Officials are investigating the cause of death of a whale that washed ashore in Ventura as dozens of marine mammals have been found dead from toxic algae. Karma Dickerson reports for the NBC4 News at 4 p.m. on April 24, 2025. Wildlife experts say the whale deaths are "deeply telling" about the scope and severity of the worsening algae blooms.

One of the largest harmful algae blooms recorded along the Southern California coast has led to the illness and death of thousands of marine mammals and birds in recent months.