Summary Estimated observations of the biotope AB.J3L3 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic aphotic sand dominated by ocean quahog (Arctica islandica)The 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.J3L3 according to HELCOM RED LIST assessment experts:The main distribution area of this biotope is the western Baltic Sea. The largest populations of A. islandica are found in Kiel and Mecklenburg Bights (Zettler et al. 2001). The distribution map indicates the area in the 100 x 100 km grid where biotope is believed to occur based on the suitability of the environmental conditions.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

This dataset represents the underlying data on core indicator Zooplankton mean size and total stock (MSTS). The core indicator evaluates zooplankton community structure to determine whether it reflects good environmental status. Quantitative thresholds are used to evaluate core indicators status in Achieve, Fail or Not assessed. As a rule, achieve status occur when large sized zooplankters occur abundantly in the plankton community. Due to strong environmental gradients, size distribution and total stock of the zooplankton corresponding to achieve status vary between the Baltic Sea sub-basins. This dataset displays the result of the indicator in HELCOM Assessment Scale 2 (Division of the Baltic Sea into 17 sub-basins). The dataset contains following attributes: DOME - output field Description CNTRY - Country that has reported the measurement (cf. CNTRY) CRUIS - Cruise identifier (unique for data submission) STNNO - Station identification (unique for each CRUIS within the same data submission) SMPNO - Sample identifier (unique for each CRUIS and STNNO within the same data submission) MPROG - Monitoring programme (cf. MPROG). Multiple programmes are possible separated by “~” (ascii 126) PURPM - Purpose of monitoring (cf. PURPM) . Multiple purposes possible separated by “~” (ascii 126) MYEAR - Monitoring year. Note that MYEAR may not always be identical to the year in date of sampling DATE - Date of sampling (DD/MM/YYYY) Latitude - Latitude of measurement (decimal degrees) Longitude - Longitude of measurement (decimal degrees) MNDEP - Minimum depth of sample (m) MXDEP - Maximum depth of sample (m) STATN - Station name as reported HELCOM_subbasin - HELCOM subbasin name (L2) HELCOM_L3 - HELCOM subbasin with coastal and offshore division – HELCOM_ID (L3) HELCOM_L4 - HELCOM subbasin with coastal WFD waterbodies or watertypes – HELCOM_ID (L4) OSPAR_region - OSPAR region ICES area - ICES Statistical Areas (cf. ICES statistical areas) RLABO - Reporting laboratory (cf. RLABO) ALABO - Analytical laboratory (cf. RLABO) SLABO - Sampling laboratory (cf. RLABO) RLIST - Reference code list used for species (cf RLIST) SPECI - Species/taxon code/name of examined specimen, as reported by submitter (according to reported reference list RLIST) SPECI_name - Species/taxon name of examined specimen, as reported by submitter (according to reported reference list RLIST) AphiaID - AphiaID (id) of species in World Registry of Marine Species (WoRMS) WoRMS_name - Taxon species/name of species in World Registry of Marine Species (WoRMS) AphiaID_accepted - Accepted AphiaID (id) of species in World Registry of Marine Species (WoRMS) WoRMS_accepted_name - Accepted species/taxon name of species in World Registry of Marine Species (WoRMS) SEXCO - Sex of specimen (cf. SEXCO) SFLAG - Species flag (cf. SFLAG) . Multiple purposes possible separated by “~” (ascii 126) SIZCL - Size class (value from reference in SIZRF) SIZRF - Size class reference list (cf. SIZRF) STAGE - Developmental stage of the species (cf. STAGE) CPORT - Number of portions counted from split sample NPORT -Number of portions in split sample (SMPNO) PARAM - Measured parameter (cf. PARAM) MUNIT - Measurement unit (cf. MUNIT) Value - Value measured Final_MUNIT - The unit of the final value (cf. MUNIT) Final_value - For values that are reported as a number only (eg. ‘nr’ or ‘g’) the final concentration (eg. ‘nr/l’ or ‘g/l’) is calculated as value*NPORT/(CPORT * SMVOL). If value is reported as a concentration, Final_value and Value are identical SMTYP - Sampler type (cf. SMTYP) SAREA - Sampler/swept area (cm2) METOA - Method of analysis (cf. METOA) MAGNI -Total magnification FLVOL - Calculated flow .volume of water (m3) CLMET MESHS - Mesh size of net or sieve (µm) CLMET - Calculation method for FLVOL (cf. CLMET) SMVOL - Total sampled volume (m3) METFP - Method of chemical fixation/preservation (cf. METFP) QFLAG - Qualifier flag for measured value, i.e. “<” (cf. QFLAG). Multiple flags possible separated by “~” (ascii 126) VFLAG - Validity flag, i.e. “S“ suspect value (cf. VFLAG). Multiple flags possible separated by “~” (ascii 126) FINFL - Factors potentially influencing guideline compliance and interpretation of data (cf. FINFL) Multiple factors possible separated by “~” (ascii 126) REFSK - Reference source or key (cf. REFSK) DCFLGs - Data conversion flags from ICES Data Centre (cf. DCFLG). Multiple flags possible separated by “~” (ascii 126) Reference to the uploaded submission (integer). Unique for a submission tblSpotID Reference to the sampling event (integer). Unique for a sampling event tblSampleID Reference to the sample (integer). Unique for a sample tblParamID Reference to the measurement (integer). Unique for the data table

This dataset represents the underlying sediment data on core indicator Polyaromatic hydrocarbons (PAH) and their metabolites. The core indicator evaluates the status of the marine environment based on concentrations of Polyaromatic hydrocarbons (PAH) in sediment and biota. Quantitative threshold value is used to evaluate if core indicators status is Achieve, Fail or Not assessed. As There is no commonly agreed threshold value for measuring metabolites available, this report only considers concentrations of contaminants. 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 "station" = Unique code for the station "stationNam" = name for the station "determinan" = determinant parameter (ANT = anthracene) "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 seawater monitoring data reported by Contracting Parties of HELCOM to ICES DOME database and extracted for use in Hazardous substances indicators under the HELCOM Third Holistic Assessment of the Ecosystem Health of the Baltic Sea (HOLAS 3). Attribute specifications and units: series region l3area: HELCOM ID for HELCOM assessment units in scale 3 l4area: HELCOM ID for HELCOM assessment units in scale 4 country station_co: station code station_na: station name station_lo: station long name latitude: latitude longitude: longitude MSTAT WLYTP determinan: determinand determin_1: determinand group filtered basis unit series_typ: series type sym_shape colour n_year_all n_year_fit n_year_pos: n year positive first_year: first year all first_ye_1: first year fit last_year p_nonlinea p_linear p_overall p_linear_t: p linear trend linear_tre: linear trend p_recent_t: p recent trend recent_tre: recent trend detectable: detectable trend mean_last_: mean last year climit_las: climit last year EAC_type EAC_value EAC_diff EAC_achiev EAC_below

This dataset is built from the following Human activities dataset: • Hunting of seals The number of hunted seals (see separate metadata on hunting of seals) were averaged over 2011-2014 separately for grey seals, ringed seals and harbour seals (e.g. number of hunted grey seals / year). In Sweden the numbers of hunted grey seals in 2011 (74) were reported for the whole Swedish territorial waters), but here the numbers were set only to Swedish Gulf of Bothnia, as corresponding numbers were reported there in 2013 (75) and 2014 (65). The area of the reporting unit was used to calculate the number of hunted seals / km2 and the data was converted to 1km x 1km grid. For the Baltic Sea Impact Index, the values were normalized. Normalized value 0.5 was set to the level of quota for hunting of seal species in the Baltic Sea. The following quotas for hunting were used: Grey seal: 2000, Ringed seal: 350, Harbour seal 230.

This dataset describes fishing intensity for OT SPF 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 core indicator evaluates the abundance of selected functional groups of coastal fish in the Baltic Sea. Quantitative thresholds are used to classify core indicators status in "Achieve", "Fail" or "Not assessed". As a rule, good status is achieved when the abundance of piscivores (i.e. fish that feed on other fish) is above a site-specific threshold value, and the abundance of cyprinids or mesopredators (i.e. mid trophic-level fish) is within an acceptable range for the specific site. The status of functional groups of coastal fish in the Baltic Sea has been evaluated by assessing the status of piscivores and cyprinids/mesopredators during the period 2016-2021. This dataset displays the result of the indicator for cyprinids/ mesopredators 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/ Opensea "level_2" = Name of scale 2 HELCOM assessment unit "level_34" = Name of scale 3 HELCOM assessment unit "coast" = Code of scale 3 HELCOM assessment unit "open_sea" = Name of Open sea HELCOM assessment unit "SAUID" = "SAUlevel" = "Indicator" = Name of the indicator "ECID" = Ecosystem component ID "EClevel" = Ecosystem component level "EcosystemC" = Ecosystem Component "EQR" = Ecological Quality Ratios "Status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”)

This core indicator evaluates the status of the marine environment based on concentrations of hexabromocyclododecane (HBCDD) in Baltic Sea fish. Quantitative threshold values are used to classify core indicators status in "Fail", "Achieve" or "Not assessed". The threshold value is an environmental quality standard (EQS), derived at EU level as a substance included on the priority list under Directive 2008/105/EC. 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: "OBJECTID" = Object identification "HELCOM_ID" = Code of the HELCOM scale 4 assessment unit "Country" = country( opensea "Contamination ratio in biota" = Contamination ratio in biota for this substance "Status in biota" = Status of the indicator in biota (“Achieve”, “Fail” or “Not assessed”) "Contamination ratio in sediment" = Contamination ratio in sediment for this substance "Status in sediment" = Status of the indicator in sediment (“Achieve”, “Fail” or “Not assessed”) "Overall Status" = Overall Status of the indicator according to one-out-all-out (“Achieve”, “Fail” or “Not assessed”) "level_2" = Name of assessment unit for the evaluation "type_desc" = Description of the assessment unit "name" = Name of the scale 4 assessment unit

This dataset was collected by HELCOM Secretariat during the HELCOM MORE project and represents monitoring stations in the Baltic Sea. This dataset contains all nutrient stations in the Baltic Sea as reported to the HELCOM MORE project.

Observations of Amphipholis squamata 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. Amphipholis squamata 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.