Sparse epibenthic community of Baltic upper circalittoral muddy sediment

This Baltic Sea benthic habitat occurs in the aphotic zone where there is at least 90% coverage of muddy sediment according to the HELCOM HUB classification. Sessile/semi-sessile epibenthic fauna is present but covers less than 10% of the seabed. One associated biotope has been identified: ‘Baltic aphotic muddy sediment dominated by seapens’ (AB.H2T1). This is characterized by conspicuous populations of seapens that usually live scattered over the sea floor but usually cover less than 10% of the muddy surface. It occurs typically from 15 to 200 meters depth in low to moderate energy exposure classes in the highest salinity regions of the Baltic (up to 23 psu in The Sound). These deep water communities are crucially important to the function of the ecosystem. They provide food and shelter for many other species, including commercially important fish.

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 suggested quality parameters including the presence of seapens which are both characterstic of this habitat and vulnerable to the most significant pressures. 

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats