Red List habitat classification > RL - Marine habitats > RLBAL - Baltic > BAL17 Unvegetated epifaunal communities on Baltic infralittoral coarse sediment

Unvegetated epifaunal communities on Baltic infralittoral coarse sediment

Quick facts

Red List habitat type code BAL17
Threat status
Europe Least Concern
EU Least Concern
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is coarse sediment according to the HELCOM HUB classification.  Three associated biotopes have been identified. ‘Baltic photic coarse sediment dominated by Mytilidae’ (AA.I1E1) is encountered in salinities higher than 5 psu, and is identified by a large representation of Mytilidae, at least 50% of the biomass among the epibenthic bivalves, and covering at least 10% of the seabed. The other two biotopes are 'Baltic photic coarse sediment characterized by mixed epibenthic macrocommunity' (AA.I1V) and 'Baltic photic coarse sediment dominated by microphytobenthic organisms and grazing snails' (AA.12W) where the benthic organisms or grazing snails (e.g. Hydrobiidae, Theodoxus spp, Bithynia spp, Radix spp) constitute at least 50% of the biomass or volume.

Indicators of quality:

Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. 

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

This habitat is present in all sub-basins of the Baltic Sea and therefore the EOO exceeds 50,000km2. There is a lack of quantitative data on overall trends in quantity or quality but expert opinion is that the habitat is considered to be stable. Changes may occur in the future as a result of variations in salinity but the scale of any likely effect is unknown.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed two relevant Baltic biotopes (AA.I1E1 and AA.I2W) as Least Concern (A1). AA.I1V was not evaluated. With no additional information on changes in extent or quality of this habitat and its relatively widespread distribution, the current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.
Red List Category Red List Criteria
Least Concern -
Red List Category Red List Criteria
Least Concern -

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • No threats or pressures
    • No threats or pressures

Habitat restoration potential


Trends in extent

Average current trend in quantity

Stable Stable
EU28 EU28+

Trends in quality

Average current trend in quality

Stable Stable
EU28 EU28+

Conservation and management needs

No specific conservation and management measures have been identified for this habitat type.

List of conservation and management needs

  • No measures
    • No measure known / impossible to carry out specific measures


For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.

Geographic occurrence and trends

Seas Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Baltic Proper Present Unknown Stable Stable
Belt Sea
Gulf of Bothnia
Gulf of Finland
Gulf of Riga
The Sound

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 >50,000 Unknown Unknown This habitat is present in all the Baltic sub-basins however there is insufficient information for accurate calculation of EOO and AOO.
EU28+ Unknown Unknown This habitat is present in all the Baltic sub-basins however there is insufficient information for accurate calculation of EOO and AOO.
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).

Characteristic species

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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