The 2008 European Marine Strategy Framework Directive (2008/56/EC) includes a re-quirement for EU Member States to report on the environmental status of the seas under their jurisdiction and to work to achieve Good Environmental Status (GES). This is de-fined by eleven qualitative descriptors, and one of them deals with "Food Webs". The Task Group 4 "Food Webs" descriptor reads: All elements of the marine food webs, to the extent that they are known, occur at normal abundance and diversity and levels capa-ble of ensuring the long-term abundance of the species and the retention of their full re-productive capacity. This report defines the terms used in this descriptor (section 2), describes the scientific understanding (section 3) and the relevant spatial and temporal scales (section 4). A framework to describe attributes of GES for food webs is provided in section 5.
JRC (European Commission Joint Research Centre), ICES (2010). Marine Strategy Framework Directive - Task Group 4 Report Food webs. CIEM et JRC (Joint Research Council). Ref. EUR 24343 EN – Joint Research Centre. 63p. https://archimer.ifremer.fr/doc/00032/14327/