Studying Fur Seal and Sea Lion Populations in Sunny Southern California - Blog Post 1

Intern Chris Moon searching for marked California sea lions on San Miguel Island. Credit: NOAA Fisheries / Sharon Melin.

July 11, 2024

Okay, the title of this blog is a little misleading. Although we are currently working on San Miguel Island, which is a part of the California Channel Islands off of southern California, it is anything but sunny during a good part of the summer. We affectionately call this special place "the island of fog and wind."

Tony Orr and Intern Chris Moon in the mobile blind among northern fur seals and California sea lions on Point Bennett of San Miguel Island. Credit: NOAA Fisheries / Heather Ziel under NMFS Research Permit #16087.

The island lived up to its name last week. It took Heather Ziel (Polar Ecosystem Program) and me 4 days to make it here because the fog was too thick for the helicopter to land on the island. Last Friday (July 5), we joined our summer intern, Chris Moon, who had been working with Dr. Sharon Melin the previous 2 weeks. They were primarily hiking around the island looking for marked (branded and/or flipper-tagged) California sea lions. From re-sight data, we can learn about the survivorship, natality (adult females), and territorial tenure (adult males) for this species.

They were also able to witness peak pupping days for California sea lions, as thousands of pups have populated the beaches and coves of San Miguel Island. Since last Friday, our focus has shifted a little. Although we are continuing to look for marked sea lions, we are putting more efforts in finding tagged northern fur seals. Last week was when we would expect to see the highest number of adult females on the island at any one time, so this past week has been a good time to see many identifiable individuals.

Chris Moon photographs tags on northern fur seals from the mobile blind on Point Bennett of San Miguel Island. Credit: NOAA Fisheries / Tony Orr under NMFS Research Permit #16087.Close-up shot of a northern fur seal's flipper showing a VHF tag affixed to the base. VHF tags can transmit data to stationary towers that record the presence of animals with VHF tags. Credit: NOAA Fisheries / Tony Orr under NMFS Research Permit #16087.

Besides looking for and recording animals using binoculars and cameras, this past week we have included the use of uncrewed aerial systems (drones). Drones allow us to see individuals farther away or not easily accessible on the ground, without causing disturbance. Unfortunately, the fog and wind have restricted many of our flight plans.

Chris Moon powers on a Mavic drone on the launch pad as Heather Ziel prepares to pilot the survey flight. Credit: NOAA Fisheries / Tony Orr.An aerial view of northern fur seals and California sea lions on the beach at Point Bennett, San Miguel Island. Credit: NOAA Fisheries / Tony Orr

This trip has been a reunion of sorts for Heather. She was a member of the California Current Ecosystem Program when she first started working at the Marine Mammal Laboratory. She now works with the Polar group on ice and harbor seals in Alaska. She was reminded of, and Chris is just experiencing, the diversity of wildlife on San Miguel Island. Six different pinniped species (including the California sea lion, Steller sea lion, Guadalupe fur seal, northern fur seal, northern elephant seal, and Pacific harbor seal) can be seen on the island during the year. Additionally, we frequently see two hybrids (California sea lion-northern fur seal and California sea lion-Guadalupe fur seal). Besides the diversity of pinniped species on the island, the number of animals is impressive, close to 100,000 total! There are a lot of blubbery bodies on the beaches of this island!

An adult male Guadalupe fur seal (center with darker color fur) establishes a territory next to California sea lions (lighter in color). Credit: NOAA Fisheries / Chris MoonIn the foreground, a harbor seal lies on the beach with California sea lions behind it. Credit: NOAA Fisheries / Tony Orr

Apart from the marine mammals that live on San Miguel Island or are in waters offshore, the island is home to many other wildlife species including the island fox. It is the largest terrestrial predator on the island (about the size of a house cat) and has recovered from near-extinction with the help of a successful captive-breeding program. The program started around the time I started coming to the island of fog and wind more than20 years ago.

An island fox on San Miguel Island. Credit: NOAA Fisheries / Chris Moon.

Stay tuned for Blog #2 where I will share more of our non-Alaskan (though at times it feels like we are in Alaska) adventures coming next week!

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