Toxic Algae and Domoic Acid Poisoning
Learn About Domoic Acid and How You Can Help
When conditions are right, waters off the coast of California can experience large-scale toxic algal blooms that are capable of sickening hundreds of sea lions in a matter of weeks, causing them to wash ashore at an alarming rate – sometimes a dozen a day.
How could tiny algae wreak so much havoc? This type of algae, known as Pseudo-nitzschia australis, produces a toxin called domoic acid that is considered one of the foremost threats to marine animals by the National Oceanic and Atmospheric Administration (NOAA). Sardines, anchovies and shellfish eat the toxic algae and then bigger animals like sea lions and dolphins unknowingly eat the contaminated fish.
Domoic acid is a naturally occurring toxin that has existed for centuries and was first identified in Japan in the late 1950s. Although domoic acid wasn’t detected in California until 1991, the prevalence of toxic algal blooms along the Pacific coast has increased dramatically in recent years. Researchers say human activities like increased fertilizer use and sewage runoff as well as warming waters due to climate change create the types of conditions in which algal blooms like these thrive.
Many different marine animals are susceptible to domoic acid, from seals and sea lions to whales and dolphins and even seabirds. Along the Los Angeles coast, one of the most common species to strand due to the effects of domoic acid is the California sea lion.
Domoic acid is a neurotoxin, which means it impacts a sea lion’s brain, as well as other vital organs like the heart and liver. Sea lions that are sickened by domoic acid often wash ashore weak, lethargic and disoriented. They also suffer from violent seizures that cause their heads to weave, or move side-to-side uncontrollably.
Young sea lion pups can suffer indirect impacts of domoic acid if a toxic algae bloom coincides with pupping season on the Channel Islands. Sick sea lion moms may be unable to care for or nurse their pups, leaving them malnourished and without the skills needed to find food on their own.
You can help ensure sea lions sickened by domoic acid get the care they need by making a donation today.
Sea lions poisoned by domoic acid can be disoriented and lethargic one moment and aggressive the next. Getting these sick animals to a safe place isn’t just urgent for their own wellbeing, but also the safety of the many people sharing the beaches with them.
The Marine Mammal Care Center’s response team rescues more marine mammals per mile of coastline than any other organization in the country, and our staff are specially trained to safely respond to sea lions suffering from the effects of domoic acid.
Our Pinniped Patrol volunteers monitor beaches for sick sea lions, educating beach-goers about keeping their distance and supporting safe rescues of animals in need.
Learn how you can join our Pinniped Patrol or another volunteer role.
If caught in time, the domoic acid toxin can be flushed from a sea lion’s body with fluids, so our animal care experts administer IV fluids to sick animals. Some patients are also treated with anti-seizure medication.
In addition to lethargy, erratic behavior and seizures, domoic acid can also cause sea lions to lose their appetite, so it’s important to provide plenty of nutritious fish meals that are free of the toxin.
During the unprecedented domoic acid outbreak in 2023, the Center admitted more than 120 adult California sea lions over the course of seven weeks.
At the height of the crisis, our Los Angeles Unified School District neighbors worked with us to expand our hospital capacity by building a triage space in the parking lot where we could provide patients with the medications, meals and space they needed to recover.
Read about AngeLA, one of the first sea lion patients to be cared for in this triage space.
When our triage space overflowed, county officials helped us create a sea lion resting zone in Marina Del Rey. This protected stretch of beach became an area where our rescue teams could bring sick sea lions to rest safely, away from the public.
Our goal for any patient rehabilitating at the Marine Mammal Care Center is to return to the ocean as soon as possible. Once a sea lion is no longer suffering the effects of domoic acid and has reached a healthy weight, our animal care experts will assess whether it can successfully compete for food and our veterinarian will give the final signoff for release.
Our California sea lions are released at a number of different beaches along the coast of Los Angeles that provide abundant food sources. Released patients are given flipper tags with a unique number that helps identify them if they are spotted again in the wild.
Former Hospital Director Dr. Lauren Palmer has been leading a research study aimed at understanding whether pups born in captivity and exposed to domoic acid can be successfully released and thrive in their wild environments.
To collect data on short-term travel and habitat use, she attached satellite transmitters to six sea lion pups born to mothers suffering from domoic acid. Although the battery only lasts a few months, the transmitters help researchers understand if the pups are foraging successfully and socializing with other sea lions after they are released.
Learn more about the pups born during the domoic acid crisis.
Although algal blooms are naturally occurring, research has shown that they are more abundant in warmer waters. As climate change continues to warm our waters, these blooms will increase as well, which means these outbreaks will only be more frequent and more severe in the future.
Domoic acid doesn’t just affect marine animals. This toxin can also cause life-threatening illness in people who eat contaminated seafood. You can help ensure a healthier ocean for marine mammals and humans alike by taking action in your everyday life.
Use Your Voice
Vote with the environment in mind. Discuss the importance of conservation and climate change with friends, neighbors and local leadership. Research candidates’ stances on the topic before heading to the polls.
Eat More Plants
Go meatless at least one day a week. Reducing meat intake lowers your carbon footprint and can help slow global warming.
Share the Shore
Give resting marine mammals space by maintaining a safe distance of at least 50 feet and keeping pets on a leash. Use the zoom on your camera rather than approaching for a selfie. Call 1-800-39-WHALE to report sick or injured animals.
None of this life-saving work is possible without the support of compassionate people like you. A gift today will help ensure our hospital is ready for the next domoic acid outbreak and gives a future patient a second chance at life in the wild.
