The advice, released on 19 June, centres on Descriptor 4 of the Marine Strategy Framework Directive (MSFD), which stipulates that components of marine foodwebs should be healthy and with a normal level of diversity, thus ensuring their long-term viability.
Each of the official 11 Descriptors uses indicators to determine and illustrate progress towards Good Environmental Status (GES), the 2020 target for European seas and coastal regions. When the indicators reach their set thresholds, GES has been attained.
With a strong heritage in indicator development, ICES was prompted earlier by the European Commission to provide advice on MSFD Descriptor 3 on populations of commercially exploited fish, stating the need for scientific and technical support for indicators to help address foodweb relationships.
The advice comprises seven potentially useful indicators which look at both functional and structural aspects of foodwebs. These seven include the long-standing indicator, the large fish index (LFI), a metric which charts changes in the proportion of fish over a certain length in a given region. The LFI has been developed by ICES over a number of years and is currently being extended for the MSFD into all European areas, with adjustments being made to account for regional differences in the natural abundance of bigger fish, such as predatory ones like older cod, hake, and haddock.
The other six indicators are: biomass of trophic guilds (changes in biomasses of a set of aggregated species that exploit the same resource), mean weight of zooplankton, mean length of the surveyed community (all individuals by species caught during a survey), the amount of primary production (phytoplankton, etc) that is needed to support fishing, seabird breeding success (measured as number of chicks per nest), and mean weight-age of predatory fish.
Alongside these metrics, a road map on how to establish them between the present and 2020 was detailed.
Despite the advice initially benefitting the European regional seas commissions – the Barcelona, Bucharest, Helsinki, and OSPAR conventions – the indicators were developed by ICES with a view to applying them worldwide. In this way, it also underpins the organization's commitment to carry out Integrated Ecosystem Assessments (IEAs) in all marine environments.
Integration for ICES is also important in terms of teamwork, with a significant factor in the creation of the advice coming in the form of transatlantic collaboration between European and North American scientists and the ICES WKFooWI workshop.
Original artwork © Sven Bertil Johnson