Harmful Algal Blooms

ABCs of HABs

Harmful algal blooms (HABs) are a worldwide phenomenon posing a significant threat to public health, economies, water quality, and fisheries. Increasingly, the phrase is repeated in the media as HABs have increased in frequency, duration, and distribution in recent decades.

HABs come in a rainbow of colors, but at the end of this rainbow there’s no pot of gold. In fact, it’s just the opposite and New York waters have more than their fair share.

During the 1950s there were green tide blooms in Long Island’s (LI) south shore bays that negatively impacted the oyster fishery. In the mid-1980s, brown tides occurred in LI’s south shore and east end bays, destroying eelgrass beds, scallop fisheries and hard clam fisheries. Since 2002, toxin-producing red tide blooms have caused shellfishery closures on LI Sound bays. For decades, the toxins in cyanobacteria (also known as blue-green algae) have negatively impacted drinking water in New York’s Great Lakes region and even fresh water ponds on Long Island.
 
What’s the difference among these harmful blooms? What should you know about the harm they can cause?

Follow the links for more on harmful algal blooms and the work of New York Sea Grant (NYSG) researchers and extension specialists.

HABs and Dogs

HABs, especially in the New York State's fresh water, are overgrowths of cyanobacteria (blue-green algae) that cause water quality problems in lakes and ponds, including the occasional production of potent toxins. Of the 8,000 or so species of cyanobacteria, only about 40 produce toxins. However, these toxins can poison people, household pets, waterfowl and livestock. Because HABs are increasing in many areas, the number of dog poisonings from cyanobacterial toxins is also on the rise.

Starting in 2014, NYSG and New York State Parks partnered to educate dog owners this summer by providing copies of the Dogs and Harmful Algal Blooms fact sheet and brochure (pdf) developed by New York Sea Grant at several State Parks.

For more, check out our related news on this topic.

The most recent news item on this topic "In Media, On YouTube: Protect Your Dog From Harmful Algal Blooms," is from September 2019.

HABs Planning and Reporting

The New York State Department of Environmental Conservation encourages the public to view its "Harmful Algal Blooms (HABs) Notifications Page," which includes important things to know about HABs as well as tips on what to do when blooms are encountered.

This builds on recent efforts between the two, highlighted most recently in Starting in 2018, New York Sea Grant (NYSG) partnered with Suffolk County Department of Health Services (SCDHS) on a HABs effort, which was most recently documented in March 2019's "Sea Grant Leads Suffolk County Effort for HAB Mitigation Planning."

In 2020, NYSG and SCDHS continued this partnership by facilitating a public reporting tool for marine HABs.

Table of Contents

June 16, 2025
News
Introducing Tools to Enhance Harmful Algal Bloom Monitoring Capabilities
Publications: Success Stories - Extension (2024)
AI technology is used to obtain faster testing results when assessing harmful algal bloom events
Read More >
May 31, 2025
News
2018 Suffolk County Harmful Algal Bloom Symposium: Summary Report
Harmful Algal Blooms - News
Read More >
May 31, 2025
Article
Brown Tide Research Initiative
Staff & Contact Information

Staff & Contact Information: Brown Tide Research Initiative

Read More >
May 31, 2025
News
Creating Public Access to “Real Time” Harmful Algal Bloom Outbreak Alerts
Publications: Success Stories - Extension (2021)
Public input can help waterfront managers to improve their marine harmful algal blooms response and better leverage resources
Read More >
May 31, 2025
News
Genome Sequence Favors Brown Tide
New York Coastlines, Summer/Fall 2011
The year 2011 has been a banner one for the single-celled alga Aureococcus anophagefferens whose prolific blooms are known as “brown tide.” With concentrations in excess of 2 million cells per milliliter in some Long Island bays, this alga turned the waters brown from western Shinnecock Bay to eastern Moriches Bay, making for intense, though localized, brown tide conditions.
Read More >
May 31, 2025
Article
Harmful Algal Blooms
Read More >
May 31, 2025
News
In Media, On YouTube: Protect Your Dog From Harmful Algal Blooms
Harmful Algal Blooms - News
“Not all algal blooms are harmful, but some dense populations of cyanobacteria, also known as blue-green algae, can produce toxins that can have serious effects on liver, nervous system, and skin of humans and their pets.”
Read More >
May 31, 2025
Press Release
In Media: Cultivating Kelp Will Help Cut Down Nitrogen in Local Waters
Harmful Algal Blooms - Press Release
Using kelp to help reduce nitrogen in Long Island waters was the subject Dr. Christopher Gobler's May 27th press conference at the School of Marine and Atmospheric Sciences (SoMAS) Marine Science Center at Stony Brook Southampton.
Read More >
May 31, 2025
News
In Media: How to Spot Blue-Green Algae and How to Protect Your Pet
Harmful Algal Blooms - News
Only allow dogs to play in ponds or lakes you visit regularly and see if conditions change. Learn more from resources including a New York Sea Grant-produced "HABs and Dogs" brochure.
Read More >
May 31, 2025
News
In Media: Kelp Could Be Environmental Elixir, And Economic Opportunity
Harmful Algal Blooms - News
Using kelp to help reduce nitrogen in Long Island waters was the subject Dr. Christopher Gobler's May 27th press conference at the School of Marine and Atmospheric Sciences (SoMAS) Marine Science Center at Stony Brook Southampton. This is a media mention related to that announcement.
Read More >
May 31, 2025
News
In Media: Public Reporting Tool Helps Long Island’s Suffolk County Track Harmful Algal Blooms
Harmful Algal Blooms - News
NYSG created a webpage to link users to the NYSDEC's "Suspicious Marine Algae Public Reporting Tool" and used the 2020 HAB season to successfully conduct a test of the new public outreach effort.
Read More >
May 31, 2025
News
In Media: Researchers Explore New Approaches to Decoding Brown Tide in Long Island Estuaries
Harmful Algal Blooms - News
Results from a five-year, NOAA NCCOS-sponsored research project on brown tide in Long Island Estuaries were highlighted this past summer during a New York Sea Grant virtual seminar
Read More >
May 31, 2025
News
In Photos, On YouTube: State of the Bays — 2021
Harmful Algal Blooms - News
"There are no local or regional options to mitigate the global rise in temperatures nor carbon dioxide," said Stony Brook University researcher Chris Gobler. "Thus, our primary tool to lessen the intensity of HABs, hypoxia, and coastal acidification is the mitigation of nitrogen."
Read More >
May 31, 2025
News
In Photos, On YouTube: State of the Bays: Noxious Seaweed Among New Threats in 2020
Harmful Algal Blooms - News
“Two of the newest findings are that wastewater from septic systems stimulates this aggressive seaweed and high nitrate in drinking water causes negative health effects,” said SBU SoMAS' Christopher Gobler.
Read More >
May 31, 2025
Press Release
Insights from the 2018 Suffolk County HAB Symposium
Harmful Algal Blooms - News
The meeting is the first in a series of public outreach meetings on Harmful Algal Blooms.
Read More >
May 31, 2025
News
LI News and Radio Report on Red Tide Detection Research
Brown Tide Research Initiative - News
As featured on WSHU Radio and in Newsday, researchers helping to mitigate the effects of harmful algal blooms on New York communities bordering Long Island Sound were awarded first-year funds of an anticipated $600,000, multi-year research grant from the National Oceanic and Atmospheric Administration’s (NOAA’s) Monitoring and Event Response for Harmful Algal Blooms (MERHAB) research program.
Read More >
May 31, 2025
Press Release
New NOAA-Funded Harmful Algal Blooms Research
Brown Tide Research Initiative - News
Researchers helping to mitigate the effects of harmful algal blooms on New York communities bordering Long Island Sound were awarded first-year funds of an anticipated $600,000, multi-year research grant from the National Oceanic and Atmospheric Administration’s (NOAA’s) Monitoring and Event Response for Harmful Algal Blooms (MERHAB) research program.
Read More >
May 31, 2025
News
On Air: Cash For Kelp — Long Island Groups Create Seaweed Farm Incentive Program To Reduce Nitrogen
Harmful Algal Blooms - News
Using kelp to help reduce nitrogen in Long Island waters was the subject Dr. Christopher Gobler's May 27th press conference at the School of Marine and Atmospheric Sciences (SoMAS) Marine Science Center at Stony Brook Southampton. This is a media mention related to that announcement.
Read More >
May 31, 2025
News
On YouTube, On Blog: NYSG Harmful Algal Bloom Workshops a Model for Helping Great Lakes Stakeholders
Harmful Algal Blooms - News
Connecting diverse stakeholders with science experts to help mitigate the environmental and economic impacts of related outbreaks.
Read More >
May 31, 2025
News
On YouTube: 'Perfect Storm' of Conditions Leads to Record Fish Kills in LI Waters
Harmful Algal Blooms - News
"So we've got really the perfect storm here," SBU's Christopher Gobler said at a Cold Spring Harbor waterfront near waters that he described as the "epicenter" of the crisis. "Climate change, excessive nitrogen loading, leading to low oxygen."
Read More >
May 31, 2025
News
On YouTube: Early 'Mahogany Tide' Algae Bloom In Great South Bay Has Experts Greatly Concerned
Harmful Algal Blooms - News
Ahead of the Summer 2021 season, Stony Brook University investigator Christopher Gobler provided his annual “State of the Bays” address. This is one of the media mentions that followed as the season was underway.
Read More >
May 31, 2025
News
On YouTube: HABs A Summer of Discontent in Long Island's Coastal Waters
Harmful Algal Blooms - News
SBU scientists have completed their assessment of water quality in Long Island’s estuaries in 2021, and the news is not good. rom June through October, every major bay and estuary was afflicted by toxic algae blooms and oxygen-starved, dead zones.
Read More >
May 31, 2025
News
On YouTube: Incentive Spurs Plans to Grow Kelp for Reducing Nitrogen in Waters
Harmful Algal Blooms - News
Using kelp to help reduce nitrogen in Long Island waters was the subject Dr. Christopher Gobler's May 27th press conference at the School of Marine and Atmospheric Sciences (SoMAS) Marine Science Center at Stony Brook Southampton. This is a media mention related to that announcement.
Read More >
May 31, 2025
News
On YouTube: Scientists — LI's Great South Bay Suffering Through Most Intense Brown Tide In Years
Harmful Algal Blooms - News
Ahead of the Summer 2021 season, Stony Brook University investigator Christopher Gobler provided his annual “State of the Bays” address. This is one of the media mentions that followed as the season was underway.
Read More >
May 31, 2025
News
On YouTube: Sea Grant Leads Suffolk County Effort for Harmful Algal Bloom Mitigation Planning
Publications: Success Stories - Extension (2019)
Harmful algal bloom disrupt Long Island's waters, resulting in significant economic loss to the fishing and outdoor recreation sectors when shellfish beds are closed for harvesting and swimming restrictions are imposed on beaches.
Read More >
May 31, 2025
News
On YouTube: State of the Bays — 2022: Science Shows Promise
Harmful Algal Blooms - News
“All of Long Island is a watershed,” SBU's Chris Gobler remarked. “All activities on land affect the quality of the groundwater.” Over the past few decades, he notes, things have been changing on the Island. With an increase in population has come an increase of nitrogen—its primary source being nitrates in wastewater.
Read More >
May 31, 2025
News
On YouTube: State of the Bays — 2023: Reasons for Optimism in State of the Bays
Research – News
Stony Brook University researchers are learning more about the health risks caused by pollution in Long Island waterways. They're also finding reasons for optimism.
Read More >
May 31, 2025
News
On YouTube: Stony Brook Researchers — Sugar Kelp Could Help Cleanup Long Island's Waterways
Harmful Algal Blooms - News
Using kelp to help reduce nitrogen in Long Island waters was the subject Dr. Christopher Gobler's May 27th press conference at the School of Marine and Atmospheric Sciences (SoMAS) Marine Science Center at Stony Brook Southampton. This is a media mention related to that announcement.
Read More >
May 31, 2025
News
On YouTube: Tests Show Brown Tide Cell Count in Patchogue at Highest Level Since 2017
Harmful Algal Blooms - News
Ahead of the Summer 2021 season, Stony Brook University investigator Christopher Gobler provided his annual “State of the Bays” address. This is one of the media mentions that followed as the season was underway.
Read More >
May 31, 2025
News
On YouTube: Worst Brown Tide in Years Threatens Great South Bay
Harmful Algal Blooms - News
Ahead of the Summer 2021 season, Stony Brook University investigator Christopher Gobler provided his annual “State of the Bays” address. This is one of the media mentions that followed as the season was underway.
Read More >
May 31, 2025
Press Release
Reporting Suspicious Marine Algal Blooms
Harmful Algal Blooms - News
We are asking for your help to document occurrences pf Harmful Algal Blooms in NY's marine waters. These data are used as guidance to make decisions to promote public health and safety during times when HABs are most active.
Read More >
May 31, 2025
News
Rust Tides Do Harm Shellfish ... But Research Offers Promise for Shellfish Farmers
Harmful Algal Blooms - News
While the alga that creates "rust tides" are very harmful to shellfish, those aquatic filter feeders that are cultivated in deeper waters do better than those cultured near the surface.
Read More >
May 31, 2025
News
State of the Bays: "But There Is Hope"
Harmful Algal Blooms - News
"Continued efforts are needed to restore Long Island's coastal waters," says Stony Brook University investigator Chris Gobler. "It's up to us to leave the environment in better shape than when we found it."
Read More >
May 31, 2025
News
Update on Harmful Algal Blooms in Sodus Bay, Lake Ontario
Harmful Algal Blooms - News
Extensive studies on Sodus Bay highlight the complexity of harmful algal blooms. It’s not a simple case of excess nutrients, or just warming summers, but a complex interaction of multiple events, including wind, weather, nutrients and localized circulation. All are necessary for a bloom to occur.
Read More >
December 30, 2020
News
On YouTube, On Air: State of the Bays: Communities Respond to Colorful Tides that Could Signal Harm
Harmful Algal Blooms - News
“2017 has been one of the worst years for brown and red tides,” said Dr. Christopher Gobler. “Conversely, blue-green algal blooms have been mild thus far.”
Read More >
December 30, 2020
Press Release
On YouTube: Sea Grant Harmful Algal Blooms Info at State Parks Alerts Dog Owners to Potential Risk
Harmful Algal Blooms - Press Release
The HABs information resources - which include a fact sheet and brochure - are being well-received by pet owners, according to New York State Parks officials.
Read More >
December 30, 2020
Press Release
On YouTube, On Air, In Photos: State Invests $2M in NYSG to Advance Cutting Edge Brown Tide Research
Harmful Algal Blooms - Press Release
NYS Governor Andrew Cuomo's investment will restore shellfish populations to improve water quality and mitigate brown tide in Long Island's waters.
Read More >
December 29, 2020
News
On YouTube: Sometimes Beaches and Lakes Aren't Completely Safe for Your Pets
Harmful Algal Blooms - News
When the summer heats up lots of people head to area beaches and lakes but there is a threat to you and your pets brewing in the water.
Read More >
August 2, 2020
News
On YouTube: Brown Tide - Blight on the Bays
Brown Tide Research Initiative - News
In July 2012, News 12 Long Island ran a special reports entitled "Brown Tide: Blight on the Bays." One of the featured interviews in the report was with Dr. Chris Gobler, an often NYSG-funded Stony Brook University researcher and professor at its School of Marine and Atmospheric Sciences.
Read More >
January 16, 2020
Press Release
'Tis the Season for Brown Tide
Brown Tide Research Initiative - News
Brown tide, which is caused by a proliferation of single-celled marine plants called phytoplankton, is in the news again this summer season.
Read More >
January 16, 2020
Press Release
NYSG Red Tide Research Featured in Newsday
Brown Tide Research Initiative - News
Researchers studying the waters of Long Island's Northport Harbor ID-ed a second type of harmful algae never seen before at these levels in New York.
Read More >
November 14, 2019
Press Release
NYSG Says Enjoy the Water this Summer and Keep Yourself and Your Pets Safe from Harmful Algal Blooms
Harmful Algal Blooms - Press Release
New York Sea Grant is reminding those that do to be informed about harmful algal blooms (HABs), how to avoid exposure of oneself and pets, and where to report potential HABs.
Read More >
November 14, 2019
News
2018 Harmful Algal Bloom Symposium
Harmful Algal Blooms - News
Read More >
November 14, 2019
News
Cloudy Waters: Harmful Algal Blooms
Harmful Algal Blooms - News
The two things that people should do when they suspect a HAB is avoid any contact with the water, and report the bloom to the proper authority.
Read More >
November 14, 2019
News
On Air, In Media: Pet owners warned of potentially lethal algae in NNY waters
Harmful Algal Blooms - News
In Summer 2018, NYSG partnered with the Pennsylvania and Lake Champlain Sea Grant programs and New York State Parks to remind dog owners to enjoy the water this summer, but remember to stay smart, safe, and informed about algal blooms and their impact on people and pets.
Read More >
November 14, 2019
News
State of the Bays: Action Plan Released on Harmful Algal Blooms
Harmful Algal Blooms - News
Sea Grant has an integral role in developing this first-of-its-kind comprehensive and integrated strategy to guide the work of multiple levels of government, scientists and academia to address increasingly frequent algae blooms that have plagued marine waters, threatening both Suffolk County’s environment and economy.
Read More >
November 14, 2019
Press Release
State of the Bays: Water Is at the Core of the Long Island Existence
Harmful Algal Blooms - News
Last summer, Long Island’s waters experienced a 10-week-long brown tide. It was not only one of the longest, it was one of the most intense on record.
Read More >
November 14, 2019
Press Release
Stay Smart about Algal Blooms in 2018
Harmful Algal Blooms - Press Release
New York Sea Grant is partnering with the Pennsylvania and Lake Champlain Sea Grant programs and New York State Parks to remind dog owners to enjoy the water this summer, but remember to stay smart, safe, and informed about algal blooms and their impact on people and pets.
Read More >
November 14, 2019
Press Release
Dogs and Harmful Algal Blooms
Harmful Algal Blooms - Press Release
Our new publications alert those who live and recreate by New York's waters of potentially lethal toxins that can poison people, household pets, waterfowl and livestock.
Read More >
November 14, 2019
Press Release
Dogs and Harmful Algal Blooms: NY Sea Grant Shares Risk Reminder for Pet Owners
Harmful Algal Blooms - News
As air and water temperatures warm, New York Sea Grant is reminding people with dogs that enjoy waterfront areas about the health risk posed by harmful algal blooms.
Read More >
November 14, 2019
News
Sea Grant Alerts Millions of U.S. Pet Owners of Potentially Lethal Toxins in NY Waters
Harmful Algal Blooms - News
n a few short weeks since their release in mid-September, New York Sea Grant’s informative “Dogs and Harmful Algal Blooms” brochure and fact sheet were well-received via both traditional and social media platforms.
Read More >
November 14, 2019
News
SUNY ESF Investigators Monitor NY Waters of Sodus Bay
Harmful Algal Blooms - News
Buoys, installed through funding by NYSG and partners, help predict toxic algal blooms
Read More >
November 14, 2019
News
To HAB or Not to HAB: Harmful Algae Are Blooming in New York's Waters
Harmful Algal Blooms - News
Harmful algal blooms have become a worldwide phenomenon, posing a significant threat to public health, economies, water quality, and fisheries. New York waters have more than their fair share.
Read More >
November 14, 2019
News
Toxic Algae Blooms Cause Illness, Death in Dogs
Harmful Algal Blooms - News
Dogs are known to play, swim and lap up water in lakes and ponds, but these simple joys can lead to illness and even fatal poisoning when harmful algae blooms muck up the water.
Read More >
September 18, 2018
Article
Brown Tide Research Initiative
About Brown Tide

About Brown Tide

Read More >
September 18, 2018
Article
Harmful Algal Blooms
Publications
Publications from Harmful Algal Blooms
Read More >
September 18, 2018
Press Release
NOAA and Sea Grant Research Featured at Symposium on Harmful Algal Blooms in NY's Coastal Waters
Brown Tide Research Initiative - News
The symposium, held at Stony Brook-Southampton, was an opportunity for Long Island residents, as well as government and non-government agencies, to learn about the most recent information regarding harmful algal blooms and other environmental problems on Long Island.
Read More >
September 10, 2017
News
The Bottom is Tops: Looking at nitrogen in Peconic sediments
New York Coastlines, Fall 2010
As part of a two-year NYSG study, a research team is characterizing Great Peconic Bay and measuring the amount of nitrogen gas produced in its bottom sediments.
Read More >
September 9, 2017
Press Release
NOAA-funded Great Lakes Study on Blue-Green Algae
The three-year, nearly $500,000 project focuses on the algal species Microcystis, which frequently causes massive and unsightly blooms in Lakes Erie and Ontario.
Read More >
September 9, 2014
Article
Harmful Algal Blooms
Related Sites
Related Sites: Harmful Algal Blooms
Read More >
August 31, 2012
Press Release
Brown and Red Tide in Long Island's Waters: Summer 2012
Brown Tide Research Initiative - News
For the sixth consecutive year, the brown tide is back. Algae-filled, murky water bursting has been washing up along Long Island's South Shore this summer, most recently in parts of the Moriches and Shinnecock bays. NYSG-funded researcher Dr. Chris Gobler, an investigator and professor at Stony Brook University's School of Marine and Atmospheric Sciences, shares his insights.
Read More >
August 28, 2012
Press Release
Harmful Algae Have the Right Genetic Stuff
Brown Tide Research Initiative - News
This feature article in the Spring 2012 issue of Woods Hole Oceanographic Institute's Oceanus magazine spotlights innovative research published in the Proceedings of the National Academy of Sciences. The study was funded by NYSG, NOAA, the Department of Energy, the National Institutes of Health and the National Science Foundation.
Read More >
August 28, 2012
Press Release
Innovative Red, Brown Tide Research Seeks to Better Understand, Manage Blooms
Brown Tide Research Initiative - News
This past summer, brown and red tides turned up in some Long Island waters. In two NYSG-funded research projects, Stony Brook University investigator Christopher Gobler is looking to better understand and manage both brown and red tides.
Read More >
August 28, 2012
News
Newsday: From Mild Winter to What's Next
Brown Tide Research Initiative - News
This past winter's more milder months may lead to hardships this spring and summer, including, as described by NYSG-funded researcher Dr. Christopher Gobler, an increase in algal blooms in Long Island's coastal waters.
Read More >
August 28, 2012
News
NYSG's Recent Harmful Algal Bloom Research
Brown Tide Research Initiative - News
“Harmful algal blooms are not a new phenomenon, although many people may know them by other names such as red tides or brown tides,” says Stony Brook University investigator Dr. Chris Gobler.
Read More >
March 3, 2011
News
Researchers Complete Genome of Brown Tide
Brown Tide Research Initiative - News
A team of researchers at at Stony Brook University has sequenced and annotated the first complete genome of a Harmful algal bloom species: Aureococcus anophagefferens.
Read More >
December 7, 2009
News
Harmful Algal Blooms Plague Long Island Waters
New York Coastlines, Fall 2009
Find out the difference among the recent Harmful algal blooms (HABs) in New York waters. HABs, which have increased in frequency, duration, and distribution in recent decades, are a worldwide phenomenon posing a significant threat to fisheries, public health, and economies.
Read More >
June 20, 2008
News
Researchers Scrutinize Brown Tide Genes
Brown Tide Research Initiative - News
Researchers believe that the genetic makeup of the tiny brown alga, Aureococcus anophagefferens, holds the key to the organism's triggering of brown tide blooms that darken bay waters, causing declines in shellfish populations and eelgrass beds.
Read More >