The Seal Deal: Part 2 of La Jolla Light series explores behavior patterns in the pinniped world at Children’s Pool

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 a seal expert for all the information we could gather about them. (Photo by Ashley Mackin)

By Ashley Mackin

In the second of at least three parts in our seal series, La Jolla Light continues its expose on the pinnipeds (fin-footed mammals) at La Jolla’s Children’s Pool with the help from marine biologist Monica DeAngelis of the National Oceanic and Atmospheric Administration (NOAA) Federal Advisory Committee.

In the second installment, DeAngelis answers questions about seal mating and pregnancy, as well as the illnesses they are subject to and how they’ve acclimated to humans.

Mating and Pregnancy

■ A seal will return to the site where it was born to give birth. Therefore, DeAngelis said the seals born at Children’s Pool would likely return there to give birth, making them more residents than visitors.

■ Because mating happens in water, very little is known about the courting habits of harbor seals. Scientists have observed tail flapping and attention-getting attempts during mating season.

■ Males typically only produce one pup per season, and males rarely produce more than one. “That male could have attempted to mate with 10 different females, but the (genetic) result of that encounter was one pup with one female,” DeAngelis said, “The action may have been there, but no result.”

■ Additionally, females can delay the implantation of a fertilized egg to ensure they give birth during pupping season. She will carry the fertilized egg for one to three months before she is officially pregnant.

Taking delayed implantation into account, a seal’s pregnancy lasts 9–11 months. (One theory of why males can only reproduce with one female per year is that she may already be carrying a fertilized egg that has not been implanted.)

■ Seals reach sexual maturity at 4-6 years old. They often give birth on land or some land-based object. However, because newborns can swim right away, seals can give birth in water. DeAngelis said she thinks the frequency of births in water is very low.

■ Because a seal’s sexual organs are internal, it is impossible to tell males from the females without an upclose inspection, which DeAngelis does not recommend. A nursing mother is one clue.

The sea wall is a popular viewing spot at the Children's Pool in La Jolla. (Photo by Susan DeMaggio)

Illness, Seal bites

■ The presence of Domoic Acid, a naturally occurring neurotoxin in the ocean that bio-accumulates in seals prey, makes them susceptible to seizures.

■ Seals are also subject to Phocine Distemper Virus, which also affects dogs. The Distemper Virus can kill.

■ A seal’s most common problem is a viral and/or bacterial infection, along with parasites that attack the heart, lungs, skin, nasal cavity and blood vessels.

■ In the event a seal bites a human, the bacterial infection could spread to the human. DeAngelis said as with any wild animal bite, it needs to be cleaned and treated or the victim could lose the area around where they were bit or the infection could become systemic. DeAngelis warns, though seals seem to be used to humans, they are still wild animals and can bite.

■ Seals bite if they feel threatened or if their pup is threatened. Seals might also be more defensive if they feel sick. Seals at Children’s Pool are so acclimated to humans, they are less likely to bite, DeAngelis said.

■ Mortality rates are higher for newborns than for adults, who could live to age 35.

The seals at Children's Pool have become acclimated to humans. Note: the people in this photo are within 50 meters of the seals, a violation of the MMPA. Ashley Mackin

Seals and Humans

■ Living in an international tourist center like the Children’s Pool in La Jolla exposes the seals to humans. They are similarly exposed at a haul-out site in Carpinteria in Santa Barbara. “At this point, I would call (La Jolla’s seals) urban wildlife because of the conditions they are used to living in now,” DeAngelis said.

■ The human interaction factor extends further when humans take pups home with them, thinking the pups are abandoned. DeAngelis said they have received reports of people keeping them in the bathtub, something she does not recommend.

“(People) take a pup home and then poor mom seal comes back from her foraging trip and her pup is gone,” she said, adding that a mother might be gone for a few hours to a few days, depending on the age of the pup.

“That’s why we have guidance in place; the public can call in if they see what they think is an abandoned seal,” she said. “What we do is put a watch on it to see if it indeed had been abandoned, if it is all alone or acting strangely, losing weight or if it’s been abandoned for a few days.”

Influencing Seal Behavior

The seals at Children’s Pool, now quite used to humans, are not easily influenced by human behavior. At the Carpinteria haul-out site, however, there was a behavior shift where seals took to hauling-out mostly at night when there were fewer humans around.

“I wouldn’t say that they were trained to change their behavior; I think it’s just a response to the threat that humans potentially posed in that area,” DeAngelis said. “They didn’t abandon the site at all, they just shifted their haul-out pattern and in different places on the beach.”

Up Next: In the April 4 issue, the community of seals at Children’s Pool, specifically, will be addressed. We will look at the legality of moving them, how they’ve impacted the environment, and how their environment has impacted them.

SeaWorld Involvement

■ If a seal gets sick or is confirmed abandoned, volunteers and staff from SeaWorld San Diego will come to rescue them. SeaWorld is not paid by NOAA for its services. Rescue Hotline: 1 (800) 541-7325.

■ David Koontz of SeaWorld addressed the rumor that the seal population at Children’s Pool has increased because SeaWorld releases rehabilitated pups in La Jolla. “We rescue, on average, less than 10 harbor seals annually,” Koontz said. “They are released in ocean areas where others of their kind are already and there is a known food source.

■ “Harbor seals are often found foraging in the kelp beds that are a mile or two off shore. We return this species to the ocean on the west side of the kelp beds. There is not only a good food source for the harbor seals present in the kelp beds, but the kelp beds also provide a degree of protection from other predators. We don’t return harbor seals at the Children’s Pool.”

What is a Haul-out?

■ Hauling-out is the behavior associated with pinnipeds of temporarily leaving the water between periods of foraging activity for sites on land or ice. A distinction is made between reproductive aggregations, termed “rookeries,” and non- reproductive aggregations, termed “haul-outs.”

■ Other benefits of hauling-out may include predator avoidance, thermal regulation, social activity, parasite reduction and rest. — Wikipedia

• PREVIOUS STORY: See Part 1 of The Seal Deal series at http://www.lajollalight.com/?p=103535

Related posts:

  1. The Seal Deal: Part 1 of series explores the pinniped world at Children’s Pool in La Jolla
  2. UPDATED (3/21): Mayor orders Children’s Pool in La Jolla closed after dark through May 15
  3. Mayor shares details of recently installed ‘seal cam’ at La Jolla Children’s Pool
  4. Coastal Commission approves permit for year-round seal rope
  5. Coastal Commission to rule on year-round seal rope July 11

Short URL: http://www.lajollalight.com/?p=104373

Posted by Ashley Mackin on Mar 29, 2013. Filed under La Jolla, News, Seal Watch. You can follow any responses to this entry through the RSS 2.0. You can skip to the end and leave a response. Pinging is currently not allowed.

3 Comments for “The Seal Deal: Part 2 of La Jolla Light series explores behavior patterns in the pinniped world at Children’s Pool”

  1. David Pierce

    That’s twice that David Koontz of Sea World has danced around the question regarding the ” rumor ” that rehab seals have been released at Children’s Pool.
    “We don’t return harbor seals at the Children’s Pool.” Yes, anymore!
    Sea World stopped releasing rehab seal there around 2005 after the damage was done. Freedom of information act inquires from NMFS tells a different story.
    I request that Ashley Mackin of the light to follow up and ask David Koontz specific questions to the fact that Sea World has in the past released rehab seals at and around Children’s Pool in the mid 90′s after the light does a freedom of information request to the National Marine Fisheries Services on rehabilitated Harbor seals dates and locations of release from 1989 to 2005
    This would be investigated reporting and the truth would come out.

    • Cheri Aspenleiter

      Yes please, I second this request. Please research and report the truth.

      • Cheri Aspenleiter

        Please research and report the fact that environmentally relocating the seals has already received approval from all agencies necessary some years back. At That point, is when some political illegal action occurred that halted this wise decision to relocate them and to dredge out the sand and open the sluice-ways to keep the pool clean for its original uses. To illegally and unethically add a use, to a dead woman’s Trust officially accepted by the City of S.D. with a legal promise by the City to maintain the pool as a human ocean pool; a Marine Mammal park at this protected ‘bathing pool for children and the infirm” was really wrong and I believe could be proved in court illegal. As the added use is scientifically not compatible to the original uses that the Children’s Pool was specifically designed and built for. At that point, is where all the mistakes started by Pease and the people making lots of money from donations from people who think they are actually helping seals. The seals are now starving. The people, especially disabled are prevented by a rope from going there. Everyone looses. Honor the trust, relocate the seals to a natural beach, and restore access via ADA standards, restore the pool, and the wall and everyone wins. People can come swim, disabled can actually swim and use the ADA shower being built for this purpose. And people can stroll the wall and watch seals swimming on one side and people on the protected side. Thank you for proper historical research . Please address the fact that I could only locate one live mussel in the area of C.P. and S.Casa. And why no studies have been ongoing since Sea World DID release Many many seals at these locations years ago. The underwater ecology is barren. And what effect the White Shark being on the endangered list and can not be hunted will have on this whole situation, especially with the seals so used to humans. Sharks are coming back; would be really a crime if a person was attacked at a pool for Children, when proper Marine Mammal management could of prevented this when it was set up to relocate the seals for their own good and for the good of Children, disabled and families, and for San Diego.

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