Abundance and catch of sensitive non-commercial fish species in Danish waters

The sea contains a significant part of Danish nature and biodiversity and is also a source of healthy food, nature experiences, renewable energy and raw materials. In order to ensure a healthy and good marine environment for the enjoyment and benefit of future generations as well as maintaining sustainable exploitation, the EU's Marine Strategy Framework Directive from 2008 specifies how we identify significant aspects of the marine environment. The significant aspects are divided into 11 descriptors: 1. Marine biodiversity, 2. Non-indigenous species, 3. Commercial fish and shellfish, 4. Food webs, 5. Eutrophication, 6. Seabed integrity, 7. Hydrographical conditions, 8. Contaminants. 9. Contaminants in seafood, 10. Marine litter and 11. Energy. For each descriptor, a number of criteria have been defined and these are examined by following the development of specific indicators. The indicators are used together with threshold values to assess whether the individual criterion is in good environmental status (on the right side of the threshold value). This report is one of a number of reports DTU Aqua has produced for the Ministry of the Environment for the Danish reporting for the marine strategy directive's descriptors.

Descriptor 1 aims to maintain biodiversity, including that of fish (European Commission, 2008). It is recommended that the list of species is developed through regional cooperation, preferably using regional seas conventions such as OSPAR (European Commission 2021).

The present report provides an update of analyses in support of Marine Strategy Directive descriptor 1. It is an update of the report ”Abundance and catch of sensitive non-commercial species in Danish waters” (Gislason et al., 2017). The methodology for estimating stock abundance from survey catch rate has been improved and data from survey and fisheries have been updated to also include the period 2017-2022.

The aim of the study was to evaluate the temporal development of bycatch (D1C1) and abundance (D1C2) of species sensitive to bottom trawling in the Baltic Sea, Kattegat, Skagerrak and the North Sea.

The report was funded by the Ministry of Environment of Denmark under the ‘Contract for Technical Assistance on the EU Marine Strategy Directive and the Regional Seas Conventions’ (MIM ID no: 355159). The Ministry of Environment has had draft reports for commenting along the way, but the choice of methods and conclusions are the sole responsibility of the authors.