A rare species of giant fish, namedsalmoniushas been discovered off the southern coast of Western Australia (WA) and typically inhabits marine environments within 200 nautical miles of the WA coastline.

The Japanese Government directs the Japanese Fisheries Agency (JFA), a government authority, to sail a fleet of JFA vessels to this area to harvest these fish and conduct scientific research. It is reported to the Australian Government that a fleet of Japanese fishing vessels have been located 150 nautical miles off coast of WA, and that these vessels have been catching large quantities ofsalmonius.

The Australian Government orders naval vessels to sail south to investigate these claims. The new fish stock is of significance to the Australian government as a potential source of revenue. Early research indicates the fish has medicinal properties.

An Australian Navy Vessel confirms the presence of the Japanese fishing vessels off the coast of WA. Naval officers board the vessel and notice commercial quantities of stock of the new species of giant fish.

As a result, an international diplomatic incident erupts between Japan and Australia. The Japanese government claims the stock was caught in open seas. The Australian government rejects this claim and contends that the vessel was in Australian waters.

For the purposes of this question, Australia and Japan have ratified the UN Convention on the Law of the Sea (UNCLOS) and both are signatories to the Convention on the Protection of Rare and Endangered Fish (CPREF, a fictitious treaty).

What issues of international law does this scenario raise?