This paper was requested by WG-EMM in 1995 (SC-CAMLR-XIV, Annex 4, paragraph 6.49). In the early years of development of the ecosystem monitoring program sea ice data, especially derived from satellite images, was recognised as an important source of information for interpreting changes in monitored predator parameters. Standard methods for collection of environmental parameters were agreed in 1990, and following a pilot study carried out by the Secretariat sea ice data derived from US Joint Ice Centre ice charts were routinely acquired and analysed by the Secretariat from 1993. An alternative source of data, digital images produced by the US National Snow and Ice Data Centre, with a relatively low resolution of 25 km, have been archived and analysed routinely by the Secretariat since 1995 to produce a number of indices of ‘sub area' scale sea ice distribution. Archiving and analysing high resolution satellite images remains the responsibility of national monitoring programs.