Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem (WGEXT; outputs from 2022 meeting)

The Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem (WGEXT) develops the understanding to ensure that marine sand and gravel extraction is sustainably managed and in order to adopt mitigative measures.

WGEXT has been monitoring the rate of marine sediment extraction in the North Atlantic, including the Baltic and North Sea for almost 40 years. The group is developing a database and associated ‘WGEXT Dredging Dashboard’ to document current extractions by end use, leased areas and, where possible, the footprint of dredged areas, all in the perspective of the long-term trends since 1993. The Dashboard can be found at https://rconnect.cefas.co.uk/content/26. Although not all member countries provide annual data, the WGEXT inventories are representative of activity in the ICES region. Volumes extracted have shown a spectacular increase from a few hundred thousand m³ per year in the early 1970s to millions m³ in the 1990s and tens of millions m³ in recent years. Over the last three decades, the demand for sand for beach nourishment and shore protection has increased substantially. Sand is now recognized as a critical, strategic resource.

Areas actually dredged in any year are much smaller than the areas licensed. The active areas and even the intensity of dredging can be determined either by Electronic Monitoring System (EMS) or Automatic Identification System (AIS) to define a dredging footprint. While still in the developmental stage, EMS data is suitable for training AIS algorithms to expand regional coverage.

The competition for access to marine resources, including space, continues to grow. Accommodation for marine sand not only impacts with fisheries and habitat concerns, but also the space needed to accommodate offshore windfarm and cable routes. Infrastructure of this nature has the potential to ‘sterilise’ areas of the sea floor such that the sediment resources are not available for exploitation.