Potential cumulative impacts of eutrophication and hazardous substances assesses the cumulative potential effect of eutrophication and hazardous substances over all ecosystem components. The evaluation is based on the pressure layer on eutrophication and hazardous substances, combined with information on all ecosystem components (57 layers) included in SPIA for HOLAS 3. The thematic analyses is calculated for each assessment unit (1 km2 grid cells) and the data set covers the time period 2016-2021. Spatial Pressure and Impact Assessment (SPIA) is the framework for assessing spatial and cumulative pressures and impacts in HOLAS 3, and this analyses present a thematic assessment including only a certain subset of layers. The framework also includes results for the Baltic Sea Impact Index (full cumulative impact assessment), Baltic Sea Pressure Index (full cumulative pressure assessment), and other thematic assessments where a subset of pressure and ecosystem layers are used. For more info please - visit the HOLAS 3 website (http://stateofthebalticsea.helcom.fi/) - download the report thematic assessment of spatial distribution of pressures and impacts 2016-2021 (https://helcom.fi/post_type_publ/holas3_spa) - or check out the HELCOM SPIA online tool to make calculations for any desired combination of pressures and ecosystem layers (https://maps.helcom.fi/website/bsii/). Please scroll down to "Lineage" for a more detailed description of the methodology.

This dataset contains core indicator "TBT and imposex - TBSN in sediment" results developed under the HELCOM Third Holistic Assessment of the Ecosystem Health of the Baltic Sea (HOLAS 3). 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

Shellfish production in kilograms in 2010-2015 in geometry form: area (polygon). Swedish data covers only the permitted production in year 2015 (Swedish data in the point dataset). The data was made available by HELCOM Contracting Parties in response to data request. The data was received from Denmark (area), Germany (points) and Sweden (points). The activity was declared as not relevant in Estonia, Finland, Latvia, Lithuania, Poland and Russia. Attribute specification and units ID: Mariculture identification (DK) NR: Identification number (DK, mariculture permits) Country: Country AVG_all: A calculated average of production in 2010-2015 (Kg/year) AVG_11_15: A calculated average of shellfish production in 2011-2015 (Kg/year) 2010_Kg – 2015_Kg: An annual shellfish production (Kg) Area: Area of the shellfish mariculture (km2)

This dataset contains results on HELCOM Assessment unit level 4b for dissolved inorganic phosphorus. The information provided represents the data and results from the HELCOM HOLAS 3 indicator evaluation for eutrophication, covering the data period from 2016-2021. Data reported from national monitoring programmes to the HELCOM COMBINE database (hosted by ICES) is utilized for open sea assessment units. Open sea data extraction is carried out by ICES for in-situ (bottle) data creating the underlying assessment dataset [link ]. Coastal assessment units (WFD water types or water bodies) are assessed based on WFD result data reported by countries. Indicator analysis of both open sea and coastal areas is carried out using the HEAT assessment tool (https://github.com/ices-tools-prod/HEAT). This analysis provide the basis of the HELCOM indicator evaluations and are utilized in the HOLAS 3 thematic assessment of eutrophication. Attribute description: ES = Eutrophication Status ES_SD = Standard Deviation ES_N = Number of Observations ES_N_Min = Minimum Number of Observations any given year ES_SE = Standards Error ES_CI = Confidence Interval ET = Eutrophication Target / Threshold ER = Eutrophication Ratio ACDEV = Acceptable Deviation BEST = ET / (1 + ACDEV / 100) EQR = Ecological Quality Ratio EQR_HG = Ecological Quality Ratio High/Good Boundary EQR_GM = Ecological Quality Ratio Good/Moderate Boundary EQR_MP = Ecological Quality Ratio Moderate/Poor Boundary EQR_PB = Ecological Quality Ratio Poor/Bad Boundary EQRS = Ecological Quality Ratio Scaled GTC = General Temporal Confidence STC = Specific Temporal Confindence TTC = Total Temporal Confidence GSC = General Spatial Confidence SSC = Specific Spatial Confidence TSC = Total Spatial Confidence TC = Total Confidence

This core indicator evaluates the status of the marine environment based on the arrival of new non-indigenous species. The new NIS have been detected both through regular environmental monitoring activities and incidental sightings. The data have been verified by national experts. Monitoring is not considered to sufficiently cover all areas of the Baltic Sea and hot spot areas for new introductions (e.g. ports) to allow for the conclusion that in areas where no new NIS have been observed there have not been any new introductions. This dataset displays the result of the indicator in HELCOM Assessment Scale 1 (whole Baltic Sea). Attribute information: "level_1" = Name of the HELCOM scale 1 assessment unit "Area (km2)" = Area of the HELCOM scale 1 assessment unit "Status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "AULEVEL" = Assessment unit level used for the indicator

This dataset represents the underlying data on core indicator Trends in arrival of new non-indigenous species for HELAS 3. This dataset contains reported observations of alien species on HELCOM Assessment unit level 2. The core indicator evaluates status of arrival of new non-indigenous species whether it reflects good environmental status. Quantitative thresholds are used to evaluate if core indicators status is Good, Not good or Not assessed. The assessment is done for HELCOM Assessment unit level 1 (whole Baltic Sea). Attribute information: "HELCOM_ID" = ID of HELCOM Level 2 assessment unit "Level_2" = Name of assessment unit "Area_km2" = Area of assessment unit "Threshold_v" = Threshold value (0 = no alien species observed) "Observatio" = Observed value (0 = no alien species observed, 1 = alien species observed) "Confidence" = Confidence of assessment "Species" = Species observed in assessment unit "Status" = Status of assessment unit (Fail / Achieve / Not assessed) "AULEVEL" = Level of the Assessment unit

This core indicator evaluates the status of the marine environment based on concentrations of perfluorooctane sulphonate (PFOS) in biota. Quantitative thresholds are used to evaluate if core indicators status is "Achieve", "Fail" or "Not assessed". Good status is achieved when the concentrations of PFOS are below the threshold value. 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

This dataset describes fishing intensity for OT CRU mobile bottom contacting gear in 2013 based on VMS/Log book data processed by ICES Working Group on Spatial Fisheries Data (WGSFD). ICES secretariat collected during 2017 relevant VMS and logbook data for 2009-2016 to produce, as a technical service to HELCOM, updated spatial data layers on fishing intensity/pressure. Improved data quality control checks were implemented. Submitted data across the HELCOM area have improved in quality compared to previous data 2009-2013 published in 2015. Standardized methods were used to produce the requested data layers. The code used to create the data products is available here: https://github.com/ices-eg/wg_WGSFD For further technical information on the advice request, see http://www.ices.dk/sites/pub/Publication%20Reports/Advice/2017/Special_requests/helcom.2017.18.pdf HELCOM secretariat did the following processing to the shapefile provided by ICES: - Conversion to ETRS89LAEA coordinate system - Added feature and attribute "Reported" to display unreported areas. Dataset attribute information: c-square: Unique reference of the c-square polygon Year: Year of fishing activity mid_lat: latitude coordinate of the centroid of c-square inWGS84 decimal degrees mid_lon: longitude coordinate of the centroid of c-square inWGS84 decimal degrees SurfaceSAR: Surface area ratio (Swept area, < 2 cm penetration depth of the gear components) Subsurface: Subsurface area ratio (Swept area, subsurface =>2 cm penetration depth of the gear components) totweight: Total Weight (kg) totvalue: Total value (Euros) Kw Fishing Hours: (Kw*h) Fishing hours: (h) Reported: Yes=Reported data. No= No reported data (area that does not contain effort/intensity value due to lack of reported data). Please note that this dataset was updated (v2) in January 2019, see further details below in the lineage section.

This dataset is built from following Human activities datasets: • https://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/3d6bd6f9-72d5-40cf-aaaa-b7c0c18878e3 • https://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/41da8e41-d907-419d-8841-f95062d002e7 The game hunting of seabirds data (see separate metadata): The total number of hunted seabirds were averaged over 2016-2021 (number of hunted seabirds / year). The area of the reporting unit was used to calculate the number of hunted seabirds / km2 and the data was converted to 1km x 1km grid. The predator control of seabirds data (see separate metadata): The total number of hunted cormorants were averaged over 2016-2021 (number of hunted cormorants / year). The area of the reporting unit was used to calculate the number of hunted cormorants / km2 and the data was converted to 1km x 1km grid. The two datasets were first separately log transformed and then summed, to get the total value for each grid cell. Zero values were given to all grid cells with no reported seabird hunting activity. The layer was normalized.

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