Spotting a gray whale in San Francisco Bay can be thrilling, but researchers now know it can be bad news for the marine mammals.
Nearly 1 in 5 gray whales that enter the bay die there, researchers report April 13 in Frontiers in Marine Science. For a population that has lost hundreds of individuals in recent years, the toll is another reminder of trouble along the whales’ 16,000-kilometer migration route.
Most gray whales (Eschrichtius robustus) migrate from the freezing Arctic waters, where they eat, all the way to Mexico, where they stop for some time to mate and give birth, before returning to the Arctic to eat again. The