The HELCOM State of the Baltic Sea Report builds upon experience gained from the HELCOM initial holistic assessment in 2010. This initial assessment provided for the first time a coherent assessment of the Baltic Sea ecosystem and its pressures from a holistic perspective, based on available data and prevailing knowledge. The regional development of indicators and assessment methods has continued since then and made the improvements in the current report possible. Through the HELCOM coordinated work of hundreds of experts, thirty regionally agreed core indicators have been made operational and are included in this assessment to reflect the status of the Baltic Sea environment, together with five indicators included as test. Several additional aspects are evaluated descriptively in order to arrive at a comprehensive assessment of the status of the Baltic Sea in 2011-2016.
The HELCOM holistic assessment is a multi-layered product; this summary report is supported by supplementary reports, several supporting HELCOM assessment reports, core indicator reports and spatial data fact sheets (Figure 2.1). Ninety-six spatial data sets at regional scale have been collated using regular HELCOM processes or dedicated data calls, to evaluate the geographical distribution of human activities, pressures, species and habitats.
The foundation of the assessment is the core indicators, which are based on the HELCOM coordinated monitoring programme and regionally agreed threshold values. The core indicators were assessed according to defined assessment units representing different levels of detail, in a regionally agreed nested system. Four assessment unit levels were used, from coastal water bodies to the entire region, to enable assessing each core indicator at its most relevant spatial scale and making comparisons across indicators and geographical areas. Assessment tools with the core indicators were used to produce thematic integrated assessment results on hazardous substances (CHASE), eutrophication (HEAT) and biodiversity (BEAT; see Box 2.1).
The current assessment focuses on the time period 2011–2016. In addition, data showing temporal development have been provided in order to understand long-term trends and evaluate the direction of ongoing changes. The focus of the assessment has been to show results of relevance at the regional scale, and large-scale patterns between geographic areas.
More detailed descriptions of the assessments applied are found in the supplementary reports, and references in relation to the integrated assessments of eutrophication hazardous substances and biodiversity, as well as of the assessment of cumulative impacts and the economic and social analyses (Figure 2.1).
Figure 2.1. Overview of key publications supplementing or supporting the State of the Baltic Sea report. The thematic assessments listed as HOLAS II supplementary material reflect the same results as in the State of the Baltic Sea report, and additionally include more detailed results and method descriptions (HELCOM 2018A-E). The core indicator reports give the assessment details and technical background to the applied core indicators, and are identified where referred to in the text. Other HELCOM assessments supporting the State of the Baltic Sea report: Maritime activities (HELCOM 2018f), Pollution load compilation (HELCOM 2015a); Thematic assessment of coastal fish (HELCOM 2018g), Ecological coherence of MPA network (Marine protected areas; HELCOM 2016b), Red List of Baltic Sea species (HELCOM 2013b), Checklist of Baltic Sea macrospecies (HELCOM 2012a).
