Mystery of the Dead Whales.Jan 7, 2008. Tierramérica. Poisoning from the red tide may have been the cause of the high rates of death among southern right whales along Argentina’s Atlantic coast. It will be difficult to determine exactly why whale deaths have shot up along the Atlantic coast of southern Argentina’s Patagonia region, but experts studying the phenomenon are pointing to poisoning from “red tide”.The annual average of deaths jumped from 40 to 85 in October and November, according to the Southern Right Whale Health Monitoring Program, conducted over the past five years by non-governmental entities in the southern province of Chubut.[See]