Descriptors under the Marine Strategy Framework Directive

Biological diversity 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

Under the Marine Directive, marine biodiversity covers all marine species of birds, mammals, reptiles, fish, and cephalopods found in EU waters. To be in good environmental status, the species’ long-term viability should be ensured. This means looking at the species’ mortality rates and abundance, as well as their distribution and several other demographic criteria, such as body size and age.

Marine biodiversity also covers all types of habitats, both pelagic and benthic. Pelagic habitats, such as habitats in the water column, need to be in a condition where their structure and functions allow species to thrive. For benthic habitats (habitats on the seabed), Member States need to look at the extent of loss and damage to the seabed. This is done under Descriptor 6.

The Birds and Habitats Directives, and the recent Commission proposal for a nature restoration law all contribute to achieving good environmental status for marine biodiversity. They aim to protect and restore several marine habitats, such as seagrass beds or sediment bottoms, that deliver significant benefits, including for climate change mitigation. They also aim to protect and restore the habitats of iconic marine species such as dolphins and porpoises, sharks and seabirds.

• Assessment of state - marine biodiversity
• MSFD competence centre - marine biodiversity

One important measure taken by Member States to protect marine biodiversity is establishing a network of Marine Protected Areas (MPAs). MPAs are designated areas of our ocean, seas and coasts where species and habitats are protected from activities that are damaging or that cause disturbance to the environment. Activities which do not have a significant impact on wildlife may be permitted, but other activities may be restricted in certain areas, or modified to avoid disturbance to wildlife. MPAs designated under the Marine Directive contribute to the target of the Biodiversity Strategy to protect 30% of EU seas, including 10% in strict protection.

See also Nature and biodiversity protection and the Marine action plan.

Non-indigenous species introduced by human activities are at levels that do not adversely alter the ecosystems

Non-indigenous species are species that expanded their typical geographical distribution. They become ‘invasive’ when they can threaten marine biodiversity.

In their marine strategies, Member States primarily must ensure that no new non-indigenous species are introduced into their marine waters through human activity. They could also look at the abundance and spatial distribution of established non-indigenous species, as well as at the proportion of species group or habitats affected by non-indigenous species.

In EU waters, non-indigenous species are mainly introduced and spread through shipping and aquaculture. Climate change also allows sub-tropical species to settle in, for example the Mediterranean Sea.

• Assessment of pressure - non-indigenous species
• MSFD competence centre - non-indigenous species

Populations of all commercially exploited fish and shellfish are within safe biological limits, exhibiting a population age and size distribution that is indicative of a healthy stock

Fisheries management is an exclusive competence of  the EU and is regulated by the Common Fisheries Policy. Overfishing and unsustainable fishing practices can lead to the progressive depletion and eventual collapse of stocks. It can also lead to seabed damage and bycatch of unwanted or sensitive species. More coherence is needed between the Common Fisheries Policy and EU environmental legislation, notably with achieving good environmental status under the Marine Directive.  Fisheries have a wide impact on marine ecosystems, including on its biological diversity, food webs and sea-floor integrity.

The Biodiversity Strategy for 2030 calls to reduce fishing pressure to sustainable levels. This includes reducing damage to the seabed and by-catch of sensitive species. In 2023, the Commission put forward an Action Plan to protect and restore marine ecosystems for sustainable and resilient fisheries.

• Assessment of pressure - commercially exploited fish and shellfish
• MSFD competence centre - fisheries

All elements of the marine food webs, to the extent that they are known, occur at normal abundance and diversity and levels capable of ensuring the long-term abundance of the species and the retention of their full reproductive capacity

Food webs are networks of feeding interactions between animals and their food (or predators and prey). This descriptor looks at the functional aspects of marine food webs. In particular, it looks at the diversity and balance between different groups of species and the characteristics of these. It is closely linked to Descriptors 1 and 6 as marine food webs can only be in a good state if marine species and habitats are healthy and in a good condition.

• Assessment of state - food webs
• MSFD competence centre - food webs

Human-induced eutrophication is minimised, especially adverse effects thereof, such as losses in biodiversity, ecosystem degradation, harmful algae blooms and oxygen deficiency in bottom waters

Eutrophication is a process driven by the enrichment of water by nutrients, usually from agriculture or urban discharges. Dissolved nitrogen and phosphorous are the main inorganic nutrients in the water column responsible for the eutrophication of marine waters. In their marine strategies, EU Member States need to look at the levels of nutrient concentrations, the levels of chlorophyll concentrations, the spatial extent and duration of harmful algal blooms, the transparency of the water column, and the levels of dissolved oxygen in the water. The Zero pollution action plan aims to reduce nutrient losses by 50% by 2030, thereby limiting the occurrence of eutrophication.

• Assessment of pressure - eutrophication
• MSFD competence centre - eutrophication

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

The seabed provides the foundation of a healthy marine environment. Home to millions of marine species and habitats, it generates food and oxygen in our seas and ocean and contributes to regulating the climate. Protecting the seabed is therefore essential to meeting the EU’s Biodiversity, Zero Pollution, Climate Adaptation and Food Security objectives.

Many human activities affect the quality of the seabed, particularly through physical disturbance and pollution. The most harmful are bottom-trawl commercial fishing, which has led to a significant loss of sensitive seabed habitats, and eutrophication, which causes long-lasting widespread damage to seabed habitats. Other potentially harmful activities and pressures include marine mining of sand and gravel, chemical and plastic waste, renewable energy operations, land claim, port operations, and the laying of submarine cables and pipelines.

Threshold values were agreed in 2023. For a seabed habitat to be considered in good environmental status, no more than 25% should be adversely affected by human pressures, including no more than 2% that should be irreversibly lost. See the recommendation on the threshold values and the corresponding press item.

The Action Plan to protect and restore marine ecosystems for sustainable and resilient fisheries commits to setting these threshold values and sets out a vision for a gradual transition to more sustainable fisheries including to reduce damage on the seabed.

• Assessment of state - Physical loss and disturbance of the seabed
• MSFD competence centre - Seafloor integrity

Technical expertise is mainly provided by the Technical Group on seabed habitats and sea-floor integrity.

Permanent alteration of hydrographical conditions does not adversely affect marine ecosystems

Hydrographical conditions typically refer to the physical parameters of seawater: temperature, salinity, depth, currents, waves, and turbidity. They play a crucial role in the dynamics of marine ecosystems and can be altered by human activities, especially in coastal areas. Human activities such as coastal infrastructural development, dredging, sand extraction and desalination can impact on the physical properties of marine waters. They can therefore alter hydrographical conditions. In the marine strategies EU Member States should consider the spatial extent and distribution of hydrographical changes to the seabed and the water column, as well as the spatial extent of the impacts on seabed habitats.

• Assessment of pressure - Hydrographical conditions
• MSFD competence centre - Hydrographical conditions

Concentrations of contaminants are at levels not giving rise to pollution effects

Pollution from contaminants ends up in the sea. Contaminants are toxic and persistent chemical substances that degrade the marine environment and can cause serious damage. They mainly come from agricultural pesticides, paint coating on ships, pharmaceutical, industry and urban waste, including heavy metals. Implementing the measures under the various EU and global laws have led to a reduction of concentrations of these pollutants.

However these substances are very persistent and are therefore still present in the marine environment. In their marine strategies, Member States need ensure that the concentrations of contaminants do not exceed certain threshold values and, where appropriate, look at health of species and the condition of habitats. They also must address significant pollution events, such as oil spills.

The Zero pollution action plan aims to reduce and chemical pesticides by 50% by 2030.

• Assessment of pressure - contamination
• MSFD competence centre - contaminants

Contaminants in fish and other seafood for human consumption do not exceed levels established by Union legislation or other relevant standards

Pollutants in the sea ultimately contaminate seafood intended for human consumption. It is therefore important for both environmental and human health reasons to ensure that the levels of contaminants in the marine environment remain low and within safe limits. In their marine strategies Member States need to ensure that the level of contaminants in edible tissues of seafood does not exceed certain levels.

• Assessment of pressure - contamination
• MSFD competence centre - marine biodiversity

Properties and quantities of marine litter do not cause harm to the coastal and marine environment

Every year millions of tonnes of litter end up in the oceans creating environmental, economic and health problems. This is caused by several reasons, including poor waste and wastewater management, lack of infrastructure and public awareness about the consequences of their actions.

The solution is to tackle the problem at source. In their marine strategies, EU Member States need to consider the composition, amount and spatial distribution of litter and microlitter on the coastline, in the water column, and on the seabed. They may also look at the amount of litter ingested by marine animals as well as the number of species that are adversely affected by litter, such as due to entanglement or mortality.

Threshold values need to be set through EU cooperation. In 2020 experts agreed that the amount of litter on the coastline should not exceed 20 items for every 100 metres of coastline. Other threshold values are being developed as required by the ‘GES’ Decision. See the recommendation on the threshold values and the corresponding press item.

The Zero pollution action plan aims to improve water quality by reducing waste, plastic litter at sea (by 50%) and microplastics released into the environment (by 30%). Most of the proposed Actions in the Strategy for Plastics are directly or indirectly related to marine litter, including the Directive on Single Use Plastics and fishing gear. The Port Reception Facilities Directive, address marine litter from ships, including from fishing vessels.

• Assessment of pressure - marine litter
• MSFD competence centre - marine litter

Technical expertise is mainly provided by the Technical Group on Litter. Additional work is accessible through this dedicated page.

Introduction of energy, including underwater noise, is at levels that do not adversely affect the marine environment

Energy use, such as heating and electricity systems, artificial lighting, noise, electromagnetic radiations, radio waves or vibrations, can also be a pressure on the marine environment. So far, policy development and marine strategies have largely focused their efforts on underwater noise. The effects are complex and not yet fully understood. Underwater noise due to human activities at sea can harm marine biodiversity, leading for example to hearing impairment and behavioural disturbances. The   ‘GES’ Decision requires Member States to look at the spatial distribution, temporal extent, and levels of anthropogenic impulsive (for example from oil and gas exploration and extraction) and continuous (such as from shipping) underwater noise.

In 2022, recommendations on the threshold values for underwater noise were agreed.

Continuous underwater noise: 20 % of the target species habitat having noise levels above the Level of Onset of Biologically Adverse Effects (LOBE) cannot be exceeded in any month of the assessment year, in agreement with the conservation objective of 80 % of the carrying capacity/habitat size.

Impulsive noise: For short-term exposure (one day, i.e., daily exposure), the maximum proportion of an assessment/habitat area utilised by a species of interest that is accepted to be exposed to impulsive noise levels higher than the LOBE over one day is 20 % or lower (≤ 20 %).

For long-term exposure (one year), the average exposure is calculated. The maximum proportion of an assessment/habitat area utilised by a species of interest that is accepted to be exposed to impulsive noise levels higher than LOBE, over one year on average, is 10 % or lower (≤ 10 %).

• Assessment of pressure - Underwater noise and other forms of energy input
• MSFD competence centre - energy and noise

Technical expertise is mainly provided by the Technical Group on underwater noise.

Climate change is not a specific descriptor under the Marine Directive, however its impacts on hydrographical conditions are fully covered by Descriptor 7. Also, the Directive’s holistic approach to marine strategies provide a good framework to monitor other climate change impacts, explore climate change mitigation measures, in particular nature-based solutions, and apply the ecosystem-based approach to climate change adaptation in the marine environment. This however has not been used to its full potential when implementing the Directive.

Climate change is of concern for all marine regions. The associated oceanographic changes can have dramatic consequences on marine biodiversity and ecosystem resilience. All the marine ecosystems assessed in the report by the Intergovernmental Panel on Climate Change (IPCC) on Ocean and Cryosphere in a Changing Climate have an elevated risk of being affected by climate trends. The policy link between the Marine Directive and climate change is also being examined in the context of the review of the Marine Directive.

• Assessment of pressure - Climate change