Marine invertebrates

Marine invertebrates account for over 50 % of the marine species documented in European waters and can include jellyfish, sea anemones, corals, lobsters, crabs, sea stars, shellfish, sponges, squid and octopus. They are found in high abundance throughout European estuaries, coastal bays and deep seas. They are also responsible for delivering a wide range of ecosystem services.

Coherent information on the health of marine invertebrates at a regional scale is very limited. In 2012, EU Member States collectively provided 30 assessments of marine invertebrates under the MSFD. All 30 assessments were categorised as being 'unknown' with respect to environmental status.

Photo: Facies of coralligenous reefs in the Mediterranean Sea.

Source: © OCEANA/Juan Cuetos.

While information is fragmented and sparse, regional assessments suggest that communities of benthic invertebrates remain under severe pressure in Europe’s seas. Member States reporting under the Habitats Directive shows that 85 % of species assessed in the Mediterranean Sea are considered to be have in 'unfavourable’ conservation status, while 25 % of species assessed in the North-east Atlantic Ocean were in 'unfavourable’ conservation status.

Ecosystem Service Case Study:
Some species of marine invertebrates play a key role in structuring seabed habitats. Aggregations of marine invertebrates can build reef communities — from the cold-water coral reefs of the North-east Atlantic Ocean and Mediterranean Sea, to the oyster reefs of the Black Sea, and the mussel beds of the Baltic Sea.

Several pressures influence the marine invertebrates e.g. physical loss and damage, and extraction of fish and shellfish">

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Relevant MSFD Descriptors

Descriptor 1. Biodiversity is maintained

 The quality and occurrence of habitats and the distribution and abundance of species are in line with prevailing physiographic, geographic and climatic conditions.

Descriptor 6. The sea floor integrity ensures functioning of the ecosystem

Sea-floor integrity is at a level that ensures that the structure and functions of the ecosystems are safeguarded and benthic ecosystems, in particular, are not adversely affected.