Abstract: Penguins are important top consumers in marine food webs and are one of the most threatened bird families, especially by climate change and food web alterations by marine fisheries. Yet, long-term population trends are lacking or are uncertain for many populations. Seven species of penguins breeding at the French Southern Territories in the southern Indian Ocean on the Crozet, Kerguelen, Saint-Paul–Amsterdam archipelagos and in Terre Adélie/Adelie Land, Antarctica are monitored regularly. This monitoring started in the early 1950s and most populations have been surveyed during the past four years, allowing assessments of population trends. King penguins increased at nearly all breeding sites within the Crozet and Kerguelen archipelagos. Emperor penguins have decreased at Terre Adélie/Adelie Land, with a partial recovery of the colony during the 2010s. Gentoo penguin populations at Crozet and Kerguelen are highly variable but stable. Adélie penguins have been increasing in Terre Adélie/Adelie Land. The trends in eastern rockhopper penguins vary between colonies and archipelagos. Northern rockhopper penguins have continuously decreased in numbers at Amsterdam Island, but appear to have increased at the nearby Saint-Paul Island. Macaroni penguins have first increased and then stabilized since the 2000s at Kerguelen and are stable at the Crozet Islands. Overall, most penguin populations breeding in the French Southern Territories increased or were stable over the past 30–60 years, with the exception of the northern rockhopper penguin, king and gentoo penguins on Crozet and the emperor penguin. The ecological reasons for these trends are poorly understood and require further investigation.

Abstract: High juvenile mortality rates are typical of many long-lived marine vertebrate predators. Insufficient development in dive and forage ability is considered a key driver of this. However, direct links to survival outcome are sparse, particularly in free-ranging marine animals that may not return to land. In this study, we conduct exploratory investigations toward early mortality in juvenile southern elephant seals Mirounga leonina. Twenty postweaning pups were equipped with (a) a new-generation satellite relay data tag, capable of remotely transmitting fine-scale behavioral movements from accelerometers, and (b) a location transmitting only tag (so that mortality events could be distinguished from device failures). Individuals were followed during their first trip at sea (until mortality or return to land). Two analyses were conducted. First, the behavioral movements and encountered environmental conditions of nonsurviving pups were individually compared to temporally concurrent observations from grouped survivors. Second, common causes of mortality were investigated using Cox's proportional hazard regression and penalized shrinkage techniques. Nine individuals died (two females and seven males) and 11 survived (eight females and three males). All but one individual died before the return phase of their first trip at sea, and all but one were negatively buoyant. Causes of death were variable, although common factors included increased horizontal travel speeds and distances, decreased development in dive and forage ability, and habitat type visited (lower sea surface temperatures and decreased total [eddy] kinetic energy). For long-lived marine vertebrate predators, such as the southern elephant seal, the first few months of life following independence represent a critical period, when small deviations in behavior from the norm appear sufficient to increase mortality risk. Survival rates may subsequently be particularly vulnerable to changes in climate and environment, which will have concomitant consequences on the demography and dynamics of populations.

Abstract: One of the fundamental principles of life history trait theory is the existence of trade-offs. The amount of energy available to living beings is a limited resource that must be shared among different biological functions. The combination of traits best suited to ecological constraints will be selected.
Growth is a crucial phase during which the future phenotype of the adult is established. This period between birth and the acquisition of independence from parents is characterized by very fast stature and weight growth and tissue maturation, particularly in bone and muscle. This phenomenon is marked by sustained parental nutrition. On an intraspecific scale, variations in individual chick growth may reflect the quality/experience of the parents. In some species, parental dietary intake may, regardless of quality, show wide seasonal fluctuations due to environmental changes and for developing individuals the quantity and quality of nutrients ingested and metabolized may be a limiting factor in growth. There is little information to understand the trade-offs in energy allocation that will be established to ensure survival and growth of the young in the case of inadequate dietary intakes.
The king penguin chick is an atypical animal model for the study of these strategies. This seabird has an unusually long one-year development cycle for a bird and its growth is interrupted by a period of severe food restriction during the 4 months of the southern winter. In addition, exceptionally with a penguin, the period of initiation of reproduction is asynchronous and extends over several months. A direct consequence is a shorter time of accumulation of energy reserves in late-born chicks. We aim to determine whether the particularly long cycle of this chick and the environmental constraints to which it is subjected result in particular adaptations in terms of the relative development of the two muscle belts, pelvic and pectoral, and whether this growth compromise is expressed in the same way in early and late born chicks.

Abstract: L’étude sismologique de la glace permet de mieux comprendre la déformation des systèmes glaciaires et leur stabilité́ dans un contexte de réchauffement climatique global. La cryosphère est très active sismiquement. De nombreux évènements comme des icequakes, des trémors glaciaires ou des évènements à l’interface glace/terre solide émanent de la base des glaciers, des marges de cisaillement, des vêlages au front des glaciers ou encore des chenaux d’eau sous- glaciaire. Nous avons observé les signaux d’une dizaine de stations sismologiques sur les côtes de l’antarctique et parmi tous les évènements visibles, un signal de quelques heures présente une forte répétabilité́ dans le temps et dans l’espace. Pour l’étudier nous avons extrait des séries temporelles d’énergie sismique sur trois stations : drv, thur, vna1 et nous avons montré sa modulation avec les forçages de marée d’abord sur l’année 2018 puis sur 8 ans à thur, 10 ans à vna1 et 20 ans à drv. Le signal d’énergie sismique présente toutes les périodicités des forçages de marée avec cependant quelques décalages temporels, indicateurs de délais de réponse du système glaciaire et d’un comportement rhéologique viscoélastique de la glace.

Abstract: Much of our understanding of gas giant exoplanets come from those transiting in front of bright stars at short orbital separations (P ~ 3 days, a ~ 0.05 au). However, these