The common ocean sunfish, Mola mola, occupies a unique position in the eastern Pacific Ocean and the California
Current Large Marine Ecosystem (CCLME) as the world's heaviest, most fecund bony fish, and one of the most
abundant gelativores. M. mola frequently occur as bycatch in fisheriesworldwide and comprise the greatest portion
of the bycatch in California's large-mesh drift gillnet fishery. In this first long-termtagging study of any ocean
sunfish species in the eastern Pacific, 15 M.mola (99 cmto 200 cm total length) were tagged in the southern California
Bight (SCB) between 2003 and 2010 using 14 satellite pop-off archival tags (PATs) and one Fastloc Mk10
GPS tag. Ten tags provided positional data for a cumulative dataset of 349 tracking days during themonths of July
throughMarch. Thirteen tags provided temperature and depth data. All M.mola remained within ~300 km of the
coast, and nearly all exhibited seasonalmovement between the SCB and adjacentwaters off northern and central
Baja California,Mexico. No tagged individualswere tracked north of the SCB. Tag depth data showed diel vertical
migration and occasional deep (N500 m) dives. Data from the Fastloc GPS tag allowed close examination of the
relationship between the movements of the largest tagged ocean sunfish (2m TL) and fine-scale oceanographic
features.Near-instantaneous satellite sea surface temperature images showed this individual associatedwith upwelling
fronts along itsmigration path,which exceeded 800 kmand ranged from 6 to 128 km from the coast. Tag
depth data showed active use of the water column within the frontal zones. Synthetic aperture radar (SAR) images
demonstrated that surface slicks, which often indicate convergent circulation, coincided with this type of
front. Zooplankton tows in the southern region of tracking off central Baja California,Mexico revealed dense populations
of salps toward thewarmside of these fronts. Satellite tag and ecosystem data suggest that bio-physical
interactions in coastal upwelling fronts create favorable foraging habitat.