A trio of humpback whales has been spotted cavorting in San Francisco Bay this week in a fairly rare sighting. As Mary Jane Schramm of the Gulf of the Farallones National Marine Sanctuary tells SFGate, "We get a lot of gray whales around this time of year. But to get three humpbacks is really special." She assures us all that there's nothing to be alarmed about with the sighting, and the whales probably just crossed under the Golden Gate Bridge in pursuit of a shoal of fish.

The sighting comes after a couple of recent beachings of a sperm whale and of a juvenile female humpback in Pacifica.

The three humpbacks were spotted swimming into the Bay Wednesday morning, and apparently two headed toward Alcatraz while a third hooked a left and headed toward Tiburon.

Some may recall the case of two humpbacks who came into the Bay in 2007 and made their way 90 miles up the Sacramento River Delta before getting stranded and being turned around. They were a mother and calf nicknamed Delta and Dawn, and they were apparently in distress after sustaining injuries from a boat propeller.

Another humpback nicknamed Humphrey made appearances in both 1985 and 1990 and both times tried to head upriver. He became stuck in 1985, before getting turned around, and made national headlines.

CBS caught wind of some whale spouts near Crissy Field via social media, but did not identify these as humpbacks.

Below, KTVU's raw footage of the whales.