For a long time, fishery-independent surveys were only carried out by scientists. On-going criticism by Dutch fishers on the North Sea beam trawl survey prompted scientists to invite fishers on board. Since 2007, fishers have annually joined the survey as observers. Observing all steps in the survey like rigging the gear, the selection of fishing locations, catch sorting, and data registration enables fishers to provide feedback based on their experience instead of preconceptions. Where possible, their suggestions for improvements are incorporated. Since fishers joined, the nature of discussions about the survey has changed to being constructive. The fishing industry’s trust in survey methods, results, and the scientific crew increased. Scientists gained a better understanding of the importance of the survey for fishers’ livelihoods. The observers also inspired continuous scientific scrutiny of the survey, its setup, and objectives. We describe the process of incorporating fishers in a fishery-independent survey, its benefits, and challenges. We show how perceptions about the survey changed. Allowing stakeholders behind the scenes of a survey and taking their expertise into account contributes to a more reciprocal relation in the co-production of knowledge through collaborative research and increases legitimacy. We propose guidelines for involving stakeholders without compromising the survey’s and professional credibility.