This paper reports on the intersessional activities of the Steering Committee of the “Workshop on plausible ecosystem models for testing approaches to krill management” in preparation for the workshop at WG-EMM 2004. The overarching Terms of Reference are (i) to review the approaches used to model marine ecosystems, (ii) to consider plausible operating models for the Antarctic marine ecosystem, and to advance a program of work to develop and implement operating models to investigate the robustness of different management approaches to underlying uncertainties in the ecological, fishery, monitoring and assessment systems. As agreed at WG-EMM in 2003, intersessional activities have included (i) provision of advice on the potential contributions from experts in preparation for the workshop and in participating in the development of models at the workshop, (ii) a review of relevant literature and information on the development of ecosystem models elsewhere as per the first term of reference, (iii) compilation of a catalogue of available software and other simulation environments for ecosystem modelling, (iv) preliminary consideration of the requirements for datasets, estimates of parameters and other aspects related to the second term of reference, and (v) preliminary outline of the aims and specifications for ecosystem modelling as it relates to the development of management procedures for krill. The results of this work are outlined. Also provided in this report is a draft agenda for the workshop.