It’s peak breeding season for northern elephant seals, and biologists with the Point Reyes National Seashore are taking extra precautions at Drakes Beach, where last winter a colony set up camp during the government shutdown and effectively blocked visitor access. The event caused a full beach closure, and the spectacle—which is not typically so accessible to the public—generated international media attention

The seals historically have hauled out along Drakes Beach, but not at the primary public access point for the beach, which abuts the parking lot and visitor center. This year, park employees are moving any pregnant seals that arrive in that area back into the water, preventing the spot from becoming populated with mothers and pups. 

“If they were to have a pup [already], we would be totally hands-off, however,” said Dave Press, the seashore’s wildlife ecologist. Employees are moving the seals by shaking tarps, an effort Mr. Press said is supported by biologists from the National Marine Fisheries Service, which administers the Marine Mammal Protection Act.

He continued, “It was very logistically complicated, very time-consuming, for our staff to manage the situation last year, when we basically had to close the entire beach. We have a few objectives as an agency that we have to balance, including protecting natural resources and providing recreational use.”

Last winter’s king tides and storms pushed the seals into the most public section of Drakes Beach since it is more sheltered than the elephant seals’ typical breeding spots on the southwest portion of the beach and the peninsula’s other outer beaches. A count from last February found 45 pups at the spot adjacent to the parking lot, out of a total of 985. This year, no pups have been born there.

Overall, the numbers of cows and pups tallied by seashore employees are on target with previous years and are consistent with general growth trends. By the end of January, there were 2,103 seals in the park, including 1,167 cows, 709 pups and 227 bulls.

Last year, there were several hundred more seals and pups by the first week in February, for a total of 2,444. Mr. Press said this year’s numbers may still catch up. “We are at peak season, but we won’t know the final numbers until the end of the season, which will take into account any late arrivals,” he said.

Mr. Press said the distribution of seals is on par with historical trends, with one exception: several bulls are on the southern end of Limantour Beach, an unusual location that has required extra patrolling, considering the number of dog walkers there.

Point Reyes marks the northernmost extent of the seals’ breeding range, which extends down along the coast of Mexico, and provides one of the few opportunities to observe a species that spends 80 percent of its life at sea. During the rest of the year, northern elephant seals travel as far north as the Aleutian Islands and are known to descend to over 5,000 feet below the ocean’s surface.

The species has made a dramatic recovery over the past century. Between 1884 and 1892, the species were thought to be extinct. A ban on hunting went into effect in 1922, and a group of around 100 seals began to rebound. Now, the International Union for the Conservation of Nature ranks both northern and southern elephant seals as species of least concern due to their expanding populations. Today the seals are at around 150,000 strong.

After being absent for more than 150 years, the seals returned to Point Reyes in the early 1970s. Between 1988 and 1993, the population grew at a dramatic annual rate of 32 percent. Since 1993, the growth rate has slowed to 8 to 9 percent a year, according to the seashore’s data. In 2018, the total Point Reyes population was around 3,000.

Besides Point Reyes, the seals haul out in just a few sites in the state, including the Farallon Islands, Piedras Blancas, Año Nuevo and the Channel Islands.

“As soon as the young females have a hard time reproducing, they move on to find a new place,” said Dr. Burney Leboeuf, a professor at the University of Santa Cruz who has surveyed elephant seals in Año Nuevo since 1968. “That’s what we’ve seen again and again throughout the recovery of the population: they settle, a spot gets crowded, they expand.”

A recent long-term study of seals born at Año Nuevo—many of which later travel north and breed in Point Reyes—found that only six percent of the females gave birth to 10 or more pups during their lifetimes. Those “supermoms” birthed the majority of the pups that survived.

But Dr. Leboeuf laid out the harsh odds. Seventy-five percent of the female pups the study tracked died before they reached the breeding age of three or four years old; of the survivors, the majority bred a few times and then died. Just a small percentage survive, breeding every year throughout their life.

The longest-lived female in the study lived to age 23 and produced 17 pups in her lifetime. Another supermom produced pups in 16 consecutive years.

Dr. Leboeuf is concerned that this population dynamic reduces genetic variability, which could spell trouble especially as the climate changes. He said further observations of the supermoms’ behaviors could reveal which traits might increase their survival in the open ocean, where white sharks, storms and varying food supplies pose challenges.

Elephant seals rarely die on land. “But these long-lived multiparous females have somehow found a way to avoid dying at sea,” Dr. Leboeuf said.