Saving Seafood

Study suggests algal blooms disorient whales, putting them in danger

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.”

More algal blooms, more whale deaths

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.

Read the full article at Mongabay 

CALIFORNIA: Algae bloom fish kills prompt new Bay Area wastewater treatment plant requirements costing $11 billion

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.

Read the full article at CBS News

Why sea creatures are washing up dead around the world

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.

Read the full article at The Washington Post

Algal Blooms Have Boomed Worldwide

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.

Read the full article at the Scientific American

The pollution causing harmful algal blooms

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.

Read the full article at BBC News

Millions of Salmon in Norway Killed by Algae Bloom

May 24, 2019 — About eight million farmed salmon have suffocated in northern Norway over the past week as a result of persistent algae bloom, an industry body estimated on Thursday, a blight that some experts suggest has been aggravated by climate change.

Norway is a dominant producer of farmed salmon, and the economic impact of the bloom is significant.

A statement from the Norwegian Directorate of Fisheries estimated the amount of salmon lost at 11,600 metric tons, worth about 720 million kroner, or more than $82 million. An industry group, the Norwegian Seafood Council, suggested the total could be much higher.

“Preliminary numbers point to eight million dead fish — corresponding to 40,000 metric tons of salmon that won’t reach markets,” Dag Sorli, a spokesman for the council, said in an email on Thursday. He put the value of the losses at 2.2 billion kroner.

Read the full story at The New York Times

Algae bloom forces suspension of shellfishing in parts of Down East Maine

It’s the second straight year that a bloom of Pseudo-nitzschia, a phytoplankton that can carry toxic domoic acid, has forced a closure along large parts of the coast.

September 15, 2017 — A marine algae bloom that can carry a potentially deadly neurotoxin has forced the suspension of shellfish harvesting in parts of Down East Maine.

The state Department of Marine Resources reported Thursday that it was monitoring an active bloom of Pseudo-nitzschia, an ocean phytoplankton that carries domoic acid, a toxin that can cause sickness, memory loss and brain damage in humans. It’s the second year in a row that a toxic Pseudo-nitzschia bloom has halted harvesting of mussels, clams and oysters along large parts of the coast.

Before 2016, there was no record of a toxic bloom of this type in the Gulf of Maine.

The department’s public health section found levels of domoic acid that exceeded health standards in shellfish tested between Mount Desert Island and Gouldsboro. That area has been closed to harvesting and the department enacted a precautionary closure from Deer Isle to Machiasport, almost a third of Maine’s coastline.

Department spokesman Jeff Nichols said officials were monitoring the situation closely. There is no indication that contaminated shellfish have made their way to consumers, he said.

“It is impossible to determine at this point if the concentrations of domoic acid will increase in other areas,” Nichols said. “But we know that the phytoplankton that produces it grows rapidly, so we are carefully monitoring the entire coast and will be able to rapidly detect harmful levels of domoic acid and take action to protect the health of Maine’s shellfish consumers.”

Read the full story at the Portland Press Herald

Lab In A Can To Help Identify Toxic Algae Off Washington Coast

After a massive toxic algae bloom closed lucrative shellfish fisheries off the West Coast last year, scientists are turning to a new tool that could provide an early warning of future problems.

Scientists at the National Oceanic and Atmospheric Administration and the University of Washington last week deployed the so-called ocean robot about 50 feet into waters off the coast of La Push, Washington, near a known hotspot for toxic algae blooms.

The tool, dubbed “a laboratory in a can,” will remain in the water until mid-July, providing real-time measurements about the concentrations of six species of microscopic algae and toxins they produce, including domoic acid.

The instrument is equipped with sensors and cellular modems that will allow it to take water samples and send that information to shore three times a week for the next several weeks. Scientists plan to deploy it again in the fall, another critical time for harmful algae blooms.

Last year, dangerous levels of domoic acid were found in shellfish and prompted California, Washington and Oregon to delay its coastal Dungeness crabbing season. Washington and Oregon also canceled razor clam digs for much of the year.

Read the full story at OPB