Young elephant seals risk shark attacks on way to SLO County beaches

September means juvenile elephant seals are coming back to the beach at the Piedras Blancas rookery north of San Simeon. It’s fall haul-out for young seals.

Adult female seals are at sea, feeding and growing the pups that will be born in January.

Adult bulls are in their northern feeding grounds, bulking up to withstand the long fast of the December-through-March breeding season. So young seals take over the beach in the fall.

More males than females on SLO County beaches

Although seals are born in roughly equal proportions of male and female, more of the juvenile seals crowding the beach now are males than females.

Female seals mature faster than males. Females may be mature enough to get pregnant at 2 years old. Just about all will be pregnant by 5 years old. Almost all will have given birth by 6.

Males take longer to attain their full maturity. They may grow bigger than adult females by age 5, but they are just beginning to mature.

That distinctive nose, or, proboscis, begins to grow around 5 years old, and takes about three more years to get to adulthood. The seals’ noses and chest shields are the visible external characteristics that indicate level of maturity.

The young of the year, last winter’s pups, are the smallest seals on the beach. They are resting from their first migration.

These young seals show no signs of recognizing the other seals, pups that were born near them on the beach in January and February.

It’s a solitary life for an elephant seal in the ocean, but on the beach, they pile on top of each other. It’s a biological response to touch stimulus called thigmotaxis.

Mostly it’s peaceful, although some young toughs try their skills by sparring with each other.

Elephant seals attract great white sharks

These fat young elephant seals attract great white sharks.

Great white sharks migrate toward the California coast from as far away as Hawaii. The Farallon Islands, Tomales Bay and Monterey Bay are more active feeding sites, but a severely shark-bitten elephant seal dragged himself out on to the beach in early September.

Despite the extensive wound, this seal survived and rested on the beach. Seals with scars from such wounds are often resting among their cohorts on the beach.

Blubber doesn’t have a rich blood supply, and I like to think that it doesn’t have many nerves, either. Seals can and do survive serious wounds.

The sharks store up oil in their livers as they feed on the elephant seals in the fall. That gets them through the long winter migration, to the so-called White Shark Café halfway between California and Hawaii. Scientists still aren’t sure why the sharks converge there.

Follow elephant seal and shark migrations at gtopp.org

The north end of the Piedras Blancas viewpoint will be closed for several weeks starting Sept. 20.

State Parks will repair the section of the trail that washed out in last January’s heavy storm. The south end remains open, and the Boucher Trail, which starts at the north parking lot, has several viewpoints within a mile of the trailhead.

This story was originally published September 21, 2021 at 7:05 AM.