MSFD Descriptors 3 and 6

At FishSec we focus on fisheries-related descriptors – Descriptor 3 (impact of fishing on target species) and Descriptor 6 (sea floor integrity). All this to achieve and maintain Good Environmental Status (GES).


Descriptor 3 – Impact of fishing on target species


Descriptor 3 specifically addresses the impact of fishing activities on target species, and the goal of Good Environmental Status (GES) has been reached when: “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”.

The descriptor contains three criteria for assessing the progress towards good environmental status and a number of indicators have been developed under each criterion.


  •  Criterion 3.1 – Level of pressure of the fishing activity
    • Primary indicator: Fishing mortality (F) – for GES, F should be equal to or lower than FMSY, the level capable of producing maximum sustainable yield.
    • Secondary indicator: Ratio between catch and biomass index (catch/biomass ratio)


  • Criterion 3.2 – Reproductive capacity of the stock
    • Primary indicator: Spawning Stock Biomass (SSB) – for GES an SSB that would achieve maximum sustainable yield under fishing mortality equal to FMSY.
    • Secondary indicator: For species with no stock assessment: catch/biomass index and/or biomass index should be used.


  • Criterion 3.3 – Population age and size distribution
    • Indicators under development.


Criteria 3.1 and 3.2 have been finalised. However, we will keep a close eye on the implementation of these criteria as they need to be aligned with the objectives of the Common Fisheries Policy. Criterion 3.3 on population age and size distribution is under development.


Descriptor 6 – Sea floor integrity

Descriptor 6 addresses the sea floor integrity, and the goal of Good Environmental Status has been reached when: “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”.

There are currently two criteria for assessing the progress towards Good Environmental Status (GES) for descriptor 6. However, no indicators have yet been agreed upon. We will follow the work on descriptor 6, which is led by ICES.

  • Criterion 6.1 – Physical damage, having regard to substrate characteristics
  • Criterion 6.2 – Condition of benthic community


Last updated: February 10, 2021