The purpose of this paper is to indicate a number of possibilities and to facilitate development of an agreed plan for selecting, assessing and monitoring species, populations, and individual characteristics that will be likely sensitive indicators of possible indirect effects of harvesting and associated activities in the Convention Area. Harvesting is considered as a form of predation which can result in changes in stock status not only of target species but dependent and related species as well. There is a list of criteria to select appropriate indicators of harvest-related changes. Observation of by-catch during fishing operations and sightings of birds and mammals by observers aboard vessels engaged in fishing, research or other activities might be useful as a source of information for assessing possible indirect effects of harvesting and related activities in the Convention Area. It is suggested that penguins and pinnipeds have the greatest potential as possible indicators of krill availability. Some practical steps to identify possible indicator species and necessary research and monitoring programs are proposed.