The MSFD describes good environmental status on the basis of eleven distinct components, the descriptors. In assessing the status of the marine environment, the aim is to determine for each descriptor whether it meets one or more of the specified criteria. For that assessment, the MSFD lists a total of 42 primary and secondary criteria. Indicators drawn up for the actual assessment are generally recognised to be feasible and reliable. Experts from a range of countries work on this collaboratively within OSPAR.

The descriptors

D1 Biological diversity (birds, fish, sea mammals)

Biological diversity is maintained. The quality and the occurrence of habitats and the distribution and abundance of species are in line with prevailing physiographic, geographical and climatic conditions.

D2 Non-indigenous species (exotic species)

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

D3 Commercially exploited fish and shellfish

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.

D4 Food webs

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.

D5 Eutrophication

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

D6 Sea-floor integrity (habitats)

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.

D7 Hydrographical conditions

Permanent alteration of hydrographical conditions does not adversely affect marine ecosystems.

D8 Contaminants

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

D9 Contaminants in fish and other seafood for human consumption

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

D10 Litter

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

D11 Introduction of energy, including underwater noise

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