Week 1 – October 1, 2015


The day started out early, as most field days do! Año Nuevo State Park is only about a 20 minute drive from our lab at UCSC, but I had some last minute checks to do on the satellite tags to make sure they were ready to be deployed. 


Año Nuevo Island, which unlike the mainland is not open to the public, is a pretty amazing place in terms of wildlife. There are California sea lions, Steller sea lions, harbor seals, and northern elephant seals that regularly use the island. The island is also an important breeding site for seabirds during certain times of the year, including rhinoceros auklets and Brandt’s cormorants. Although it may look beautiful in photographs, a lot of people don’t realize that pinniped and seabird rookeries are not the most glamorous of places – Año smells strongly of ammonia, rotting kelp, and  the unique, not overly pleasant smell of pinniped. On non-windy days the flies can be really bad and we are pretty much covered in them while we work.


We didn’t reach the island until about 8:30 – we take a small zodiac across the channel from the mainland to the island. The zodiac only fits about 5 people and their gear, so it took three trips to get our entire field crew across. By the time we reached the island, the researchers from Stanford were already out at the island. They took a boat up from Santa Cruz and were hanging out on the backside of the island…..tagging white sharks


We had a successful first capture of animals, and before 10:00 we had 11 juveniles! We were able to deploy four of our satellite tags, three on juvenile females and 1 on a juvenile male. The tags are glued to the fur of the animals with epoxy, and because the sea lions are currently undergoing their annual molt (where they shed their old coat and regrow a new one), we have to be picky about who we put tags on. We want to make sure we put tags on animals that already have a new fur coat so that the tag will stay on for as long as possible. Hopefully these little guys will collect data on their own movements for at least 6 months!


As we were wrapping up and getting ready to head home for the day, the MBARI ship showed up just off the backside of the island. They are out collecting oceanographic data to be used in conjunction with the movements of marine predators. They will be trying to design some of their surveys based off some of the movements of the tagged juveniles, so it was a great feeling to know that we were able to get tags out while they were there!


It is always a little nerve racking deploying tags on animals – even though I have done this before I am always plagued by doubts that the tags won’t work. This is also our first time ever deploying on juveniles and it is shark season; I am crossing my fingers that all of our little guys manage to avoid predation and have good luck finding food. After some excessive checking, I was very relieved to see that they seem to be transmitting just fine. Check out the TOPP (Tagging of Pelagic Predators) website to see the latest locations for these guys and to check out white shark movements around the island.



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A Steller sea lion pup draped over a California sea lion. Photo: Patrick Robinson 

 Elephant seals mingling with California sea lions on the main beach at Año Island.

Researchers from Stanford tagging white sharks 

Satellite tagged juvenile California sea lion heading to the water. Photo: Patrick Robinson. NMFS Permits # 17952, 17115 


 Photo: Patrick Robinson. NMFS Permit # 17952 17115


 California sea lion with a fresh shark bite. Photo: Patrick Robinson

Photo: Patrick Robinson 


Rachel Holser

Rachel is a PhD student in the Costa Lab. Her research focuses on individual variability among elephant seals and looks at differences in foraging behavior, responses to climatic disturbance, and personality types.

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