Public Vigilance Needed During Domoic Acid Response
- Domoic acid
The Uptick in Responses Comes Amidst Reduced Personnel Due to the Impact of the Coronavirus Pandemic
Disoriented California sea lions, some convulsing uncontrollably from neurotoxin-induced seizures along Central Coast beaches, present a difficult challenge this spring for trained responders and veterinarians at The Marine Mammal Center. Since mid-May, the Center’s Sausalito hospital has admitted more than twenty sea lions of varying ages suffering from domoic acid poisoning, a condition that, if left untreated, can cause permanent brain damage and death.
The Center urges beachgoers to keep themselves and their pets at a safe distance from these sick animals and understand that trained responders may not be able to rescue sick sea lions right away due to the impacts of the current coronavirus pandemic.
As an essential business, we’re committed to continuing our core work of marine mammal rescue and response in a way that is responsible and optimizes human safety.
“As an essential business, we're committed to continuing our core work of marine mammal rescue and response in a way that is responsible and optimizes human safety," says Dr. Cara Field, Medical Director at The Marine Mammal Center. "The public plays a critical role in notifying us about these sick animals and we ask for their understanding and patience as our response teams deal with fewer available volunteers and delayed response times.”
Monterey, Santa Cruz and San Luis Obispo counties are the busiest areas for response during this current spike in cases. Given historic patterns, the Center expects to continue rescuing animals with domoic acid poisoning throughout the summer months.
With reduced personnel due to the current pandemic, if a large outbreak event occurs, the public should expect a slower response time from the Center, particularly for larger animals that require more trained responders and resources to rescue.
“The early timing of this year’s outbreak is especially concerning because adult female sea lions could get sick on their way to the Channel Islands to give birth, putting their pup’s survival at serious risk,” says Dr. Field.
It’s critical that beachgoers maintain a safe distance when these animals come to shore sick. Getting too close to a sick sea lion before our trained responders arrive increases the risk of even more damaging health effects to an already physically stressed animal.
Domoic acid poisoning primarily attacks the sea lion’s brain, causing lethargy, disorientation and seizures. These symptoms are the most likely visuals that beachgoers can expect if they come across a sick sea lion impacted by the toxin.
It’s critical for beachgoers to stay at least 50 feet away from sea lions during this outbreak to avoid stressing the animal further and to keep themselves and their pets safe from a potentially unpredictable wild animal. Beachgoers should call the Center’s 24-hour hotline at 415-289- SEAL right away if they have concerns.
Domoic acid in sea lions is most commonly caused by a type of algae called Pseudo-nitzschia australis. This naturally occurring neurotoxin accumulates in small fish, like sardines and anchovies, which are then eaten by sea lions in large quantities.
Pregnant females cannot quickly clear domoic acid poisoning from their system in one to two days like other sea lions. Instead, the neurotoxin remains in the fetal fluid where it recirculates in the mother’s body for days to weeks, continually exposing mom and unborn fetus to its effects.
Pups that are exposed to domoic acid poisoning in utero are often stillborn or exhibit developmental changes such as epileptic seizures and other conditions that result in their death within their first few years of life.
The history of domoic acid along the California coast is not new. The Marine Mammal Center was the first organization to discover the neurotoxin in California sea lions in 1998 and has authored or coauthored a dozen scientific papers on its impacts. In recent years, increasing ocean temperatures have led to spikes in domoic acid poisoning occurring year-round instead of seasonally. This change and its impact on marine mammal species raises the alarm for the Center’s scientists.
The Center works closely with the National Oceanic and Atmospheric Administration (NOAA) to investigate the disease processes in wild marine mammal populations, including California sea lions. The documentation of the disease both through samples and treatment is critical to better understanding larger threats to the populations at large and human health as well.
Although most of the patients the Center’s experts treat for domoic acid poisoning are California sea lions, other marine mammals are susceptible to its effects. Domoic acid poisoning has been reported in several other seal and sea lion species, as well as in endangered southern sea otters and whales. In 2014, researchers at the Center were the first to detect domoic acid in Guadalupe fur seals, a threatened species.
Toxicity from domoic acid can also affect humans who eat contaminated shellfish, causing a life-threatening condition known as amnesiac shellfish poisoning. As sentinels of ocean health, sea lions are often the first to be affected by the toxin, so the Center alerts the public health department to any outbreaks. This action is invaluable as it gives health officials an early warning sign to better target their surveillance of seafood to protect human health.
How The Public Can Help
The Marine Mammal Center would like to remind the public that they play an important role in the conservation of marine mammals by keeping these marine wildlife viewing tips in mind:
- Keep A Safe Distance. California sea lions suffering from domoic acid poisoning can act unpredictably toward beachgoers and their pets. A safe viewing experience starts with keeping your distance and keeping pets on a leash.
- Use Your Zoom. It’s ok to take photos, but if you’re so close that you’re not using your zoom or they’re reacting to you, then you’re too close. No SEAL-FIES please!
- Call Us. If you see a seal or sea lion in distress, call The Marine Mammal Center’s rescue hotline at 415-289-SEAL (7325). The Center will monitor the animal and, if necessary, send a trained responder to rescue it safely.
For more information or to set up an interview on this topic, please contact us at firstname.lastname@example.org.
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California Sea Lion