Why are so many whales dying on California beaches?
On June 21, a 45-foot-long dead gray whale, longer than a city bus, washed ashore on Ocean Beach on the western border of San Francisco. A day earlier, a fin whale washed up on another beach south of the city. In May, seven gray whale carcasses landed on Bay Area beaches. Six other stranded whales were discovered in April. Each year, gray whales travel along the West Coast between Mexico and Alaska, a journey as long as 12,000 miles round trip. In 2019, whale strandings along the coast began to surge (the National Oceanic and Atmospheric Administration designates them as an unusual mortality event). Other whales seem to be dying farther out in the water and sinking, so the true number of deaths isnt clear. We know that for every one whale that washes up on our shores, that another ten whales can die offshore and never be seen, says Steve Jones, a senior media specialist for the oceans program at the nonprofit Center for Biological Diversity. By one estimate, the total population of the species along the coast dropped by more than 7,000 animals, or a quarter of the population, between 2016 and 2020. Scientists still dont know why so many whales are dying, but climate change may be part of the problem. In the Arctic, where they are feeding, the waters are warming, says Kathi George, the director of field operations and response at the Marine Mammal Center, a Bay Area nonprofit that rescues injured marine animals. With warming waters, youre not going to have as productive waters. So the quantity and quality of the food that they eat in the Arctic has not been as high in recent years. The whales have been starting these migrations not as healthy as they have in years past.  The whales have also started taking unusual detours on their trip. While they typically dont eat while travelinggorging themselves in the Arctic, and then making it to Mexico without feedingthey have started to make stops in the Bay Area to feed more. Research in Mexico has shown that many whales are now skinnier than they should be. When theyre malnourished, they may be more susceptible to human-caused impacts, she says. It hasnt been possible to determine the cause of death for all the whales that have stranded on California beaches this year, but many were clearly hit by ships, something that may have happened while they were feeding near the shore.