This dataset represents the underlying data on core indicator Abundance of waterbirds in the breeding season 2018. The data is resulting from a data call carried out by HELCOM for State of the Baltic Sea report. Attribute information: "YEAR" = Year of the observation "SPECIES" = Species accepted scientific name "ABUNDANCE" = Abundance count "Country" = Country of observation "SITECODE" = Unique site code

Introduction of radionuclides is based on HELCOM MORS discharge data (2016-2020) . Annual averages of CO60, CS137 and SR90 from the period 2016-2020 per nuclear power plant. Gradual buffer around outlet to 10km distance (Type B decline). 10 km buffer with linear decline composed of 5 rings from discharges of radioactive substances (Type B decline)12.

Pressure layer combines all human activities that cause physical disturbance or damage to seabed. For several human activity datasets, spatial extents were given (table below). Buffers with decreasing value rates were applied to represent the impact distance of physical disturbance. The following human activities were combined into the physical disturbance layer; - Cables (under construction, 1 km buffer) - Coastal defence and flood protection (under construction, 500 m buffer) - Deposit of dredged material (500 m buffer for points and areas) - Dredging (maintenance) (500 m buffer for points and areas) - Extraction of sand and gravel (500 m buffer) - Finfish mariculture (1 km buffer) - Fishing intensity 2011-2016 average (subsurface swept area ratio) - Furcellaria harvesting - Pipelines (0,3 km buffer) - Recreational boating and sports - Shellfish mariculture - Shipping density - Wind farms (under construction) (1 km buffer) - Wind farms (operational) (0,1 km buffer) The human activity data sets were first processed separately covering the whole Baltic Sea and then summed together. In this integration, some data layers were down-weighted to arrive at a balanced pressure layer, as described below. High pressure intensity and/or slow recovery (weighting factor 1): Coastal defence and flood protection, Deposit of dredged material, Dredging, Extraction of sand and gravel and Fishing intensity Moderate to high (Weighting factor 0,8): Pipelines and Shipping density Moderate (Weighting factor 0,6): Finfish mariculture, Shellfish mariculture and Wind farms (under construction) Low to moderate (Weighting factor 0,4): Cables Low (Weighting factor 0,2): Maerl and Furcellaria harvesting, Recreational boating and sports and Wind farms (operational) Harbours and marinas were left out from the physical disturbance pressure to avoid double counting due to their representation in the shipping density and recreational boating and sports data sets. Detailed information about this pressure layer can be found in the indicator report.

The dataset contains the number of hunted cormorants (Phalacrocorax carbo) per year per county. A total sum and a calculated average (hunted individuals/year) are given for the time period 2016-2021 The data was made available by HELCOM Contracting Parties in response to a data call. The data was reported by Estonia, Finland, and Sweden. The activity was declared as not relevant in Germany, Latvia and Poland. Attribute specification and units: Area: Name of the EG administrative unit or other areas in which the activity is taking place Corm_2016-Corm_2021: Number of hunted birds/unit area per year for each target species (cormorant) AVRG: Average of the number of hunted birds/unit area per year

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

The dataset represents urban land use (artificial surfaces) around the Baltic Sea coast. The dataset is constructed from CORINE Land Cover (CLC) 2018, Version 2020_20u1 (https://land.copernicus.eu/pan-european/corine-land-cover/clc2018?tab=metadata) for EU countries and from Open Street Map (OSM) open source data for Russia. Attribute specification and units: Code_18: Class applied for CLC 2018 ID:CLC 2018 ID or OpenStreetMap ID Code: Nomenclature of the class source: "Corine" or "OSM"

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

Observations of Gammarellus inaequicauda were collected from the Baltic Sea area for HELCOM Red List species list. The HELCOM Red List of Baltic Sea species in danger of becoming extinct (2013) is the first threat assessment for Baltic Sea species that covers all marine mammals, fish, birds, macrophytes (aquatic plants), and benthic invertebrates, and follows the Red List criteria of the International Union for Conservation of Nature (IUCN). Almost 2800 species were considered in the Red List assessment and about 1750 were evaluated according to the IUCN Red List criteria. Gammarellus inaequicauda has been placed to the Red List category of Data Deficient (DD) species. Dataset for download contains spatial grid of the Baltic Sea. Distribution of the species can be found in corresponding name column. Values are coded: 1 - Present before year 2000 or in 2000, 2 - Present after year 2000, 3 - Present both before and after year 2000.

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