Julia S. Stewart, PhD

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    Having completed my PhD and a postdoc in the Gilly lab, I am currently a research scientist at the National Center for Ecological Analysis and Synthesis (NCEAS) at the University of California, Santa Barbara. Please see my website at http://juliastewart.org

In the Gilly lab, my doctoral research focused on the Humboldt squid Dosidicus gigas, which is a large, pelagic predator living in the eastern Pacific Ocean. As these squid have recently expanded their range into the northern California Current System off the coast of the western United States and Canada, many questions have been raised as to why as well as what impacts they will have on local ecosystems and economies.

I studied the behavior and habitat of Humboldt squid using electronic tags that tracked individual squid and remotely operated vehicles (ROVs) operated by the Monterey Bay Aquarium Research Institute (MBARI) that observed thousands of Humboldt squid off central California since their initial invasion in late 1997. Highlights of my research (references below) that identify capabilities to help understand ecosystem effects and fisheries management, include:

• faster velocities that are sustained for longer periods than previously known

• daily vertical migrations to depths over 0.5 kilometers

• over nine hours in hypoxic conditions in the oxygen minimum zone (OMZ)

• deep dives to nearly 1.5 kilometers depth, through the OMZ

• movement on and off the continental shelf


I am currently working at Stanford on a project funded by NOAA through their Fisheries and the Environment program. This research extends from my doctoral work, using the in situ observations collected with ROVs to create a robust index of relative abundance to be used in fisheries and ecosystem modeling.

jules32 at gmail dot com

Photo credits: G. Auger

JS Stewart, JC Field, U Markaida, and WF Gilly. 2013. Behavioral

ecology of Jumbo squid (Dosidicus gigas): in relation to oxygen

minimum zones. Deep Sea Research II 95: 197-208. link


JS Stewart, WF Gilly, JC Field and JC Payne. 2013. Onshore-offshore

movement of jumbo squid (Dosidicus gigas) on the continental shelf.

Deep Sea Research II 95: 193-196.  link


RK O’Dor, JS Stewart, WF Gilly, J Payne, T Cerveira Borges and T Thys.

2013. Squid rocket science: how squid launch into air. Deep Sea

Research II 95: 113-118. link


JC Field, C Elliger, K Baltz, G Gillespie, WF Gilly, I Ruiz-Cooley, D

Pearse, JS Stewart, W Matsubu and W Walker. 2013. Foraging ecology and

movement patterns of the Humboldt squid in the California Current.

Deep Sea Research II, 95: 37-51. link


JS Stewart, EL Hazen, DG Foley, SJ Bograd, and WF Gilly. 2012. Marine

predator migration during range expansion: Humboldt squid (Dosidicus

gigas) in the California Current System. Marine Ecology Progress

Series 471: 135-150. link


JS Stewart. 2012. Humboldt squid in the northern California Current

System. PhD Dissertation, Stanford University. link


Press: New Scientist article with accompanying video: ‘Doing battle

with the red devils of the Pacific’ by Peter Aldhous


WF Gilly, LD Zeidberg, JAT Booth, JS Stewart, G Marshall, K Abernathy

and LE Bell. 2012. Locomotion and behavior of Humboldt squid,

Dosidicus gigas, in relation to natural hypoxia in the Gulf of

California, Mexico. Journal of Experimental Biology 215: 3175-3190.

Selected Publications

2012Humboldt squid’s impressive dives (Jonathan Amos, BBC)

http://www.bbc.co.uk/news/science-environment-17117200


2012Squid can fly to save energy (Jessica Marshall, Nature News)

http://www.nature.com/news/squid-can-fly-to-save-energy-1.10060


2011Hunt for the Giant Squid (National Geographic Wild and Ammonite)

http://www.ammonite.co.uk/news/hunt-for-the-giant-squid


2011Kraken (Wendy Williams, Abrams Image publishers)

capewindbook.typepad.com/kraken


2010Doing Battle with the Red Devils of the Pacific (Peter Aldhous, New Scientist) newscientist.com/article/mg20527425.400-doing-battle-with-the-red-devils-of-the-pacific.html





I grew up in the San Francisco Bay Area and completed my bachelor’s degree in marine biology at UCLA in 2004.  Before beginning my PhD at Stanford in 2006 I worked as a volunteer with Gilly studying the fish-eating behavior of the California cone snail Conus californicus.  I am very interested in the interface of science and policy, particularly in the effective communication of science. I travel often, speak French and Spanish, and have lived abroad in several countries.












Media Highlights

About Me