Red List habitat classification > RL - Marine habitats > RLBAL - Baltic > BAL38 Epifaunal communities on Baltic infralittoral muddy sediment

Epifaunal communities on Baltic infralittoral muddy sediment

Quick facts

Red List habitat type code BAL38
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 muddy sediment according to the HELCOM HUB classification. No perennial attached erect group, perennial unattached algae or annual algae cover more than 10% of the substrate but there is at least 10% coverage by sessile/semi-sessile epibenthic polychaetes. This habitat is found in low to moderate energy exposure classes. Three associated biotopes have been identified where the dominant species constitute at least 50% of the biomass of the epibenthic bivalves. These are; ‘Baltic photic muddy sediment dominated by Mytilidae’ (AA.H1E1) ‘Baltic photic muddy sediment dominated by Zebra mussel (Dreissena polymorpha)’ (AA.H1E2); and  ‘Baltic photic muddy sediment dominated by valve snails (Valvata spp.)’ (AA.H1E3).

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. Diversity, abundance and biomass of fauna are potential indicators of quality.

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

Threat status

Synthesis of Red List assessment

The presence of this habitat type in the Baltic is known and although it has been recorded in all the sub-basins quantitative data on the area covered is not available. There is also a lack of quantitative data on current status and changes in extent and quality for the entire Baltic over the last 50 years but expert opinion is that overall it is considered to have been stable.
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 the two associated biotopes AA.H1E1 and AA.H1E2 as Least Concern (A1). A further two biotopes AA.H1E3 and AA.H1V were not evaluated. With no additional data available the current expert opinion is that this habitat should be assessed as 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

  • Biological resource use other than agriculture & forestry
    • Fishing and harvesting aquatic resources
    • Professional active fishing

Habitat restoration potential


Trends in extent

Average current trend in quantity

Stable Stable
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

Beneficial management measures for this habitat include the regulation of fishing activities which damage or disturb seabed communities, including through the estabishment of marine protected areas.

List of conservation and management needs

  • Measures related to marine habitats
    • Restoring marine habitats
  • Measures related to spatial planning
    • Other marine-related measures
  • Measures related to hunting, taking and fishing and species management
    • Regulation/Management of fishery in marine and brackish systems


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 Unknown 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

The full list of characteristic species and genus are available above from the Summary. The species available in the EUNIS database are shown here.
Invertebrates Dreissena polymorpha
Species scientific name English common name Species group
Dreissena polymorpha Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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