Japan and other major fishing countries will likely introduce an international documentation system to better keep track of Pacific bluefin tuna catches as a step against overfishing, sources said Tuesday.

The documentation plan is designed to certify fishing ports and methods to prevent illegal fishing and trade, and provide information such as catch volumes and their shipping destinations.

The launch of the catch documentation system, which is expected to be discussed at an international conference in September in Fukuoka Prefecture, is intended to help restore depleted stocks of the Pacific tuna. Since 2015, fishing of the tuna has been regulated.

In Japan, local fisheries associations gather data on bluefin tuna catches and report them to the Fisheries Agency, but there have been cases of unauthorized fishing that go unreported.

The envisaged plan is also aimed at tracking shipments of relatively small bluefin tuna to fish farmers as well as diversifying sales channels that bypass local fisheries associations and reach fish markets, according to the sources.

There are catch documentation systems for Atlantic bluefin tuna and Southern bluefin tuna.

Officials participating in a meeting related to the Western and Central Pacific Fisheries Commission are expected to discuss creating such a system for Pacific bluefin tuna, according to the sources.

Japan is a member of the commission that seeks to conserve and manage stocks of migratory fish in the region.

The international body aims to increase parent fish to 43,000 tons by 2024 and since 2015 has halved the cap on takes of small-size bluefin tuna weighing less than 30 kilograms from average levels in 2002 to 2004.