Biology Reference
In-Depth Information
Sea lions can be easily seen at San Francisco's Pier 39. In the waters of Aquatic
Park nearby, sea lions have been known to butt or harass bay swimmers. Because
these marine mammals use subtle currents in the often murky water to find fish,
they may be drawn to the wake left behind by paddling hands and feet.
(Anna Davison)
California Sea Lions can grow to an intimidating size, with males—dis-
tinguishable by the sagittal crest or bump on their heads—reaching 800
pounds and just shy of 10 feet long. Females are considerably smaller at
250 pounds and less than eight feet long.
The bay's sea lion population is small (1,000-2,000) relative to the
state's population of 200,000. Sea lions stay in the bay through fall and
winter, then move to southern California and Mexico to breed. Their pres-
ence in San Francisco Bay coincides with herring spawning season. The
masses of fish make easy pickings for sea lions, pelicans, gulls, and other
predators. Around the estuary, sea lions are generalists that will eat ancho-
vies, rockfish, salmon, and even Smooth-hound Sharks. Sea lions have
been known to toy with their smooth-hound prey, tossing them out of the
water several times before ingesting the victims whole and headfirst.
Most visitors to San Francisco's Pier 39 have visited the docks crammed
with California Sea Lions. No one knows why these marine mammals
abandoned Seal Rock off Ocean Beach in the late 1990s, though some sus-
pect it was due to the dwindling numbers of salmon traveling through the
Golden Gate. These opportunistic predators certainly may have been
drawn to the pier's newly constructed docks by the waste fish and crabs
discarded off Fisherman's Wharf.
