The pressure layer represents biological pressure caused by introduction of non-indigenous species. The data is obtained from core indicator Trend in the arrival of new non-indigenous species (BSEP 129b: http://www.helcom.fi/Lists/Publications/BSEP129B.pdf). For the Baltic Sea Impact Index, the layer was normalized.

Large shallow inlets bays (according to Habitats Directive Annex I) are large, shallow indentations of the coast, sheltered from wave action and where, in contrast to estuaries, the influence of freshwater is generally limited. The distribution map is based on data submission by HELCOM contracting parties. Most of the submitted data is based on GIS analysis and modelling, but also field inventories and ground-truthing has been carried out in some areas. Data coverage, accuracy and the methods in obtaining the data vary between countries.

The dataset contains the location of oil refineries downloaded from the European Pollutant Release and Transfer Register. E-PRTR covers all HELCOM Contracting Parties except Russia. See attribute specification and units at: https://www.eea.europa.eu/data-and-maps/data/industrial-reporting-under-the-industrial-5/database-structure-and-use-information/eea_industrial_reporting_metadata_v6/at_download/file

This dataset contains core indicator results for the bird species breeding in the Baltic Sea area by assessing fluctuations in abundance, visualized for wading feeders. Quantitative regional thresholds are used to evaluate if the core indicator achieves good status. The indicator performs status evaluations by aggregating annual single species index values for all waterbird species and on the basis of aggregated indices for five species groups (wading feeders, surface feeders, pelagic feeders, benthic feeders, grazing feeders). Good status is achieved when the abundance of 75% of the considered species of a species group does not decline by more than 30% (20% in species laying only one egg per year) compared to a baseline during the reference period 1991-2000. This dataset displays the result of the indicator in HELCOM Assessment Scale 3 (Division of the Baltic Sea into 17 sub-basins and further division into coastal and offshore areas). Attribute information: "HELCOM_ID" = ID of the HELCOM scale 3 assessment unit "level_2" = Name of scale 2 HELCOM assessment unit "level_3" = Name of scale 3 HELCOM assessment unit "Area (km2)" = Area of HELCOM assessment unit "Coastal" = HELCOM ID of the coastal areas "Open_sea" = Open sea assessment unit name "Abundance" = Assessed parameter "Wading feeders" = Results for the category "Wading feeders status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "Surface feeders" = Results for the category "Surface feeders status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "Pelagic feeders" = Results for the category "Pelagic feeders status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "Benthic feeders" = Results for the category "Benthic feeders status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "Grazing feeders" = Results for the category "Grazing feeders status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "AULEVEL" = Assessment unit level used for the indicator "Group area" = Name of the group area

Essential fish habitat (EFH) map on Potential spawning areas for European flounder was prepared in PanBalticScope project (co-founded by the European Maritime and Fisheries Fund of the European Union) http://www.panbalticscope.eu/ European flounder (Platichthys flesus) is a key species in many coastal areas of the Baltic Sea, mainly in the central and southern sub-basins. Adults feed in shallow, coastal areas during summer and move out to deeper areas in winter, where the spawning takes place in spring. European flounder spawns above the sea floor in deep water, in areas with sufficiently high salinity for fertilization and pelagic egg development. ‘Potential spawning areas’ were initially delineated by a species distribution model (Orio et al. 2017) developed based on years 1993-1997 to consider a period with relatively better oxygen conditions, but applied with more recent data (2011-2014). The area was further delineated to encompass only areas deeper than 30 m in order to represent pelagic spawning habitat. ‘High probability spawning areas’ were identified as the sub-section encompassing salinity > 10. It should be noted that flounders in the Baltic Sea were recently separated into two species, and that spawning areas of the Baltic flounder (Platichthys solemdali) are described separately. The two data layers do not overlap and can be combined to obtain a map on spawning areas for both flounder species taken together. Stock: ICES identifies two stocks of European flounder in the Baltic Sea: ICES subdivisions 22-23 (Belt Sea and the Sound), and 24-25 (West of Bornholm and Southern Central Baltic Sea). EFH type: Spawning areas Approach: Species distribution modelling combined with identification of environmental salinity window and depth conditions for spawning. Variables and thresholds: Depth > 30 m, Salinity > 10 Quality: The data layer is based on species distribution modelling focusing on mature flounder at the spawning stage and should be considered a rough estimation. The data layers on environmental variables are based on modelling. Other variables than those tested in the model may also be influential. The studies from which the thresholds values for environmental variables have been obtained are based on publications conducted before the separation of Baltic flounder from European flounder but have taken the specific characteristics of the separate spawning ecotypes into account. Note: the map on European flounder spawning areas is currently missing information for the western Baltic Sea including the Kattegat. Attribute information: Raster value representing no spawning (0), potential spawning area (0.5) and high probability spawning area (1). References: - Momigliano, P, GP Denys, H Jokinen, and J Merilä (2018) Platichthys solemdali sp. nov. (Actinopterygii, Pleuronectiformes): a new flounder species from the Baltic Sea. Frontiers in Marine Science 5:225 - Nissling, A, L Westin, and O Hjerne (2002) Reproductive success in relation to salinity for three flatfish species, dab (Limanda limanda), plaice (Pleuronectes platessa), and flounder (Pleuronectes flesus), in the brackish water Baltic Sea. ICES Journal of Marine Science 59:93-108 - Orio, A, U Bergström, M Casini, M Erlandsson, R Eschbaum, K Hüssy, A Lehmann, L Ložys, D Ustups, and A-B Florin (2017a) Characterizing and predicting the distribution of Baltic Sea flounder (Platichthys flesus) during the spawning season. Journal of Sea Research 126:46-55 - Seifert, T, F Tauber, and B Kayser (2001) A high resolution spherical grid topography of the Baltic Sea -2nd edition. Baltic sea Science Congress, Stockholm 25-29 November 2001, Poster #147

This core indicator evaluates the status of the marine environment based on concentrations of heavy metal cadmium (Cd) in biota. Quantitative thresholds are used to evaluate if core indicators status is "Achieve", "Fail" or "Not assessed". Threshold values are based on Environmental quality standards (EQS), defined at EU level for substances included in the priority list under the Water Framework Directive. This dataset displays the result of the indicator in HELCOM Assessment Scale 4 (Division of the Baltic Sea into 17 sub-basins and further division into coastal and off-shore areas and division of the coastal areas by WFD water types or water bodies). Attribute specifications and units: "HELCOM_ID" = Code of the HELCOM scale 4 assessment unit "country": country in which the HELCOM assessment unit is located or a mention to an open sea area "level_2" = Name of the HELCOM assessment unit in scale 2 "Name" = Name of the HELCOM assessment unit in scale 4 "Open_sea" = Name of the HELCOM assessment unit in the open sea "F2_Name" = Name of the HELCOM assessment unit "determinan" = Determinat "est" = The estimated mean loge concentration in the assessment unit "se" = The standard error on the estimated mean log concentration in the assessment unit "fit" = The estimated mean concentration in the assessment unit "upper_cl" = Upper one-sided 95% confidence limit on the mean concentration: exp(est + qnorm(0.95) * see) "Status" = Overall Status of the indicator according to one-out-all-out

Pressure layer combines all human activities that cause changes to hydrological conditions. The human activities were presented as point data which were given spatial extents (given below). The pressure value was given as the proportion of the grid cell under the pressure. The following human activities were combined into the changes to hydrological conditions layer; - Hydropower dams (a 1km2 grid cell in the river estuary was selected) - Water course modification (1 km) - Wind turbines (operational, 0.3 km, linear decline) - Oil platforms (0.5 km, linear decline) The human activity datasets were first processed separately covering the whole Baltic Sea and then summed together and overlapping areas were dissolved to remove double counting. Attenuation gradients are assigned to each layer as described above. Area effected decreases when distance from avtivity increases. Layer was normalized.

This dataset represents the Integrated biodiversity status assessment for seals (grey seal, harbour seal and ringed seal). Status is shown in five categories based on the integrated assessment scores obtained in the tool. Biological quality ratios (BQR) above 0.6 correspond to good status. The status of the seals was assessed using four core indicators: population trends and abundance of seals, distribution of Baltic seals, nutritional status of seals, and reproductive status of seals. In the latter two only grey seals are considered for the 2018 State of the Baltic Sea report. The assessment is based on the one-out-all-out approach, i.e. the species reflecting the worst status in each assessment unit. This dataset displays the result of the integrated biodiversity status in HELCOM Assessment unit Scale 2 (Division of the Baltic Sea into 17 sub-basins). Attribute information: "HELCOM_ID" = ID of the HELCOM scale 2 assessment unit "level_2" = Name of the HELCOM scale 2 assessment unit "EcosystemC" = Ecosystem component analyzed "BQR" = Biological Quality Ratio "Conf" = Confidence of the assessment "Total_indi" = Number of indicators used "% of area assessed" = Share of the total assessed area "D1CX" = MSFD descriptor 1 criteria X "conf_D1CX" = Confidence for MSFD descriptor criteria X "Confidence" = Conifdence of the assessment ("high"/ "moderate"/ "low") "STATUS" = Status of the assessment (0-0.2 = not good (lowest score), 0.2-0.4 = not good (lower score), 0.4-0.6 = not good (low score), 0.6-0.8 = good (high score, 0.8-1.0 = good (highest score))

Data set represents the HELCOM 20x20 km Baltic Sea grid. The grid is based on the European Environment agency (EEA) grid system, and its compatible with other grid sizes. Each grid cell have an unique identifier, that is based on the EEA coding system, where the identifier consists of the cell size and cell coordinates. The grid covers the HELCOM marine area and uses the LAEA projection. HELCOM is making the grid available to offer a standardized and equal area grid system for the Baltic Sea that can be used in different assessments and that is alligned with different grid sizes, such as the "HELCOM 1x1km Baltic Sea grid" or any other EEA based grid system in Europe. The grid is available in two versions: 1. The basic version (HELCOM 20x20km Baltic Sea grid) with full grid cells. This is the version that is visualized in MADS and avaliable for download below as the first link and also as the download link in MADS 2. The second version (HELCOM 20x20km Baltic Sea grid without land areas) where all land areas are removed within the grid cells. This version is not visualized in MADS, but is available for download below. Further details on the 2 different grids can be found in the lineage section below. Attribute information: Unique_ID: Unique ID of the grid cell, based on the EEA coding system Area_km2: Area of the grid cell (for the second version the area is without land areas)

This dataset contains core indicator results developed under the HELCOM Third Holistic Assessment of the Ecosystem Health of the Baltic Sea (HOLAS 3).