Morgan Godard (EMBIO) will defend his thesis on Friday, March 12 at 2:00 pm in distance

On the following topic :

"Characterization of the feeding behavior of the elephant seal Mirounga leonina and links with sub-mesoscale (1-10km) physical structures in the Southern Ocean: a functional data analysis approach".
Thesis Director: David Nerini, AMU Lecturer

Abstract

The consequences induced by climate change on a vulnerable ecosystem such as the Southern Ocean are difficult to estimate. Indeed, many questions remain unanswered about relationships between biological and physical processes in this ocean. To answer these questions, electronic devices are deployed on marine predators, such as southern elephant seals. These recorders sample a wide variety of physical, biological or behavioral high frequency data, producing a considerable amount of information. All these data are called functional because they have a common character: they evolve along a continuum, whether spatial or temporal. The aim of this thesis is therefore twofold, to study the foraging activity of female elephant seals in relation to the physical processes of the Southern Ocean, while integrating the functional nature of the sampled data. The results obtained show that (1) compared to the classically employed methods, functional data analysis methods allow the identification of a greater variety of diving behaviors with defined biological meaning. (2) These functional approaches are more adapted for data with variable sampling frequencies. (3) Functional data analysis also allows us to access the density of our individuals, reflecting their body condition. Their diving behaviors have a real influence on this body condition, at different time scales. (4) There is a relationship between the characteristics of the water masses encountered by female elephant seals and the dives they perform.

Keywords : Functional data analysis, Southern Ocean, Southern elephant seals, Foraging behaviors, Physical process.