Los Farallones

Dispatches from Point Blue’s field station on the Farallon Islands National Wildlife Refuge

E Seal, E Seal! Read All About It!

As of March 7th, the 2021 elephant seal breeding season has come to a close. This marks the 49th year of data collected on the Farallones for Northern Elephant Seals and we are excited to share some of what we learned this season! But first…

Why Do Elephant Seals Matter?

In 1884 Northern elephant seals were thought to be extinct after being hunted throughout the 18th century for their blubber. After not being seen for 24 years, a small group was found on Guadeloupe Island off Baja California, Mexico. The total N. Elephant Seal population has now grown to an estimated 179,000 individuals as of 2014, a huge conservation success. 

Colonies of breeding individuals can be found along the California Coast and coastal islands, such as SFI (which includes West End Island, the Southeast Island, and the islets). Elephant seals can be important indicators for the health of an ecosystem and how well it is doing. With the long term data set on the Farallones, we hope to explore the productivity of this ecosystem and how it relates to a changing climate. 

A group of breeding seals on Sand Flat, SEFI

2021 Breeding Season

So what else happened this year? Lots! We had 102 cows arrive and 88% pupped this year. The pup survival was 71% for SEFI and 91% for WEI, which means we now have a total of 72 weaners roaming around the islands!

Weaner 1 lived up to her name and became the first to leave Sand Flat and venture into the unknown. After two weeks of scouting for her, she was spotted safe and sound at Sea Lion Cove. She wanders to this day bringing luck to all who see her.

A weaner from West End swimming in the waters around North Landing


Many of the cows on SEFI have returned year after year and we get to know their life story quite well. Butternut, tagged on SEFI as a weaner 13 years ago, successfully weaned her 5th pup this year on SEFI. You go, Butternut!

Once all the breeding cows departed, Sand Flat (the main breeding area) is left much more spacious for the weaners to hang out


Even with the breeding season over, the islands are still used by elephant seals to haul out on and molt. After our last cow left on March 7th, we’ve now begun to see the return of many immatures. There are still a few non-breeding cows and males hanging around, basking in the calm after the bustle of the breeding season. 


A Unique and Important Colony! 

Northern Elephant seals first recolonized SFI in 1972 and their population peaked in 1989, with 349 pups born that year! Quite the comparison to the 90 pups we had this year. Although the population used to be much higher, it has stabilized around 100 for the past 10 years. 

Although SFI may not have the highest number of elephant seals in comparison to some of the other colonies along coastal California, it is extremely important to understand what factors may limit this population and the impact those factors may have on other aspects of the environment. By monitoring this smaller population, we can get more in-depth knowledge about the E Seals that would be much more challenging to acquire with a larger colony.

In 1999 there was quite a dramatic drop on West End, as you can see in the graph below. 

This lines up with some major storm events from the 1997-1998 El Nino and one of the largest breeding sites on West End, Shell Beach, was hit hard. The sand from the beach was washed out, and the small access point for seals disappeared, making it harder for them to haul out there. The population has now re-stabilized at a much lower number than prior to 1998. This year we had 6 cows on Shell Beach, and the number has consistently been in the single digits for the last 10 years.

Now that the seasons are changing, the islands beginning to see an increase in seabirds as they prepare to breed. It’s never a dull moment out here on the Farallon Islands. 


Lowry, M.S., R. Condit, B.Hatfield, S.G. Allen, R. Berger, P.A. Morris, B.J. Le Boeuf, and J. Reiter. 2014. Abundance, Distribution, and Population Growth of the Northern Elephant Seal (Mirounga angustirostris) in the United States from 1991 to 2010. Aquatic Mammals 40(1):20-31.
Marine Mammal Center “