By Giulia C.S. Good Stefani

A new study published in the journal Ecology and Evolution confirms that the North Atlantic right whale—one of the world's most endangered whales—has reversed course and is no longer recovering, but rather, is in perilous decline. The authors estimate the probability that the population is declining at 99.99 percent and found a strong divergence between male and female survival rates, leaving the population with a troubling imbalance. There are substantially more males left than females.

How can the authors (two of whom are from the government's own National Marine Fisheries Service) be 99.99 percent certain that they are correct? Because there are so few whales we can count them. North Atlantic right whales are individually identifiable by the unique, white, callosity patterns on their lower jaw. And, sadly, there aren't that many to count. The estimated population of North Atlantic right whales is fewer than 500.