This project is directly relevant to the conservation of harbour porpoises and thus to the objectives of ASCOBANS. Pingers have proven an effective tool to mitigate bycatch, but here we aim to assess potential side-effect of pingers (habituation and habitat exclusion), which will determine whether pingers can actually be implemented in areas of high porpoise density such as SACs. This project is urgent not only in relation to the management of nationally appointed SACs in the EC, but also to the general protection of harbour porpoises elsewhere. The project will significantly add to information requested under “Conservation issues “points 1 and 3 in the ASCOBANS Draft Triennial Work Plan (2010-2012), with point 1 addressing bycatch of porpoises and the need for Parties and Range States to provide information “on the implementation, efficacy and impacts of measures introduced to reduce bycatch and point 3 requesting review of the extent of negative effects of sound on small cetaceans. The proposed study is also included in one of the recommendations in the draft Conservation Plan for Western Baltic, Belt Sea and Kattegat. Furthermore, the issue of pinger side-effects have been discussed on numerous occasions in meetings organised under the auspices of ASCOBANS e.g. the Jastarnia Group, the North Sea group and the AC meetings.