One of the challenges of coastal governance is to connect a variety of knowledge systems. The purpose of this paper is to show how a coastal governance practice can emerge and stabilize, such that actors with disparate knowledge systems collaborate towards the shared goal of sustainable resource use. We analyze this stabilization in terms of the coproduction of knowledge and policy. This paper is empirically informed by a case study on the transition towards a sustainable mussel fishery in the Dutch Wadden Sea. Our study illuminates the difficulties of underpinning a coastal governance practice with scientific research, since the relevance, quality, and results of research are interpreted differently from the perspectives of resource users and conservationists. Furthermore, our analysis shows that such a governance practice can stabilize through a combination of rule negotiation, legal, societal, and political pressure, along with collaborative knowledge creation. Based on our analysis, we identify several aspects of collaborative knowledge creation that enable the formation of a shared knowledge base for governance in a context of controversy. These include the shared ownership of research, knowledge creation as an integral part of governance, a focus on data and basic facts, and the close involvement of trusted experts. The findings of this study suggest that a controversial setting strongly structures knowledge creation, while at the same time knowledge creation enables coastal governance as a way of dealing with conflicts.