Ocean Front and Eddy Utilization By Highly-Migratory Large Pelagic Fishes from Satellite Tagging Data
Ocean fronts and eddies are well known habitats for fishes. But most of the knowledge on ocean front and eddy utilization are based on commercial fisheries data or ecological theory, there have been few direct observations of the fisheries processes inherent to these systems. Despite the development and advances in satellite tracking in the past decade, current methods of geolocation based on light level and sea surface temperature (SST) are too coarse to resolve any detailed front and eddy utilization by fish. We recently developed a new methodology that uses ocean heat content (OHC) as substitute for SST. OHC is a measurement of the heat stored in the upper ocean, and is calculated from the depth of the 26 oC isotherm to the ocean surface. Using this approach, we estimated the OHC from PSAT data and ocean model data to refine the geolocations of individual fish tracks. Our results indicate many of tagged highly-migratory large pelagic fishes displayed an affinity for ocean fronts and eddies, thus providing us with valuable information on their behavioral ecology and migration secrets, which will provide key information to help us more effectively assess their population dynamics, and advance sustainable fisheries policy.