The Earlylife research program focuses on the first year at sea of juvenile top predators such as seabirds and sea mammals. This video shows the different strategies throughout a large latitudinal gradient.
The Project : aims & objectives
Today a major challenge in ecology is to understand the consequences of climate change and human activities on populations for predicting their fate in future environmental conditions. The answer to this question requires a thorough study of the influence of environment on all components of the life cycle, and to incorporate the effects in predictive models (Ådahl et al. 2006). However, so far, most studies on wild populations have focused on their adult component, whereas the other component, i.e. first year juveniles and immatures that can represent up to 50% of the total population, is little known. Information on the ecology of early life of animals (especially in vertebrates) is lacking mainly because of the difficulty of studying young animals after they become independent of parents and before they return to breed. The aim of this project is to take up this major challenge.
The main reason why early life remains almost unknown is the difficulty of studying the behaviour and fate of free-ranging individuals at this stage for logistical reasons. This is even more acute in the marine environment, where juvenile individual disperse in the open ocean and are impossible to observe or to recapture.
The aim of this project is to carry out a large scale comparative study of the early life of long lived marine animals, seabird and pinnipeds, by combining the use of the latest miniaturised telemetry and bio-logging technologies together with biochemical markers, state of the art analytical methods, and unique long term data base on the demography and tracking of a wide range of marine predators, and statistical and modeling analysis. The program will address many fundamental questions concerning the ontogeny of foraging behaviour, dispersal, learning processes, navigation, phenotypic selection, population dynamics, conservation and the impact of global changes
Figure 1 – Left: Conceptual framework showing the schematic interconnections among climate, environment, foraging and demography in animals
Information on juvenile and immature stages is essential because their mortality controls recruitment to reproductive stages (Ferrer et al. 2003) and thus the future of populations (Gaillard et al. 1998), but also because it is young individuals that disperse most and have the potential to emigrate and colonise new environments. In nearly all animals, mortality is highest in the juvenile period, i.e. at the early stages of life after birth, or when offspring become independent of parents (e.g. for fish: Victor 1986; for great herbivores: Gaillard et al. 1998; for seabirds: Daunt et al. 2007). At the population level many studies have documented an increase in survival with age in a variety of species. Typically, mortality is higher in juveniles and gradually decreases with age until reaching that of adults, with important differences between families and species. At the individual level, foraging performances are central to explain the ability or not of animals to survive during the early stage and the links between emography and the environment more generally (Figure 1), yet foraging performances are generally poorly known in animals in general, and in juvenile animals in particular.
Juveniles top predators of the Southern Ocean
learning to feed alone in a new environment
The life of a juvenile frigatebird
the longest period of learning found in any bird species
The Early life at sea of two species of boobies on Christmas Island
resident vs migratory strategy