Excerpt:

Bottlenose dolphins do not usually come to mind when thinking of wildlife at Alameda Point. In fact, just three dolphins have been observed there in recent years, and those sightings were from canoes and kayaks. But on July 24, two more dolphins were observed with two regulars meandering around next to Breakwater Island. The standalone rock wall, or breakwater, is visible from Pier 3 where the USS Hornet Museum is berthed.

The first-time visitors were from Monterey Bay and identified by researchers with Golden Gate Cetacean Research (GGCR). The group tracks the dolphins using a catalog of 91 dolphins showing individual markings, some with names.

The newcomer dolphins, named Coffeemate and Big Sur, were identified by markings on their dorsal fins that include notches in the back of the fin, possibly caused by shark bites, and scars. “They are hanging out with Arc, the adult female that has been a resident in the bay for a couple of years,” said Bill Keener with GGCR. The fourth dolphin was likely Kaimi, a dolphin seen by members of Alameda’s outrigger canoe center for the past two years, according to Keener.

Bottlenose dolphins began appearing in San Francisco Bay around 2008. “There were no coastal bottlenose dolphins in Northern California before 1983,” said Keener. “That’s when a big El Nino brought them north with warm water. They stayed in Monterey Bay even after the water cooled down, and since then they have moved slowly north. They can go back and forth from Monterey Bay — it’s only a day or two away for them,” Keener explained.