Sea lions are stranding on a long stretch of California coast with signs of poisoning by a naturally occurring bloom of harmful algae. The Channel Islands Marine & Wildlife Institute said that since July 26 it has been inundated by reports of sick sea lions on 155 miles of coastline along Santa Barbara and Ventura counties, northwest of Los Angeles. The mammals are suffering from domoic acid, a neurotoxin that affects the brain and heart. The institute said it had rescued 23 animals as of Thursday. The California coast commonly sees outbreaks of domoic acid poisoning. An outbreak last year was particularly severe, with hundreds sea lion deaths and dozens of dolphin deaths in the first weeks of June.