An "unprecedented" toxic algae bloom has overrun the coast of Southern California, sickening marine animals and staining the shoreline amid the invasion.

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.

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,