The distribution and abundance of tuna stocks are influenced by the currents, water temperature, dissolved oxygen and nutrient supply (Bell et al. Collectively, these states, which are also members of the Parties to the Nauru Agreement (PNA), control the world’s largest sustainable tuna purse seine industry. Only around 20 per cent of catches occur outside the waters of the Commonwealth Pacific small states, including in Indonesia’s and the Philippines’ waters, and up to 7 per cent occurs in international waters.