A harmful algal bloom off the Southern California coast continues to sicken and kill marine life, with at least seven dolphins washing ashore this week alone on Venice Beach.

Marine experts are taking samples and planning necropsies to determine if domoic acid toxicity is the cause, which has already affected thousands of sea lions and birds in recent months.

Now, whales and dolphins are dying in larger numbers.

“It’s heartbreaking and sad to see dolphins washed ashore. It’s not something you see on a regular basis,” one beachgoer told KTLA’s Kimberly Cheng on Thursday.

Experts believe toxins are ingested by fish, affecting food chain

Keith Matassa, with the nonprofit Ocean Animal Response and Research Alliance, said the number of deaths in Los Angeles County alone is astounding.

“This year, as of April 24th, 223 animals have died, including large whales and many common dolphins,” Matassa said.

Earlier this month, a minke whale became disoriented and trapped inside a Long Beach harbor and ultimately died. The National Oceanic and Atmospheric Administration later confirmed it had suffered from domoic acid poisoning.

Experts believe the toxins are ingested by fish, affecting the food chain. Since many of the deceased sea lions were pregnant, experts are concerned about the impact on the population.

Experts advise public to stay away from dying, dead animals

Factors contributing to the algal bloom may include January’s wildfires and rain runoff, which washed nutrients and toxins into the ocean. The algae, however, was prevalent before the fires and severely impacted wildlife, particularly sea lions.

“All the nutrients and toxins from the ash and rain runoff are washing into the ocean, providing nutrients for the algae,” said Matassa.

Marine experts will continue taking samples for a few hours before burying the dolphins in the sand closer to the water. They advise the public to keep their distance from dying or dead animals on the beach.