ecosystems; 

and (6) providing forecasts of water quality 

conditions in major estuaries. 

Examples of USGS research that is directly 

relevant to marine HABs are: monitoring delivery 

of streamflow, sediment, nutrients, and pesticides 

from major rivers to coastal estuaries and bays; 

investigating contributions of groundwater and the 

associated nutrients to nearshore environments, 

including potential implications for HABs; 

collaborating with other agencies to investigate 

mortality events potentially associated with 

marine HABs—particularly those that involve 

threatened or endangered species; development 

and application of methods to measure marine 

algal toxins in coastal ecosystems; development 

of methods for forecasting HABs in coastal 

ecosystems; and long-term studies to characterize 

estuarine conditions and dynamics including 

factors affecting HABs in selected major estuaries 

in the United States.

Other Agencies

Other agencies, such as the U.S. Army 

Medical Research Institute of Infectious Diseases 

(USAMRIID), U.S. Department of Agriculture 

(USDA), and U.S. Fish and Wildlife Service 

(USFWS), conduct some marine HAB-related 

research as part of their larger missions. 
Scientific Assessment of Marine Harmful Algal Blooms 31

Research on Marine HABs in the United States

Box 3.1 Highlights of Major Advances in the Northeastern United States 

Alexandrium spp. (New England Red Tide)

• A coupled biological-physical model was 

developed that provides early warnings. 

The model has also been used to evaluate 

causes, and the knowledge gained has 

explained patterns and variations in 

toxicity and how regional populations of 

Alexandrium persist year after year. 

• Weekly predictions of Alexandrium

fundyense blooms in coastal Gulf of 

Maine were issued in demonstration mode 

in 2005, 2006, 2007, and 2008. These 

predictions helped shellfish mangers to 

focus sampling and design more precise 

and selective closures, minimizing 

economic impacts on local communities 

while safeguarding human health. 

• Successful multi-agency event response 

assisted states with monitoring and early 

warnings during large Alexandrium blooms 

in 2005 and 2006. 

• A list server was established to improve 

communications among state, Federal, and 

academic researchers in New England. 

• New maps of Alexandrium resting cysts, 

which are the seeds for future blooms, improved predictions.

• Saxitoxin resistance has been shown in some commercial bivalves due to a genetic mutation. 

Understanding shellfish toxin resistance, which allows more rapid toxin accumulation, will improve 

prediction and management of shellfish toxicity.

• An economic assessment of the 2005 Alexandrium bloom estimated direct impacts to commercial 

shellfishers and growers to be as high as $18 million in Massachusetts and at least $2.4 million in 

Maine.

Aureococcus anophagefferens (Brown Tide) 

• The geographic range and impacts of brown tide along the East Coast of the United States is 

better understood. Impacts include reduction in seagrass habitat and negative impacts on some 

commercially or ecologically important shellfish. This knowledge aids assessment of management 

needs and development of management strategies. 

• Organic nutrient availability and reduced mortality from grazing were both shown to be important for 

brown tide bloom development in various locations on the East Coast. These findings are not the 

typical ‘eutrophication scenario’. The knowledge highlights the importance of nutrient ‘quality’ and 

affects management strategies for prevention.

• First genome sequence of a HAB species was completed for Aureococcus anophagefferens and 

will allow better understanding of factors causing blooms.

Forecasts of Alexandrium fundyense abundance (red represents 

higher abundance) in May 2008 under four different weather 

scenarios, taken from weather and ocean conditions of 2004, 

2005, 2006, and 2007 (clockwise starting with upper left panel). 

All four scenarios were initiated from a map of resting cysts 

surveyed in late 2007.

Graphic by Dennis McGillicuddy, Woods Hole Oceanographic 

Institution, and Ruoying He, North Carolina State University
32 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

3.2. Research and 

Accomplishments

3.2.1. Bloom Ecology and Dynamics

The topic ‘bloom ecology and dynamics’ refers 

to research aimed at understanding the biological, 

physical, and chemical factors that control HAB 

initiation, maintenance, transport, and decline. 

Much research has focused on this topic because it 

is the fundamental basis for advancing prevention, 

control, and mitigation of HABs and HAB impacts. 

Important steps to improve understanding of 

bloom ecology and dynamics include developing 

appropriate methods of cell detection and 

determining growth conditions through lab and 

field studies for a particular HAB species in 

the natural environment. This information will 

ultimately evolve to yield models of population 

growth and mortality and, potentially, predictive 

models of bloom development, maintenance, 

dissipation, and impact. Predictive models, along 

with cell and toxin detection methods, are the 

ultimate tools for exploring impacts of blooms and 

developing mitigation strategies to reduce HAB 

impacts. 

3.2.1.1. Organism Life Cycle, Physiology, 

and Molecular Biology

Life cycle studies have been conducted to 

investigate the role of resting stages in bloom 

initiation. These resting stages, or cysts, are 

formed by some algae at the end of a bloom 

and settle to the seafloor where they can survive 

for years. When environmental conditions are 

favorable, the cysts can emerge to seed a new 

bloom. The ECOHAB:Gulf of Maine project (Table 

3.2) improved understanding of Alexandrium

cyst distributions in the Gulf of Maine82,83,84. This 

knowledge is important because the location of cyst 

beds and abundance of cysts within the beds play a 

critical role in bloom development. This research 

confirmed that cyst germination was controlled 

by an internal clock84 and provided measurements 

of germination rates as a function of light and 

temperature82. These findings have been critical 

for improving predictions of blooms in the Gulf of 

Maine region. 

Laboratory and field studies have been used 

to explore optimal growth conditions for various 

species (ECOHAB; NOAA CCEHBR, CCFHR, 

Sea Grant; NSF), as well as what factors influence 

toxin production (also see Section 3.2.2, ECOHAB; 

NOAA Sea Grant, CCEHBR; NSF). These 

governing factors have been shown to be complex 

and to vary both among and within species. 

Research on Pfiesteria species, for example, has 

shown a range of nutrient uptake capabilities and 

toxicity among strains and culture conditions44

(ECOHAB; also see Section 3.2.1.2).

Researching HAB species at the genetic level 

has led to development of molecular probes for 

detecting target organisms (see Section 3.2.1.6), a 

better understanding of population genetics, and 

an improved ability to understand the complex 

ecology and toxicity of HAB organisms. For 

example, ‘microarrays’ have been developed for 

profiling gene expression changes related to cell 

division and toxin synthesis in Karenia brevis in 

response to different environmental conditions85

(NOAA CCEHBR; NSF-NIEHS COHH). These 

types of technologies will help uncover the primary 

environmental factors that control growth and 

toxin production for a particular species or strain. 

Additionally, research investigating the genes 

involved in saxitoxin biosynthesis by Alexandrium

has led to considerable insight into dinoflagellate 

genes and their regulation86 (NSF). This research 

served as a springboard for research on genetic 

heterogeneity of Alexandrium bloom populations87

(NSF-NIEHS COHH; NIH NIEHS), which will 

feed into refining existing biological/physical 

models described in Section 3.2.1.5. 

3.2.1.2. Nutrient Dynamics

Eutrophication has been suggested as an 

important link to the occurrence of many HABs, so 

research into HAB causes has largely focused on 

how nutrient dynamics influence success of specific 

HAB organisms. For example, relationships 

have been shown between nutrient enrichment 

and Pfiesteria spp. occurrence44 (ECOHAB) as 

well as macroalgal blooms88 (ECOHAB; NOAA

Sea Grant). Furthermore, research has shown 

variability in nutrient controls among regions as 
Scientific Assessment of Marine Harmful Algal Blooms 33

Research on Marine HABs in the United States

Box 3.2. Highlights of Major Advances along the Mid- and South-Atlantic 

Coasts 

Pfiesteria spp. and Karlodinium

• There is a better understanding of Pfiesteria distributions. 

Pfiesteria is common in low abundances in estuaries along 

the East and Gulf Coasts and is most abundant in nutrientenriched environments. 

• A free radical forming metal complex has been isolated 

from Pfiesteria cultures that may be a novel and ephemeral 

toxin. 

• Development of molecular probes for detecting cells 

led to better identification, improved understanding of 

occurrence of Pfiesteria and other HABs, and identification 

of Karlodinium as an important fish-killing species in the 

region.

• Economic assessment of the ‘halo’ economic effect 

showed that the 1997 Pfiesteria event resulted in an 

estimated $43 million (1997 dollars) in lost seafood sales 

due to consumer concerns of seafood safety.

• New continuous, real-time tools were developed to measure environmental parameters at high 

temporal and spatial resolutions. These tools are part of the Maryland “Eyes on the Bay” program 

(http://mddnr.chesapeakebay.net/eyesonthebay/index.cfm). 

• Epidemiological cohort studies exploring human health effects of Pfiesteria exposure indicated that 

occupational (i.e., repeated, low-level) exposure to estuarine waters in which Pfiesteria is present 

was not a significant risk factor for illness.

Pyrodinium bahamense

• Successful multi-agency event response to saxitoxin puffer fish poisonings in Florida in 2002 

identified the putative causative agent as saxitoxin-producing Pyrodinium bahamense and tracked 

illnesses. As a result, a recreational fishery closure was instituted in the affected area and was 

extended indefinitely for all species of puffer fish, as was routine testing of saxitoxin in shellfish, to 

protect human health. 

Aureococcus anophagefferens (Brown 

Tide) 

• Brown tide in Delaware, Maryland, and 

Virginia waters was documented (also see Box 

3.1). 

Toxic Raphidophytes 

• An emerging HAB problem was identified 

through documentation of toxic raphidophyte 

blooms in Delaware’s Inland Bays.

Multiple Species

• An ecological forecast for water quality 

conditions and HAB occurrence has been 

developed for the Chesapeake Bay (http://www.

chesapeakebay.net/bayforecast.htm).

Karlodinium cell under light microscopy.

Photo: Lucie Novoveska, Dauphin Island Sea 

Lab

Sampling during collaborative response to saxitoxin puffer fish 

poisonings in Florida.

Photo: FDA
34 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

well as among species. For example, Pseudonitzschia occurrence in Louisiana coastal waters 

was associated with coastal eutrophication61,62

(NSF; NOAA Sea Grant), but in the Pacific 

Northwest, Pseudo-nitzschia blooms are linked to 

nutrients provided by a natural offshore source, 

the nutrient-rich Juan de Fuca Eddy89 (ECOHAB; 

NOAA NWFSC, OHHI). In southern California, 

an area where less information on Pseudo-nitzschia

blooms is available69, a current project is exploring 

the potential connection between urban river 

discharge, associated inorganic nutrient and trace 

metal loadings, and Pseudo-nitzschia blooms 

(ECOHAB). In addition, recent research in a 

number of areas, including Maui (http://pubs.usgs.

gov/sir/2006/5283/), Florida90, Washington91, and 

the Chesapeake Bay (http://md.water.usgs.gov/

publications/fs-150-99/html/index.htm), have 

highlighted the importance of the flow of nutrients 

from ground water to coastal ecosystems and, 

in some cases, groundwater nutrients have been 

linked to HABse.g., 90 (USGS; NASA; ECOHAB).

Research on the role of nutrients has also 

improved understanding of the importance of 

various modes of nutrition in the development 

of some HABs (ECOHAB; NSF; NOAA). 

Discoveries that some HAB species, such as 

Aureococcus anophagefferens92 (ECOHAB; 

NOAA Sea Grant) and Pfiesteria93 (ECOHAB; 

NSF), grow well and potentially outcompete 

other beneficial phytoplankton by using organic 

nutrients when inorganic sources are low have 

highlighted the importance of nutrient quality for 

some HABs. Some species, such as Pfiesteria94,95

and Karlodinium96 (NSF), have also been 

shown to feed on other cells to gain nutrition, 

and a recent technological development using 

digital holographic microscopy has allowed 

better understanding of this behavior97 (NSF). 

Furthermore, unexpected nitrogen sources for 

growth have been hypothesized in some cases, 

such as nitrogen fixed by cyanobacteria fueling 

blooms of Karenia brevis98 (ECOHAB; NSF). A 

current regional ECOHAB project is focusing 

on unraveling the critical elements of K. brevis

nutrient dynamics (Table 3.2).

3.2.1.3. Physical Processes and Bloom 

Dynamics

Investigating the role of physical processes in 

bloom dynamics, and integrating that knowledge 

with biological information into predictive models 

(see Section 3.2.1.5), has been another important 

focus. Important physical processes that govern 

bloom dynamics include small-scale turbulence, 

water column stratification and mixing, and 

horizontal transport processes.

The ECOHAB Gulf of Maine project (Table 3.2) 

contributed significantly to our understanding of 

the Gulf of Maine’s physical oceanography and the 

extent to which regional Alexandrium populations 

are connected hydrographically. For example, 

direct linkages were made between Bay of Fundy 

populations and blooms in the Eastern Maine 

Coastal Current (EMCC). Links were also made 

between EMCC populations and toxicity in the 

Western Gulf, and results suggest that variability 

in transport of offshore populations and this eastwest connectivity may be the primary drivers of 

interannual variability in toxicity99,100. The Gulf of 

Maine Coastal Plume101 was also identified as an 

important feature by which cells can travel inshore 

into the Western Maine Coastal Current region. 

The ECOHAB Florida project (Table 3.2) 

revealed that, in waters along the West Florida 

Shelf, the bottom water layer serves as a primary 

conduit for transport of cells from offshore to 

inshore. These findings highlight that threedimensional data on Karenia distributions and 

transport is necessary for monitoring and bloom 

prediction purposes. 

Researchers with NOAA NWFSC and the 

Pacific Northwest COHH (NSF-NIEHS) are 

making progress, in collaboration with ECOHAB

(Table 3.2) and NOAA MERHAB, toward a better 

understanding of the oceanographic processes that 

result in toxic outbreaks of Pseudo-nitzschia spp. 

and the impacts of these outbreaks on humans. 

Development of larger Pseudo-nitzschia blooms 

within the Juan de Fuca Eddy likely depend on 

sustained periods of downwelling that strengthen 

the eddy, as was seen in September 2004102. In 

addition to being nutrient-replete, the Juan de 
Scientific Assessment of Marine Harmful Algal Blooms 35

Research on Marine HABs in the United States

Fuca Eddy is more iron-deficient than surrounding 

coastal waters, and both factors likely contribute to 

the eddy acting as an incubator for toxic Pseudonitzschia blooms89. Results also show that the 

variability of inshore toxicity is likely related to 

variability in transport pathways from the eddy66. 

In Puget Sound, data over a 13-year period 

showed that a combination of low streamflow, 

weak surface winds, and small tidal variability 

tended to precede toxic blooms of Alexandrium

catenella (NOAA OHHI, NWFSC). This 

information will be useful for forecasting toxic 

events in Puget Sound and evaluating possible 

influences of climate change on the occurrence of 

future events.

3.2.1.4. Biological Controls of HAB Dynamics

Investigations of bacterial, viral, parasitic, 

and grazer interactions with HAB organisms 

(ECOHAB; NOAA CCEHBR, CCFHR, Sea Grant; 

NSF) have not only revealed better understanding 

of the cause and decline of blooms, but have also 

provided insights into potential avenues for control 

(also see Section 3.2.5). For example, algicidal 

bacteria have been identified and isolated that 

can lyse Karenia brevis cells and reduce toxicity 

as toxins are released103 (NOAA CCEHBR; 

ECOHAB). These bacteria may represent an 

indicator of bloom decline, and the algicidal 

compounds they produce may also represent a 

potential option for HAB control. In addition to 

the nutrient regime (see Section 3.2.1.2), lowered 

grazing mortality has been shown to be important 

for the development of brown tides, and viruses 

may be important as a mortality agent for brown 

tides as well as a bloom promoter104 (ECOHAB). 

NOAA Sea Grant-supported researchers are 

investigating the potential of ribbed mussels for 

reducing the incidence of harmful blooms, such 

as brown tides. Research supported by NSF and 

ECOHAB has developed probes specific for the 

parasitic dinoflagellate Amoebophrya105, which will 

yield information about the interactions between 

parasite and HAB host in the natural environment. 

Research on grazer interactions is discussed in 

further detail in Section 3.2.3.

3.2.1.5. Developing Predictive Models

Models are developed in order to better predict 

HAB events and forecast HAB impacts so that 

appropriate management actions can be taken 

for mitigation and control. They are also useful 

for looking at past events to determine the most 

important factors driving bloom dynamics. 

Such models may incorporate information on 

cell life cycles, physiology, grazer impacts, 

physical processes, and important environmental 

parameters. Ultimately, these models can also be 

used to test the efficacy of proposed management 

actions that may lead to bloom prevention.

The ECOHAB Gulf of Maine project ultimately 

led to a coupled bio-physical model that allows 

simulation of Alexandrium bloom dynamics. It has 

been used to evaluate numerous factors, from cyst 

dynamics to how factors that control growth vary 

in space and time106,107,108. Circulation (ECOHAB;

NOAA Sea Grant, MERHAB) and sediment 

models (USGS) contributed critical components 

to this effort. Observations and model simulations 

together revealed, among other things, that the 

primary environmental controls of A. fundyense

growth in offshore waters were light and inorganic 

nutrients and that two major cyst seedbeds, 

one in the Bay of Fundy and one offshore of 

Penobscot and Casco Bays, were critical to bloom 

dynamics109. This knowledge gained from the 

collective efforts in the Gulf of Maine explained 

patterns and variations of toxicity and how the 

regional populations of Alexandrium persist year 

after year. These model projections are being 

refined by research supported by ECOHAB and 

NSF-NIEHS COOH.

A model for Pfiesteria population dynamics 

was developed that incorporated measurements of 

nitrogen uptake, turbulence responses, and grazing 

impacts to simulate differences in nontoxic versus 

toxic strains (ECOHAB; NOAA MERHAB). 

Results suggested that toxic Pfiesteria blooms 

are more likely to occur in environments that are 

calm, have low grazing, and are rich in organic 

nutrients, whereas non-toxic blooms are more 

likely in more turbulent and inorganic nutrient rich 

environments110. 
36 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

Box 3.3. Highlights of Major Advances in the Gulf of Mexico 

Karenia spp. (Florida and Texas Red Tide)

• A coupled biological-physical model for 

Karenia bloom dynamics was developed, 

which has helped clarify important 

environmental factors controlling blooms and 

is now used to guide monitoring.

• One of the longest (48 years) datasets for 

marine ecosystems in general was made 

available. These data are being used to study 

bloom dynamics and environmental factors 

controlling blooms. The data were also the 

basis of the Harmful Algal Blooms Observing 

System case study and used to validate 

satellite imagery used in the HAB Forecasting 

System.

• Potential methods of control for Karenia

blooms have been discovered. These include 

bloom removal by clay flocculation and 

algicidal bacteria. 

• Field testing of bloom control by clay flocculation was conducted. This was the first ‘demonstration’

of this technology in Florida.

• Various methods were developed for detection of Karenia, including the ‘Brevebuster’, which 

optically detects Karenia in the water and can be deployed on underwater vehicles and moorings to 

provide higher temporal resolution than monitoring by any other means. 

• Two highly sensitive and accurate methods—enzyme-linked immunosorbent assay (ELISA) and 

liquid chromatography mass spectrometry (LCMS)—for detecting brevetoxin in shellfish were 

developed and are being considered by the Interstate Shellfish Sanitation Conference for regulatory 

use. The tests are more sensitive and have higher throughput than the standard mouse bioassay.

• Biomarkers of human exposure to brevetoxins were identified and an LCMS method for 

confirmation of clinical diagnosis of NSP was developed.

• The mechanism for chemical synthesis of brevetoxin was discovered. 

• Human health effects, including respiratory effects, due to acute exposures to brevetoxin have been 

established. 

• Brevenal, a natural inhibitor of brevetoxin, has been isolated. Additional research is leading to its 

characterization as a potential therapeutic for cystic fibrosis and other respiratory disorders. 

• A comprehensive monitoring network was established for Florida. 

• ‘Microarray’ technology was developed that can be used to determine factors influencing Karenia

growth and toxin production.

• A HAB Forecasting System has been in operational mode for Florida since 2004 and is currently in 

demonstration mode for the Texas Coast.

Control by clay flocculation has shown effectiveness for 

controlling blooms under certain conditions.

Photo: J. Culter, Mote Marine Laboratory
Scientific Assessment of Marine Harmful Algal Blooms 37

Research on Marine HABs in the United States

• Formal evaluation of HAB outreach and education materials, specifically the Aquatic Toxins Hotline, 

demonstrated that the materials provided useful HAB-related information. Results are leading to 

expansion and improvement of HAB outreach, education, and surveillance tools. 

• An unusual mortality event of bottlenose dolphins in the Florida panhandle was associated with 

brevetoxin exposure. Research during this event also identified for the first time the accumulation 

and persistence of brevetoxin in the muscle and viscera of fish, which can serve as a pathway for 

toxin transfer to higher trophic levels.

• Several unusual mortality events of manatees were associated with brevetoxin exposure. 

Research identified accumulation of brevetoxin in epiphytes on seagrasses, which are consumed 

by manatees providing another mode of toxin transfer. 

• A biomarker for brevetoxin exposure in manatees through liver fatty acid analysis has been 

developed. This research allows easier identification of manatees killed by brevetoxicosis.

Ciguatera

• A recent increase in CFP cases has been associated with grouper and barracuda landed in Florida 

and Texas and are possibly tied to toxic Gambierdiscus associated with hard structure provided by 

oil platforms and artificial reefs in the northwestern Gulf of Mexico. This research suggests CFP

may be expanding to new areas in the Gulf of Mexico.

• An industry advisory on ciguatera emergence in the Flower Garden Banks National Marine 

Sanctuary in the northern Gulf of Mexico was issued by the FDA.

• A two-tiered screening confirmatory method protocol for ciguatera toxins from the Caribbean and 

Pacific Coast was developed.

Reef fish can be contaminated with toxins that cause ciguatera fish poisoning.

Photo: FDA
38 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

Bio-physical models have also been developed 

through two other regional ECOHAB projects 

(Table 3.1). In Florida, a model has been used to 

elucidate environmental factors controlling blooms 

and is now used as a component of the NOAA

MERHAB-supported comprehensive monitoring 

network (see Section 3.2.5). In the Pacific 

Northwest, a model is helping to understand the 

generation of the Juan de Fuca Eddy and Pseudonitzschia bloom dynamics, including transport to 

the coast (ECOHAB; NOAA NWFSC). 

3.2.1.6. Understanding Occurrence of HABs 

through Better Detection 

From studies on HAB physiology and molecular 

biology, many new technologies for detecting 

HABs are emerging. New molecular-based assays 

are being developed and, in several regions of 

the country, are used routinely for HAB detection 

(ECOHAB; NOAA MERHAB, NOAA; NSF;

NSF-NIEHS COHH). NOAA CICEET is working 

to advance a number of innovative approaches 

to detect, quantify, and monitor different HAB 

species and toxins, including a molecular assay for 

Karenia brevis developed by NOAA AOML. DNA 

fingerprinting techniques have been developed for 

the rapid identification of Pseudo-nitzschia spp. as 

well as associated bacteria, which, when combined, 

provide the ability to link species distributions 

with toxicity and environmental conditions (NSFNIEHS COHH). 

These improved tools for cell detection are 

leading to a better understanding of species 

distributions as well as identification of new 

species of potential concern. For example, speciesspecific probes developed through Pfiesteria

research (EPA; NOAA) showed that Pfiesteria is 

common and widespread, but generally in low 

abundance in the water column111. This research 

also revealed that another phytoplankton species,

now called Karlodinium veneficum, was toxic to 

fish, had previously been misidentified, and may 

have caused some fish kills previously attributed to 

other species46. Research in Hawaii has identified 

two entirely new species of Gambierdiscus, as well 

as a species of Osteropsis, as potentially associated 

with CFP in Hawaiian waters (NSF-NIEHS

COHH; NOAA CCEHBR). Furthermore, NOAA

CCFHR is working to isolate and molecularly 

characterize dinoflagellates responsible for CFP 

and is conducting a systematic survey for these 

organisms in Florida waters. The COHH (NSFNIEHS) at the University of Miami has also 

identified and is isolating a number of potentially 

harmful algal species4.

3.2.1.7. Long-term Data Sets for 

Understanding Causes and Distributions

In addition to field and laboratory studies, 

long-term time series of phytoplankton and 

environmental data in U.S. estuaries and coastal 

waters shed light on historical bloom patterns—

which is important knowledge for understanding 

bloom dynamics and anthropogenic or natural 

drivers of change. For example, three decades of 

observation in San Francisco Bay revealed how 

climate-influenced changes in the Pacific Ocean 

modified the conversion efficiency of land-based 

nutrients into algal biomass, illustrating a strong 

linkage with the coastal ocean that influences 

the potential for HABs in the estuary112 (USGS, 

http://toxics.usgs.gov/highlights/phytoplankton_

blooms/). Additionally, long-term data sets from 

California have been used to identify shifts in 

algal species composition113 (NSF) and exceptional 

algal bloom events114 (USGS). NOAA NWFSC 

also participates in the HAB section of the North 

Pacific Marine Science Organization (PICES) (see 

Chapter 4) which aims to develop and implement 

annual bloom reporting procedures so data can 

be incorporated into the Harmful Algal Event 

Database (http://ioc.unesco.org/hab/HAEDAT.htm). 

This database will be important for assessing HAB 

impacts and improving predictive capabilities.

3.2.2. Toxins and their Effects

One of the first steps in research on toxins 

and their effects is to chemically characterize 

and elucidate the structure of the toxin. Once 

characterized, routine methods for detection can 

be developed, and the mechanisms for toxin 

biosynthesis as well as the impacts on humans and 

animals can more easily be researched. 
Scientific Assessment of Marine Harmful Algal Blooms 39

Research on Marine HABs in the United States

Box 3.4. Highlights of Major Advances along the Pacific Coast

Pseudo-nitzschia spp.

• The Olympic Region HAB Monitoring Network (ORHAB) focused on early warning of domoic acid 

in razor clams, including Federal, state, academic, tribal partners, is now operational and funded by 

Washington State. 

• A rapid, low-cost test for domoic acid was developed with the Quileute Nation’s natural resources 

agency and is currently being commercialized for use in environmental sampling.

• Research confirmed that the Juan de Fuca Eddy is an important regional source of toxic Pseudonitzschia blooms. Weakened or broken eddy circulation allows the toxic phytoplankton to escape 

the eddy where they can be transported to coastal areas of the Pacific Northwest. This knowledge 

will be valuable for improving predictions of toxic events in coastal areas of the Pacific Northwest.

• Multiple studies have postulated a link between domoic acid production and low copper and iron 

concentrations in the environment. Genes have also been identified that may be used as markers 

for determining the growth status or toxicity of cells in the field. These findings will improve 

understanding of toxin occurrence.

• Successful test deployment of the Environmental Sample Processor to detect Pseudo-nitzschia

and domoic acid in California represented the first automated, in situ detection of both algal cell 

abundance and toxin presence in coastal waters.

• A five-year epidemiological cohort study with Native populations in the Pacific Northwest has 

been undertaken to determine human health effects of 

low-level exposure to domoic acid through razor clam 

consumption. This research will help identify at-risk 

populations.

• In California, research showed domoic acid penetrated 

many components of the food web, including both 

benthic and pelagic species. The toxin was shown to 

quickly enter the food chain and be transferred up to 

higher trophic levels, including humpback whales.

• Research established that domoic acid exposure in 

sea lions causes not only acute mortality but also brain 

damage and reproductive failure. Chronic effects due 

to repeated, sub-lethal exposures have also been 

documented. 

Alexandrium catenella

• Resting cysts for Alexandrium catenella were mapped for Puget Sound, Washington, which is 

important for predicting bloom hot spots. 

• A sensitive, high-throughput, real-time method has been developed for assessing the abundance of 

Alexandrium catenella in Puget Sound, Washington. 

• The zebrafish model was developed and can be used as a model to test toxin exposure effects in 

vertebrates; the model illustrated sub-lethal effects in larval fish due to saxitoxin exposure. 

General

• A list server for Puget Sound researchers and fish mariculturists was established to improve 

information exchange and response to HABs. 

• Long-term datasets illustrated linkage between changes in climate and algal bloom occurrence 

(e.g., http://toxics.usgs.gov/highlights/phytoplankton_blooms/)

California sea lion in rehabilitation undergoing MRI 

scanning to detect extent of brain injury due to 

domoic acid toxicosis

Photo: MMC
40 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

3.2.2.1 Toxin Characterization and Detection 

Research on toxin characterization and synthesis 

is important not only to advance research on the 

mechanisms of toxicity, the factors controlling 

toxin biosynthesis, and the toxin impacts on human 

and ecosystem health, but also because it leads to 

improved availability of toxins for research. NIH

NIGMS is supporting numerous projects that aim 

to unravel the mechanisms for chemical synthesis 

of algal toxins, including saxitoxin, brevetoxins, 

maitotoxin, gonyautoxins, and ciguatera toxins, 

as well as other algal toxins that may have public 

health impacts. As a result of these efforts, a 

breakthrough in the mechanism for the chemical 

synthesis of brevetoxin, which may approximate 

the biosynthetic mechanism and be applicable to 

other ‘ladder’ toxins, was recently published115. 

NIH NIEHS-supported researchers have achieved 

total synthesis of an azaspiracid toxin and partial 

characterization of biological effects. Other 

studies to explore the mechanism for domoic acid 

biosynthesis in Pseudo-nitzschia spp. (NOAA Sea 

Grant) and the environmental factors controlling 

biosynthesis (NOAA; NSF) suggest a link 

between domoic acid production and low copper 

and iron concentrations in the environment116. 

From this research, genes have been identified 

that may be used as markers for determining the 

growth status or toxicity of cells in the field117. 

Additionally, NOAA Sea Grant has supported work 

to characterize Heterosigma fish-killing toxins and 

determine the cellular mechanism that regulates 

toxin biosynthesis. NOAA CCEHBR (supported 

by ECOHAB) identified an ephemeral free radicalforming metal complex produced by Pfiesteria45, 

which may partly explain the observed variable 

nature of toxicity associated with Pfiesteria. NIH

NIGMS is also supporting work to characterize 

new neurotoxins derived from marine algae, which 

may have potential ecosystem or health impacts.

A range of analytical methods for detection— 

from very accurate and expensive laboratory 

analytical techniques to quick and easy screening 

methods for the field—is necessary for successful 

management of toxic outbreaks. Developing 

modern methods to improve detection of algal 

toxins in a variety of matrices has been a research 

focus for many agencies (ECOHAB; FDA; NOAA

MERHAB, CCEHBR, CCFHR, CICEET, OHHI, 

NWFSC, and Sea Grant; NSF; NIH NIEHS and 

NIGMS; USAMRIID). Several newly developed 

tests for PSP (NOAA CCEHBR) and NSP (FDA; 

NOAA MERHAB) that are more sensitive and 

efficient than the traditional mouse bioassay are 

being considered for regulatory approval. Other 

quick and easy tests are being developed for 

environmental sampling. Such simple test kits 

are desirable as screening methods to reduce 

the number of samples taken for laboratory 

analysis. For example, a new, low cost enzymelinked immunosorbent assay (ELISA) method 

for detecting domoic acid in razor clams was 

developed in collaboration with the Quileute tribe 

in the Pacific Northwest118, and a dip stick version 

of this test for use in the field is in development 

(NOAA MERHAB, CCFHR, NWFSC). A NOAA

MERHAB project in California is comparing newly 

developed test kits for domoic acid and saxitoxins 

to evaluate their efficacy. Researchers at the FDA

have developed a two-tiered ciguatoxin analytical 

procedure that does a much more efficient job of 

identifying ciguatoxic fish than any previously used 

methodology. The two-tiered procedure will be 

assessed for Caribbean and Pacific ciguatera in a 

proposed collaborative study with the University 

of Texas Marine Science Institute and the Pacific 

Research Center for Marine Biomedicine (NSFNIEHS COHH). It is expected that this new 

approach will find broad application in CFP studies 

globally. 

Toxin detection methods are typically validated 

for extracts from the causative algae and/or the 

affected seafood. There are presently no officially 

validated methods for detecting marine toxins 

in clinical matrices. This capability is required 

to confirm intoxication during outbreaks and to 

investigate specific case studies. Furthermore, 

relevant information on human toxicokinetics and 

treatment windows are lacking due predominantly 

to the absence of these validated methods for 

clinical matrices. There is an ongoing collaboration 

between USAMRIID and FDA to improve 

detection capabilities for PSP toxins by extending 

the use of the Lawrence High Performance Liquid 
Scientific Assessment of Marine Harmful Algal Blooms 41

Research on Marine HABs in the United States

Chromatography (HPLC) method (validated 

for seafood extracts) to clinical samples. This 

enhanced detection capability was tested during 

an actual PSP outbreak in 2007 (see Box 2.1) and 

researchers found that PSP toxins in human urine 

and serum could be detected and monitored with 

minimal modifications to the method. Results are 

encouraging that this method could be employed 

during future PSP outbreaks and lead to an 

improved knowledge base about human health 

effects.

3.2.2.2. Toxin Effects on Humans and 

Ecosystems (also see 3.2.3 and 3.4.4)

Assessing the impact of HAB toxins on 

individual species, including humans, and across 

ecosystems has been slower than research in some 

other areas, but has become more of a priority in 

recent years. Most assessments of human impacts 

have been through animal studies, but there 

have also been case studies during events (see 

Section 3.4.4 for public health studies). NOAA

NWFSC research established the zebrafish as an 

appropriate model for evaluating toxin impacts 

on vertebrates in general. Initial studies with 

saxitoxin showed important sublethal effects on 

marine fish populations119,120 (ECOHAB; NOAA

NWFSC). The zebrafish model is now being 

used to test potential human impacts from longterm, low-level exposures to various toxins and to 

characterize embryonic effects, such as behavioral 

deficits or reproductive failure (NOAA NWFSC, 

CCEHBR; NSF-NIEHS COHH). Other research 

(NSF-NIEHS COHH) using animal models is 

evaluating the effects of domoic acid exposure 

on brain developmental processes and responses, 

including proliferation, differentiation, oxidative 

stress, cell toxicity, and cell death, in both prenatal 

and postnatal phases. NOAA CCEHBR has 

shown that early life exposure to domoic acid 

results in behavior and memory impairment in 

rats121. It has also been confirmed that inhalation 

of brevetoxins causes airway responses in humans 

at environmentally relevant concentrations122, and 

the biological basis for these responses is being 

investigated (NIH NIEHS; CDC). 

Research with California sea lions has shown 

reproductive failure associated with domoic acid 

exposure123 (NOAA NMFS, OHHI, and CCEHBR). 

Furthermore, findings suggest chronic effects, such 

as epilepsy and behavioral changes, can occur in 

sea lions from sublethal, repeated exposures to 

domoic acid69 (NOAA NMFS, OHHI, CCEHBR). 

Research with California sea lions has been 

significant not only for assessing environmental 

effects, but also as an important source of 

information to protect human health.

There has also been considerable effort to 

increase wildlife illness surveillance, which is 

not only important for wildlife assessments, but 

also for human health threat identification. For 

example, recent association of domoic acid 

exposure with whale mortalities on the East 

Coast expanded the known geographic range of 

this threat. Furthermore, as a result of increased 

surveillance during HAB events, NOAA’s Marine 

Mammal Health and Stranding Response Program 

is establishing that more and more mammal 

stranding events are linked to biotoxins25. The 

development of biomarkers for identifying 

effects due to toxin exposure, such as fatty acid 

biomarkers for brevetoxin in manatees (MMC), 

is an important goal that will help assessments 

of wildlife impacts. In addition, the MMC has 

dedicated funds to improving and analyzing the 

manatee mortality database. USGS, at its National 

Wildlife Health Center in Madison, Wisconsin, 

has worked collaboratively with universities 

and Federal laboratories to document impacts of 

biotoxins on marine and aquatic birds, mammals, 

and reptiles. This Center receives carcasses 

Box 3.5. Highlights of Major 

Advances in Hawaii and the Pacific 

Territories

• Potentially new CFP-causing species have 

been discovered and isolated. 

• A tiered protocol to assess ciguatoxicity in 

fish tissues has been developed; research is 

currently working toward derivation of advisory 

levels for ciguatoxins in Caribbean and Pacific 

waters. 
42 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

and tissue samples from the entire United States 

including Alaska, Hawaii, and U.S. territories. 

USGS also maintains a database of the findings. 

Research to explore therapeutics for reducing 

impacts of toxins on human and animals has led 

to some promising discoveries. For example, 

brevenal, a compound antagonistic to effects of 

brevetoxin, may represent a possible treatment 

for people exposed to brevetoxin122 (NIH

NIEHS). Brevenal is being further characterized 

as a potential therapeutic for cystic fibrosis and 

other respiratory disorders (NIH NIEHS), which 

highlights the ancillary benefits of HAB research. 

Additionally, NIH NIGMS is supporting research 

on mechanisms of toxicity, including one study 

investigating how potential antagonists may protect 

against toxicity of brevetoxins and could be used 

for therapeutics. 

3.2.3. Food webs and fisheries

Analysis of food web function and fisheries 

dynamics in relation to HABs has recently been an 

active area of research. This research has focused 

on the interaction of HABs and food web structure, 

toxin transfer through the foodweb, and toxin 

accumulation and depuration (elimination) in food 

web components. 

3.2.3.1. Food Web Alterations

Alterations in food web structure play a 

disruptive role in ecosystem balance, and such 

alterations, which can include grazer decline, 

can be both a cause and an effect of HABs. For 

example, research supported through ECOHAB

and NOAA Sea Grant showed that reduced 

grazing is an important factor in brown tide bloom 

development (reviewed by Gobler et al.38) and that 

prolonged brown tides can also affect recruitment 

of filter-feeding bivalves124, thereby reducing 

grazing pressure. Further, research in Florida Bay 

(NOAA Sea Grant) attributed the decline in filterfeeding sponges as a key factor in the proliferation 

of nuisance algae, which indirectly resulted in the 

significant loss of critical seagrass habitat through 

light limitation125. 

Grazing studies with zooplankton and Karenia 

brevis suggest that brevetoxins can cause 

behavioral changes in some copepods, but that 

accumulation and behavioral effects vary among 

species of copepods126,127 (ECOHAB; NOAA

CCFHR; NSF). Further, some copepods may 

be able to acquire a level of resistance to toxin 

exposure. In lab studies, copepods that had been 

historically exposed to Alexandrium blooms 

were less severely affected by exposure to toxic 

Alexandrium than copepods that had little or no 

exposure to blooms128 (ECOHAB). HABs may 

have other physiological traits, aside from toxin 

production, that make them a less desirable or 

nutritious food source. Research has shown that 

brown tides adversely impact recruitment of hard 

clams by prolonging the time spent in the more 

vulnerable larval stage129 (ECOHAB; NOAA Sea 

Grant). Other research found that brine shrimp and 

scallops were unable to metabolize unusual sterols 

from some harmful dinoflagellates130 (ECOHAB;

NOAA NEFSC). These results suggest that HAB 

sterols may have detrimental consequences for 

commercial fisheries and for the zooplankton 

grazers that might otherwise control a bloom. 

3.2.3.2. Toxin Transfer, Accumulation, and 

Depuration in Food Webs

Understanding how certain HAB toxins 

are transferred through the food web is very 

important for explaining or predicting impacts 

from a bloom. In the Gulf of Maine, saxitoxin 

has been documented in both North Atlantic 

Right Whales and the zooplankton community, 

Racks of Pacific oysters grown in Drakes Estero, one of 

California’s largest oyster-producing areas and an area 

intensively monitoring for Alexandrium and the PSP toxins.

Photo: Gregg Langlois, California Department of Health Services
Scientific Assessment of Marine Harmful Algal Blooms 43

Research on Marine HABs in the United States

Box 3.6. Highlights of Major Advances Applicable in Multiple Regions of the 

United States

• A receptor binding assay for PSP toxins has been developed 

and is being considered by the ISSC for regulatory use. The test 

is more sensitive and has higher throughput than the standard 

mouse bioassay so would give managers more lead time. 

• The Jellett Rapid Test for PSP toxins was approved by the ISSC 

as a Type IV screening method with restrictions (http://www.cfsan.

fda.gov/~ear/nss3-42j.html). This rapid test can be used in lieu of 

the mouse bioassay to maintain an area in open status, implement 

a precautionary closure of an area in open status, and determine 

when to perform a mouse bioassay in a previously closed area.

• Citizen monitoring networks have been created. A number of 

states have established citizen monitoring programs for HAB 

species. FDA and NOAA have supported establishment of these 

programs and training for volunteers. These programs can reduce 

the cost of monitoring and managing our coastal resources.

• NOAA CCEHBR’s Analytical Response Team was established. It 

is national in scope and maintains a database of all samples and 

analyses conducted since 1998 (see Section 3.1.1). 

• NOAA CSCOR Event Response Program was established. This program supports researchers and 

managers faced with responding to unusual or unexpected HABs (see Section 3.1.1). 

• CDC’s HABISS was established to coordinate with states to mitigate HAB exposure and employ 

illness prevention strategies to more effectively to protect public health.

• NOAA’s National Marine Mammal Health and Stranding Response Program monitors the shoreline 

for stranded marine mammals and responds quickly to gather data necessary to identify the cause 

of strandings. 

• Outreach and communication has been improved through development of the following (also see 

Section 4.1):

• State web sites (see Appendix I)

• National Office for Harmful Algal Blooms

• National HAB Committee

• U.S. HAB Symposia Series

indicating that zooplankton may serve as an entry 

point for saxitoxin into the pelagic food web and 

potentially lead to exposure of fish and marine 

mammals131,132 (ECOHAB; NOAA CCEHBR). 

NOAA CCEHBR has also identified that domoic 

acid can co-occur with saxitoxin in North Atlantic 

Right Whales. In Florida, investigation of an UME 

of bottlenose dolphins in the Panhandle region led 

to the first-time identification of the accumulation 

and persistence of brevetoxin in the muscle and 

viscera of fish, which can serve as a vector to 

higher trophic levels27 (NOAA NMFS). Similarly, 

the accumulation of brevetoxin in some copepods126

and in layers on seagrass leaves27 have illustrated 

additional pathways for brevetoxin entry into the 

food web (NOAA CCFHR; ECOHAB). Research 

in California (ECOHAB) revealed that during 

toxic bloom events, domoic acid quickly entered 

the food chain and was then transferred to large 

predators, including blue and humpback whales133. 

NOAA NWFSC is exploring potential impacts 

Preparing a shellfish sample extract for 

a the Jellett rapid test for PSP toxins 

(Jellett Rapid testing Systems, Ltd.) 

Photo: Gregg Langlois, California 

Department of Health Services
44 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

of domoic acid on salmon and killer whales (via 

consumption of salmon) on the West Coast. 

It is also important to know which components 

of the food web accumulate toxins and how 

long it takes for toxins to be eliminated. NOAA

OHHI research is identifying pathways by which 

brevetoxin accumulates in fish, which will help 

identify which species may present a human health 

risk and what parts of the fish should be avoided. 

Experiments with shellfish in Puget Sound and 

along the Washington coast indicate that razor 

clams consume Pseudo-nitzschia (and associated 

domoic acid) at a much slower rate than oysters 

and mussels, but retain some of the highest levels 

of toxin (NSF-NIEHS COHH). This research will 

explore properties of the toxin receptors in razor 

clams, which may help design methods for purging 

the toxin from the clams. These data can also be 

incorporated into predictive models. For example, 

the high feeding rate of mussels and oysters found 

in Puget Sound, combined with the ability of 

mussels to quickly purge toxin from their tissues, 

may explain the decreased frequency of beach 

closures for Pseudo-nitzschia in Puget Sound. A 

current food web study (EPA) is developing a 

model of domoic acid elimination in razor clams 

and crabs, which will be useful for risk managers 

who need to predict how long it takes for shellfish 

to eliminate domoic acid and become safe for 

human consumption. Furthermore, shellfish 

may biotransform toxins by initially producing a 

suite of compounds of variable toxicity. Studies 

are underway (ECOHAB and FDA) to identify 

and determine the toxicity of these degradation 

products and develop the best analytical methods 

for assessing shellfish toxicity for protecting 

human health. Intraspecies variations in toxin 

accumulation are also important as other work has 

shown commercial bivalves from areas exposed 

to Alexandrium blooms can be more resistant to 

saxitoxin due to a genetic mutation and can, thus, 

accumulate toxin more rapidly134 (ECOHAB;

NOAA NWFSC). NOAA NWFSC is working to 

develop genetic markers that distinguish this PSP 

toxin susceptibility. Understanding shellfish toxin 

resistance will improve prediction and managing of 

shellfish toxicity. 

3.2.4. Public Health and Socioeconomic 

Studies (also see Section 3.4.2)

3.2.4.1. Public Health Research

Research on public health impacts of HAB 

toxins has been slower to advance. In the late 

1990s to early 2000s, formal risk assessment 

or cohort-based epidemiological studies related 

to HABs were limited, for the most part, to 

Pfiesteria-related studies supported by CDC in 

the Mid-Atlantic states135,136,137. Those initial 

Pfiesteria incidents in North Carolina and Maryland 

highlighted the presence of public health issues 

associated with human exposure to HABs. 

More recently, an epidemiological cohort study 

and risk analysis began in the Pacific Northwest 

with Native American infants, children, and adults 

who may be exposed to domoic acid through razor 

clam consumption (NIH NIEHS). This research is 

making headway for identifying populations most 

at-risk for exposure and effects from toxic HABs. 

Additionally, CDC is now supporting numerous 

state activities to monitor and assess public 

health impacts of HABs. NIH NIEHS, NSFNIEHS COHH, and CDC are working with the 

state of Florida and to assess inland air transport 

of aerosolized brevetoxins, chronic effects 

A sign indicates shellfish beds are closed to harvesting due to 

PSP toxins. 

Photo: Judy Kleindinst, WHOI
Scientific Assessment of Marine Harmful Algal Blooms 45

Research on Marine HABs in the United States

from aerosolized brevetoxin exposure, and the 

biological basis for respiratory effects. Research 

demonstrated, for example, that during active 

Karenia brevis blooms, there was an increased rate 

of respiratory emergency department admissions 

(for upper airways disease, asthma, pneumonia, 

and bronchitis), particularly for coastal residents, 

compared to the rate for a similar unexposed 

period138 (CDC; NIH NIEHS). 

HABISS was also created by CDC in 

collaboration with its state partners to help track 

blooms and their public health impacts. The 

information collected through this system will be 

useful for developing predictive criteria.

The geographic areas impacted by major HAB 

illness syndromes are well-known, but recent 

work has identified public health issues emerging 

in new areas. For example, a collaborative public 

health investigation into the cause of human illness 

associated with puffer fish in Florida identified 

the causative agent was saxitoxin produced by the 

dinoflagellate Pyrodinium bahamense 23 (CDC;

FDA; ECOHAB). CDC’s partnership with the 

American Association of Poison Control Centers 

and the use of the Toxic Exposure Surveillance 

System was integral to identifying additional 

illnesses during the puffer fish poisoning incident. 

Furthermore, some illnesses are likely 

underreported and better tools for diagnosis are 

needed. For example, CFP, although the most 

common illness associated with algal toxins, is 

difficult to diagnose and, therefore, typically is not 

reported. CDC is currently supporting research 

to develop a biomarker to verify CFP exposure, 

which will facilitate research and surveillance of 

CFP occurrence and impacts. NOAA CCEHBR 

is also developing ‘biomonitoring’ methods 

for monitoring domoic acid, brevetoxin, and 

ciguatoxin exposure in living animals to provide 

early diagnosis. Accomplishments include the 

development of blood collection cards that can be 

used for monitoring ciguatoxin and brevetoxins 

in blood. Improved communication between 

public heath and wildlife managers is benefiting 

monitoring programs that aim to protect public 

health. One example has been the use of sentinel 

organisms, such as sea lions and brown pelicans 

in California, for early warning of potential public 

health threats.

3.2.4.2. Socioeconomic Research

In the last decade, several thorough, yet 

conservative, assessments of the economic 

impacts of HABs in the United States have been 

conducted22,31,139 (NOAA Sea Grant; ECOHAB;

NSF). Additionally, assessments of individual 

events have been supported by Federal and state 

agencies and illustrate well the large economic 

impact that just one event can have on local 

communities. These assessments include direct 

impacts to the commercial shellfishing industry 

in Maine and Massachusetts due to the 2005 

Alexandrium bloom33 (approximately $20 million 

in 2005 dollars), the effect of red tide on the 

Florida Gulf Coast tourist industry each year58

($18-29 million in 2005 dollars), and the Pfiesteria

halo effect on seafood sales in Maryland32 ($60 

million in 2005 dollars, NOAA Sea Grant). Cost/

benefit studies of HAB management strategies and 

assessments of sociocultural impacts are new areas 

that are just starting to be addressed1

.

NOAA Sea Grant conducted significant 

outreach efforts to accurately inform the public 

during the Pfiesteria events in the 1990s. Products 

included a scientifically accurate documentary on 

HABs with emphasis on Pfiesteria, an education 

resource guide, and a survey to better understand 

public perceptions and concerns with a goal of 

Recreational clam harvesting.

Photo: Washington Department of Fish and Wildlife
46 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 3

more effective education. Most coastal states 

combating HAB problems now have a significant 

outreach component, resulting in more effective 

management. 

NSF-NIEHS COHH supported the first formal 

evaluation of use and satisfaction of HAB outreach 

and education materials, specifically the Florida 

Poison Information Center-Miami’s Aquatic Toxins 

Hotline. The research found that the hotline was 

successful at quickly providing useful information 

on HABs to a large majority of the callers; results 

are expected to lead to expansion and improvement 

of this tool140. 

3.2.5. Prevention, Control, and 

Mitigation Studies

Most of the advances discussed in the previous 

sections have led to improved HAB management, 

but this section highlights examples of research 

directly applicable to HAB prevention, control, and 

mitigation. These advances are covered in more 

detail in the Harmful Algal Bloom Management 

and Response: Assessment and Plan (Box 1.3).

3.2.5.1. Prevention

HAB prevention requires a thorough 

understanding of HAB physiology, ecology, and 

oceanography (see Section 3.2.1). Although the 

underlying causes of most HABs are not well 

understood, it is generally accepted that some 

HAB events are intensified by high nutrients or 

by changes in nutrient regime13. Therefore, some 

agencies have looked directly at potential benefits 

of nutrient management. Other agencies have 

focused on water quality monitoring, which has 

given important long-term information on nutrients 

and other water quality changes. This knowledge 

is a critical basis for developing methods of 

prevention. Examples include:

• In Puerto Rico, USDA is collaborating with 

NOAA to investigate impacts of upstream 

nutrient conservation on downstream water 

quality. NOAA Sea Grant is also investigating 

potential impacts of upstream land use changes 

in South Carolina.

• EPA is supporting a new project to assist 

management decisions in the Gulf of Maine 

by identifying causal relationships between 

river basin inputs, coastal condition, and HABinduced shellfish toxicity using a probabilistic 

model.

• EPA and USGS have supported nutrient 

monitoring and development of nutrient models 

which have utility in management of nutrient 

loadings to estuaries and coastal waters of the 

United States (e.g., http://water.usgs.gov/nawqa/

sparrow/index.html).

3.2.5.2. Control

Bloom control has been an active area of 

research and a number of potential control agents 

have been identified: 

• The use of naturally occurring HAB-specific 

pathogens, such as bacteria, viruses, and 

parasites, is being investigated, but this 

research is still in its early stages (ECOHAB;

NOAA CCEHBR; NSF-NIEHS COHH, see 

Section 3.2.1.4). 

• Physical cell removal by clay flocculation is a 

form of mechanical control that has been tested 

in a series of projects and has shown promise 

(ECOHAB). Further evaluation in the context of 

risk management and cost/benefit analysis is the 

next step for consideration. 

3.2.5.3. Mitigation

Mitigation, or minimizing impacts of HABs, is 

currently the most feasible, and thus operational, 

management strategy for HABs. Mitigation 

strategies include monitoring for cells and toxins 

(also see Sections 3.2.1.6 and 3.2.2.1), short-term 

predictions/early warnings, and event response. 

Operational examples of these mitigation strategies 

A mussel cage used in the Washington Department of 

Health’s Sentinel Mussel Biotoxin Monitoring Program.

Photo: Liz Cox-Bolin and Frank Cox
Scientific Assessment of Marine Harmful Algal Blooms 47

Research on Marine HABs in the United States

are provided below. Cell and toxin detection 

methods are discussed in Sections 3.2.1.6 and 

3.2.2.1. Outreach and education are also important 

components of successful mitigation, and those 

advances are discussed in Section 3.2.4.2.

Improving Monitoring Capabilities 

Monitoring is essential for mitigation of HAB 

impacts, and the responsibility for most coastal 

monitoring resides at the state level (except in 

Federal waters where FDA has jurisdiction). 

Federal programs have assisted states by 

supporting development and transfer to operations 

of regional HAB monitoring systems: 

• Outcomes of the ORHAB regional project 

(Table 3.3), supported by NOAA MERHAB 

and conducted in collaboration with NWFSC 

and other partners (http://www.orhab.org/

partners.html), include a monitoring network in 

Washington focused on early warning of domoic 

acid in razor clams. 

• A regional project investigating Pfiesteria and 

other HAB events in Chesapeake Bay (NOAA

MERHAB) produced new continuous, real-time 

tools to measure environmental parameters in 

critical shallow water areas at unprecedented 

temporal and spatial resolutions. These tools 

are part of the Maryland “Eyes on the Bay” 

program (www.eyesonthebay.net) and are vital 

to the state strategy of building community and 

institution partnerships to sustain monitoring 

programs and improve predictive capabilities. In 

addition, in situ nutrient monitoring technologies 

developed with support from NOAA MERHAB 

are now being adopted by the States of Maryland 

and Florida. 

• In the Gulf of Mexico, a networked system of 

autonomous sampling platforms incorporating 

physical, chemical, and biological sensor 

packages is being developed and assessed 

(NOAA MERHAB). This project facilitates 

model and forecast initializations and statewide, 

adaptive field sampling. For example, the data 

is used for near real-time ‘ground-truthing’ of 

the NOAA HAB forecasting system (NOAA

CCMA, CSC, NESDIS, CO-OPS). 

• The first field test of an automated, in situ

method for domoic acid detection onboard the 

Environmental Sample Processor was successful 

(NOAA CCEHBR), showing promise for 

integration in ocean observing systems (toxin 

detection is also discussed in Section 3.4.2). 

• A number of states have established citizen 

monitoring programs for HAB species. FDA

and NOAA have supported establishment of 

these programs and training for volunteers. 

NOAA Sea Grant also leads the citizen 

monitoring program in Delaware (http://www.

ocean.udel.edu/mas/DIBCMP/about.html) and 

in the Great Bay Estuary in New Hampshire 

(http://www.gbcw.unh.edu/). Citizen monitoring 

programs can reduce the cost of monitoring and 

managing our coastal resources.

Short-term Predictions

Short-term predictions allow early warnings of 

bloom occurrence and transport. This knowledge 

allows managers to have advanced preparation, 

focus sampling in critical areas, and warn the 

public of potential impacts.

• In Florida, the HAB forecasting system (http://

tidesandcurrents.noaa.gov/hab/), which 

incorporates field data, satellite imagery, 

and surface transport information, has been 

operational since 2004 and is issued twice 

weekly to warn managers and the public of 

potential HAB impacts (NOAA CCMA, CSC, 

NESDIS, CO-OPS).

• Data from model simulations in the coastal Gulf 

of Maine have been used successfully since the 

historic Alexandrium bloom of 2005 to provide 

early warnings of potential toxicity, allowing 

managers to focus sampling in critical areas 

to safeguard human health while minimizing 

impacts on fishers (ECOHAB). 

• The ORHAB partnership described above has 

allowed early warnings of domoic acid in razor 

clams in Washington. Estimates indicate that 

selective beach openings made possible by 

the ORHAB partnership have saved at least 

$3 million per year for Washington’s coastal 

fisheries (NOAA MERHAB, NWFSC). 

• The Chesapeake Bay Program, in partnership 

with multiple Federal agencies (EPA; NOAA;
USGS) produces an ecological forecast for HAB 

occurrence in the Chesapeake Bay (http://www.

chesapeakebay.net/bayforecast.htm).

Rapid Response to HAB Events

HAB events can occur unexpectedly and 

sometimes involve species and toxins that are new 

to a geographic area. Within the past 10 years, 

some Federal agencies have developed programs 

to provide immediate funding and/or scientific 

expertise for responding to such HAB events. The 

Harmful Algal Bloom Management and Response: 

Assessment and Plan presents a strategy for 

improving this type of response. Below are recent 

examples of collaboration for successful event 

response: 

• Timely and effective responses to the 

Alexandrium bloom in 2005 by states with 

assistance from FDA and NOAA resulted in 

protection of humans from PSP illnesses despite 

remarkably high toxicity in the unmarketed 

product (see Box 26 in the Prediction and 

Response Report5

).

• Collaborative efforts from the State of Florida, 

American Association of Poison Control 

Centers, CDC, FDA, and NOAA identified 

saxitoxin as the causative agent of human illness 

associated with puffer fish consumption and 

allowed tracking of additional illnesses in 2002. 
Scientific Assessment of Marine Harmful Algal Blooms 49

Coordination and communication in response to the growing problem of marine HABs 

in the United States has improved greatly since 

the first marine HAB assessment, the National 

Assessment of Harmful Algal Blooms in U.S. 

Waters6, was completed for Congress in response 

to the original HABHRCA legislation. This 

chapter provides a descriptive overview of the 

opportunities for information exchange and 

coordination both at the national and international 

levels. 

These enhanced opportunities will lead to 

improvements in 1) interagency, intramural 

and extramural research program planning, 2) 

intramural and extramural program planning 

integration, 3) Federal, state, local, private, 

academic, and international research program 

implementation, and 4) dissemination of research 

results. These improvements will also speed and 

enhance the development of infrastructure, tools, 

information, and guidance needed by state, local, 

and tribal governments to develop options and 

strategies for reducing the risks posed by HABs 

and HAB toxins in U.S. marine waters. Improved 

communication and coordination will help prevent 

duplication of effort.

4.1. National Coordination 

and Communication

4.1.1. Synergy of HAB Programs Will 

Continue to Advance HAB Research

Many agencies and programs conduct research 

on marine HABs (Table 3.1) with the ultimate goal 

to protect public health, economies, communities, 

ecosystems, and fisheries. Together these programs 

constitute an integrated HAB research program. 

The relationship of all of these programs was 

laid out in the HAB Management and Response: 

Assessment and Plan3 (Box 1.3). HARRNESS2, 

a plan developed by the HAB research and 

management community to guide research from 

2005 to 2015, identified the major research needs. 

The four HABHRCA reports (Box 1.1), including 

this report, lay out how the Federal government is 

responding to the HAB problem and recommend 

approaches for improving future HAB research 

and response. A number of other reports address 

specific areas of HAB research and response1,141,142. 

Several themes are recurring in all of these reports: 

• Basic research provides new understanding 

of the causes and impacts of HABs and 

new technologies for improved monitoring 

and prediction. These provide the basis for 

developing new strategies and technologies for 

HAB prevention, control, and mitigation. 

• Programs that focus on HABs in the 

environment and programs that focus on 

human and community impacts need to be well 

coordinated in order to derive the most benefit 

from the research.

• Programs dedicated to moving new information, 

predictive models, and potential prevention and 

control methods to operational use by managers 

at the Federal, state, and local levels will greatly 

advance HAB response.

• A combination of extramural and intramural, 

competitive and noncompetitive research, and 

operations can best meet the multiple goals 

required to improve HAB response.

No single approach, program, or agency can 

fulfill all of these needs, but a well coordinated 

suite of programs can do so.

4.1.2 Federal Coordination

The 2004 reauthorization of HABHRCA

calls for this report to “identify ways to improve 

Coordination and 

Communication for Marine 

HAB Research and Response 

Chapter 4
50 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 4

coordination and to prevent unnecessary 

duplication of effort among Federal agencies and 

departments with respect to research on harmful 

algal blooms.” HABHRCA 2004 also calls for 

three other reports about different aspects of HAB 

research and response (Box 1.1), all of which 

are required by the legislation to address Federal 

coordination. 

Federal coordination for HAB research and 

response, including marine HABs, should be 

provided by the IWG-4H. As described in 

Chapter 1, the IWG-4H was formed by the JSOST 

to fulfill the requirement of the HABHRCA 2004 

to reestablish the Interagency Task Force on HABs 

and Hypoxia (Box 1.2). Section E.2 of the Charter 

of the IWG-4H specifies that it will “(e)nsure 

interagency communication, coordination and 

cooperation.” 

4.1.3. Coordination of Federal Agencies 

with the HAB Research and Management 

Community

U.S. National Office for Harmful Algal 

Blooms. The U.S. National Office for Harmful 

Algal Blooms, established with funding from 

NOAA CSCOR and administered at Woods 

Hole Oceanographic Institution, provides 

critical infrastructure, including communication, 

coordination, and technical support capabilities 

that enhance the Nation’s ability to respond to and 

manage the growing threat posed by HABs. It 

aids coordination by organizing HAB meetings, 

symposia, and workshops and facilitates training 

and student participation in HAB activities. 

Communications are facilitated by maintaining the 

“Harmful Algae Page” web site (http://www.whoi.

edu/redtide/), hosting list servers for national and 

regional HAB issues, archiving HAB reports and 

providing a central location for announcements of 

funding opportunities and meetings. The National 

Office maintains databases of U.S. HAB events 

that are coordinated at the international level, 

provides technical information through its web 

site, and assists with the preparation of national 

and international HAB reports. The activities of the 

National Office also facilitate some functions of the 

National HAB Committee (NHC).

The National HAB Committee. The 

HARRNESS report (HARRNESS 2005) called for 

the formation of a NHC to facilitate coordination 

and communication of activities for the U.S. HAB 

community at a national level (http://www.whoi.

edu/page.do?pid=13935). The NHC is a body 

elected by and representing the HAB research 

and state and local management communities. 

Representatives from some Federal agencies serve 

as non-voting ex-officio members and, as described 

in the Scientific Assessment of Freshwater Harmful 

Algal Blooms report8, provide a linkage between 

the IWG-4H and NHC (Box 5.1) so that common 

coordination activities can be undertaken. An 

Interprogram Coordination Subcommittee of the 

NHC will develop a framework and strategy for 

communication and coordination, with multiple 

national and international programs which are 

relevant to HAB issues.

Ocean Observing Systems. The U.S. Integrated 

Ocean Observing System (IOOS) (http://www.

ocean.us/) is a coordinated national network 

of observations and data transmission, data 

management, and communications intended to 

routinely and continuously acquire and disseminate 

quality-controlled data and information on current 

and future states of the oceans and Great Lakes 

from the global scale of ocean basins to local scales 

of coastal ecosystems. The IOOS is part of the U.S. 

Integrated Earth Observing System (IEOS), the 

U.S. contribution to the Global Ocean Observing 

System (GOOS, http://www.ioc-goos.org/), and 

a contribution to the Global Earth Observation 

System of Systems (GEOSS). These broad, 

coordinated observing systems have the potential 

to greatly enhance HAB forecasting capabilities 

and to coordinate data flow within regions, but 

their utility in these respects will depend upon 

the appropriate location and integration of 

HAB-specific sensors and data in regions where 

HABs are common occurrences (see ‘Regional 

Coordination’ section below). 

Regional Coordination. Regional coordination 

is also important because HAB problems are 

often similar within regions. The Gulf of Mexico 

Alliance is a regional alliance of the five Gulf of 

Mexico states that shares and coordinates science, 
Scientific Assessment of Marine Harmful Algal Blooms 51

Coordination and Communication

expertise, and financial resources to protect the 

Gulf of Mexico ecosystem. They have a number 

of HAB-related goals related to the improvement 

of HAB detection and forecasting in the region. 

Similar efforts are occurring in other regions, such 

as the West Coast Governor’s Alliance. In addition, 

the HAB Management and Response: Assessment 

and Plan, another report required by HABHRCA 

2004 (Box 1.1), recommends regional coordination 

of HAB research infrastructure and event response.

Further, Regional Coastal Ocean Observing 

Systems, components of IOOS, are meant to 

provide the local-scale data and information to 

address issues that are important to the stakeholders 

in a particular region, which in some cases includes 

HABs. The Gulf of Maine Ocean Observing 

System, which has provided oceanographic data 

for use in conjunction with other data in order to 

monitor and predict Alexandrium bloom movement 

in the Gulf of Maine, offers a preliminary example 

of their application for enhancing HAB prediction.

Interstate Shellfish Sanitation Conference. 

The Interstate Shellfish Sanitation Conference 

(ISSC), formed in 1982, fosters and promotes 

shellfish sanitation through the cooperation of state 

and Federal control agencies, the shellfish industry, 

and the academic community. The ISSC: 1) adopts 

uniform procedures, incorporated into an Interstate 

Shellfish Sanitation Program, and implemented by 

all shellfish control agencies; 2) gives state shellfish 

programs current and comprehensive sanitation 

guidelines to regulate the harvesting, processing, 

and shipping of shellfish; 3) provides a forum for 

shellfish control agencies, the shellfish industry, 

and academic community to resolve major issues 

concerning shellfish sanitation; and 4) informs 

all interested parties of recent developments 

in shellfish sanitation and other major issues 

of concern through the use of news media, 

publications, regional and national meetings, 

internet, and by working closely with academic 

institutions and trade associations. The ISSC 

promotes cooperation and trust among shellfish 

control agencies, the shellfish industry, and 

consumers of shellfish, and insures the safety of 

shellfish products consumed in the United States. 

The ISSC Biotoxin Committee provides guidance 

and recommendations concerning biotoxin issues, 

including addressing methods of analysis for 

regulation of biotoxins in shellfish. A biennial 

meeting is held to address emerging issues, which 

is widely attended by state and Federal regulators. 

More information about ISSC can be found at 

http://www.issc.org/.

The Working Group on Unusual Marine 

Mammal Mortality Events. The working group 

on unusual marine mammal mortality events was 

created under the Marine Mammal Protection Act 

as an advisory board to the Secretary of Commerce 

and Secretary of the Interior and is another 

component of the NOAA NMFS Marine Mammal 

Health and Stranding Response Program. The 

Working Group is made up of 12 members that 

rotate every three years, two international observers 

from Canada and Mexico, and representatives 

from Federal agencies, including NOAA NMFS, 

USFWS, and MMC. The primary role of the 

Working Group is to determine when a UME is 

occurring and then to direct responses to such 

events. Response to UMEs is coordinated by the 

NMFS regional offices and the regional stranding 

networks, as well as other Federal, state, and local 

agencies. Increased marine animal strandings 

can be the first sign of a HAB event, so UMEs 

can serve to identify HABs in areas not actively 

monitored. Investigation of such events has also 

led to a greater understanding of HAB impacts on 

marine mammal populations.

The National Water Quality Monitoring 

Council. The National Water Quality Monitoring 

Council was created in 1997 and has taken the lead 

to design the National Water Quality Monitoring 

Network. It has 35 members and has a balanced 

representation of Federal, tribal, interstate, state, 

local and municipal governments, watershed and 

environmental groups, the volunteer monitoring 

community, universities, and the private sector, 

including the regulated community. The Council 

is co-chaired by the USGS and EPA, and its other 

Federal members include NOAA, Tennessee Valley 

Authority, U.S. Army Corps of Engineers, USDA, 

and the remaining U.S. Department of the Interior 

agencies. The purpose of the Council is to provide 

a national forum for coordination of consistent and 
52 Scientific Assessment of Marine Harmful Algal Blooms

Chapter 4

scientifically defensible methods and strategies 

to improve water quality monitoring, assessment, 

and reporting. The Council promotes partnerships 

to foster collaboration, advance the science, and 

improve management within all elements of 

the water quality monitoring community. More 

information on the National Water Quality 

Monitoring Council is available at: http://acwi.gov/

monitoring/.

National Workshops and Meetings. Currently 

in the United States, communication between 

HAB researchers and Federal, state, and local 

managers is facilitated by the U.S. HAB 

Symposia Series, a biennial national meeting 

that is organized by the U.S. National Office for 

Harmful Algal Blooms and sponsored by NOAA. 

The latest research findings and their application 

to resource and public health management are 

the main topics of these meetings (http://www.

whoi.edu/sbl/liteSite.do?litesiteid=13352). The 

Gordon Research Conference on Mycotoxins and 

Phycotoxins provides a forum for the presentation 

and discussion of leading edge research on 

the biology, chemistry, risk assessment, and 

toxicology of fungal, algal, and cyanobacterial 

toxins that are known food or water contaminants. 

The conference has a history of support from 

numerous Federal agencies, including the USDA, 

FDA, NIEHS, and NOAA (http://www.grc.

org/conferences.aspx?id=0000175). The first 

Gordon Research Conference for Oceans and 

Human Health (http://www.grc.org/programs.

aspx?year=2008&program=oceans) from June 29-

July 4, 2008, included a substantial component on 

HABs and human health.

4.2. International 

Coordination and 

Communication

4.2.1. U.S. Participation in International 

Organizations

HABs are a global phenomenon and many 

countries have a long history of research and 

management responses. Representatives from 

the United States participate in a variety of 

international organizations that address HAB 

issues. Through these activities, the United States 

benefits from the experience with similar problems 

in other countries, preventing duplication of effort. 

The Intergovernmental Oceanographic 

Commission (IOC) HAB Programme focuses 

on HAB management and research in order to 

understand HAB causes, predict their occurrences, 

and mitigate their impacts (http://ioc.unesco.org/

hab/intro.htm). It also supports infrastructure such 

as training courses, web-based learning modules, 

the Harmful Algae News newsletter, and databases 

of global HAB events. It is also one of several 

sponsors of the Global Ecology and Oceanography 

of Harmful Algal Blooms (GEOHAB) Program.

GEOHAB is an international program aimed 

at fostering and promoting co-operative research 

directed toward improving the prediction of 

HAB events (http://www.obs-vlfr.fr/LOV/OMT/

GEOHAB/). Through open science meetings, it 

has developed plans for comparative research on 

HABs in upwelling systems, eutrophic coastal and 

estuarine systems, fjords and coastal embayments, 

and stratified systems focused on HAB biodiversity 

and biogeography, nutrients and eutrophication, 

adaptive strategies comparative ecosystems, and 

observation, modeling, and prediction.

The International Society for the Study of 

Harmful Algae (ISSHA) was founded in 1997 

(http://www.issha.org/). It co-sponsors meetings 

at the national, regional, and international levels 

and promotes and fosters research and training 

programs on harmful algae.

The Association of Analytical Communities 

(AOAC) International’s Marine and Freshwater 

Toxins Task Force (http://www.aoac.org/

marine_toxins/task_force.htm#Overview) is an 

international group of experts on marine and 

freshwater toxins and stakeholders who have a 

strong and practical interest in the development 

and validation of methods for detection of these 

toxins. In response to the global need for improved 

testing methods for these toxins, the Task Force 

validates and provides training in new methods. 

Regional meetings, online forums, and journals of 
Scientific Assessment of Marine Harmful Algal Blooms 53

Coordination and Communication

the AOAC provide an opportunity for the exchange 

of information about new methods.

U.S. representatives participate in regional 

groups in the North Pacific and North Atlantic—

PICES HAB Section and the International Council 

for the Exploration of the Sea Working Group on 

Harmful Algal Bloom Dynamics. Both groups are 

working with the IOC to create a global “Harmful 

Algal Event Database” and also hold meetings to 

address current HAB issues and share regional 

experience in HAB management. 

4.2.2. International Scientific Meetings

International meetings attended by HAB 

researchers and managers, such as the International 

Conference on Harmful Algae organized by 

ISSHA, also provide a forum to exchange recent 

research results that may lead to new management 

approaches. The United States (NOAA and 

NSF) as well as other countries and international 

organizations, have provided support for this 

meeting. The International Union of Pure and 

Applied Chemistry International Symposia on 

Mycotoxins and Phycotoxins have a broader 

focus on research in toxin analysis, human health 

effects, risk assessments, and control and treatment 

strategies. U.S. participation in and support of these 

meetings benefit both the United States and the 

international community. 
54 Scientific Assessment of Marine Harmful Algal Blooms

References

1. Bauer M. (ed.) 2006. Harmful Algal Research and Response: A Human Dimensions Strategy. National Office for Marine Biotoxins 

and Harmful Algal Blooms, Woods Hole Oceanographic Institution, Woods Hole, MA., 58 pp http://coastalscience.noaa.gov/

stressors/extremeevents/hab/HDstrategy.pdf

2. HARRNESS. 2005. Harmful Algal Research and Response: a National Environmental Science Strategy 2005-2015. Ramsdell 

JS, Anderson DM, and Glibert PM. (eds.) Ecological Society of America, Washington, D.C., 96pp. http://www.whoi.edu/fileserver.

do?id=24149&pt=10&p=19132 

3. Jewett EB, Lopez CB, Dortch Q, Etheridge SM, Backer LC. 2008. Harmful Algal Bloom Management and Response: Assessment 

and Plan. Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint Subcommittee on 

Ocean Science and Technology. Washington, DC.

4. Sandifer, P., Sotka, C., Garrison, D., and Fay, V. 2007. Interagency Oceans and Human Health Research Implementation Plan: 

A Prescription for the Future. Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint 

Subcommittee on Ocean Science and Technology. Washington, D.C. 

5. Jewett EB, Lopez CB, Dortch Q, Etheridge SM. 2007. National Assessment of Efforts to Predict and Respond to Harmful Algal 

Blooms in U.S. Waters. Interim Report. Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the 

Joint Subcommittee on Ocean Science and Technology. Washington, DC.

6. CENR. 2000. National Assessment of Harmful Algal Blooms in U.S. Waters. National Science and Technology Council 

Committee on Environment and Natural Resources, Washington, D.C., 38 pp.

7. Van Alstyne KL, Wolfe GV, Freidenburg TL, Neill A, Hicken C. 2001. Activated defense systems in marine microalgae: evidence 

for an ecological role for DMSP cleavage. Marine Ecology Progress Series 213: 53-65.

8. Lopez CB, Jewett EB, Dortch Q, Walton BT, Hudnell HK. 2008. Scientific Assessment of Freshwater Harmful Algal Blooms. 

Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint Subcommittee on Ocean Science 

and Technology. Washington, DC.

9. Anderson DM. 1989. Toxic algal blooms and red tides: A global perspective, pp. 11-16. In: Okaichi T, Anderson DM, and Nemoto 

T (eds.) Red Tides: Biology, Environmental Science and Toxicology. Elsevier, New York.

10. Smayda TJ. 1990. Novel and nuisance phytoplankton blooms in the sea: evidence for a global epidemic, pp. 29-40. In: Graneli 

E, Sundstrom B, Edler L, Anderson DM. (eds.), Toxic Marine Phytoplankton. Elsevier. 

11. Hallegraeff GM. 1993. A review of harmful algal blooms and their apparent global increase. Phycologia 32: 79-99.

12. Hallegraeff GM. 2003. Harmful algal blooms: a global overview. In: Hallegraeff, G.M., Anderson, D.M., and Cembella, A.D. 

(eds). Manual on Harmful Marine Microalgae. UNESCO, Paris, 793 pp.

13. GEOHAB. 2006. Global Ecology and Oceanography of Harmful Algal Blooms, Harmful Algal Blooms in Eutrophic Systems. 

P.Glibert (ed.). IOC and SCOR, Paris and Baltimore, 72 pp.

14. Heisler J, Glibert P, Burkholder J, Anderson D, Cochlan W, Dennison W, Gobler C, Dortch Q, Heil C, Humphries E, Lewitus 

A, Magnien R, Marshall H, Stockwell D, Suddleson M. 2008. Eutrophication and harmful algal blooms: A scientific consensus. 

Harmful Algae. In press.

15. Jackson JB, Kirby MX, Berger WH, Bjorndal KA, Botsford LW, Bourque BJ, Bradbury R, Cooke R, Erlandson J, Estes JA, 

Hughes TP, Kidwell S, Lange CB, Lenihan HS, Pandolfi JM, Peterson CH, Steneck RS, Tegner MJ, Warner R. 2001. Historical 

overfishing and the recent collapse of coastal ecosystems. Science 293: 629 - 638.

16. Hallegraeff GM, Bolch C J. (1992) Transport of dinoflagellate cysts in ships’ ballast water: implications for plankton biogeography 

and aquaculture. Journal of Plankton Research 14, 1067–1084

17. Vanderploeg HA, Liebig JR, Carmichael WW, Agy MA, Johegen TH, Fahnenstiel GL, Nalepa TF. 2001. Zebra mussel (Dreissena 

polymorpha) selective filtration promoted toxic Microcystis blooms in Saginaw Bay (Lake Huron) and Lake Erie. Can. J. Fish. 

Aquat. Sci. 58: 1208-1221.

18. Ferreira JG, Wolff WJ, Simas TC, Bricker SB. 2005. Does biodiversity of estuarine phytoplankton depend on hydrology. 

Ecological Modeling 187: 513-523. 

19. Edwards M, Johns DG, Leterme SC, Svendsen E, Richardson AJ. 2006. Regional climate change and harmful algal blooms in 

the northeast Atlantic. Limnol. Oceanogr. 52(2): 820-829.

20. Dale B, Edwards M, Reid PC. 2006. Climate change and harmful algal blooms. In Granéli E, Turner JT (eds.), Ecology of 

Harmful Algae. Ecological Studies. 189: 367-378.

21. Glibert PM, Anderson DM, Gentien P, Graneli E, Sellner KG. 2005. The global complex phenomena of harmful algal blooms. 

Oceanography 18(2): 136-147.

22. Hoagland P, Scatasta S. 2006. The economic effects of harmful algal blooms. In Graneli E and Turner J (eds.), Ecology of 

References
Scientific Assessment of Marine Harmful Algal Blooms 55

References

Harmful Algae. Ecology Studies Series. Dordrecht, The Netherlands: Springer-Verlag, Chap. 29.

23. Landsberg JH, Hall S, Johannessen JN, White KD, Conrad SM, Abbott JP, Flewelling LJ, Richardson RW, Dickey RW, Jester 

EL, Etheridge SM, Deeds JR, Van Dolah FM, Leighfield TA, Zou Y, Beaudry CG, Benner RA, Rogers PL, Scott PS, Kawabata 

K, Wolny JL, Steidinger KA. 2006. Saxitoxin puffer fish poisoning in the United States, with the first report of Pyrodinium 

bahamense as the putative toxin source. Environ Health Perspect. Oct;114(10):1502-7.

24. Landsberg JH. 2002. The effects of harmful algal blooms on aquatic organisms. Reviews in Fisheries Science 10: 113-390.

25. Gulland FMD, Hall AJ. 2007. Is marine mammal health deteriorating? Trends in the global reporting of marine mammal disease. 

EcoHealth; 4:135-150.

26. Lefebvre KA, Powell CL, Busman M, Doucette GJ, Moeller PD, Silver JB, Miller PE, Hughes MP, Singaram S, Silver MW, 

Tjeerdema RS. 1999. Detection of domoic acid in northern anchovies and California sea lions associated with an unusual 

mortality event. Natural Toxins. 7(3):85-92.

27. Flewelling LJ, Naar JP, Abbott J, Baden D, Barros N, Bossart GD, Bottein MD, Hammond DG, Haubold EM, Heil CA, Henry MS, 

Jacocks HM, Leighfield TA, Pierce RH, Pitchford TD, Rommel SA, Scott PS, Steidinger KA, Truby EW, Van Dolah FM, Landsberg 

JH. 2005. Unexpected vectors of brevetoxins during marine mammal mortalities. Nature 435:755-756.

28. Lund JK, Barnett HJ, Hatfield CL, Gauglitz EJ, Wekell JC, Rasco B. 1997. Domoic acid uptake and depuration in Dungeness 

crab (Cancer magister Dana 1852). J. Shellfish Res. 16: 225-231.

29. Onuf CP. 1996. Seagrass response to long term light reduction by brown tide in upper Laguna Madre, Texas: Distribution and 

biomass patterns. Marine Ecology Progress Series 138:219-231.

30. Valiela I, McClelland J, Hauxwell J, Behr PJ, Hersh D, Foreman K. 1997. Macroalgal blooms in shallow estuaries: Controls and 

ecophysiological and ecosystem consequences. Limnology and Oceanography 42:1105-1118.

31. Hoagland P, Anderson DM, Kaoru Y, White AW. 2002. The economic effects of harmful algal blooms in the United States: 

estimates, assessment issues, and information needs. Estuaries 25(4b): 677-695.

32. Lipton DW. 1999. Pfiesteria’s economic impact on seafood industry sales and recreational fishing. In: Gardner BL, Koch L (eds.), 

Economics of Policy options for Nutrient Management and Pfiesteria. Proceedings of the Conference, Nov. 16, 1998, Laurel, MD.

33. Jin D, Thunberg E, Hoagland P. 2008. Economic impact of the 2005 red tide event on commercial shellfish fisheries in New 

England. Ocean and Coastal Management. 51(5): 420-429.

34. Doucette, G.J., Cembella, A.D., Martin, J.L., Michaud, J., Cole, T.V.N., Rolland, R.M. 2006. Paralytic shellfish poisoning (PSP) 

toxins in North Atlantic right whales Eubalaena glacialis and their zooplankton prey in the Bay of Fundy, Canada. Marine Ecology 

Progress Series 306: 303-313.

35. Anderson D, McGillicuddy D, Townsend D, Turner J. 2005. Preface, Deep Sea Research Part II: Topical Studies in 

Oceanography, The Ecology and Oceanography of Toxic Alexandrium fundyense Blooms in the Gulf of Maine, 52(19-21): 2365-

2368

36. Kahn J, Rockel M. 1988. Measuring the Economic Effects of Brown Tides. Journal of Shellfish Research. 7(4): 677-682.

37. Lomas MW, Gobler CJ. 2004. Aureococcus anophagefferens research: 20 years and counting. Harmful Algae 3: 273-277.

38. Gobler CJ, Londsdale DJ, Boyer GL. 2005. A review of the causes, effects, and potential management of harmful brown tide 

blooms caused by Aureococcus anophagefferens (Hargraves et Sieburth). Estuaries 28(5): 726-749.

39. Maranda L, Keller MD, Hurst JW, Bean LL, Mcgowan JD, Hargraves P. 2000. Spatio-temporal distribution of Prorocentrum lima 

in coastal waters of the Gulf of Maine: a two-year survey. Journal of Shellfish Research 19(3):1003-1006.

40. Maranda L, Shimizu Y. 1987. Diarrhetic shellfish poisoning in Narragansett Bay. Estuaries 10(4): 298-302.

41. Trice RM, Glibert PM, Lea C, Van Heukelem L. 2004. HPLC pigment records provide evidence of past blooms of Aureococcus 

anophagefferens in the Coastal Bays of Maryland and Virginia, USA. Harmful Algae 3: 295-304.

42. Wazniak CE, Glibert PM. 2004. Potential impacts of brown tide, Aureococcus anophagefferens, on juvenile hard clams, 

Mercenaria mercenaria, in the Coastal Bays of Maryland, USA. Harmful Algae 5: 321-329.

43. Burkholder JM, Noga EJ, Hobbs CW, Glasgow HB, Smith SA. 1992. New “phantom” dinoflagellate is the causative agent of 

major estuarine fish kills. Nature 358:407-410.

44. Glibert PM, Burkholder JM. 2006. Ecology of Pfiesteria. Harmful Algae Special Issue 5(4): 339-480.

45. Moeller PDR, Beauchesne KR, Huncik KM, Davis WC, Christopher SJ, Riggs-Gelasco P, Gelasco AK. 2007. Metal Complexes 

and Free Radical Toxins Produced by Pfiesteria piscicida. Environ. Sci. Technol., 41 (4), 1166 -1172.

46. Place AR, Saito K, Deeds JR, Robledo JAF, Vasta GR. 2007. Pfiesteria spp toxins: unresolved questions and an alternative 

hypothesis. In Botana L (ed.), Seafood and Freshwater Toxins, Pharmacology, Physiology, and Detection. Taylor and Francis, 

2nd Edition. CRC.

47. Chesapeake Quarterly. 2007. Was there another fish killer? Volume 6, Issue 1. http://www.mdsg.umd.edu/cq/v06n1/index.

html#TOC
56 Scientific Assessment of Marine Harmful Algal Blooms

References

48. Bordelais AJ, Tomas, CR, Naar J, Kubanek J, Baden DG. 2002. New fish-killing alga in coastal Delaware produces neurotoxins. 

Environmental Health Perspectives 110(5)465-470.

49. Keppler CJ, Hoguet J, Smith K, Ringwood AH, Lewitus AJ. 2005. Sublethal effects of the toxic alga Heterosigma akashiwo on 

the southeastern oyster (Crassostrea virginica), Harmful Algae 4: 275–285.

50. Glibert PG, Sellner KG (eds.) 2005. Ecology and physiology of Prorocentrum minimum. Harmful Algae Special Issue 4(3): 447-

650. 

51. Lapointe BE, Barile PJ, Littler MM, Littler DS, Bedford BJ, Gasque C. 2005. Macroalgal blooms on southeast Florida coral reefs: 

I. Nutrient stoichiometry of theinvasive green alga Codium isthmocladum in the wider Caribbean indicates nutrient enrichment. 

Harmful Algae, 4:1092-1105.

52. Murphy EB, Steidinger KA, Roberts BS, William J, Jolley JW. 1975. An explanation for the Florida east coast Gymnodinium 

breve red tide of November 1972. Limnol. Oceanogr. 20:481-486.

53. Steidinger, K.A., Vargo, G.A., Tester, P.A., Tomas, C.R., 1998. Bloom dynamics and physiology of Gymnodinium breve with 

emphasis on the Gulf of Mexico. In: Anderson DM, Cambella AD, Hallegraeff GM. (eds.), Physiological Ecology of Harmful Algal 

Blooms. Springer, New York, pp. 135–153. 

54. Thessen AE, Bowers BA, Stoecker DK, Oldach DW. 2006. Pseudo-nitzschia spp. and domoic acid in Maryland and Virginia 

waters. 12th International Conference on Harmful Algae, Copenhagen, Denmark, September 4-8, 2006.

55. Magaña HA, Contreras C., Villareal TA. 2003. A historical assessment of Karenia brevis in the western Gulf of Mexico, Harmful 

Algae 2:163–171.

56. Maier Brown AF, Dortch Q, Van Dolah FM, Leighfield TA, Morrison W, Thessen AE, Steidinger KA, Richardson B, Moncreif CA, 

Pennock JR. 2006. Effect of salinity on the distribution and growth, and toxicity of Karenia spp. Harmful Algae, 5, 199-212.

57. Haywood AJ, Steidinger KA, Truby EW, Bergquist PR, Bergquist PL, Adamson J, MacKenzie L. 2004. Comparative morphology 

and molecular phylogenetic analysis of three new species of the genus Karenia (Dinophyceae) from New Zealand. J. Phycol. 40: 

165-179.

58. Steidinger KA, Landsberg JH, Tomas CR, Burns JW. 1999. Harmful algal blooms in Florida, Unpublished technical report 

submitted to the Florida Harmful Algal Bloom Task Force, Florida Marine Research Institute, 63pp.

59. Evans G, Jones L. 2001. Economic Impact of the 2000 Red Tide on Galveston County, Texas A Case Study. Final Report. TPWD 

No. 666226. Texas Parks and Wildlife. 

60. Villareal TA, Hanson S, Qualia S, Jester ELE, Granade HR, Dickey RW. 2007. Petroleum production platforms as sites for the 

expansion of ciquatera in the northwestern Gulf of Mexico. Harmful Algae 6: 253-259.

61. Dortch Q, Robichaux R, Pool S, Milsted D, Mire G, Rabalais NN, Soniat TM, Fryxell GA, Turner RE, Parsons ML. 1997. 

Abundance and vertical flux of Pseudo-nitzschia in the northern Gulf of Mexico. Marine Ecology Progress Series 146:249-264. 

62. Parsons ML, Dortch Q, Turner RE. 2002. Sedimentological Evidence of an Increase in Pseudo-nitzschia (Bacillariophyceae) 

Abundance in Response to Coastal Eutrophication. Limnology and Oceanography 47(2): 551-558.

63. Lapointe BE, Bedford BJ. 2007. Drift rhodophyte blooms emerge in Lee County, Florida, USA: Evidence of escalating coastal 

eutrophication. Harmful Algae 6: 421-437.

64. Moikeha SN, Chu GW. 1971. Dermatitis producing alga Lyngbya majuscula Gomont in Hawaii. II. Biological properties of the 

toxic factor. J. Phycol. 7: 8. 

65. Osborne NJT, Web PM, Shaw GR. 2001. The toxins of Lyngbya majuscule and their human and ecological health effects. 

Environmental International. 27:381-392.

66. Hickey BM, MacFadyen A, Trainer VL, Lessard EJ, Cochlan WP, Trick CG, Wells ML. 2007. Regional oceanography leading to 

toxic Pseudo-nitzschia events on beaches in the northern California Current. Fourth Symposium on Harmful Algae in the U.S. 

28Oct -1Nov 2007. Woods Hole, Massachusetts.

67. Ayres D, Reed H. 2004. Managing important recreational and commercial shellfish fisheries around harmful algal blooms. In: 

Droscher TW and Fraser DA (eds.). Proceedings of the 2003 Georgia Basin/Puget Sound Research Conference. Session 4F. 

http://www.psat.wa.gov/Publications/03_proceedings/start.htm [February 2004]

68. Gulland F. 2000. Domoic acid toxicity in California sea lions (Zalophus californianus) stranded along the central California coast, 

May-October 1998. Report to the National Marine Fisheries Service Working Group on Unusual Marine Mammal Mortality 

Events. U.S. Department of Commerce, NOAA Technical Memo. NMFS-OPR-17, 45p.

69. Goldstein T, Mazet JA, Zabka TS, Langlois G, Colegrove KM, Silver M, Bargu S, Van Dolah F, Leighfield T, Conrad PA, Barakos 

J, Williams DC, Dennison S, Haulena M, Gulland FM. 2008. Novel symptomatology and changing epidemiology of domoic acid 

toxicosis in California sea lions (Zalophus californianus): an increasing risk to marine mammal health. Proc. Biol. Sci. 275: 267-

76.

70. Schnetzer A, Miller PE, Schaffner RA, Stauffer BA, Jones BH, Weisberg SB, DiGiacomo PM, Berelson WM, Caron DA. 2007. 

Blooms of Pseudo-nitzschia and domoic acid in the San Pedro Channel and Los Angeles harbor areas of the Southern California 

Bight, 2003-2004. Harmful Algae 6: 372-387.
Scientific Assessment of Marine Harmful Algal Blooms 57

References

71. Horner RA, Garrison DL, Plumley FG. 1997. Harmful algal blooms and red tide problems on the US West Coast. Limnol. 

Oceanagr. 42(5): 1076-1088. 

72. Rensel J. 1995. Harmful algal and finfish resources in Puget Sound. In Puget Sound Research 95 Proceedings. Puget Sound 

Water Quality Authority, Olympia, Wash. pp. 422–429.

73. O’Halloran C, Silver MW, Holman TR, Scholin CA. 2006. Heterosigma akashiwo in central California waters, Harmful Algae 5: 

124–132. 

74. Nelson TA, Lee D, Smith BC. 2003. Toxic extracts from ulvoid macroalgae: Are “green tides” harmful algal blooms?, J. Phycol. 

39: 874–879. 

75. Sutherland C, Silver M. 2007. Dinophysis species and diarrhetic shellfish toxins in Monterey Bay, CA. Fourth Symposium on 

Harmful Algae in the U.S. 28Oct -1Nov 2007. Woods Hole, Massachusetts.

76. RaLonde R. (ed). 2001. Harmful algal blooms on the North American West Coast. University of Alaska Sea Grant. AK-SG-0105.

77. Cesar H, van Beukering P, Pintz S, Dierking J. 2002. Economic Value of the Coral Reefs of Hawaii, Final Report, December 23, 

2002.

78. NOAA. 2006. NOAA Economic Statistics Report. http://www.economics.noaa.gov/library/documents/economic_statistics_and_

methodology/NOAAEconomicStatistics-May2006.pdf 

79. Arnold H. 1959. Seaweed dermatitis apparently caused by a marine alga. Clinical Observations. In: Proceedings of the 34th 

Annual Meeting of the Hawaiian Academy of Sciences.

80. Nagle DJ, Paul VJ. 1999. Production of secondary metabolites by filamentous tropical marine cyanobacteria: Ecological 

functions of the compounds. J.Phycology 35(6): 1412-1421

81. ICGPSIA (Interorganizational Committee on Guidelines and Principles for Social Impact Assessment). 2003. Principles and 

guidelines for social impact assessment in the USA. Impact Assessment and Project Appraisal 21(3): 231-250

82. Anderson DM, Stock CA, Keafer BA, Bronzino Nelson A, Thompson B, McGillicuddy DJ, Keller M, Matrai PA, Martin J. 2005. 

Alexandrium fundyense cyst dynamics in the Gulf of Maine. Alexandrium fundyense cyst dynamics in the Gulf of Maine. DeepSea Research II. 52: 2522-2542

83. Kirn SL, Townsend DW, Pettigrew NR. 2005. Suspended Alexandrium spp. hypnozygote cysts in the Gulf of Maine. Deep-Sea 

Research II. 52: 2543-2559.

84. Matrai P, Thompson B, Keller M. 2005. Circannual excystment of resting cysts of Alexandrium spp. from eastern Gulf of Maine 

populations. Deep-Sea Research II. 52: 2560-2568.

85. Lidie KB, Ryan JC, Barbier M, Van Dolah FM. 2005. Gene Expression in the Florida Red Tide Dinoflagellate Karenia brevis: 

Analysis of an Expressed Sequence Tag (EST) Library and Development of a DNA Microarray. Mar Biotechnol. 7(5):481-493. 

86. Erdner DL, Anderson DM. 2006. Global transcriptional profiling of the toxic dinoflagellate Alexandrium fundyense using 

massively parallel signature sequencing. BMC Genomics. 7: 88.

87. Erdner DL, McCauley LAR, Libera K, Anderson DM. 2007. Population genetics of toxic Alexandrium blooms in the Gulf of Maine. 

Fourth Symposium on Harmful Algae in the U.S. 28Oct -1Nov 2007. Woods Hole, Massachusetts.

88. Martinetto P, Teichberg M, Valiela I. 2006. Coupling of estuarine benthic and pelagic food webs to land-derived nitrogen sources 

in Waquoit Bay, Massachusetts, USA. Marine Ecology Progress Series 307: 37–48.

89. Trainer VL, Hickey BM, Horner RA. 2002. Biological and physical dynamics of domoic acid production off the Washington Coast. 

Limnol. Oceanogr. 47(5): 1438-1446.

90. Hu C, Muller-Karger FE, Swarzenski PW. 2006. Hurricanes, submarine groundwater discharge, and Florida’s red tides. 

Geophysical Research Letters. 33, L11601.

91. Swarzenski PW, Simonds FW, Paulson AJ, Kruse S, Reich C. 2007. Geochemical and geophysical examination of submarine 

groundwater associated nutrient loading estimates into Lynch Cove, Hood Canal, Wa. Environ. Sci.Technol. 41: 7022-7029.

92. Kana TM, Lomas MW, MacIntyre HL, Cornwell JC, Gobler CJ. 2004. Stimulation of a brown tide organism, Aureococcus 

anophagefferens, by selective nutrient additions to in situ mesocosms. Harmful Algae 3:403-438. 

93. Glibert PM, Burkholder JM, Parrow MW, Lewitus AJ, Gustafson D. 2006. Rates of direct uptake of nitrogen and nitrogen 

nutritional preferences by functional types of Pfiesteria piscicida and Pfiesteria shumwayae. Harmful Algae 5: 380-394. 

94. Seaborn DW, Dunstan WM, Marshall HG, Gordon AS, Seaborn AM. 2001. Growth and toxicity studies of the dinoflagellates 

cryptoperidiniopsis sp., Gyrodinium galatheanum, and Pfiesteria piscicida. In: Hallegraeff GM, Blackburn SI, Bolch CJ, Lewis RJ, 

Editors, Harmful Algal Blooms, Proceedings of the Ninth International Conference on Harmful Algal Blooms IOC UNESCO, Paris, 

France (2001), pp. 92–96.

95. Egerton TA, Marshall HG. 2006. Feeding preferences and grazing rates of Pfiesteria piscicida and a cryptoperidiniopsoid preying 

on fish blood cells and algal prey. Harmful Algae 5(4): 419-426.
58 Scientific Assessment of Marine Harmful Algal Blooms

References

96. Adolf JE, Stoecker DK, Harding LW. 2006. The balance of autotrophy and heterotrophy during mixotrophic growth of Karlodinium 

micrum (Dinophyceae). Journal of Plankton Research 28(8):737-751. 

97. Sheng J, Malkiel E, Katz J, Adolf J, Belas R, Place AR. 2007. Digital holographic microscopy reveals prey-induced changes in 

swimming behavior of predatory dinoflagellates. PNAS 104:17512-17517.

98. Lenes JM, Darrow BP, Cattrall C., Heil CA, Callahan M, Vargo GA, Byrne RH. 2001. Iron fertilization and the Trichodesmium 

response on the West Florida Shelf. Limnol. Oceanogr. 46(6): 1261-1277.

99. Keafer BA, Churchill JH, Anderson DM. 2005a. Blooms of the toxic dinoflagellate, Alexandrium fundyense in the Casco Bay 

region of the western Gulf of Maine: Advection from offshore source populations and interactions with the Kennebec River plume. 

Deep-Sea Research II. 52: 2631-2655.

100. Bean LL, McGowan JD, Hurst JW. 2005. Annual variations of paralytic shellfish poisoning in Maine, USA 1997–2001. DeepSea Research II. 52: 2834-2842.

101. Keafer BA, Churchill JH, McGillicuddy DJ, Anderson DM. 2005b. Bloom development and transport of toxic Alexandrium 

fundyense populations within a coastal plume in the Gulf of Maine. Deep-Sea Research II. 52: 2674-2697.

102. MacFadyen A, Hickey BM, Foreman MGG. 2005. Transport of surface waters from the Juan de Fuca eddy region to the 

Washington coast. Continental Shelf Research 25: 2008-2021.

103.Doucette GJ, McGovern ER, Babinchak JA. 1999. Algicidal bacteria active against Gymnodinium breve (Dinophyceae). I. 

Bacterial isolation and characterization of killing activity. J. Phycol. 35:1447-1454.

104.Gobler CJ, Deonarine S, Leigh-Bell J, Downes Gastrich M, Anderson OR, Wilhelm SW. 2004. Ecology of phytoplankton 

communities dominated by Aureococcus anophagefferens: the role of viruses, nutrients, and microzooplankton grazing. Harmful 

Algae 6: 471-483.

105.Gunderson JH, Goss SH, Coats W. 2001. FISH probes for the detection of parasitic dinoflagellate Amoebophrya sp. infecting 

the dinoflagellate Akashiwo sanguinea in Chesapeake Bay. J. Eukaryot. Microbiol. 48(6)670-675.

106. McGillicuddy DJ, Signell RP, Stock CA, Keafer BA, Keller MD, Hetland RD, Anderson DM. 2003. A mechanism for offshore 

initiation of harmful algal blooms in the coastal Gulf of Maine . Journal of Plankton Research, 25(9), 1131-1138. 

107. McGillicuddy DJ, Anderson DM, Lynch DR, Townsend DW. 2005. Mechanisms regulating large-scale seasonal fluctuations in 

Alexandrium fundyense populations in the Gulf of Maine: Results from a physical–biological model. Deep-Sea Research II. 52: 

2698-2714.

108. Stock CA, McGillicuddy DJ, Solow AR, Anderson DM. 2005. Evaluating hypotheses for the initiation and development of 

Alexandrium fundyense blooms in the western Gulf of Maine using a coupled physical–biological model. Deep-Sea Research II. 

52: 2715-2744.

109. Anderson DM, Keafer BA, McGillicuddy DJ, Mickelson MJ, Keay KE, Libby PS, Manning JP, Mayo CA, Whittaker DK, Hicky 

JM, He R, Lynch DR, Smith KW. 2005. Initial observations of the 2005 Alexandrium fundyense bloom in southern New England: 

General Patterns and Mechanisms. Deep-Sea Research II. 52: 2856-2876.

110. Hood RR, Zhang X, Glibert PM, Roman MR, Stoecker DK. Modeling the influence of nutrients, turbulence and grazing on 

Pfiesteria population dynamics. Harmful Algae: 5(4)459-479.

111. Rublee PA, Kempton JW, Schaefer EF, Allen C, Harris J, Oldach DW, Bowers H, Tengs T, Burkholder JM, Glsgow HB. 2001. 

Use of molecular probes to assess geographic distribution of Pfiesteria species. Environmental Health Perspectives 109(5):765-

767.

112.Cloern JE, Jassby AD, Thompson JK, Hieb KA. 2007, A cold phase of the East Pacific triggers new phytoplankton blooms in 

San Francisco Bay: Proceedings of the National Academy of Sciences USA, v. 104, p.18,561-18,565. 

113. Carter M, McGowan J, Buss L, Venrick E, Hilbern M. 2007. Coastal bloom dynamics in sourthern California – Have there been 

any changes since 1917? Fourth Symposium on Harmful Algae in the U.S. 28Oct -1Nov 2007. Woods Hole, Massachusetts.

114.Cloern JE, Schraga TS, Lopez CB, Knowles N, Labiosa RG, Dugdale R. 2005. Climate anomalies generate an exceptional 

dinoflagellate bloom in San Francisco Bay. Geophysical Research Letters 32, LI4608. 

115. Vilotijevic I, Jamison TF. 2007. Epoxide-Opening Cascades Promoted by Water. Science, 317, 1189-1192.

116. Maldonado MT, Hughes MP, Rue EL, Wells ML. 2002. The effect of Fe and Cu on growth and domoic acid production by 

Pseudo-nitzschia multiseries and Pseudo-nitzschia australis. Limnology and Oceanography, 47: 515-526.

117. Parker MS, Armbrust EV, Lin EO, Jenkins BD, Iverson VS, Rodrigues H, Kudela R. 2006. Gene Expression Associated With 

Domoic Acid Production and Silicate Limitation in the Diatom Pseudo-nitzschia australis. Eos Trans. AGU, 87(36), Ocean 

Sciences Meeting Supplement, Abstract OS24D-06.

118. Litaker RW, Trainer V, Le Eberhart B-T, Wekell J, Spencer S, Moon M, Schumacker J, Northcut K, Krueger K, Wojciechowski 

M, Wojciechowski M, Bonaventura C, Tester P. 2003. Detecting Domoic Acid. Estuarine Research Federation Conference 2003 

14-18 September, 2003 Seattle, Washington.

119. Lefebvre KA, Trainer VL, Scholz NL. (2004) Morphological abnormalities and sensorimotor deficits in larval fish exposed to 
Scientific Assessment of Marine Harmful Algal Blooms 59

References

dissolved saxitoxin. Aquatic Toxicology 66:159-170.

120. Lefebvre K A, Elder N, Hershberger PK, Trainer VL, Stehr CM, Scholz NL. 2005. Dissolved saxitoxin causes transient inhibition 

of sensorimotor function in larval Pacific herring (Clupea harengus pallasi). Marine Biology, 147:1393-1402.

121. Levin ED, Pizarro K, Pang WG, Harrison J, Ramsdell JS. 2005. Persisting behavioral consequences of prenatal domoic acid 

exposure in rats. Neurotoxicol Teratol. Sep-Oct; 27(5):719-25.

122. Abraham WM, Bourdelais AJ, Sabater JR, Ahmed A, Lee TA, Serebriakov I, Baden DG. 2005. Airway Responses to Aerosolized 

Brevetoxins in an Animal Model of Asthma Am. J. Respir. Crit. Care Med. 171: 26-34. 

123.Brodie EC, Gulland FMD, Greig DJ, Hunter M, Jaakola J, St Leger J, Leighfield TZ, Van Dolah FM. 2006. Domoic acid causes 

reproductive failure in California sea lions (Zalophus californianus). Mar Mamm Sci. 2006;22(3):700–707.

124.Bricelj VM, MacQuarrie SP, Smolowitz R. 2004. Concentration-dependent effects of toxic and non-toxic isolates of the brown 

tide alga Aureococcus anophagefferens on growth of juvenile bivavles. Marine Ecology Progress Series 282:101-114.

125. Peterson BJ, Chester CM, Jochem FJ, Fourqurean JW. 2006. Potential role of sponge communities in controlling phytoplankton 

blooms in Florida Bay. Marine Ecology Progress Series. 328: 93-103.

126.Cohen JH, Tester PA, Forward R.B. 2007. Sublethal effects of the toxic dinoflagellate Karenia brevis on marine copepod 

behavior. Journal of Plankton Research. 29(3): 301-315. 

127. Prince EK, Lettieri L, McCurdy KJ, Kubanek J. 2006. Fitness consequences for copepods feeding on a red tide dinoflagellate: 

deciphering the effects of nutritional value, toxicity, and feeding behavior. Oecologia. 147(3):279-288.

128.Colin SP, Dam HG. 2007. Comparison of the functional and numerical responses of resistant versus non-resistant populations 

of the copepod Acartia hudsonica fed the toxic dinoflagellate Alexandrium tamarense. Harmful Algae. 6: 875-882.

129.Bricelj VM, MacQuarrie SP. 2007. Effects of brown tide (Aureocuccus anophagefferens) on hard clam Mercenaria mercenaria 

larvae and implications for benthic recruitment. Marine Ecology Progress Series 331:147-159.

130.Giner JL, Zhao H, Dixon MS, Wikfors GH. 2007. Metabolism of algal sterols by Bay Scallops and Brine Shrimp. Fourth 

Symposium on Harmful Algae in the U.S. 28Oct -1Nov 2007. Woods Hole, Massachusetts.

131.Doucette GJ, Turner JT, Powell CL, Keafer BA, Anderson DM. 2005. Trophic accumulation of PSP toxins in zooplankton during 

Alexandrium fundyense blooms in Casco Bay, Gulf of Maine, April–June 1998. I. Toxin levels in A. fundyense and zooplankton 

size fractions, Deep-Sea Research II. 52: 2764-2783.

132. Turner JT, Doucette GJ, Keafer BA, Anderson DM. 2005. Trophic accumulation of PSP toxins in zooplankton during 

Alexandrium fundyense blooms in Casco Bay, Gulf of Maine, April–June 1998. Zooplankton abundance and size-fractionated 

community composition. Deep-Sea Research II. 52: 2784-2800.

133. Lefebvre KA, Bargu S, Kieckhefer T, Silver MW. 2002. From sanddabs to blue whales: the pervasiveness of domoic acid. 

Toxicon. 40: 971-977

134.Bricelj VM, Connell LB, Konoki K, MacQuarrie SP, Scheuer T, Catterall WA, Trainer VL. 2005. Sodium channel mutation leading 

to saxitoxin resistance in clams increases risk of PSP. Nature. 434: 763-767.

135. Grattan LM, Oldach D, Morris JG. 2001. Human health risks of exposure to Pfiesteria piscicida. BioScience 51(10): 853-857. 

136. Moe CL, Turf E, Oldach D, Bell P, Hutton S, Savitz D, Koltai D, Turf M, Ingsrisawang L, Hart R, Ball JD, Stutts M, McCarter 

R, Wilson L, Haselow D, Grattan L, Morris JG, Weber DJ. 2001. Cohort studies of health effects among people exposed to 

estuarine waters: North Carolina, Virginia, and Maryland. Environmental Health Perspectives 109: 781-786.

137. Morris Jr JG, Grattan LM, Wilson LA, Meyer WA, McCarter R, Bowers HA, Richard Hebel J, Matuszak DL, Oldach DW. 

2006. Occupational Exposure to Pfiesteria Species in Estuarine Waters Is Not a Risk Factor for Illness. Environmental Health 

Perspectives 114(7): 1038-1043.

138. Kirkpatrick B, Fleming LE, Backer LC, Bean JA, Tamer R, Kirkpatrick G, Kane T, Wanner A, Dalpra D, Reich A, Baden DG. 

2006. Environmental exposures to Florida red tides: effects on emergency room respiratory diagnoses admissions. Harmful 

Algae. 5(5)526-533.

139. Anderson DM, Hoagland P, Kaoru Y, White AW. 2000. Estimated Annual Economic Impacts from Harmful Algal Blooms (HABs) 

in the United States. WHOI Tech Rept. No. 2000-11. Woods Hole, MA: Department of Biology and Marine Policy Center, Woods 

Hole Oceanographic Institution.

140. Fleming LE, Jerez E, Stephan W, Cassedy A, Bean JA, Reich A, Kirkpatrick B, Backer L, Nierenberg K, Watkins S, Hollenbeck 

J, Weisman R. 2007. Florida aquatic toxins hotline: formal evaluation of HAB outreach and educational activities. Fourth 

Symposium on Harmful Algae in the U.S. 28Oct -1Nov 2007. Woods Hole, Massachusetts.

141. Hudnell HK. (ed.). 2008. Cyanobacterial Harmful Algal Blooms: State of the Science and Research Needs. Advances in 

Experimental Medicine & Biology. Vol. 619. Springer. 500 pp.

142. Dortch, Q., Anderson, D., Ayres, D., Glibert, G. (eds). 2008. Harmful Algal Bloom Research, Development, Demonstration 

and Technology Transfer National Workshop Report. Woods Hole, Massachusetts. http://www.whoi.edu/fileserver.

do?id=43464&pt=10&p=19132
60 Scientific Assessment of Marine Harmful Algal Blooms

Appendices

Appendix. Marine HAB Research and Response by State, 

Local, and Tribal Governments 

State and local governments and tribal entities are involved in HAB monitoring and mitigation, and 

some states also have research programs. Tribal and state public health or resource management agencies 

are responsible for monitoring programs and shellfish harvesting or beach closures. FDA works closely 

with state shellfish control authorities to ensure the safety of shellfish harvested from state waters. State 

programs disseminate toxin advisory information to the public through web sites, the media, and written 

materials. Several citizen HAB monitoring networks have also been established, which assist state efforts 

to track HABs and contribute to ground-truthing of HAB forecasts. Entities conducting HAB research 

and response are outlined by region and state below. 

Northeast

Connecticut

• Department of Agriculture: monitoring and shellfish closures, http://www.ct.gov/doag/cwp/view.

asp?a=1369&q=259172

Maine

• Department of Marine Resources

• Red tide and shellfish sanitation status information, http://www.maine.gov/dmr/rm/public_

health/closures/shellfishhotline.htm

• Maine Red Tide Information System, http://megisims.state.me.us/dmr_redtide/

• Maine volunteer phytoplankton monitoring program, http://www.umext.maine.edu/

shorestewards/phyto.htm

Massachusetts

• Division of Marine Fisheries: protocols for monitoring, harvesting closures, and other regulatory 

information, http://www.mass.gov/dfwele/dmf/

• Department of Public Health: permit procedures and food safety

New Hampshire

• Department of Environmental Services Shellfish Program and New Hampshire Fish and Game 

Department: shellfish monitoring, http://www.des.state.nh.us/wmb/shellfish/index.html

New Jersey

• Department of Environmental Protection, Division of Marine Water Monitoring: water quality 

procedures and shellfish monitoring, http://www.state.nj.us/dep/bmw/

• Department of Environmental Protection, Division of Science, Research and Technology: Brown 

Tide information, http://www.state.nj.us/dep/dsr/browntide/bt.htm

New York

• Department of Environmental Conservation: shellfish closure information, http://www.dec.

ny.gov/outdoor/345.html

• Brown Tide Research Initiative, http://www.seagrant.sunysb.edu/btri/

Rhode Island

• Bureau of Environmental Protection: shellfish closures, http://www.dem.ri.gov/programs/

benviron/water/shellfsh/clos/index.htm 
Scientific Assessment of Marine Harmful Algal Blooms 61

Appendices

Mid-Atlantic and South-Atlantic

Delaware

• Department of Natural Resources and Environmental Control, in collaboration with the 

University of Delaware Sea Grant College Program: supports the Inland Bays Citizen Monitoring 

Program, http://www.ocean.udel.edu/mas/DIBCMP/index.html

Maryland

• Department of Natural Resources: HAB monitoring; website with HAB information, bloom status 

reports, hotline for reporting potential HAB events, http://www.dnr.state.md.us/Bay/hab/index.

html

• Eyes on the Bay: interactive access to Chesapeake monitoring stations with HAB data, http://

mddnr.chesapeakebay.net/eyesonthebay/index.cfm

• Department of the Environment: notices of shellfish closures and fish advisories, http://textonly.

mde.state.md.us/CitizensInfoCenter/FishandShellfish/home/index.asp

• Department of Health and Mental Hygiene: cooperative agreement with CDC to conduct HAB 

public health response activities.

North Carolina

• Department of Environment and Natural Resources, Division of Water quality: monitoring data 

and fish kill maps for area rivers; Division of Marine Fisheries: shellfish closure status

• Department of Health and Human Services: cooperative agreement with CDC to conduct HAB 

public health response activities.

South Carolina

• Department of Health and Environmental Control: monitoring and shellfish closure status and 

Cooperative agreement with CDC to conduct HAB public health response activities, http://www.

scdhec.gov/environment/water/shellfish.htm

• South Carolina Algal Ecology Lab: HAB research, partnership between Department of Natural 

Resources and University of South Carolina, http://www.dnr.sc.gov/ael/research/research.html

Virginia

• Department of Environmental Quality: procedures and regulations for water quality monitoring, 

http://www.deq.virginia.gov/watermonitoring/pfiest.html

• Department of Health: cooperative agreement with CDC to conduct HAB public health response 

activities

Gulf of Mexico

Florida

• Florida Fish and Wildlife Research Institute: HAB research, current red tide status for the Florida 

coast, network of volunteers monitoring for Karenia brevis (developed with MERHAB funding), 

http://research.myfwc.com/features/view_article.asp?id=12373

• Department of Agriculture and Consumer Services, Division of Aquaculture: shellfish closure 

status

• Department of Health: cooperative agreement with CDC to conduct HAB public health response 

activities, http://www.doh.state.fl.us/environment/community/aquatic/index.html

• Florida’s Harmful Algal Bloom Task Force: Advisory body to address specific HAB issues and 

human health risks
62 Scientific Assessment of Marine Harmful Algal Blooms

Appendices

Mississippi

• Department of Marine Resources: shellfish closure status

Texas

• Parks and Wildlife Department: Texas coast red tide status reports, inland golden algae bloom 

status reports, http://www.tpwd.state.tx.us/landwater/water/environconcerns/hab/

• Department of Health: shellfish closures due to red tide, http://www.dshs.state.tx.us/seafood/

RedTide.shtm

• Red Tide Rangers: volunteer HAB monitoring 

West Coast

Alaska

• Department of Environmental Conservation, Division of Environmental Health: monitoring for 

PSP and status of shellfish closures, http://www.dec.state.ak.us/eh/fss/seafood/psphome.htm

California

• Department of Health Services, Division of Drinking Water and Environmental Management: 

advisories and reports for marine biotoxin monitoring, http://www.cdph.ca.gov/healthinfo/

environhealth/water/Pages/Shellfish.aspx

• Department of Fish and Game: Investigations of wildlife mortalities

Oregon

• Department of Human Services: beach monitoring programs and fish advisories, http://www.

oregon.gov/DHS/ph/envtox/index.shtml

Washington

• Department of Health: shellfish closure status, monitoring program, and biotoxin bulletins, http://

www.doh.wa.gov/ehp/sf/BiotoxinProgram.htm

• Department of Fish and Wildlife: shellfish harvesting regulations, collection of shellfish tissue 

samples, collection and analysis of phytoplankton samples, http://wdfw.wa.gov/fishing/

• Olympic Region Harmful Algal Bloom Program: monitoring of phytoplankton and toxins in 

seawater, http://www.orhab.org/

Hawaii

• Department of Health: information on ciguatera fish poisoning, http://hawaii.gov/health/familychild-health/contagious-disease/wnv/comm-disease/factsheet/ciguatera.pdf