A toxic algae bloom in coastal waters from San Luis Obispo to San Diego has killed dozen of marine animals, including whales and dolphins, and the area has been labeled an extreme danger zone Thursday by health and environmental groups.

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 in Venice Beach. Marine experts are taking samples and planning necropsies to determine if domoic acid toxicity is the cause,

In the past week, there have been more than 50 dead and dying dolphins found along the L.A. County coast. Experts say it's due to a neurotoxin called domoic acid.