Springtime Chl-a concentration is here used as a proxy for productive surface waters. In the Baltic Sea Spatial Pressure and Impact Index (SPIA), areas with high springtime phytoplankton production will be given higher importance, as they are considered important areas for the Baltic Sea food web. In the current map, mean of springtime maximum weekly values (weeks 12-22 for the HOLAS3 assessment period 2016-2021). Satellite Chl-a concentration of the surface waters has been used and converted to index by Finnish Environment institute with resolution of 1 km x 1 km grid cells.

This dataset contains datasets for the Eutrophication assessment developed under the HELCOM Third Holistic Assessment of the Ecosystem Health of the Baltic Sea (HOLAS 3). The dataset contains all Baltic Sea monitoring CTD data reported by HELCOM Contracting Parties to ICES for the HOLAS3 assessment period 2016-2021. The data have been reported using the ICES Ocean reporting format: https://www.ices.dk/data/data-portals/Pages/ocean-format.aspx https://www.ices.dk/data/Documents/ocean/ICES-Oceanography-Data-Submission-Format.zip

This core indicator evaluates the status of abundance of wintering waterbirds in the Baltic Sea region, here visualizedfor pelagic feeders. The wintering waterbirds are considered to reflect good status when at least 75% of the considered species deviate less than 30% downwards (species laying more than one egg per year) or 20% downwards (species laying one egg per year) from the baseline condition 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 "country" = Country "Group area" = Name of the group area "level_2" = Name of scale 2 HELCOM assessment unit (subbasin) "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 "Threshold" = Threshold value "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

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 dataset represents the underlying sediment data on core indicator Polybrominated diphenyl ethers (PBDE). The core indicator evaluates the status of the marine environment based on concentrations of Polybrominated diphenyl ethers (PBDE) in biota and sediment. Quantitative thresholds are used to evaluate if core indicators status is Achieve, Fail or Not assessed. 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 information: "region" = name of subbasin "country" = country/ opensea "station" = Unique code for the station "stationNam" = name for the station "determinan" = determinant parameter "detGroup" = the grouping of determinands used to display the results "_shape" = shape used to map assessment results "colour" = colour used to map assessment results "l3area" = HELCOM assessment unit on scale 3 "l4area" = HELCOM assessment unit on scale 4 "nyall" = total number of years of data "nyfit" = number of years of data used in the assessment "nypos" = number of years with at least one measurement above the limit of detection "lastyear" = most recent year of data "prtrend" = the significance of the change over the most recent 20 years; for the assessment conducted in November 2017 and published in June 2018, this is the period 1996-2016 "rtrend" = annual ‘linear’ change over the most recent 20 years "meanLY" = fitted value in last monitoring year "clLY" = upper one-sided 95% confidence limit on fitted value in last monitoring year "EQS" = Threshold value "EQSdiff" = difference between clLY and EQS "EQSbelow" = whether the mean value in the last monitoring year is significantly below EQS

This dataset contains the in-situ monitoring data used for calculating eutrophication indicator results for following indicators: Chlorophyll-a 2018 Dissolved inorganic nitrogen 2018 Dissolved inorganic phosphorus 2018 Total nitrogen 2018 Total phosphorus 2018 Water clarity 2018 This dataset is extraction for 2011-2016 assessment period from HELCOM COMBINE database, which contains all HELCOM oceanographic monitoring data. Full COMBINE database can be accessed from dedicated web page Attribute information: "Cruise": Platform code of the monitoring cruise, which can be queried from http://vocab.ices.dk/ "Station": Station number "Year": Year of sampling event "Month": Month of sampling event "Day": Day of sampling event "Hour": Hour of sampling event "Minute": Minute of sampling event "Latitude": Latitude coordinate of the sampling location (WGS84 decimal degrees) "Longitude": Longitude coordinate of the sampling location (WGS84 decimal degrees) "BotDepth": Bottom depth (m) of sampling location "Secchi": Secchi depth at sampling location "StationNam": Station name from ICES Station dictionary "Assessment" = HELCOM assessment unit ID "Depth": Sampling depth (m) "Temperature": Temperature (ºC) "Salinity": Salinity "Oxygen": Oxygen (ml/l) "Phosphate": Phosphate (umol/l) "TotalPhos": Total phosphorus (umol/l) "Silicate": Silicate (umol/l) "Nitrate": Nitrate (umol/l) "Nitrite": Nitrite (umol/l) "Ammonium": Ammonium (umol/l) "TotalNitr": Total nitrogen (umol/l) "HydrogenS": Hydrogen sulphide (umol/l) "pH": pH "Alkalinity": Alkalinity (mEq/l) "Chlorophyl": Chlorophyll-a (ug/l)

This core indicator evaluates the status of the Baltic Sea based on the number- and the size of illegal oil spills detected in annual aerial surveillance. Quantitative thresholds are used to evaluate if core indicators status is "Achieve", "Fail" or "Not assessed". Good status is achieved when the amount of oil spills are below the threshold value. This 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" = Code of the HELCOM scale 2 assessment unit "level_2" = name of he HELCOM scale 2 assessment unit (subbasin) "Area (km2)" = Area of the HELCOM scale 2 assessment unit "AULEVEL" = Assessment unit level used for the indicator "STATUS" = Status of the indicator (“Target achieved”, “Target exceeded” or “Not assessed”)

The Diatom/Dinoflagellate index (Dia/Dino index) reflects the dominance patterns in the phytoplankton spring bloom. It has high relevance for the pathway of the food into the pelagic or benthic food web. In principle, the indicator is applicable in all coastal and open sea assessment units, except lagoons, large river plumes and the Bothnian Bay; however, thresholds for the good status are defined only for the southern and central Baltic Sea up to now. In this assessment unit, the average Dia/Dino index of the years 2016-2021 was just below the threshold value of 0.5 for good status. The confidence of the indicator evaluation depends on the data frequency. The data have to represent the diatom and dinoflagellate blooms adequately. If the diatom bloom is not sufficiently represented in the data, an alternative Dia/Dino index may be applied, based on silicate consumption data. This indicator is robust; its calculation is simple and traceable. The phytoplankton monitoring is operational in the whole Baltic Sea using methods prescribed in the COMBINE manual. Currently, a high quality of the data is assured by the experts of the HELCOM Phytoplankton Expert Group (PEG). The basic data are phytoplankton biomass data, determined as explained in the HELCOM COMBINE manual, originating from the depth of 0 – 10 m. Also silicate data were used that were taken parallel to the phytoplankton sampling. Diatom-dinoflagellate ratio 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" = ID of the HELCOM scale 2 assessment unit "level_2" = Name of the HELCOM scale 2 assessment unit "Indicator_" = Name of the indicator "Period" = Interval of year of the sampling "AnnualSamp" = Assessment average sampling value "Unit" = Unit of the indicator "Type" = Type of indicator (1=monotonic, 2=unimodal, optimal range) "Threshold_" = Threshold value of indicator "Indicator1" = Result of the indicator "Status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”)

Illegal oil discharges data is based on airborne surveillance supplemented with remote sensing equipment in the Baltic Sea Area carried out by HELCOM Contracting Parties within HELCOM IWGAS group. Aerial surveillance is limited within Russia and Latvia. Attribute information: "HELCOM_ID" = HELCOM ID "Country" = Country of observation "Year" = Year of observation "FlightType" = Flight observation performed at Day or Night "Date" = Date of the observation "Time_UTC" = Time of the observation (time zone is UTC) "Wind_speed" = Wind speed during observation "Wind_direc" = Wind direction during observation "Latitude" = longitude coordinate of observed oil spill "Longitude" = longitude coordinate of observed oil spill "Length__km" = length in km "Width__km_" = Width in km "Area__km2_" = Area in km2 "Spill_cat" = Spill category (oil or orther substance detected) "EstimVol_m" = Estimated volume of oil spill (m3) "Category" = Category of oil spill "SPILL" = Spill ID

This dataset contains data used for assessing the HELCOM core indicator Nutritional status of seals 2018. The data has been collated by indicator leads based on national monitoring data. For this dataset, the data is aggregated and summarized by ICES Subdivisions. Attribute information: "Major_FA": FAO Major Area "SubArea": FAO Subarea "Division": ICES division "SubDivisio": ICES sub-division "Unit" "Area_full" "Area_27" "Area_km2": Area of ICES sub-division "ICES_SD": ICES sub-division "Female": Number of females per ICES sub-division "Male": Number of males per ICES sub-division "F1_year_ol": Number of 1 year old individuals per ICES sub-division "F2_year_ol": Number of 2 year old individuals per ICES sub-division "F3_year_ol": Number of 3 year old individuals per ICES sub-division "n_hunted": Number of hunted individuals per ICES sub-division "n_by_caught": Number of by caught individuals per ICES sub-division "n_stranded": Number of stranded individuals per ICES sub-division "Length_100": Number of individuals with 100 to 110 cm length per ICES sub-division "Length_111": Number of individuals with 111 to 120 cm length per ICES sub-division "Length_121": Number of individuals with 121 to 130 cm length per ICES sub-division "Length_131": Number of individuals with 131 to 140 cm length per ICES sub-division "Length_141": Number of individuals with 141 to 150 cm length per ICES sub-division "Length_151": Number of individuals with 151 to 160 cm length per ICES sub-division "Length_161": Number of individuals with 161 to 170 cm length per ICES sub-division "Length_171": Number of individuals with 171 to 180 cm length per ICES sub-division "Length_mor": Number of individuals with more than 181 cm length per ICES sub-division "Data_sourc": Data provider "Data_origi": Country of the data "Data_restr": Data restriction "Blubber_10": Number of individuals with measured blubber of 10 to 20 mm "Blubber_21": Number of individuals with measured blubber of 21 to 30 mm "Blubber_31": Number of individuals with measured blubber of 31 to 40 mm "Blubber_41": Number of individuals with measured blubber of 41 to 50 mm "Blubber_51": Number of individuals with measured blubber of 51 to 60 mm "Blubber_61": Number of individuals with measured blubber of 61 to 70 mm