Ontogeny of foraging behaviour during the early life of deep diving predators

• Main Author: Orgeret, Florian
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de La Rochelle, Chistophe Guinet - co-directeur, Charles-André Bost - co-directeur
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2018
• Subjects: penguins; elephant seals; juveniles; first year at sea; learning; diving beahviour; orientation navigation; exploration; migration; mortality; orientation; comportement de plongées; navigation; manchots; éléphants de mers; première année en mer; apprentissage; mortalité; [SDE]Environmental Sciences; Manchots; Elephant Seals
• Online Access: https://hal.archives-ouvertes.fr/tel-02408715; https://hal.archives-ouvertes.fr/tel-02408715/document; https://hal.archives-ouvertes.fr/tel-02408715/file/Orgeret_Florian.pdf

AbstractThe juvenile phase is critically important for the future of animal populations. However this phase of the life cycle is still poorly understood in ecology. In long-lived species, the juvenile phase is long and first reproduction is late; it is during the juvenile phase that mortality rate is the highest. Three hypotheses have been formulated to point out the selective pressures driving the early life patterns of juvenile‘s long-lived organisms. First, according to the ―dispersion‖ hypothesis, juveniles are forced to leave their natal area and use less profitable habitats compared to those used by adults. Second, the ―constraint‖ hypothesis predicts that juveniles have lower foraging capacities than adults. Third, the ―selection‖ hypothesis predicts that juveniles with poorer phenotype (ex: poor body condition) at departure from their natal site are more likely to die after independence. These three non-exclusive hypotheses are used to explain changes in survival rate with age in juveniles of long-lived species.Understanding and describing the ontogeny of foraging behaviour in juveniles in thus crucial to explain the higher mortality rate observed in juveniles. The ontogeny of behaviour is complex and results from interactions between genes, organisms and environments. This is particularly true for the ontogeny of foraging behaviour. Understand and describe the ontogeny of the foraging behaviour therefore requires tailored study models and advanced methods. Some marine predators need to return to land frequently to breed, and are generally faithful to their breeding site. Moreover, juvenile marine predators such seabirds and pinnipeds often show a long learning phase and thus seem to be ideal for studying the ontogeny of foraging behaviour. However, because of their long-distance dispersion after their independence and their high mortality rate, juveniles are difficult to monitor. Thanks to new bio-technologies, in this thesis we managed to monitor the ontogeny of foraging behaviour in 52 juveniles from ...