The assessment results for waterbirds for the HELCOM Third Holistic Assessment of the Ecosystem Health of the Baltic Sea (HOLAS 3) contains the following datasets: Overall seal integrated result map, Grey seal integrated result map, Ringed seal integrated result map, Harbour seal integrated result map, and Harbour porpoise integrated result map. 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 datasets were created using the BEAT tool. https://github.com/helcomsecretariat/BEAT Attribute information: "Mammals_ag" = Aggregated area "SAULEVEL" = spatial assessment unit ID in which the assessment status took place "ECID" = Ecosystem component ID "EClevel" = Ecosystem Component level "EcosystemComponent" = Ecosystem component assessed "BQR" = Biological Quality Ratio "Conf" = Confidence of the assessment (0-1, higher values mean higher confidence) "ConfClass" = Confidence class

This core indicator evaluates the status of the marine environment based on concentrations of heavy metal Lead (Pb) in biota. Quantitative thresholds are used to classify core indicators status in “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

This core indicator evaluates the status of the marine environment based on concentrations of radioactive substances (Cs-137) in seawater and biota. Quantitative thresholds are used to evaluate if core indicators status is "Achieve", "Fail" or "Not assessed". Good status is achieved when concentrations reach levels measured before the Chernobyl accident in 1986. This dataset displays the result of the indicator in HELCOM Assessment Scale 2 (Division of the Baltic Sea into 17 sub-basins) for herring. Attribute information: "OBJECTID" = Object identification "HELCOM_ID" = Code of the HELCOM scale 2 assessment unit "Indicator" = Name of HELCOM Core indicator "Type" = Type of indicator "Threshold value" = Threshold value for specific assessment unit "Indicator value" = Value of indicator calculated for specific assessment unit "Status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”)

Summary Estimated observations of the biotope AB.H2T1 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic aphotic muddy sediment characterized by sea-pensThe HELCOM Red List of Baltic Sea underwater biotopes, habitats and biotope complexes (2013) is an updated and improved version of the Red List assessment of marine and coastal biotopes and biotope complexes published in 1998. The classification of the report follows the proposed International Union for Conservation of Nature (IUCN) criteria and assessment principals but with some modifications for the Baltic Sea.Altogether, the HELCOM Underwater Biotope and habitat classification (HELCOM HUB) includes 209 biotopes of which 59 were red-listed. Many of the red-listed biotopes are located in deep areas of the Baltic Sea due to oxygen-free nature as well as in the southwestern Baltic Sea due to the salinity restricted distribution of species in certain biotope. The HELCOM assessment relies heavily on expert judgment and inference, and the questionnaire data represents the estimated presence-absence data not in-situ measured data. This must be taken in account when observing the map presentation. The biotopes are shown on the map using the EEA 100 km grid. This dataset displays estimated presence of AB.H2T1 according to HELCOM RED LIST assessment experts:Because of its salinity and depth requirements, this habitat occurs mostly in the deeper parts of Kattegat. The most common sea pen species Virgularia mirabilis and Pennatula phosphorea have been observed for example in the deep trenches of the Kattegat (The Kattegat trench, the Ddupa Rännan trench), in the Groves Flak and near the island Ven in the Sound. The habitat has likely suffered from bottom trawling as trawling marks and badly disturbed seabeds has been recorded in the area of their distribution. Distribution map indicates the area in the 100 x 100 km grid where biotopes are known to occur.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

This dataset contains results on HELCOM Assessment unit level 4b for water clarity. 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

MORS Environment monitoring stations This data set contains information about stations where HELCOM contracting parties monitor the concentrations of radioactive substance in seawater, sediment, fish, aquatic plants and benthic animals.The Data set was updated in May 2013 after MORS EG 3 2013 meeting according to modifications done in the MORS guidelines as requested by Sweden.

This core indicator evaluates the status of the marine environment based on the reproductive status of seals in the Baltic Sea. Quantitative thresholds are used to evaluate if core indicators status is Achieve, Fail or Not assessed. Good status is achieved when the annual reproductive rate (i.e. pregnancy/birth rate) is at least 90% for five years and older (harbour seals) and six years and older (grey and ringed seals). Currently, a full status evaluation has only been carried out for the grey seal based on Finish and Swedish data. The indicator is applicable for all species of seals and marine mammals that occur in the Baltic Sea, however the amount of data have so far been insufficient for an evaluation of other marine mammal species. This dataset displays the result of the indicator in HELCOM Assessment Scale 1 (Whole Baltic). Attribute information: "Species" = Species "CODE" = Code of the assessment unit "Assessment" = Assessment unit name "Threshold" = Threshold value of core indicator "Result value" = Result value of core indicator "Binomial proportion confidence interval" "Status" = Status for the whole indicator "Notes" = Additional information "AULEVEL" = Assessment unit level used for the indicator "ConfA" = Confidence of classification "ConfT" = Temporal confidence of classification "ConfS" = Spatial confidence of classification "ConfM" = Methodological confidence of classification

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 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

Data set represents the reported beach litter items on monitoring sites at the Baltic Sea area. Data includes the sum value of items per category for each monitoring site, as an average for the whole monitoring period. Categories include: Artificial polymer materials (plastic), rubber, cloth/textile, paper/cardboard, processed/worker wood, metal, glass/ceramics and unclassified. Number of items in the data set is always in relation to a 100 m strip of beach. In Map and data service the category "plastic" is visualised. Litter data is provided by HELCOM contracting parties in response to data call for State of the Baltic sea report. NOTE: Spatial data set includes only categorised sum values of beach litter items, the link to download the spatial data can be found below. An excel file including the complete national data sets with all litter items, and all individual monitoring events, is available as a separate data set below the spatial data. Please also note that countries have used different categorisation protocols for their data, and the spatial data set is a harmonisation of these protocols, on a category level. The excel file will provide further details on what protocols have been used. NOTE: Please note that in Latvia monitoring is carried out only in the summer season and is not completely comparable with other countries that carry out monitoring seasonally. Attribute information: Country: country where the site is located Monitoring site: Name of the monitoring site Beach type: rural/urban/reference Length: Length of monitored beach Width: Width of monitored beach HELCOM sub-basin National: National description of the sub-basin HELCOM sub-basin: HELCOM sub-basin on assessment level 2 Litter categories: Artificial polymer material - unclassified: The sum of all material belonging to this category. Value is an average of all individual monitoring events. sum: The sum of all categories. Value is an average of all individual monitoring events. monitoring period: The first and last monitoring period of monitoring site