Surge in Stranded Marine Animals in Southern California Linked to Algal Blooms
Marine life care facilities in Southern California are facing an alarming increase in stranded dolphins and sick seals, a situation that experts attribute to a growing toxic algal bloom along the coast. The Marine Mammal Care Center, located in the greater Los Angeles area, and SeaWorld San Diego have reported numerous cases of stranded marine animals, many of which are likely suffering from the effects of the algae known as Pseudo-nitzschia.
The National Oceanic and Atmospheric Administration (NOAA) has indicated that when marine mammals consume shellfish contaminated with this algae, dangerous toxins can build up within their systems. The consequences can be severe, leading to seizures, brain damage, and even death. Staff at the Marine Mammal Care Center have noted, "This week, we saw more stranded dolphins—both alive and deceased—than during the major domoic acid bloom in 2023. Recent testing in Southern California shows increased levels of the algae that produces this toxin, and we fear it may only get worse in the weeks to come."
Historically, these neurotoxins have not posed a significant threat to fish or swimmers, but public health officials advise caution. Residents are urged to stay away from any stranded mammals, as human interaction can add to their distress.
In light of recent findings, the California Department of Public Health has issued a warning for individuals to avoid consuming sport-harvested mussels, clams, or scallops from Santa Barbara County. The agency has clarified that cooking these shellfish does not eliminate the harmful toxins, which can result in a range of distressing symptoms in humans, including loss of balance, slurred speech, and difficulties with coordination.
Fortunately, commercially harvested shellfish are not subject to the same risks, as these products undergo rigorous testing for possible toxins before reaching consumers.
According to NOAA, the rapid growth of these harmful algal blooms is fueled by natural occurrences such as significant upwelling along the coast. This often happens during the spring and summer when winds mix colder ocean waters with warmer surface waters. Agencies initially worried that runoff from recent wildfires could have contributed to the current bloom but now believe it is primarily related to the Pseudo-nitzschia algae.
Local residents have observed that significant algal blooms in the past tended to occur every four to seven years. However, over recent years, there has been a noticeable increase in the frequency and severity of these events. Experts point to several potential contributors, including human activity. Increased fertilizer use, sewage runoff, and the rising temperatures of ocean waters—often linked to climate change—create favorable conditions for these harmful blooms.
Domoic acid, the primary toxin associated with Pseudo-nitzschia blooms, has a long history, first identified in Japan in the late 1950s. Though it was not detected in California until 1991, the frequency of toxic algal blooms along the Pacific Coast has surged. This raises concerns about the long-term health of marine ecosystems and our coastal communities.
For those who may encounter a stranded animal, experts from the Marine Mammal Care Center recommend taking specific precautions. It’s important to keep a safe distance—at least 50 feet away—to avoid causing additional stress to the animal. Individuals should immediately contact the stranding hotline at 1-800-399-4253 to report the sighting.
Interfering with the animal or attempting to return it to the water can be harmful and counterproductive. Furthermore, marine specialists advise minimizing noise and keeping pets on a leash to reduce stress for the stranded animals.
In conclusion, the uptick in stranded marine mammals and the related public health advisories highlight a growing issue that deserves our attention. It encourages us not only to protect our coastal ecosystems but also to remain informed and responsible in our interactions with wildlife. It is vital for all of us to understand the impact our activities can have on these creatures and to support efforts aimed at preserving the health of our oceans.
