Communities of Mediterranean lower circalittoral (shelf-edge) detritic bottoms or open-sea detritic bottoms
_detritic_bottoms_or_open-sea_detritic_bottoms_(1).jpg "European Red List of Habitats 2016")
_detritic_bottoms_or_open-sea_detritic_bottoms_(2).jpg "European Red List of Habitats 2016")
Quick facts
| Red List habitat type | code MEDA5.47 |
|---|---|
| Threat status | |
| Europe | Data Deficient |
| EU | Data Deficient |
| Relation to |
|
| Source | European Red List habitat factsheet |
| European Red List of habitats reports | |
| European Red List of habitats (Excel table) |
Summary
This habitat develops on a mixture of gravel sediments, sand and mud. The fine part of the mix appears in a greater proportion than in the sediments that support the coastal detritic biocenosis. The gravel, mainly organogenic, is largely formed by calcareous debris of quaternary thanatocenoses. The open-water detritic bottoms normally belong to the lower circalittoral and constitute the deepest layer of the circalittoral zone on soft bottoms. These communities are present in detritic bottoms with abundance of dead shells, bryozoans and coral skeletons. This habitat hosts a biocenosis of great diversity and abundance. The high production of plankton at the shelf break makes it an important feeding ground for large shoals of fish and cetaceans. Some facies of the edge of the platform, such as the one made by the crinoid Leptometra phalangium, increase the structural complexity of the habitat enhancing the abundance and species richness. They also host a high abundance of spawners of commercially important species, e.g. Red Mullet (Mullus barbatus), Hake (Merluccius merluccius), Blue Whiting (Micromesistius poutassou) and Trisopterus minutus capelanus. Thus, the conservation of shelf-edge habitat is also important with a view to reducing the fish mortality in the sensitive phases (recruitment, spawning, postspawning) of the life cycle of demersal fish species.
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.
Threat status
Synthesis of Red List assessment
| EU | |
| Red List Category | Red List Criteria |
| Data Deficient | - |
| Europe | |
| Red List Category | Red List Criteria |
| Data Deficient | - |
Confidence in the assessment
Pressures and threats
- Biological resource use other than agriculture & forestry
- Professional active fishing
- Benthic or demersal trawling
- Benthic dredging
Habitat restoration potential
Trends in extent |
|
Average current trend in quantity |
|
Unknown  |
Unknown |
| EU28 | EU28+ |
Trends in quality |
|
Average current trend in quality |
|
Decreasing  |
Decreasing |
| EU28 | EU28+ |
Conservation and management needs
Designation of Marine Protected Areas (MPA) and Fisheries Restricted Areas (FRAs) in sites where this habitat occurs, particularly where Leptometra phalangium, Neolampas rostellata and Ophiacantha setosa occur, should be established to create a representative network of Mediterranean MPAs. This will also help to control the fishing effort, especially the establishment of closed areas over part of the distribution of this habitat to protect juvenile and spawning fish and fragile benthic communities.
List of conservation and management needs
- Measures related to spatial planning
- Establish protected areas/sites
- Legal protection of habitats and species
- Measures related to hunting, taking and fishing and species management
- Regulation/Management of fishery in marine and brackish systems
- Measures related to special resouce use
- Regulating/Managing exploitation of natural resources on sea
Distribution
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) |
|---|---|---|---|---|
| Adriatic Sea | Present | Unknown | Decreasing | Unknown |
| Aegian-Levantine Sea | ||||
| Ionian Sea and the Central Mediterranean Sea | ||||
| Western Mediterranean Sea |
Extent of Occurrence, Area of Occupancy and habitat area
| Extent of Occurrence (EOO) (Km2) | Area of Occupancy (AOO) | Current estimated Total Area | Comment | |
|---|---|---|---|---|
| EU28 | 1,038,660 | 1,242 | Unknown | EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status. |
| EU28+ | >1,242 | Unknown | EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status. |
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
