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Toward a global observation and modelling system for studying the ecology of the open ocean using acoustics

Workshop (Foresight)
EUR-OCEANS organisation / funding

Overview (adapted from the proposal)


Integrated ecosystem models are increasingly important for understanding, predicting and managing marine ecosystems in a global change context. In those models, mid-trophic level organisms link phyto- and zooplankton to the dynamics of predators which are harvested by fisheries. In this perspective, the CLIOTOP Program ( has identified the lack of information and understanding about mid trophic levels in oceanic ecosystems as a critical bottleneck jeopardizing the development of such “end-to-end” ecosystem models. Addressing this critical issue requires a substantial European and international collaborative effort to design and widely deploy an observation system suited to monitor and subsequently model the key processes involved in the dynamics of oceanic pelagic mid-trophic organisms. This is why CLIOTOP promotes the development of a Mid-trophic Automatic Acoustic Sampler (MAAS) to be deployed on a large scale.

Acoustics, and complementary technologies, have been identified as tools capable of addressing this critical gap, especially because of their flexible operation from various platforms, such as vessels, unmanned vehicles, stationary rigs and drifting buoys, including ADCP observatories


The CLIOTOP MAAS (Mid-trophic Automatic Acoustic Sampling) project and the EurOcean consortium are organizing a workshop in May 2011 in Bergen to address both technological and modeling issues related to the MAAS development, and their interactions.

The technological challenges that will be covered are plans and concepts for novel platforms carrying acoustics (and complementary techniques: any technology that can be used to supplement acoustics - e.g. for species identification - will be considered), energy supply and consumption, and data transfer technology.

Presently, acoustics cannot provide measures of the species-specific biomass of all taxa. Complementary technologies have to be used and ecosystem models need to be tailored to the available data. The modeling part of the workshop will focus mainly on the model-data links. It will cover the topics required to design a large scale observational systems and to improve the combination of models and observations through data assimilation. The use of acoustic data in marine ecosystem models is indeed often done in a fairly naïve way, typically by assuming that acoustic measurements can provide acute and precise estimates of biomass. This leads to underestimated uncertainty and potentially biased results. Conversely, our approach will be based on the use of state-space models, including separate sub-models for observation (coupling observed acoustic signal to real abundance) and for biological processes (e.g., spatio-temporal changes in abundance).

The workshop will follow up on a CLIOTOP workshop organized in Sete in 2007 (, where the technical specifications of MAAS were discussed in detail and plans for its large scale deployment were made. Further progress made can be found in and the references therein. 

Organizing scientists and institutions

  • Nils Olav Handegard, Institute of Marine Research, Norway
  • Nils Christian Stenseth, Centre for Ecological and Evolutionary Synthesis (CEES) / Oslo University
  • Olivier Maury, Institut de Recherche pour le Développement (IRD), France

Planned outputs

The output from the workshop will be:

  1. Updated white paper on the state of the art of acoustic monitoring; information of funding agencies on the possibilities to fill the crucial data gap isolating lower trophic level physical and biological oceanography models from upper trophic levels and fisheries models.
  2. Synthesis of the outputs of the meeting in an appropriate peer review journal. Submission of the manuscript should be completed in 2011
  3. Development of a roadmap paving the way for the next steps necessary to actually carry out the MAAS project, including a plan to submit a proposal for a future EO flagship proposal and/or EC project. This should be completed by the end of 2011.


Attendance will be open, but invitations to key speakers will be sent. Funding will cover in priority travel costs of invited EUR-OCEANS and CLIOTOP participants committing to contribute to the review paper. Please visit this website to register to the workshop:


Nils Olav Handegard: nilsolav [at]


(Update of Oct. 2011)

The outcome of the WS was presented at the joint Acoustical Society of America and the American Fisheries Society, and the ICES working group on Fisheries Acoustics Science and Technology.

The ideas developed during the WS were used in an EU FP7 call (oceans of tomorrow), addressing planned output 3.

A paper is being finalized (planned output 2), which will include the roadmap (mentioned in planned output 3).

Activity leader(s): 
Nils Olav Handegard, IMR, Norway; Nils Christian Stenseth, CEES/UiO, Norway; Olivier Maury, IRD, France
IMR, Bergen, Norway
Financial support: 
15 k€ from EOC to organizers, 10 k$ from CLIOTOP/IMBER
Start date: 
End date: 

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