A toxic algal bloom off Southern California is blamed for making sea lions sick

STEVE INSKEEP, HOST:

OK, residents of Southern California who go to the beach on this holiday should pay attention because sea lions are behaving in a way that beachgoers may find aggressive.

ALISSA DEMING: So we're currently seeing a massive influx of sick California sea lions and mostly common dolphins showing up on our beaches, having seizures, that are kind of unaware, dazed and confused.

ROB SCHMITZ, HOST:

That's Alissa Deming at the Pacific Marine Mammal Center in Laguna Beach. She says an intense algae bloom just off the coast is generating a harmful neurotoxin.

DEMING: Domoic acid can impact the receptor in your brain or even in your heart and causes it to be overexcited, essentially, which can result in seizures or damage to the heart.

INSKEEP: And this toxin has spread up the food chain.

DEMING: Sea lions and dolphins eat mostly sardines, anchovy and hake, which are concentrating this toxin. We think we're seeing these domoic acid blooms more frequently as well as lasting longer and potentially even producing a higher level of toxin that's resulting in worse clinical signs.

INSKEEP: So if you spot a sea lion in distress, Deming says leave it be.

DEMING: Give them their space, and call the professionals.

SCHMITZ: Authorities are warning beachgoers to stay at least 50 feet away from all marine mammals for their own safety. Deming adds that while a bite from a sea lion will not transmit the toxin, it's still smart to see a doctor.

DEMING: If you get bit by a sea lion, you have to worry about two things - No. 1, the trauma associated with that bite. And also, there's a lot of bacteria both in their mouths and in the ocean water itself, and that can result in significant infections.

INSKEEP: Many creatures are affected by this problem. The California Department of Public Health is telling people to avoid eating some shellfish that is harvested for sport because of high toxin levels. But if you're clamoring for clams on this Fourth of July, they say seafood sold commercially is fine.

(SOUNDBITE OF SVANEBORG KARDYB'S "SOMMER") Transcript provided by NPR, Copyright NPR.