Final Report Summary - EARLYLIFE (LEARNING TO SURVIVE IN A CHANGING WORLD)
The early life of animals after independence from parents is critical stages in the life-history animals, young animals have to learn to survive in the environment, and a high mortality occurs. How young animals improve their foraging capacities and what are the proximate and ultimate causes of mortality and consequences for the population is poorly known, especially in the marine environment. EARLYLIFE addressed these fundamental questions through a large scale tagging programs of juveniles seabirds and seals belonging to 15 species, being the first comprehensive field study of the early life of marine animals.
We obtained information on the dispersal, ontogeny of foraging behaviour and diving capacities of more than 450 individuals through the combined use of miniaturised loggers that recorded not only locations in three dimension, but activity, diving performances, temperatures as well as the environmental conditions encountered. Surprisingly, in almost all species mortality occurred after the first two months at sea, and not during the first two months which were previously considered to be the critical period for survival. However, during this first period individuals improved consistently their foraging capacities. Mortality occurred mainly during the third and fourth months, and was not related only to the ability of individuals to improve foraging capacities, but also to other factors, such as the sector where they dispersed, as well as the environmental conditions encountered during dispersal. We also showed that initial conditions encountered by juvenile individuals before independence, due to the parental quality and genotypes affect the mortality rates and timing of mortality.
The EARLYLIFE project has allowed proposing a general framework to describe the common pattern occurring during the juvenile phase of marine animals, and explain the causes and consequences of mortality during this critical phase. Many avenues for further studies have been identified and are currently under investigation.
We obtained information on the dispersal, ontogeny of foraging behaviour and diving capacities of more than 450 individuals through the combined use of miniaturised loggers that recorded not only locations in three dimension, but activity, diving performances, temperatures as well as the environmental conditions encountered. Surprisingly, in almost all species mortality occurred after the first two months at sea, and not during the first two months which were previously considered to be the critical period for survival. However, during this first period individuals improved consistently their foraging capacities. Mortality occurred mainly during the third and fourth months, and was not related only to the ability of individuals to improve foraging capacities, but also to other factors, such as the sector where they dispersed, as well as the environmental conditions encountered during dispersal. We also showed that initial conditions encountered by juvenile individuals before independence, due to the parental quality and genotypes affect the mortality rates and timing of mortality.
The EARLYLIFE project has allowed proposing a general framework to describe the common pattern occurring during the juvenile phase of marine animals, and explain the causes and consequences of mortality during this critical phase. Many avenues for further studies have been identified and are currently under investigation.