Marin Trust
https://www.marin-trust.com/
Independent third-party audit and certification programme, allowing producers to demonstrate that marine ingredients are responsibly sourced & produced. Chain of Custody certifification included.

Chain of custody models and definitions
https://www.isealalliance.org/sites/default/files/resource/2017-11/ISEAL_Chain_of_Custody_Models_Guidance_September_2016.pdf
The Chain of Custody (CoC) System (CoC Standard and supporting assurance system) is one of the key elements of most sustainability standards systems.

The objective of the CoC System is to validate claims made about the product, process, business or service covered by the sustainability standard. This is achieved by defining a set of requirements and measures that provide the necessary controls on the movement of material or products, and associated sustainability data, from approved or certified businesses through each stage of the supply chain. Many standard systems set a CoC standard for this purpose, in addition to their production or management standard