The pressure layer represents biological pressure caused by introduction of non-indigenous species. The data is obtained from core indicator Trend in the arrival of new non-indigenous species (BSEP 129b: http://www.helcom.fi/Lists/Publications/BSEP129B.pdf). For the Baltic Sea Impact Index, the layer was normalized.

This online application serves as a joint regional tool to identify low risk routes for IMO Ballast Water Convention exemptions (A-4) for HELCOM and OSPAR marine areas. Data are provided following the port survey protocol described in the HELCOM/OSPAR Joint Harmonised Procedure. https://helcom.fi/wp-content/uploads/2021/01/HELCOM-OSPAR-Joint-Harmonized-Procedure-for-BWMC-A-4-exemptions_2020.pdf The database contains environmental data recorded from OSPAR and HELCOM ports as well as species observations and applies World Register of Marine Species (WoRMS) taxonomy. The data model used is based on Darwin Core format, with required extensions added. The database can be searched, viewed and downloaded using a specific web application. The whole database can be downloaded as a zipped ESRI File geodatabase. The HELCOM/OSPAR Ballast Water Exemptions Decision Support Tool was further developed in the EU INTERREG Baltic Sea Region project COMPLETE, following work developed with funding through the HELCOM ALIENS 2 and 3 and BALSAM projects by the HELCOM Secretariat and Germany (BSH/Brockmann consult). The data contained in the database are resulting from various sources and contains also historical legacy data from old projects. Main sources are listed below: - HELCOM and OSPAR countries national projects - HELCOM ALIENS 2 - HELCOM ALIENS 3 - HELCOM BALSAM

The layer presents the cumulative negative impacts on marine biodiversity caused by alien species in the Baltic Sea. The layer is based on the Cumulative IMPact of ALien species (CIMPAL) index, developed by Katsanevakis et al. (2016). The original methodology was applied for the Baltic Sea similarly as Korpinen et al. (2019) applied it for the EU waters in their report Multiple pressures and their combined effects in Europe’s seas. The list of species and habitats together with the sensitivity scores are originating from this study and listed in the linage section of this metadata. The index follows a conservative additive model for calculating the cumulative negative impacts of invasive alien species (IAS), based on magnitude of impact and the related strength of evidence following an uncertainty averse strategy. Cumulative impacts of IAS were estimated on the basis of the distributions of invasive species and ecosystems, and both the reported magnitude of ecological impacts and the strength of such evidence. 29 invasive species and 12 habitats were used for the layer, detailed information on the species, habitats and sensitivity scores used in the assessment are given in the lineage section. The information on species and habitats were aggregated to 10x10 km grid, based on their occurrence within each grid cell. Calculation of the index was done with the HELCOM SPIA tool, and the result were converted to the 1x1km SPIA grid. The layer was normalized to be used in the assessment.

The aim of HELCOM Biodiversity database is to collate all available species observation data made available by HELCOM Contracting Parties from a single entry point. The database contains +1M species observations and applies World Register of Marine Species (WoRMS) taxonomy. The data model used is based on Darwin Core format, with required extensions added. Species observations are mostly pointwise observations, but also gridded observations are included for some species. The database can be searched, viewed and downloaded using a specific web application. The whole database can be downloaded as a zipped ESRI File geodatabase. Disclaimer: Data in the database is stemming from various sources. While there has been considerable quality assurance efforts, the accuracy of data can not be quaranteed.

Observations of Fucus vesiculosus 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. Fucus serratus 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: 0 = no observations 1 = present before year 1995 or in 1995 2 = present after year 1995 3 = present before and after year 1995