Individuals, populations and habitats

Representatives : Claire Saraux (Ifremer) and Yann Tremblay (IRD)


Marine ecosystems are spatially structured as a result of many ecological processes (with abiotic and biotic forcings) taking place at various spatial and temporal scales. The stakes are therefore (i) to understand and model the spatio-temporal dynamics of individuals and populations of marine species in relation to the spatio- temporal variability of the environment (biotic or abiotic) and (ii) to characterize their habitats. The originality of this topic is to bring into line individual approaches where behavioral phenomena (including social) preside over the displacement of individuals and large scales population approaches where physical determinants dominate.
Covering broad disciplinary fields, from ethology to ecology, integrating the results of this topic
in studies encompassing the entire species range and successive habitats colonized during their life cycles will clarify the relationship between quality and availability of marine habitats, connectivity patterns at the intraspecific scale (intra- or inter-population) and population dynamics.


  • To characterize and understand the behavioral, individual or collective strategies of space occupancy in connection with the environment

  • To understand and model population dynamics in relation to the environment

  • To quantify the connectivity between geographic areas (individuals, genes and material flow)
Multifactorial characterization of habitats (ecological niches)
To provide population health’s indicators


  • Study areas : the Mediterranean, upwelling areas (Humboldt, Benguela), Indian and Atlantic high-sea oceans, coastal lagoons.

  • Study objects : fish (Teleostei and condrichtyens), birds, shellfish, marine mammals.


  • Data and methods : in situ observations, timely and sustainable, from scientific surveys at sea (trawling and acoustic) and commercial fisheries campaigns ; individual indicators such as genetic or isotopic markers, tracers of soft and calcified tissue, conventional and electronic artificial tags (GPS, diving recorders, acoustic, archival, pop-up), including instrumentation vectors (marine mammals, fishing ships, buoys) to obtain information on habitats or some populations ("bio-logging") ; satellite data.

  • Analyses and modeling : Statistical models (State-space models, random walks, (semi-)Markov models, classifications, multivariate analyses ; Lagrangian models ; Mecanistic models (partial differential equations).


MARBEC MARine Biodiversity, Exploitation and Conservation, is a research unit which includes the staff of 4 organizations: IRD, IFREMER, UM and CNRS. Its objective is the study of marine biodiversity in lagoon coastal and offshore ecosystems, at different integration levels, molecular, individual, population and community aspects and the way humans use this biodiversity.