Eddies from altimetry help understand northern elephant seals' behavior

The northern elephant seals live in the Eastern part of North Pacific, along the coasts of North America, from Mexico to Alaska south to north, and west to the Bering Strait longitude. They mainly eat small fish (myctophids) and squid. The role of mesoscale features such as eddies are poorly known for such predators. With eddy-detection from altimetry and tracking data, this can be better studied, even if their prey can’t be observed continuously.

Large records exist for northern elephant seals, including tracking, dive depth and temperature data from sensors in the tracking platforms. A comparison of 221 adult female northern elephant seals tracking with eddies atlas from altimetry enabled to better assess the use of the mesoscale features by the seals.
The analysis detected 129 encounters with anticyclonic eddies and 83 with cyclonic eddies with high confidence (thus probably more were actually encountered). It globally does not show that northern elephant seals are looking specifically for eddies, except possibly for some individuals. However, when they encounter one, they tend to stay a bit longer around the edge of the cyclonic eddies, within and across the edge for the anticyclonic ones. Behaviors were widely variables depending on individuals, though. 
Even larger databases of both tracking and eddies, and possibly also the submesoscale features we will see soon thanks to Swot should enable to complete such approaches. Combining data to assess the use of its environment by a species can help in deciding protection measures and laws.