There seems to be a problem in the Bering Sea with increased temperatures reducing the benthic invertebrates they eat. Hence, malnutrition. The Grays eat all summer but consume little food on the breeding grounds in Mexico so less food up there is an issue.

Further, if the population is to remain stable and a female produces 10 calves over the course of her breeding years only two (20%) need to survive for stability. That would be 80% loss.

It will be interesting to see if they invade the Arctic Ocean and move east to the Atlantic where they would recolonize following extirpation in the 15-1600s.