How to transform systems, what is the role of actors, agency and leverage and how can we stimulate transformations towards sustainability? Negative impacts on ocean health from human activities, combined with a growing understanding of the human relation with, and dependency upon, the ocean have all contributed to a rapidly growing discourse on sustainable seafood. Calls for transformations are now common, and actors in science, among policy makers and by corporations involved in seafood production and distribution actively seek to communicate that they are part of the solution to challenges facing the ocean and the planet, including through voluntary initiatives. In parallel have advances in monitoring technologies generated vast and, in some cases, real-time data sets about vessels at sea, enabling new understanding and scrutiny of such claims and activities by researchers, businesses and civil society organizations. This thesis applies process tracing and descriptive quantitative data analysis to investigate how transformation can happen, and the conditions that enable such processes. First, focus is placed on the inner mechanics and causal actions of voluntary initiatives carried out in the Barents Sea between 1998- 2019 to address responses to illegal fishing and the expansion of bottom trawling into previously unfished waters (Paper I). Second, by collecting and synthesizing new data investigating transshipment, a practice in fisheries which has been repeatedly described as problematic and opaque despite an increasing availability of data, presenting promising entry points for transformation are identified (Paper II). Combined the findings presented in this thesis illustrate a unique perspective of corporate actors engaged in fisheries and can be used by anyone who seeks to interact and engage with the seafood industry. In particular, these cases highlight that in order to change practices, it’s essential to understand actors within the system, how they relate to each other, and how to leverage those relations. While the ocean is no longer entirely "out of sight, out of mind," numerous challenges to achieve sustainable fisheries persist. This thesis, through empirical cases drawn from the seafood industry, transcends disciplinary boundaries, aiming not only to contribute to the academic discourse, but also to address the practical challenges of achieving sustainable fisheries governance in the face of complex challenges. The thesis identifies a number of potential and previously unknown leverage points for system change, while also illustrating how diversity has historically stimulated resilience that support transformative change at the international level.