Weekly Elephant Seal Monitoring Update: March 3, 2018

News This Week

  • Only 79 elephant seal cows remain in Point Reyes as of Feb. 27, down from seasonal peak of 1225.
  • Majority of weaned pups appear to be well nourished and healthy.
  • Researchers continue flipper tagging pups, and have tagged 397 unique animals so far!

A group of grey and black weaned elephant seal pups rest their heads on each other, and look at the camera.
A pile of plump and healthy weaned pups.

NPS / Marjorie Cox, NMFS Permit No. 17152-00

A very large bull elephant seal rears up, and prepares to strike a smaller male elephant seal.
A bull elephant seal battles a much smaller sub-adult male.

NPS / Marjorie Cox, NMFS Permit No. 17152-00

Two park researchers kneel behind a sleeping elephant seal pup, and prepare to apply a tag to its rear flipper.
Researchers apply a flipper tag to a sleeping weaned pup.

NPS / Sean Pickton, NMFS Permit No. 17152-00

Wonderful Weanlings

Now that the majority of pups born in Point Reyes are without mom, it is time for them to learn how to be an independent seal. However, achieving this independence relies on important social interactions with fellow weaned pups. Pups will practice aggressive behaviors that they will need to be successful adults. Males more frequently display mock aggressive behavior such as neck biting and body slamming, and female pups mimic the “head banter” behavior of adult females. After weaning and molting, pups will begin to move into the water, often following the lead of older pups. In shallow tidal areas weaned pups will practice swimming, foraging behavior, and breath holding. After approximately 5 weeks of swimming practice pups will be excellent divers, and be proficient enough swimmers to head out into open water to find food.

A female pup floats on her back in a tide pool with head submerged, and practices breath holding.
A female pup floats on her back and practices breath holding.

NPS / Marjorie Cox, NMFS Permit No. 17152-00

A black elephant seal pup, with its head out of the water, swims in a tide pool.
A weaned pup swims in a tide pool.

NPS / Marjorie Cox, NMFS Permit No. 17152-00

Dominating D1

Researchers were pleased to read the flipper tag of Drakes Beach alpha male D1. The tag was spotted earlier in the season, but as D1 was surrounded by cows and pups it was too difficult to read. We got our chance this past week. The green tag was from Año Nuevo, after reaching out to researchers there we found out that D1 was tagged as a pup ten years ago, and re-sighted once at Año 5 years later. It will be exciting to see if this 10 year old bull returns to Drakes Beach next year!

A massive bull elephant seal, dye marked ”D1”, rests on his belly.
Alpha male D1 on Drakes Beach.

NPS / Sean Pickton, NMFS Permit No. 17152-00

Preliminary Data

Total Elephant Seal Counts, Winter 2017-2018

Stacked bar graph of the total number of elephant seals surveyed at three locations in Point Reyes National Seashore by survey date, overlayed on a stacked area graph showing the average number of seals surveyed at the same sites between 2005 and 2017.
Total elephant seal counts this season compared to average totals from 2005-2017 at the three Point Reyes National Seashore breeding colonies. Surveys this season reveal more elephant seals than average on Point Reyes beaches starting in January. A decrease in the number of seals is continuing the trend that began Jan 31st.

Female Elephant Seal Counts, Winter 2017-2018

Stacked bar graph of female elephant seal counts at three colonies in Point Reyes in 2017-2018 by survey date, overlayed on a stacked area graph showing the average number of females surveyed at the colonies between 2005 and 2017.
Female elephant seal counts this season compared to average female counts from 2005-2017 at the three Point Reyes National Seashore breeding colonies. The total number of cows on Point Reyes beaches is significantly higher than average, and we continue to see a decline in numbers due to females leaving after weaning their pups. The highest increase from the average was seen at Drakes Beach, the Point Reyes Headlands colony is declining, and the South Beach colony numbers are close to average.

Elephant Seal Pup Counts, Winter 2017-2018

Stacked bar graph of the number of elephant seal pups counted at three colonies in Point Reyes in 2017-2018 by survey date, overlayed on a stacked area graph showing the average number of pups counted at the colonies between 2005 and 2017.
Number of elephant seal nursing pups counted at the three breeding colonies in Point Reyes this winter compared to the average number of pups surveyed at those colonies between 2005 and 2017. The first pups of the season were counted on December 28. A decline in nursing pups began February 7th at Point Reyes Headlands, Drakes Beach, and South Beach colonies, and continues to decline as pups wean.

Weaned Elephant Seal Counts, Winter 2017-2018

Stacked bar graph of the number of weaned elephant seals counted at three colonies in Point Reyes in 2017-2018 by survey date, overlayed on a stacked area graph showing the average number of weaned seals counted at the colonies between 2005 and 2017.
Number of elephant seal weaned pups counted at the three breeding colonies in Point Reyes this winter compared to the average number of weaned pups surveyed at those colonies between 2005 and 2017. The first weaned pups were recorded at the Drakes Beach and Point Reyes Headlands colonies around January 24. An increase in weaned pups continues at all of the colonies.

Elephant Seal Seasonal Monitoring Updates Home


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Last updated: March 19, 2018