California sea lions – 2015 Año Nuevo Island


I am rolling out our first ever field blog for the Costa Lab with some sea lion field work we just started at Año Nuevo Island yesterday! The field effort is being led by researchers from UCLA to understand the dynamics of Leptospirosis outbreaks in California sea lions. Leptospirosis is caused by a bacteria and is a zoonotic disease, meaning it can be transferred from animals to people, that infects not only marine but also terrestrial species. Our role in the field effort is in attaching satellite tags to a small number of these animals to understand where they go when they are at sea. This seems like a relatively simple and easy question, and while we can certainly make some good guesses about where these animals might go to find food, this effort marks the first time that sea lions from Año Island have ever been tracked at sea!


This field effort is overlapping with efforts by scientists from Stanford and the Monterey Bay Aquarium Research Institute (MBARI) to understand where the hotspots of use are for predators (whales, sea lions, and sharks) in Monterey Bay, how these hotspots relate to oceanography (things like sea surface temperature and primary productivity), and the interactions between large predators (white sharks) and prey (sea lions). I will be updating the blog every week throughout the month of October so check back to see when we deploy tags and where tagged animals go!


Check out their movements on the TOPP website or


Hope you all enjoy!




Juvenile California sea lion with satellite tag post-release. Photo: Patrick Robinson. NMFS Permits # 17952, 17115 



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