The Working Group on the effects of extraction of marine sediments on the marine ecosystem (WGEXT) met at Stony Brook University, Manhattan, New York, USA, between 14 and 17 April, 2009. The meeting was chaired by Mr Gerry Sutton. Thir-teen participants from eight ICES Member Countries were able to supply figures for marine aggregate extraction. Four other ICES countries participated by correspon-dence and the figures likely account for the majority of the total marine aggregate extracted in 2008 The objective of WGEXT is provide a summary of data on marine sediment extraction, marine resource and habitat mapping, changes to the legal re-gime, and research projects relevant to the assessment of environmental effects. Rep-resentatives of the member countries provided reports for each of the WGEXT terms of reference and reports were also solicited by correspondence from countries not represented in person. A discussion of the reports is provided in the text and details given in the annexes. ICES WGEXT collated available information for member coun-tries on the annual amounts of sand and gravel extraction ICES WGEXT also re-viewed and reported programmes of national mapping of the seabed which include not only geological mapping, but also specific efforts to map benthic habitats. WGEXT reviewed and evaluated the use of ICES Extraction guidelines across mem-ber countries. In addition, WGEXT reviewed the output of other, relevant ICES work-ing groups and relevant international effort in this sector. Explicit attention was given to the use of Electronic Monitoring Systems and to possible revisions to the 2003 guideline for Marine Sediment extraction. The majority of the extraction takes place from the North Sea and the English Chan-nel, with additional extractions in the North Atlantic primarily by France. Activity in the Netherlands and the United Kingdom accounted for 75% of the total extractions. The main use for marine aggregates continues to be for construction (41%) and beach recharge (39%), with additional volumes used primarily for land reclamation in the Netherlands. Less than 15% of marine aggregate is exported. Although use of the guidelines continues to be quite variable, most members do refer to the guidelines in national regulatory frameworks, and some make more explicit reference to some or all the provisions in statutory regulations. Few changes to legislative and administra-tive frameworks were also reviewed and reported. Reports were reviewed from thirteen (of 21) member countries. Although eight member countries did not provide reports, the available data are thought to provide a representative assessment of the overall total of material extracted from the member states. ICES WGEXT agreed to meet again in April 2010 in Sweden. ICES WGEXT agreed to meet again in Sweden, from 20–23 April 2010 as guests of Professor. Ingemar Cato. Geological Survey of Sweden, University of Gothenburg