September 30, 2026 — This past weekend’s nor’easter may have helped with an algae bloom that led to a shellfish ban in parts of Maine.
A member of the Department of Marine Resources says the bloom, that’s been a threat to shellfish, is spreading offshore into Downeast Maine.
Read the full article at Fox 23
June 3, 2026 — Algae is vital to a healthy marine system, and most of the hundreds of varieties in Alaska’s waters are beneficial or benign.
But the handful that are harmful are, like other algae, proliferating in warmer conditions and releasing or threatening to release toxins that can sicken people and wildlife and, in the worst cases, cause deaths.
The best-known type of algae that poses risks to people, mammals and birds in Alaska is called Alexandrium. The toxins it produces cause paralytic shellfish poisoning; they block the delivery of sodium to cells, thus interfering with or shutting down nerves essential to bodily functions.
The most potent Alexandrium toxin is saxitoxin, but there are related toxins produced by the same algae called gonyautoxins, or GTX. Some GTX varieties, including one detected in tomcod harvested in December by Nome-Beltz High School students in a yearslong science project, are nearly as toxic as saxitoxin. For simplicity’s sake, testing for paralytic toxins often lumps measurements of saxitoxin and GTX compounds together as “saxitoxin equivalent,” said Thomas Farrugia, coordinator of the Alaska Harmful Algal Bloom network.
June 3, 2026 — As oceanic temperatures continue to climb, harmful algal blooms have become an increasingly worrisome threat on the seabed floor of the Alaskan Arctic Ocean.
According to NOAA, a Global Ocean Monitoring and Observing-funded project conducted by the Woods Hole Oceanographic Institution (WHOI) found that warming waters are “causing algal blooms to occur more frequently in the Arctic Sea.”
March 27, 2026 — Over the past two summers, a pair of remote and treeless volcanic islands in the eastern Bering Sea broadcast signals of climate change danger in the marine ecosystem that feeds Alaska residents and supports much of the state’s economy.
Tribal employees monitoring St. Paul Island’s beaches came across 10 dead but seemingly well-fed northern fur seals in August of 2024, their bodies lying amid piles of dead fish and birds.
Testing revealed that the seals had been killed by an algal toxin that causes paralytic shellfish poisoning. It was the first ever conclusive case of marine mammals killed by saxitoxin, the algal toxin that causes paralytic shellfish poisoning.
The people living on St. Paul, numbering about 400, most of them Unangax, are highly dependent on the marine environment for their food. They are aware of the algal toxins that pose risks of paralytic shellfish poisoning in faraway Southeast Alaska. But seal deaths from algal toxin poisoning on their own island came as a big surprise to local people, said Aaron Lestenkof, who is part of the tribe’s Indigenous Sentinels Network.
“It never occurred to us that it may happen to our marine mammals here,” Lestenkof said. “I guess it was just a matter of time.”
The St. Paul die-off was not a one-time incident. In August of 2025, tribal residents found 21 dead fur seals on a beach at St. George Island, a sister island of St. Paul. Along with the seals were two dead fin whales, a dead sea lion and several dead seabirds.
September 17, 2025 — The U.S. Senate has passed legislation reauthorizing and strengthening the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA), a law designed to coordinate a government response to harmful algal blooms (HABs).
“Unchecked HABs can threaten our marine life and coastal ecosystems, the livelihoods of our commercial fisheries and coastal communities, and the health and well-being of Alaskans,” U.S. Senator Dan Sullivan (R-Alaska) said in a release. “Alaska is our country’s leading seafood producer and home to more coastline than the contiguous lower 48 states combined, making our response to HABs critically important. I want to thank all of my Senate colleagues for unanimously approving this important legislation, which will develop and coordinate effective responses to harmful algal blooms and improve the monitoring of the health of our oceans for the sake of coastal communities, especially those that rely on subsistence.”
February 4, 2025 — When certain algae flourish in the sea, they produce neurotoxins that can sicken both humans and marine animals. Acute exposure to these toxins is known to kill whales and other marine mammals outright, but many carry the toxins chronically without displaying obvious symptoms. The authors of a new study suggest these chronic exposures may nonetheless prove lethal.
The study, published in Frontiers in Marine Science in November, found an association between so-called harmful algal blooms (HABs) and whale deaths due to human causes in U.S. waters. The authors propose the reason may be that HAB toxins disorient whales, increasing their vulnerability to ship strikes and entanglements in fishing gear, which were by far the main causes of death and injury in the data they analyzed.
“Non-fatal concentrations of algal neurotoxins may render whales more susceptible to injury because they are less able to respond to entangling fishing gear and oncoming ships,” study lead author Greg Silber, an independent researcher and former coordinator of whale recovery efforts at the National Oceanic and Atmospheric Administration (NOAA), told Mongabay by email. “Knowing this provides an opportunity to reduce whale mortality by using algal bloom prediction capabilities.”
To explore the link between HABs and whale deaths, Silber and his daughter and coauthor, Katy Silber, an ecologist at the Institute for Applied Ecology in Santa Fe, New Mexico, studied the timing and location of HAB events alongside large whale mortalities and injuries in U.S. coastal waters. They analyzed data from the East Coast (2000-2021) and West Coast (2007-2021), from UNESCO’s Harmful Algal Event Database, and NOAA’s National Marine Mammal Health and Stranding Response Program. And they looked only at cases of whale injury or death attributed to human activities, excluding those attributed to natural or unknown causes.
Their main finding? “The number of mortalities/injuries was frequently higher in years with large-scale or severe HABs,” the paper states.
Although yearly changes occurred, both human-caused whale deaths and injuries and HABs showed general increases over time. The paper suggests that while improved monitoring and public reporting may partly explain this rise, year-to-year variations in HABs are influenced by oceanographic processes and warming ocean temperatures linked to climate change. HABs are also intensified by human activities that provide excess nutrients for algae growth.
The study also found differences between the two coasts. On the Pacific coast, it found a clear correlation between HABs and human-caused whale deaths and injuries: In areas with active HABs, there were at least three more whale deaths or injuries compared to places without HABs. On the Atlantic coast, the connection was still there but weaker. This might be because the ocean conditions, algal species, or the way whale and HAB data are collected differ between the two coasts, the researchers wrote.
March 18, 2024 — Ten years. That’s how much time the Bay Area’s 37 wastewater treatment plants will have to reduce fertilizer and sewage in their water by 40%. The estimated price tag for the facility upgrades is $11 billion.
The San Francisco Regional Water Quality Control Board plans to adopt the change as part of its new discharge permit requirement beginning June 12. Previous permits did not require reductions, according to Lorien Fono, executive director of the Bay Area Clean Water Agencies, which oversees the region’s wastewater treatment plants. She spoke from the Oro Loma Sanitary District in San Lorenzo on Thursday. The facility is considered a model for upgrades.
The regulatory change follows a damaging algae bloom in 2022 and 2023. A brown algae species called Heterosigma akashiwo, which feeds off the nitrogen in wastewater, infected the Bay and damaged aquatic ecosystems.
March 29, 2023 — Dead fish in Florida. Beached whales in New Jersey. Sea urchins, starfish and crayfish washing ashore in New Zealand. Millions of rotting fish clogging up a river in the Australian outback. A mass fish die-off in Poland. Around the world, freshwater and marine creatures are dying in large numbers, leaving experts to puzzle over the cause.
In some cases, scientists say climate change may be leading to more algal blooms and other events that starve fish of oxygen. Warming oceans and marine heat waves are driving sea creatures from their normal habitats. Human activities including coastal shipping are suspected in a spate of recent marine mammal deaths in the United States.
Here’s a look at some of the events that led to the deaths of swaths of aquatic creatures around the globe in the past year.
Harmful algal blooms, called red tides, have sent scores of dead fish ashore in southeastern Florida in recent weeks. A similar red-tide event killed off thousands of fish in the San Francisco Bay Area last summer.
March 3, 2023 — Algal blooms are growing bigger and more frequent worldwide as ocean temperatures rise and circulation patterns change.
Climate change is likely one cause of the alterations, which favor the growth of phytoplankton, according to a new study published in Nature.
Whether it’s good or bad is a murky question. Algae are an important food source for many marine animals, and large blooms can sometimes be a benefit for ocean ecosystems and fisheries.
But some algal blooms also release toxins into the water and poison the environment. And when blooms die off and begin to decompose, they can reduce the oxygen concentrations in the water, harming the ecosystem.
January 12, 2023 — It is the “smell of decay and death”, says Beth Stauffer, from the University of Louisiana. “It has a physical presence. This layer of very striking greens and blueish greens…when you put your paddle in it, you can feel it.”
She’s describing the harmful algal blooms (HABs) that used to be more associated with marine environments. But in recent years they’ve been moving further inland and affecting freshwater systems, too. And scientists such as Stauffer are trying to find out why.
HABs occur when certain kinds of algae grow very quickly due to increased nutrients in the water – typically when artificial nitrogen and phosphorus applied to farmers’ fields wash out in the rain and enter waterways. The algae receive a meal on a scale they would never get naturally, and a bloom is formed. Sometimes this is harmless. But at scale, many types of algae can turn toxic and harmful to humans and animals. And this scale can be extraordinary.
The explosive growth of algal blooms is linked to rising temperatures and rising pollution. These green waves are both a warning sign and a symptom of a changing climate. As farming fertiliser and a tsunami of human sewage hit our warming waterways, we are in danger of turning our very drinking water toxic.