Observations of Cobitis taenia 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. Cobitis taenia has been placed to the Red List category of Least Concern (LC) species. The map shows the sub-basins in the HELCOM area where the species is known to occur regularly and to reproduce in coastal areas (HELCOM 2012).

Observations of Macroplea mutica 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. Macroplea mutica has been placed to the Red List category of Least Concern (LC) 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.

Observations of Hippasteria phrygiana 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. Hippasteria phrygiana has been placed to the Red List category of Vulnerable (VU) 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 dataset contains results on HELCOM Assessment unit level 4b for dissolved inorganic nitrogen. 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 population trends and abundance of the three species of seals that occur in the Baltic Sea. This dataset is for Harbour seal. Good status is achieved for each species when the abundance of seals in each management unit is at least 10,000 individuals and the species-specific growth rate is achieved. Harbour seals in the southwestern Baltic and the Kattegat form a metapopulation, where subpopulations are genetically connected. The combined sizes of the subpopulations are here used to evaluate the Limit Reference level (LRL). The status evaluation is presented separately for the three seal species. The grey seal in the Baltic proper is evaluated as a single unit, whereas the Kattegat grey seals are evaluated separately. The status of ringed seals is evaluated for two management units. The status of harbour seals is evaluated for three management units. Harbour seal dataset displays the result of the indicator in HELCOM Assessment Scale 2 (Division of the Baltic Sea into 17 sub-basins). Attribute information: "HELCOM_ID" = HELCOM ID of the scale 2 assessment unit "level_2" = Name of the HELCOM scale 2 assessment unit "Assessment" = Name of assessment unity area considered "Area (km2)" = Area of the HELCOM scale 2 assessment unit "Status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "AULEVEL" = Assessment unit level used for the indicator "Indicator unit" = Unit of indicator (Abundance - Ringed seal / % decrease) "Threshold value" = Threshold value of the indicator "Notes" = Additional information "ConfA" = Confidence of classification "ConfT" = Temporal confidence of classification "ConfS" = Spatial confidence of classification "ConfM" = Methodological confidence of classification

Observations of Mya truncata 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. Mya truncata has been placed to the Red List category of Near Threatened (NT) 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 dataset describes fishing intensity for DRB MOL mobile bottom contacting gear in 2009 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) (this attribute is visualised in MADS) 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.

Essential fish habitat (EFH) map on Potential recruitment areas for pikeperch was prepared in PanBalticScope project (co-founded by the European Maritime and Fisheries Fund of the European Union) http://www.panbalticscope.eu/ Pikeperch (Sander lucioperca) is a species of freshwater origin, which spawns predominantly in freshwater tributaries and has a relatively limited dispersal away from its recruitment area. Species distribution modelling studies have shown the importance of suitable environmental conditions for pikeperch recruitment. Due to lack of coherent data on pikeperch spawning and nursery areas across the Baltic Sea countries, the distribution of pikeperch recruitment areas was delineated based on areas with suitable conditions of depth, wave exposure, salinity, water transparency (Secchi depth) and distance to deeper (10 m) waters. The threshold values were obtained from literature. Temperature, although important for pikeperch, was left out due to high variation in timing of suitable spawning temperatures across the Baltic Sea. The map on pikeperch recruitment areas was originally developed within the HOLAS II project (HELCOM 2018) when it was approved by all HELCOM Contracting Parties in a dedicated review process after correction to Swedish waters. The map was subsequently considered by the Pan Baltic Scope project, who proposed adjustments to Estonian, German, Lithuanian and Polish waters. Stock: Several, undefined EFH type: Recruitment areas Approach: Environmental window with national approach for Finnish waters, selected data points corrected for Estonian, German, Lithuanian, Polish, and Swedish waters. Variables and thresholds: Depth < 5 m, Logged exposure < 5, Salinity < 7, Secchi depth < 2, Distance to deep (10m) water < 4km. Based on the model for the Finnish coastline, pikeperch recruitment areas were defined as: Unsuitable for reproduction: P(catch larvae) < 0.5, Suitable for reproduction: P(catch larvae) > 0.5, Important for reproduction: the smallest area where the expected cumulative larval abundance is 80% of the total expected abundance over study area. Quality: Recruitment area here refers to essential habitats for young-of-the-year pikeperch (based on inventory data from spawning until the end of the first summer). The map is based on literature and environmental variables, derived from inventory data. The species distribution modelling studies, where the thresholds values for environmental variables have been obtained, are from the northern Baltic Sea. Also, the data layers on environmental variables are based on modelling. Here, same thresholds have been applied in the southern Baltic. Due to these constraints, the data layer should be considered as a rough estimation. In addition, temperature is important for pikeperch recruitment but was not included as a delineating variable due to high variation in timing. The data layer may underestimate pikeperch in Finnish waters with respect to habitats for young-of-the-year pikeperch, as it focused on newly-hatched larvae when the dispersal is more limited compared to later in the season. Attribute information: Raster value representing the potential occurrence of pikeperch reproduction area (either 0 or 1). References: - Alikas, K, and Kratzer, S (2017) Improved retrieval of Secchi depth for optically-complex waters using remote sensing data. Ecological Indicators 77: 218-227 - Bergström, U, G Sundblad, A-L Downie, M Snickars, C Boström, and M Lindegarth (2013) Evaluating eutrophication management scenarios in the Baltic Sea using species distribution modelling. Journal of Applied Ecology 50:680-690 - HELCOM (2018) State of the Baltic Sea - Second HELCOM holistic assessment 2011-2016. Baltic Sea Environment Proceedings 155 - HELCOM (2020) Essential fish habitats in the Baltic Sea – identification of potential spawning, recruitment and nursery areas - Gunnartz, U, M Lif, P Lindberg, L Ljunggren, A Sandström, and G Sundblad (2011) Kartläggning av lekområden för kommersiella fiskarter längs den svenska ostkusten - en intervjustudie (In Swedish with summary in English). Finfo 2011:3:1-42 https://www.havochvatten.se/download/18.64f5b3211343cffddb2800018015/1348912838028/finfo2011_3.pdf - Isæus, M (2004) Factors structuring Fucus communities at open and complex coastlines in the Baltic Sea. PhD thesis, Stockholm University - Kallasvuo, M, J Vanhatalo, and L Veneranta (2017) Modeling the spatial distribution of larval fish abundance provides essential information for management. Canadian Journal of Fisheries and Aquatic Sciences 74:636-649 - 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 - Sundblad, G, Bergström, U, Sandström, A, and P Eklöv (2013) Nursery habitat availability limits adult stock sizes of predatory coastal fish. ICES Journal of Marine Science 71:672-680 - Veneranta, L, L Urho, A Lappalainen, and M Kallasvuo (2011) Turbidity characterizes reproduction areas of pikeperch (Sander lucioperca (L.)) in the northern Baltic Sea. Estuarine, Coastal and Shelf Science 95:199-206

This core indicator evaluates the status of the marine environment based on concentrations of heavy metal Mercury (Hg) in fish muscle. Quantitative threshold value is 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

Observations of Amauropsis islandica 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. Amauropsis islandica has been placed to the Red List category of Near Threatened (NT) 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.