A record 21 gray whales were found dead in the San Francisco Bay area in 2025, with seven more already killed this year, prompting urgent scientific investigation into the role of climate change, shrinking Arctic prey supplies, and vessel strikes. Researchers say the whales — normally bypassing the bay on their 15,000–20,000 km annual migration between the Arctic and Baja California — have increasingly been entering the bay since 2018, apparently driven by hunger as food sources in the Arctic decline, leaving them underweight and highly vulnerable to collisions with ships and ferries. The Eastern North Pacific gray whale population has nearly halved, from 27,000 in 2016 to 12,500 in 2025, a decline the US National Oceanic and Atmospheric Administration has classified as an "unusual mortality event," with scientists warning that low calf counts and rising human-caused mortality could prevent the species from recovering without immediate conservation measures.