via NOAA Fisheries

World - From Baja to the Arctic, scientists struggle to solve the mystery of gray whale deaths

Scientists struggle to explain why the gray whale population plummeted by nearly a quarter between 2016 and 2020.

PUERTO ADOLFO LÓPEZ MATEOS, MÉXICO - As early morning fog lifts off the Baja California coastline, Alushe Camacho steers a small fishing boat through a mangrove-lined estuary, his eyes fixed on the horizon. During most of the year, Camacho hunts grouper, sole, and hammerhead sharks. Today he’s in search of gray whales.

After several minutes Camacho spies his target: a heart-shaped cloud of ocean spray erupting from the water. Suddenly an adult whale thrusts its tapered head straight through the surface, pausing for five long seconds before disappearing under the waves.

Encounters like these have for decades drawn tourists to this marshy stretch of Mexico, where each winter thousands of Eastern Pacific gray whales arrive from Alaska’s Arctic. Here the adults mate, and females give birth and rear their young in a network of tranquil lagoons.

Over the dozen years he’s been guiding, Camacho, 33, has devised nicknames for whales that return each season. Lucrecio splashes boats with his tail; Olivia nudges her calves to be caressed by starry-eyed tourists.

But over the last three years, Camacho and others have noticed ominous changes. The whales are arriving in the estuary later in the year, and many appear malnourished, the jagged outline of vertebrae visible on their typically fatty backs. More whales than usual have been washing up dead along the shore.

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