Life cycle of Southern Elephant seals: phenotypic variability in their adaptations to environmental constraints and deep diving

Climate and environmental changes influence the dynamics and structure of marine ecosystems, which affect the distribution and the abundance of marine species. Southern elephant seals (Mirounga leonina), alternating between foraging periods at sea and fasting time on land, may be particularly affected by such variability. When breeding and moulting on land, they might be exposed to excessive heat stress, while food resources may deepen and/or shift further south with the rapid warming of the southern ocean. Different life history, behavioural and phenotypic traits may lead to fitness differences between individuals, i.e. differences in individual performances or quality. Large inter-individual differences are observed in foraging locations, diving aptitudes and foraging performances. Are those differences relate to the individual immune status, metabolic performances?
This project is the research complement of the Austral Seals Observatory (IPEV project 1297) which encompasses ecological (SEE-Life Elephant Seals) and oceanographic components (SNO-MEMO). This project initiated in 2004, is aiming at collecting in-situ oceanographic data while studying the foraging behaviour of these seals, and relies on seals’ phenotypic foraging and diving plasticity.
In that context, our work aims at 1) linking environmental conditions, energetic constraints and individual quality (i.e. “brain health”, immune and metabolic status) of a marine predator during its life cycle, alternating foraging and fasting periods; and 2) exploring whether individual strategies related to phenotypic traits and individual quality would be linked with foraging success, moult speed, and ultimately with energetic and fitness components.
By exploring both the immediate (physiological, immune, behavioural, energy strategies and brain health) and ultimate (foraging success, reproductive success, moulting rate) factors of individuals, this work contributes to our understanding of: i) the way in which environmental stressors influence the metabolic ability of individuals to feed and reproduce, ii) the use and validation of new blood-biomarkers in relation to individual quality and deep diving for long-term population monitoring, and iii) how foraging and diving strategies might be influenced by individual quality and phenotypic traits, in order to explore possible consequences for long-term population adaptations.