PASSIVE NATURE RESTORATION OF MARINE HABITATS (PReMaH)

In the recent Marine Strategy Framework Directive assessment of the Danish seas in 2023, several seabed habitats were adversely affected to an extent of ”not in Good Environmental Status” (i.e., subGES). In the Skagerrak, the deeper muddy habitats were considered in subGES due to mobile bottom contacting gears (i.e., bottom trawling). In the Kattegat, some habitats were in subGES due to both bottom trawling and hypoxia, while in the western Baltic Sea several habitats were in subGES due to hypoxia. 

Due to the known effects of bottom trawling fishery on the seabed, an initiative was included in the political agreement “En ny kurs for dansk fiskeri” of the 2 July 2025 to reduce the use of bottom-trawling gear in areas in the internal Danish waters, and thereby also promote more environmentally friendly fishing.

The aim of the PReMaH project is to investigate ecosystem and climate effects of fishery closure of bottom trawling in these new Marine Protected Areas (MPAs) in the Kattegat and the Belt Seas. The project investigations will focus on quantifying changes and potential recovery of ecosystem functioning and services in the new designated areas closed to bottom trawling and adjacent areas. 

The PReMaH project has a specific focus on four core elements:

• Physical seabed habitats, environment and climate
  Closure to fuel-intensive bottom trawling is expected to facilitate a shift to low fuel consumption and alleviate physical impacts within the designated areas, but documentation of the resulting climate footprint changes of fishery is limited.

• Benthic invertebrate and fish biodiversity and source-sink functions
  Natural recovery of seabed habitats and communities depends on degradation state of biodiversity and recruitment potential, however effects of bottom trawling closures on processes supporting passive habitat restoration are complex and require quantification.

• Food web interactions between benthic invertebrates, fish and mammals
  Effects of bottom trawling go beyond the impacts on target species, yet effects on other components of the benthic ecosystem and their interactions are understudied.

• Ecosystem functioning and services
  Valuation of ecosystem health, biodiversity and other ecosystem services has become a central approach to evaluate efficiency of policy interventions and facilitate ecosystem-based management that considers diverse impacts on nature and socio-economic and cultural effects on local people and society as a whole.

Duration
PReMaH is a long-term research project running from 2025-2036.

Structure
The project is structured in seven work packages – see diagram.

Field trials
The experimental design and analytical framework are comparable to a BACI design, where different elements of WP1-4 will be quantified both spatially and temporally before (B) and after (A) the new MPA closured to bottom contacting fishing gear, both outside MPAs (C, control) and within MPAs (I, impact).

The baseline field trials are conducted in 2026 and will be followed by additional field trials in some of the consecutive years during the project period.

Reporting
Project reporting will take place every third year.

Technical University of Denmark (DTU)
National Institute of Aquatic Resources (DTU Aqua) 
Website: dtu.dk

Geological Survey of Denmark and Greenland (GEUS)
Website: geus.dk

University of Copenhagen (KU)
The Department of Food and Resource Economics (KU-IFRO) 
Department of Biology (KU-BIO)
Website: ku.dk

University of Southern Denmark (SDU)
Department of Biology (SDU-BIO)
The Marine Biological Research Centre
Website: sdu.dk

The PReMaH project is funded under 'Green Programme: Green transition of fisheries and aquaculture' focus area 1: The effects of a ban of use of bottom contacting fishing gear (GROFA-24-0010).

The programme is administered by the Danish Veterinary, Food, Agriculture and Fisheries Agency.