Summary

Estimated observations of the biotope AB.H3L5 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 Astarte spp.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.H3L5 according to HELCOM RED LIST assessment experts:The Astarte borealis is found in the Western parts of the Baltic Sea, it’s most eastern populations appearing in the Bornholm Basin. Dense populations of the Astarte elliptica were common on the muddy sediments of the Kiel Bay at depths greater than 15 meters (Trutschler & Samtleben 1988). The distribution map indicates the area in the 100 x 100 km grid where environmental conditions required by the biotope are known to occur and the biotope is estimated to occur in the grid cells.(Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)