This paper discusses the potential value of catch documentation schemes (CDS) in deep-sea fisheries (DSF), and the implementation modalities that have to be envisaged, to ensure the effectiveness of this trade-based tool to combat illegal, unreported and unregulated (IUU) fishing. The paper argues that CDS are indeed capable of directly addressing a number of IUU fishing practices known to occur in DSF, and that their adoption would improve compliance with fisheries management requirements. Key infringements that may be directly detected and addressed through a CDS include – but are not limited to – violations of closed areas harbouring protected vulnerable marine ecosystems (VMEs) in the deep ocean, and quota overfishing. The paper also establishes the notion that partial coverage of given species through a CDS at the level of individual RFMOs is incongruous from a trade monitoring and control perspective, and that CDS should be considered as either/or propositions with regard to species coverage. With most DSF species having broad distributions straddling many RFMOs, the implementation modality that avails itself as the most suitable option, enabling the operation of an effective CDS, is that of a centrally operated electronic CDS platform – called a super-CDS – shared by a plurality of institutional and state players
