The project WAKO wants to give a first attempt to map the current knowledge and the knowledge gaps on the effects of trammel net and beam trawl fisheries for the Belgian part of the North Sea. The project focuses on three ecosystem components, i.e. benthic invertebrates, sea birds and marine mammals. The aim of this project consists of three phases: (1) compilation and analysis of existing, experimental data for the Belgian part of the North Sea on the effects of trammel net and beam trawl fisheries; (2) current knowledge on the impact of beam trawl and trammel/gill net fisheries, based on literature review and (3) evaluation of the direct effects of beam trawl and trammel/gill net fisheries on three ecosystem components, knowledge gaps and investigation of an appropriate methodology to evaluate the environmental impact of fishing gears.WAKO indicates that direct, short-term effects of trammel net and beam trawl fisheries are clearly directed to different ecosystem components. Similarities between analogous, scientific studies allow a first evaluation of the effects, but quantitative data (on both biological impact data and data related to fishing effort and distribution) are so far insufficient to allow the development of a decision support tool for environmental and fisheries management.