Bottlenose Dolphins Splash Through SF Bay

By Mary Jane Schramm
Media Liaison, Gulf of the Farallones National Marine Sanctuary

 

Bottlenose standoffs with a gull. Credit: Jamie Hall

If you’re surfing at Ocean Beach and see a gray dorsal fin rise out of the water, look twice before you panic, it may only be a bottlenose dolphin trying to catch a wave.  Long considered a tropical species, bottlenose dolphins have been journeying more and more often into Bay Area waters.  In the past month alone, there have been numerous sightings just off the FMSA office at Crissy Field.

Bottlenose Dolphins range all over the Pacific, from South America to Southern California, but not until the El Niño of 1983 were they spotted off the Northern California coast.  Aboard a whale watching cruise in the Gulf of the Farallones during the 1982-83 El Niño event, several marine life enthusiasts were relishing an encounter with a mixed-species pod of dolphins. 

Common dolphins, northern right whale dolphins and Pacific white-sided dolphins were slicing foamy crisscross patterns across the surface of the gulf’s cold green waters.  Mixed in among them, however, was a fourth species—larger, more robust, drab gray, and lacking the striking counter-coloration that the others sported so elegantly. But this drab group set two people shouting with excitement: they were bottlenose dolphins!

A search of the scientific literature revealed that this was a northern record for live bottlenose sightings, the previous being Point Conception near Santa Barbara, dating back to the late 1800s.

These dolphins had apparently taken advantage of the invitingly warm waters of the El Niño event to hitch a ride north, expanding their range by nearly 300 miles.  And ironically, while the El Niño wrought havoc with other marine life, this opportunistic and adaptable species carved out a new niche and settled in – permanently, it seems.

As the El Nino faded, and the ocean resumed its chilly low-50s temperatures, the dolphins continued to travel north.  Since then they have been regular near shore visitors, enchanting beachgoers and startling unwary surfers with their shark-like dorsal fins.

In 2003, Maria Brown, Superintendent of the Farallones Sanctuary, noticed a single dolphin off Crissy Field Beach. It was a bottlenose dolphin, and when reported to NOAA, it became the very first San Francisco Bay sighting of a live bottlenose dolphin on record.  This year there has been a noticeable spike in sightings just off Crissy Field Beach, including groups of up to ten individuals. They have been seen swimming and diving vigorously, fluke-slapping and splashing—possibly to herd or stun prey such as anchovy and other small fish.  More than one sighting has involved a cow-calf pair.

Come by the FMSA Visitor Center and you might be lucky enough to see some of these playful creatures!

 

All photos by Jamie Hall