Pacific gray whales are showing up dead in North America’s oceans and shores at a rate four-times greater than typical. As of July 11, 182 gray whales have been found dead or beached this year in Mexico, the US, and Canada according to the US National Oceanic and Atmospheric Administration (NOAA).
While that might seem like a relatively small figure for a species that numbers in the tens of thousands, the dead whales that are spotted by mariners or found on ashore only represent roughly 10% of total deaths: 90% of whales simply sink to the ocean floor when they die, according to Jeffrey Boehm, CEO of the Marine Mammal Institute.
The gray whale migrates from the Arctic to Baja California in Mexico during the winter before migrating back north in the summer. The whales were removed from the US endangered species list in 1994. Nearly 22 years after the Marine Mammal Protection Act made it a federal offense to harm or kill any marine mammal. Researchers estimate the population has recovered to roughly 27,000 whales, levels not seen since before the peak of whale hunting in North America in the 19th century.
NOAA is investigating this as an “unusual mortality event,” and so far, the cause of the deaths is inconclusive. Pádraig Duignan, chief research pathologist at the Marine Mammal Center, told Quartz there are several theories that rely on a combination of a lack of food, climate change, and ship strikes.
Photo by Christopher.Michel