Species thresholds : review of methods to support the EU Marine Strategy Framework Directive

The species status assessment for the Marine Strategy Framework Directive is structured around five Good Environmental Status (GES) criteria, i.e., by-catch rate, population abundance, population demographic characteristics, species distribution and habitat for the species. The MSFD Biodiversity theme for species includes, among others, some highly mobile species that require regional coordination for their assessments. To achieve comparable and consistent assessments for the GES it is imperative to harmonise the methods in order to set threshold values for the GES criteria within and if possible, across the four EU regions and the five species groups (marine mammals, seabirds, marine reptiles, fish and cephalopods). The EC Joint Research Centre coordinates the MSFD Biodiversity expert network and brought together appointed experts from the EU Member States, the Regional Sea Conventions and other relevant organisations to share knowledge on developed and promising methods for harmonising the threshold setting for marine species. The scientific advice and recommendation in this report are based on the outcome of the JRC's workshop "MSFD D1 SPECIES WORKSHOP ON METHODS FOR SETTING THRESHOLD VALUES" that took place in Italy, in January 2019. The Regional Sea Conventions and European policies such as the Birds Directive and the Habitats Directive provide operational methods to set thresholds, and for several species threshold values, to classify the species status. However, depending on the region, the species group, and the GES criterion, several gaps were identified in operational methods. The recommendation includes methods to cover these gaps and harmonise the assessments, where the existing assessment outcomes are not consistent and comparable. From the GES criteria perspective, by-catch rate has thresholds and operational indicators only for a few marine mammal species. Population abundance is the most advanced criterion in terms of methods and thresholds, mostly because of the Habitats Directive assessments and their monitoring programmes. Many gaps were noticed in the assessments and methods of the other criteria for all species groups. From the species groups perspective, marine mammals are well studied and have operational methods and, in some cases, agreed thresholds. Seabirds' indicators and assessments are well coordinated in the Baltic and Northeast Atlantic Sea, but not in two other regions. Fish and cephalopods have no operational methods for the MSFD criteria assessment, except for some HD derived species. However, the Common Fisheries Policy provides a potential source of data and methods. For marine turtles there were no agreed methods for assessment and threshold setting. The recommendation for harmonised methods to set comparable threshold values for the GES species criteria will support the follow-up work of the MSFD competent authorities and their experts towards an environmental efficient and scientific sound MSFD implementation. The recommended methods and the identified gaps could be covered through regional or EU-wide coordination.