What can we learn about the open ocean from tracking white sharks? In this short video I provide an overview of some of the results of our work that investigates the use of mesoscale eddies by large pelagic fish.
In the coming week, we will again venture into the North Atlantic to continue our investigation of the role of eddies in structuring pelagic ecosystems. Even though it feels like we just returned from our first cruise (November-December, 2015), we have had a bit of time to digest some of the observations made during NAAMES-1. During our first expedition, we discovered that eddies indeed have a significant influence on mesopelagic fish. Eddies affected not only the depth at which these organism live, but also their abundance.
Using our custom-built deep-water echosounder (the RUMP), we observed that deep scattering layers, the acoustic signature of these mesopelagic ecosystems, are not only deeper in anticyclones, but also have stronger back scattering, when compared to cyclones (Fig. 5). This suggests that the observed pattern of white sharks preferentially using anticyclone eddies may be the result of these eddies affecting their prey. In the weeks to come, we will expand on these observations and surely gain more insight into the roles of eddies in structuring pelagic ecosystems.