Why California gray whales starve

RECENTLY, WHILE sailing with friends on San Francisco Bay, I enjoyed the sight of harbor porpoises, cormorants, pelicans, seals and sea lions — and then the spouting plume and glistening back of a gray whale that gave me pause.

- DAVID HELVARG GUEST CONTRIBUTOR

Too many have been seen inside the bay recently.California’s gray whales have been considered an environmental success story since the passage of the 1972 Marine Mammal Protection Act and 1986's global ban on commercial whaling. They’re also a major tourist attraction during their annual 12,000-mile round-trip migration between the Arctic and their breeding lagoons in Baja California. In late winter and early spring — when they head back north and are closest to the shoreline, with the moms protecting the calves — they can be viewed not only from whale-watching boats but also from promontories along the California coast including Point Loma in San Diego, Point Lobos in Monterey and Bodega Head and Shelter Cove in Northern California.

In 1972, there were some 10,000 gray whales in the population on the eastern side of the Pacific. Generations of whaling all but eliminated the western population — leaving only about 150 alive today off of East Asia and Russia. Over the four decades following passage of the Marine Mammal Protection Act, the eastern whale numbers grew steadily to 27,000 by 2016, a hopeful story of protection leading to restoration. Then, unexpectedly over the last nine years, the eastern gray whale population has crashed, plummeting by more than half to 12,950, according to a recent report by the National Oceanic and Atmospheric Administration, the lowest numbers since the 1970s.