The International Bottom Trawl Working Group (IBTSWG) met in Lisbon, Portugal, from 8-12 April 2013. Altogether 22 participants from 12 countries took part in the meeting, most of who are involved in designing and conducting bottom trawl surveys. One participant represented the ICES Data Centre. Terms of reference (a) to (f) have been met and progress is described in the relevant sections of the report (see table of contents). Work on ToR (g), the submission of updated manuals to SISP, is planned for early summer of 2013 in order to allow WKESST to review the manuals during their meeting in September 2013. Major developments, achievements, agreed actions of the group itself and recommendations from the 2013 meeting are summarized below: Section 5 (on ToR a) presents individual annual surveys coordinated by IBTSWG using a standard reporting format, containing the individual survey’s coverage as well as aggregated results, including tables presenting samples obtained for the target species, or additional samples collected under the DCF (Data Collection Framework). For the areas of the North Sea and the Northeastern Atlantic, combined maps of species distributions have been produced (see Section 5.4 and Annex 6). Section 6 (on ToR b) documents ongoing work on the improvement of survey manuals. Section 7 (on ToR c) provides a review of the outcome of the workshop WKDATR, initiated by IBTSWG 2012 and held in January of 2013, in order to overcome observed issues in data handling in DATRAS. Progress is being summarized, and an action list for IBTSWG has been agreed to follow up (included in the overall Action List in Annex 4). Section 8 (on ToR d) reviews the conditions for producing from survey data indices based on swept-area, instead of haul time. This work build upon work of WGISDAA, and will be continued over the next two years, in order to create the conditions for such indices and start initial comparisons with selected datasets. Section 9 (on ToR e) presents the first year’s work toward compile the status quo, and proposing ways forward in standardization on the different materials and specifications of the GOVs and gear currently used by the IBTS participants. A table has been created which all members are asked to fill in by December 2013, to collate the details of the currently applied rigging routines. In a Working Document (WD1, Annex 7), the effect of variable sweep length has been evaluated with a GOV using groundgear type D. Section 10 (on ToR f) presents two tables created in collaboration with WGBEAM, answering an OSPAR request on maximizing the use of available sources of data for monitoring of biodiversity.