Gray whales, once rare in San Francisco Bay, dying there at alarming rates

Researchers find increase in whale deaths in the bay, largely because of collisions with vessels on busy shipping route

Gray whales have historically been a rare sight in the San Francisco Bay. They trek from the warm lagoons of Mexico's Baja California more than 10,000 miles (16,000km) north to the Arctic region to feast on shrimp-like animals during the summers, seldom stopping in the busy shipping corridor for prolonged periods.

But in recent years, that story has changed in a dire way. A new study, published this week in the journal Frontiers in Marine Science, has found that gray whales in the bay have been dying at alarming rates, largely due to collisions with vessels.