Major Clue Emerges in Mystery Of Right Whale Deaths, Researchers Say

Endangered right whales, especially young calves of the southern population, have been having a hard time in recent years, and
southern-right-whale-calf-140.jpg
Southern right whale and calf near Peninsula Valdes
scientists haven’t been able to determine why. For example, the average number of right whale deaths per year at Peninsula Valdes, a breeding ground off central Argentina’s Atlantic coast, jumped more than 10-fold from 2005 to 2014 — from fewer than six per year to 65 per year, researchers say. Roughly 90 percent of the deaths were calves fewer than three months old. Now researchers have closed in on a suspect: blooms of a type of algae known as Pseudonitschia, which produce harmful neurotoxins, the researchers write in the journal Marine Mammal Science. Scientists from the United States and Argentina found that the number of whale deaths at the peninsula closely tracked the concentrations of the toxic algae, offering strong circumstantial evidence that the algal blooms are likely behind the whale deaths.