Friend of the Sea’s criteria follow the FAO Guidelines for ecolabelling and include traceability. FOS chain of custody standard is designed to ensure certified seafood can be traced back to the sustainable source. The requirements state that a program must be in place to prevent product mixing with uncertified sources, that origin and fishing method are identified, and that the fishery uses all available interconnected traceability methods for larger boats as part of a marking system and non-forgeable document tracing system. Furthermore, one test at the beginning and end of a batch of finished product must be conducted, inspecting relevant documents for conformity to the standard. Audits are run onsite by independent certification bodies.