The Seal Deal: Part 3 of La Jolla Light series explores the pinniped world at Children’s Pool
Editor’s Note: The presence of harbor seals at the Children’s Pool in La Jolla generates a lot of interest and a lot of controversy. Visitors and residents alike have questions about the seals, and much misinformation abounds. In the interest of setting the record straight, La Jolla Light reached out to seal expert Monica DeAngelis with National Oceanic and Atmospheric Administration (NOAA) for all the information we could gather. This is Part 3 and the last installment for the 3-part series, The Seal Deal.
By Ashley Mackin
The seals at Children’s Pool, while tending to exhibit typical seal behaviors, are more acclimated to humans than other seals around the world:
■ Lifting parts of their body into the air or laying on their sides is simply done for temperature regulation.
■ Between 100 and 300 seals haul-out at the Children’s Pool, though that number depends on the year, DeAngelis said.
■ About 40 pups are born each pupping season, and births typically occur on land.
■ DeAngelis said she suspects that during pupping season, there are more females than males at Children’s Pool. “It looks like it is just full of females and pups and a couple of odd ducks that don’t seem to have a pup. We don’t know if they are males or non-pregnant females.”
■ Males would be at Children’s Pool waiting to breed. When females are done nursing, they take a break to build their strength back, and then once again are ready to mate.
■ The amount of rest needed depends on the age of the seal. Like human babies, seal pups need more rest than juveniles and adults. Pregnant females also need more rest than when they are not pregnant.
■ Seals spend about half of their day resting, and seals can rest on land or in the water, so adult seals would not likely drown. In the water, they bob in the ocean with their heads above water and their noses in the air. A young seal pup that has yet to be weaned could drown if out at sea for too long, but it is not because they cannot swim or bob, but because they would lose energy and starve, DeAngelis said.
Leaving Children’s Pool
■ When not at the Children’s Pool, seals are likely to be foraging for food. There are times when they travel to the Channel Islands, though it is not known how regularly they travel back and forth.
■ Juveniles travel further and more often for what scientists think is an exploration of their new independence, out of curiosity, or in their search for food. “We suspect juveniles would extend their range a little bit farther because they are not breeding at that time, so there is no call back to the natal site,” she said. While they typically stay within 15 miles from shore, juveniles have been known to travel more than 300 miles away.
■ Seals do not hold their breaths for very long or make long dives. The average recorded time is about five minutes, though the longest recorded dive (where the seal was continuously under water) was 31 minutes.
■ When it comes to legally moving or shooing seals away, the only statutes that justify it do not apply at Children’s Pool. Under the Marine Mammal Protection Act (MMPA), a person could legally shoo seals away for any of the following reasons: the health and welfare of the animal, if it’s a nuisance animal, or the safety of the human is in jeopardy.
“As the owner of a boat, you can enforce a non-lethal deterrent measure to shoo it off or preclude it from hauling-out,” DeAngelis said. However, in most cases, NOAA is notified ahead of time to make sure hypothetical efforts are legal. “So we already know about it and then we ask they provide a report on how effective that was and what the problems are,” she said.
Fish life at Children’s Pool
■ While seals eat small reef fish and squid sometimes eaten by bigger fish, retired California Fish and Game marine biologist and consultant Doyle Hannon said he would not expect Children’s Pool harbor seals to have an impact on San Diego fishing.
“It may help increase fish production. Any time you harvest a stock of fish, that stock of fish tends to repopulate,” he said. “When you fish down a stock, or animals eat some of those fish, then there is a niche available and so those fish will tend to reproduce to fill that niche.”
Hannon added that as long as the predator population and prey population are both at carrying capacity, the relationship is in balance.
However, “If you have an overabundance of seals, then you could have overfishing, where they would be taking more than what would be sustainable, so they would drive that stock down,” he said. If the fish numbers were to increase, the predator population would eventually go up as well. It’s a very closely tied ecological relationship.”
■ The seals also eat more than fisherman could ever catch.
People at Children’s Pool
■ People who unintentionally scare the seals and cause them to flush might be subject to fines or investigation. Penalties would depend on their knowledge of the area and whether the incident is reported to NOAA.
“If it’s a tourist, who has no idea and who accidentally did that, they would probably get a phone call explaining to them that this is not allowed under the law, to educate them more than punish them,” DeAngelis said.
■ Mark McPherson, Chief of the San Diego County Department of Environmental Health, said the safety of the water at Children’s Pool for humans is monitored regularly. When seals are present, the bacteria levels in the water almost always exceed state safety standards. This is not the case at beaches where large numbers of seals are not present.
Children’s Pool seals vs. others
■ DeAngelis said the harbor seal population at Children’s Pool is stable and at carrying capacity. As of today, they are not on the endangered or threatened species list.
“Genetically, we don’t know what the Children’s Pool seals contribute to the seal population,” she said, adding that she doesn’t know the ramifications to California’s seal stock of removing the Children’s Pool seals from the site at which they give birth.
Should the seals be removed from the Children’s Pool, they might go elsewhere over time, she posited. There are more than 1,000 miles of coastline in California.
Why don’t we know more about seals?
■ DeAngelis said the reason so little is known about harbor seals is that they are difficult to study. “Not impossible, just difficult,” she said, especially in an urban environment where it is hard to determine why something happened — whether weather is a factor or people, from a scientific standpoint, “It’s hard to get a good solid answer.”
■ The long-term effect of the seals living in urban environments is also unknown, which DeAngelis said might be a good thing.
“What’s beneficial is what we don’t see. We don’t know what type of stress such close proximity might have on those animals — or what the long-term implications might be. No one has actually tracked an animal from birth to death at Children’s Pool and noted any shift.”
— Please note: La Jolla Light would like to thank all the experts who contributed to this series, especially Monica DeAngelis, who returned every e-mail and was available for every phone call, taking time to answer each question to the best of her knowledge.
- The Seal Deal: Part 2 of La Jolla Light series explores behavior patterns in the pinniped world at Children’s Pool
- The Seal Deal: Part 1 of series explores the pinniped world at Children’s Pool in La Jolla
- Sea lion found resting in patio chair at La Jolla hotel part of unexplained starvation trend [VIDEO & STORY]
- Mayor shares details of recently installed ‘seal cam’ at La Jolla Children’s Pool
- Coastal Commission approves permit for year-round seal rope
Short URL: http://www.lajollalight.com/?p=104524