A research group in the UK has developed a technique for monitoring practices in the fishing industry so that buyers and processors can know the provenance of the fish they are purchasing, and the information can even be seen by retail customers on their smartphones. It uses the same blockchain technology used by the Bitcoin virtual currency.

This means processors can avoid being scammed when they buy fish, and consumers can check whether their fish were caught ethically. It's currently being tested by a food company in the UK.

https://www.theguardian.com/sustainable-business/2016/sep/07/blockchain-fish-slavery-free-seafood-sustainable-technology

https://www.provenance.org/