Summary Estimated observations of the biotope 1650 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Boreal Baltic narrow inletsThe 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 the biotope 1650 according to HELCOM RED LIST assessment experts:Fjords are present in Swedish and Finnish coastal areas of the Bothnian Sea, the Gulf of Finland and the Baltic Proper. The present and past distribution is in areas of crystalline bedrock. The distribution map indicates the area in the 100 x 100 km grid where biotope is known to occur (Naturvårdverket 2011).(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

Summary Estimated observations of the biotope AA.A1H2, AB.A1H2, AA.M1H2 and AB.M1H2 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic photic or aphotic rock and boulders or mixed substrate dominated by erect moss animals (Flustra foliacea) 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 AA.A1H2, AB.A1H2, AA.M1H2 andAB.M1H2according to HELCOM RED LIST assessment experts: The Flustra foliacea dominated biotope commonly occurs from Kattegat to the Mecklenburg Bight andArkona Basin (Kadetrinne). The spatial restriction to the Western Baltic Sea is due to the salinityrequirements of the dominant species Flustra foliacea. The more to the west or north-west this biotopeoccurs the higher the salinities, and in consequence the higher the diversity of inhabiting invertebrateand fish communities. The distribution map indicates the area in the 100 x 100 km grid where biotope isknown to occur, the occurrence of the biotope in the photic zone is restricted to the negative surfaces offor example boulders. AA.A1H2, AB.A1H2, AA.M1H2 and AB.M1H2 have been placed in the Red List classification to the category of Near Threatened (NT) biotopes. (Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

Summary Estimated observations of the biotope AA.E1C4 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic photic shell gravel dominated by kelpThe 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 AA.E1C4according to HELCOM RED LIST assessment experts:The kelp biotopes are common from Kattegat to the Bornholm Basin. The spatial restriction to the Western and Southern Baltic Sea is due to the salinity requirements of the dominant kelp species. The higher the salinities, the higher the diversity of the biotope with respect to accompanying plant species and inhabiting invertebrate and fish communities. The distribution map indicates the areas where the biotope can occur in a 100x100 km grid.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

Summary Estimated observations of the biotope AB.A1J and AB.M1J were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic aphotic rock and boulders or mixed substrates dominated by sponges (Porifera)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.A1J and AB.M1J according to HELCOM RED LIST assessment experts:The sponge biotopes are distributed along the whole Baltic Sea coastline. But as aphotic stony bottoms are scarce in the South-western and Southern Baltic Sea the biotopes are distributed mainly along the Swedish, Danish, Estonian and Finnish coastline or at some offshore reefs. The higher the salinities, the higher the diversity of the sponges and due to the more erect growth also the diversity of the inhabiting invertebrate and fish communities. The distribution map indicates the area in the 100 x 100 km grid where biotopes are known to occur.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

Summary Estimated observations of the biotope AC were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic Sea seasonal sea iceThe 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 AC according to HELCOM RED LIST assessment experts:The distribution of the biotope covers the whole Baltic Sea, but is most common in the northern regions. From a time series of the maximum annual ice extent of sea ice, a declining trend can be detected. During the last two decades all ice winters of the Baltic Sea have been between average and extremely mild. The length of the ice season shows a decreasing trend by 14–44 days in the latest century (Vihma & Haapala 2009). The distribution area in the 100 x 100 km grid where the biotope occurs during an average ice winter when the ice covers approximately 200 000 km2.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

Summary Estimated observations of the biotope AA.H3L6 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic photic muddy sediment dominated by UnionidaeThe 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 AA.H3L6according to HELCOM RED LIST assessment experts:The biotope is known to occur in the eastern parts of the Curonian lagoon in Lithuania. Mussel species of the family Unionidae occur in the whole Baltic Sea region and can occur in densities high enough to be habitat forming in estuaries. The distribution map indicates the area in the 100 x 100 km grid where biotope is known to occur.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

Summary Estimated observations of the biotope AA.M1Q2, AA.H1Q2, AA.I1Q2 and AA.J1Q2 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic photic mixed substrate, mud, coarse sediment or sand dominated by stable aggregations of unattached Fucus spp. (dwarf form) 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 AA.M1Q2, AA.H1Q2, AA.I1Q2 andAA.J1Q2according to HELCOM RED LIST assessment experts:The Fucus spp. dwarf form is known from Sweden, Finland, Germany andEstonia. In all countries plusPoland also unattached Fucus spp. occurswidespread in sheltered areas. But it is not clear for each ofthose countries, ifthese unattached forms are built of the typical F. vesiculosus morphology, thedwarfform or both forms. In Poland the unattached Fucus biotope hasdisappeared from the Puck Lagoon, soit might be difficult to clear this question.Presently this biotope is only known to occur in Sweden andGermany. InGermany it exists only in very few coastal lagoons with low to moderateeutrophicationpressures and salinities of around 7–10 psu (Vitter Bodden,Kubitzer Bodden, Wieker Bodden.Distribution map indicates the area in the 100 x 100 km grid where biotope is known to occur.AA.M1Q2, AA.H1Q2, AA.I1Q2 andAA.J1Q2have been placed in the Red List classification to the category of Critically Endangered (CR) biotopes. (Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

Summary Estimated observations of the biotope AB.H4U1 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes. Description Baltic aphotic muddy sediment dominated by meiofaunaThe 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.H4U1 according to HELCOM RED LIST assessment experts:The biotope is assumed to occur throughout the Baltic Sea both in shallow coastal waters and in the deeper central parts of the sea. The distribution map indicates the area in the 100 x 100 km grid where biotope is reported to occur. The biotope may have a significantly wider distribution.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)

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)

Summary Estimated observations of the biotope AB.J2K7 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 striped venus (Chamelea gallina)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.J2K7 according to HELCOM RED LIST assessment experts:The biotope is known to occur in the northern Kattegat in Swedish and Danish waters. The distribution map indicates the area in the 100 x 100 km grid where biotope is known to occur.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)