Closing facilities or closing debates? Knowledge politics in sustainable aquaculture governance

In 2018, Tromsø municipal council adopted a resolution to only allow aquaculture operations in closed facilities that separate fish farming from ocean water. This is a radical proposal in the context of Norwegian aquaculture governance due to tensions between the industry’s key role in the economy and growing environmental concerns. The resolution sparked a heated public debate that resulted in an amendment in 2019, defining closed facilities as any facility with zero salmon lice, escapes, and pollution. In this article, we examine the discursive journey from the original resolution to the amended resolution. By mapping actors, issues, and arguments, we explore the controversy through the lens of knowledge politics to show actors’ claims to epistemic authority, including how they use, contest, and define authoritative knowledge. The analysis reveals three tendencies that contributed to the amendment of the resolution: 1) a polarisation of the debate in which knowledge also came to be seen as polarised, 2) a rhetorical shift leading to closed facilities becoming near synonymous with land-based facilities, 3) attempts to attack the credibility of publicly elected representatives. In the end, pens did not become closed, but the debate was. Surprisingly however, the debate did not become depoliticised, despite tendencies to turn the controversy into a technical issue requiring specialised expertise to comment on. Instead, the polarisation was exacerbated by attempts to introduce more knowledge and expertise. We argue that this adds important nuances to scholarly assumptions about the role of expertise in the depoliticisation literature.