The major objective of this Concerted Action is to review all current knowledge in the field of fish reaction to stimuli, and to provide guidelines for future research in this area in relation to fishing gear selectivity and environmental impact. This review will be given in a document, including a list of references. Several research projects have been started at a national level in various countries, with hardly any interaction at all. Particular work with repulsive sound generation was recently done in Norway and in The Netherlands. Another objective is therefore to enable mobility between research workers on these current activities. The method of work in this concerted action is mainly literature search and reviewing existing papers.