Mathilde Chevallay

Studying the ecology of mesopelagic prey from the fine-scale foraging behavior of their predators in the Southern Ocean

Myctophids account for a large proportion of the Southern Ocean fish biomass and play a major role in the transfer of energy from zooplankton to higher trophic levels, including seabirds and marine mammals. However, despite their ecological importance, little is known about their distribution and habitat characteristics. My thesis project therefore seeks to better understand the ecology of these key prey species in the Southern Ocean via the very fine-scale feeding behavior of three of their top predators, namely king penguins (Aptenodytes patagonicus), Antarctic fur seals (Arctocephalus gazella), and southern elephant seals (Mirounga leonina) in relation to local oceanographic features. This will allow me to better understand prey selection processes and capture tactics in these three diving predator species, while determining the distribution of myctophids and modeling their habitat in the Southern Ocean. Ultimately, my work will help fill gaps in our knowledge of the links between the physico-chemical parameters of the marine environment, the distribution and habitat characteristics of key prey species, and their relationship to their predator behaviors and foraging success, which is essential to better understand ecosystem dynamics.
PhD student in the Marine Predators team
Supervisors: Tiphaine Jeanniard du Dot and Christophe Guinet