Why are gray whales and other marine life visiting San Francisco Bay?
When Bill Keener started working at the Marine Mammal Center as a field biologist in the 1970s, there were no whales or dolphins in San Francisco Bay. The waters east of the Golden Gate Bridge were chock- full of life — sea lions and harbor seals galore — but not a cetacean to be seen. Starting in the late 2000s, things began to change. There are now four cetacean species living in or regularly visiting the busy waters east of the Golden Gate — harbor porpoises, gray whales, humpback whales and bottle-nosed dolphins. Yet Keener and other marine researchers aren’t sure if the animals’ presence is a sign of ecosystem health and rejuvenation or a portent of planetary disaster. And in each case, the story is a little different. Regardless of the cause for their return, they’re growing increasingly worried that as the numbers of these charismatic megafauna grow, so too does their risk of injury and death in these high-traffic waters.