Number of hunted cormorants (Phalacrocorax carbo) per year per county. A total sum and a calculated average (hunted individuals / year) is given for the time period 2011-2015. The data was made available by HELCOM Contracting Parties in response to data request. The data was received from Denmark, Estonia, Finland and Sweden. The activity was declared as not relevant in Germany, Lithuania and Poland. From Latvia and Russia no data was reported. Attribute specification and units: Country: Country County: County SUM: Total number of hunted individuals during 2011 – 2015 AVERAGE: A calculated five (or four) year average of hunted cormorants per year (hunted individuals/year) 2011 – 2015: Number of hunted cormorants in the year in question

The dataset contains the location of fossil fuel energy production facilities derived from the European Pollutant Release and Transfer Register (E-PRTR). E-PRTR cover all HELCOM Contracting Parties except Russia. Attribute specification and units: See E-PRTR code lists at https://www.eionet.europa.eu/schemas/eprtr/listOfValues In the HELCOM data review process, some facility locations appeared to be spatially slightly misplaced, adding up to uncertainty of data products derived from this dataset.

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.

Springtime Chl-a concentration is here used as a proxy for productive surface waters. In the Baltic Sea Impact Index (BSII), 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, years 2003-2011) Chl-a concentration of the surface waters has been used, derived from satellite data (MERIS). Years 2003-2011 have been used, as there is no MERIS data available for years 2012-2016. The data for eastern Baltic Sea is provided by the Finnish Environment Institute (~300m resolution). Outside this high resolution data, MERIS-data downloaded from JRC-database has been used (~4 km resolution, to calculate average of maximum monthly values for April or May for 2003-2011). Both datasets were converted to 1 km x 1 km grid cells.

The amount of collected mussels with dredging. Data is presented from the Danish mussel areas within the HELCOM marine areas. The data was made available by HELCOM Contracting Parties in response to data request. The data was received from Denmark. The activity was declared as not relevant in Estonia, Finland, Latvia, Lithuania, Poland, Russia and Sweden. Germany indicated that data is not available. Attribute specification and units: Nr: Identification number of the mussel area Name: Name of the mussel area BluMusl05 – BluMusl15: Amount of Blue mussel (kg) collected per year ComCockl05 – ComCockl15: Amount of Common Cockle (kg) collected per year Sum_BMus: Total amount of collected Blue mussel in 2005 to 2015 (kg) AVG_BMus: A calculated average of the collected blue mussels in 2005 – 2015 (kg/year) AVG_2_BM: A calculated average of the collected blue mussels in HOLAS2 period 2011 – 2015 (kg/year) Sum_ComC: Total amount of the collected common cockles in 2005 – 2015 (kg) AVG_ComC: a calculated average of the collected common cockles in 2005 – 2015 (kg/year) AVG_2_ComC: A calculated average of the collected common cockles in HOLAS2 period 2011 – 2015 (kg/year) Area: The mussel area within the dredging occurs (km2)

This dataset contains all PCB in biota monitoring station locations, observed matrix, biota matrix and monitored species as reported to HELCOM secretariat by HELCOM Contracting Parties by 2016.

HOLAS II data set on Nuclear power plants discharge water outlets (name, delta temperature of water discharge, heat load) for 2011-2015. The coverage of the data set is full, except for the Leningrad power plant the data is not available.

The occurrence of suitable nursery habitats is crucial for maintaining fish populations (Sundblad et al. 2013). For perch, species distribution modelling studies (Snickars et al. 2010, Bergström et al. 2013, Sundblad et al. 2013) have shown the importance of suitable environmental conditions for reproduction. Due to lack of coherent data on perch spawning and nursery areas across the Baltic Sea countries, environmental variables were used in delineating potential recruitment areas for perch. The distribution area or perch recruitment is delineated by selecting areas where depth < 4 m (For Danish waters < 3 m), logged exposure < 5 (exposure model described in Isæus 2004), and salinity < 10 PSU. The threshold values have been obtained from literature (Snickars et al. 2010, Bergström et al. 2013, Skovrind et al. 2013, Sundblad et al. 2013). Relatively “loose” thresholds have been used, to rather overestimate than underestimate the recruitment area (precautionary approach). Along the Finnish coastline a national model has been used (Kallasvuo et al. 2016), with suitable environments for perch recruitment generalized to 1 km x 1 km grid.

This map presents the Special Protection Areas (SPAs) with reported breeding areas for birds. The spatial data on Special Protection Areas were gathered from the HELCOM contracting parties by Lund University, Sweden. In the data, the countries also indicated whether the sites were designated mainly due to wintering or breeding birds in the area. For Denmark, the information was obtained from standard forms for Natura 2000 sites. For Denmark, the data was updated after review process 20 February 2017. For Germany, the areas that were reported as “NA”(=information not available) were included in both breeding and wintering area maps. Many of the SPAs are both wintering and breeding areas. For the Baltic Sea Impact Index, the data was converted to 1 km x 1km grid cells.

This dataset contains all TBT in sediments monitoring station locationsas reported to HELCOM secretariat by HELCOM Contracting Parties by 2016.