Catch documentation schemes (CDS) have been a topic of debate for more than 16 years, and continue to mean different things to different people.

This paper clarifies the nature of CDS and what they can achieve, and identifies the factors to be considered in the design of such schemes as a management and MCS tool in tuna fisheries. This paper does not review existing schemes. Existing CDS have been analysed to varying degrees – for example by Agnew, 2000; Clarke, 2010; Tsamenyi et al., 2010; Palin et al., 2013; Clarke and Hosch, 2013; Knucky and Koopman, 2014; DG MARE, 2014. This paper makes reference to existing CDS to illustrate points which are useful to the achievement of the paper’s objectives.
The paper sets out to clarify and to discuss the following:
• what is a CDS, and what does it intend to achieve?
• how does it work – what is the basic concept and design?
• which key functions does a CDS need to meet its objective?
• what factors must be carefully considered when designing a CDS?
• what would a model CMM and model certificates look like?

FAO TP 596 Tuna