CLIOTOP timeline

CLIOTOP is a ten year programme implemented as a GLOBEC regional programme. CLIOTOP is devoted to the study of oceanic top predators within their ecosystems and is based on a worldwide comparative approach, i.e. among regions, oceans and species.

The general objective of CLIOTOP is to organise a large-scale worldwide comparative effort aimed at identifying the impact of both climate variability (at various scales) and fishing on the structure and function of open ocean pelagic ecosystems and their top predator species by elucidating the key processes involved in open ocean ecosystem functioning. The ultimate objective is the development of a reliable predictive capability for the dynamics of top predator populations and oceanic ecosystems that combines both fishing and climate (i.e. environmental) effects.

These objectives require an approach involving research teams currently working in process-oriented projects which address the mechanisms linking physical forcing, zooplankton production, prey abundance and distribution, and top predator physiological, behavioural and population ecology. The work will therefore require cross-disciplinary studies by modellers involved in climate, physical and biogeochemical oceanography, and individual, population and ecosystem dynamics.

To be able to conduct standardized worldwide comparative analysis, homogeneous comprehensive records of climate variability, ocean and atmospheric circulation changes and related regional and local environmental changes will be used. Parts of such records are already available in several research centres and are being used by various scientists. CLIOTOP should serve to improve the availability of these data sets to the ocean and fisheries sciences communities, and to encourage incorporation of historical archived data. This should provide a unique opportunity to synthesize long-term fisheries data over the last 50 years (i.e. the industrial fishing era) and yield an unprecedented framework for comparative studies.

Integrative process-oriented studies (including retrospective analysis, field experiments, survey and monitoring) in a comparative framework are a key objective. In this respect, a strong modelling component is also fundamental for CLIOTOP. This will include a range of models if different complexity from simple box models, through more detailed energy budget and behavioural models to spatially explicit ecosystem models driven by OGCMs. The validation of ongoing ocean modelling and the development of more realistic models is a prime objective.


CLIOTOP is aimed at improving understanding of ocean top predators in their ecosystem. However, its successful implementation might have a significant impact on the management of the very important fisheries that exploit tunas an tuna like species. These fisheries are managed by international organizations, which rely on international scientific consensus in understand the dynamics of the populations they exploit. A comparative project such as CLIOTOP, by improving understanding will provide the basis for a better fisheries management.


CLIOTOP should develop strong interactions with the already existing multi-national GLOBEC project OFCCP (Oceanic Fisheries and Climate Change Project) that shares common general objectives, but is limited to the Pacific Ocean. It is believed that the CLIOTOP comparative approach between the three oceans will bring a major additional value to the research developed in each ocean separately. In addition, given the complex nature of its foci, the CLIOTOP program strongly encourages co-operation and exchange with other IGBP programs such as SOLAS, GAIM and IMBER as well as WCRP programs such as CLIVAR, the SCOR affiliated CoML project (CMarZ, TOPP, SEAMAP, MAR-ECO and FMAP), and the International Human Dimensions Programme on Global Environmental Change (IHDP). Being able to make use of the tools and expertise provided by those international programs will be crucial for an effective “open sea” project.

CLIOTOP will address:

  • The need for a global comparative approach of processes linking climate to top predators ecosystems.
  • The need for an international effort to urgently elucidate those processes in a global change context, that is a constant and rapid process with no equivalent in any ocean systems, to date.
  • The need for both improving our basic knowledge and developing a reliable predictive capability.

This project will federate international scientific projects and research groups already involved in those topics.