(NewsNation) — A toxic algae bloom commonly known as red tide is stretching along the Southern California coast poisoning larger marine mammals. It’s expected to last several more weeks.

Experts estimate it has already killed hundreds of sea lions and dozens of dolphins so far this month.

While many marine mammals and birds cannot withstand the ingestion of the algal toxin in bloom, fish and other animals can. This is threatening the larger animals on the food chain, which have been dying and beaching themselves up and down the coast.

“Neurotoxins are pretty tricky, we don’t know why it affects some animals and then it doesn’t affect other animals, what concentration does it take to start affecting them, but we do know the end result is that we do see these animals coming ashore, not doing well, and in most cases dying,” said Justin Viezbicke of the National Oceanic and Atmospheric Administration.

Beachgoers have been urged to stay away from sick animals so the survivors can be professionally rescued and nursed back to health.

“Right now, what we’re seeing are a bunch of mostly female sea lions, there’s some males as well, that have succumbed to what we call domoic acid toxicosis. They’re very sick, they range from lethargic to aggressive, having seizures, it’s a really critical condition,” said Dave Bader, an employee at the Los Angeles Marine Mammal Care Center.

Symptoms of lethargy, vomiting and disorientation usually clear up in about three days.

The center, which has taken in dozens of sea lions and dolphins, is at capacity as they try to treat as many of the impacted creatures as possible. But experts say it is only the second week of an algae bloom that could last as long as eight weeks.