Increased food availability: San Francisco Bay is home to a variety of food sources that gray whales find appealing, including krill, shrimp, and small fish. In recent years, the population of these prey species has increased in the bay, which may be one reason why more gray whales are visiting.

Changes in migration patterns: Gray whales typically migrate from their feeding grounds in the Arctic to their breeding grounds in Mexico and back again each year. However, in recent years, some gray whales have been observed staying in San Francisco Bay for longer periods of time or even changing their migration patterns altogether. This could be due to a number of factors, including climate change, changing food availability, or increased human activity in their traditional migration routes.

Whale-watching activities: San Francisco Bay is a popular destination for whale-watching tours, and this activity may also be contributing to the increase in gray whale sightings. Whale-watching vessels can provide a source of food for the whales, such as scraps from fishing nets or food intentionally thrown overboard by tourists. This can encourage the whales to stay in the bay longer than they might otherwise.