Specifically, this approach could address how the ecological efficiency of a community changes as the productivity of the primary producers remains constant, while their relative body size shifts. Fundamental to the study of species interactions is the need to develop models that can relate the various trophic levels and provide some integration. For this purpose it may be more instructive to select important indicator species for each trophic level that can be used to track these relationships described in Table 3 . Ideally these species should have retrospective data sets available and sub populations that exist within different regimes for comparative purposes. Most of the indices presented in Table 3 can be measured using existing methodologies.
Some data sets exist for various components in specific environments.
Ideally, examination of carrying capacity would require simultaneous collection of these parameters over appropriate time periods. The importance of long time series to measure these parameters was emphasized in discussions. However, there are fiscal and logistical limitations. However, short time series will not allow examination of interdecadal processes, regime shifts and lower frequency change. A final aspect of the discussions was to address the issues of the importance of bottom up versus top down control of marine ecosystems.