Last year, nearly one in every six fish sold had been caught illegally.

That number is now set to fall sharply, thanks to the Port State Measures Agreement (Port State Measures Agreement, PSMA), the first international treaty designed specifically to combat illegal, unreported and unregulated fishing.

What the PSMA provides for

Under this new agreement, parties are obliged to ensure that any fishing vessel arriving at one of their ports — even simply to refuel — must notify the authorities and submit to an inspection of its logbook, licences, fishing equipment and, to be certain, the actual catch it is carrying. Port state authorities commit to sharing information on violations, making it harder for fraudulent fishers to shift their operations elsewhere.

The treaty, which was adopted by FAO members in 2009, marks a major step forward, going beyond the fishing industry's self-regulation, whose illicit activities siphon off up to 23 billion dollars a year.

Now that 30 countries plus the European Union have formally deposited their instruments of accession with the FAO, the treaty has entered into force and a new era has begun.

All those who fish illegally — who not only make illicit profits but also jeopardise efforts to sustainably manage the planet's marine resources — will now face higher operating costs and the very real risk of being detected and penalised.

The more countries sign up to the treaty, the sooner illegal fishing will be beaten

The treaty currently applies only to the countries that have signed it. For it to carry greater force, and to accelerate both its effectiveness and its impact, more countries will need to join. When that happens, there will be fewer and fewer opportunities for rogue vessels to move undisturbed from port to port, flouting the catch limits imposed to protect fish stocks and biodiversity levels.

I congratulate the countries that have already signed the treaty: Australia, Barbados, Cape Verde, Chile, Costa Rica, Cuba, Dominica, the European Union (as a member of the organisation), Gabon, Grenada, Guinea, Guyana, Iceland, Indonesia, Mauritius, Mozambique, Myanmar, New Zealand, Norway, Oman, Palau, Republic of Korea, Saint Kitts and Nevis, Saint Vincent and the Grenadines, Seychelles, Somalia, South Africa, Sri Lanka, Sudan, Thailand, Tonga, United States of America, Uruguay, Vanuatu.

But the path is now set and membership is bound to grow.

The agreement makes it harder to bring illegally caught fish to market, disrupting a critical link in the complex food chain from sea to table.

Some vessels may choose to sail on and seek a port that is not party to the treaty — though that is a costly and discouraging decision. Moreover, ports that offer this kind of unlawful service will certainly not go unnoticed. PSMA member countries will fund capacity-building measures for countries that need them — and the FAO is already providing technical and legal assistance — and tolerating illegal behaviour is likely to increase the burden of any resulting penalties.

Compliance will ultimately be unavoidable. Fishing industry operators worldwide are increasingly leveraging their sustainable practices as a marketing asset, and catch documentation schemes and eco-labelling are becoming ever more widespread. Acceding to the treaty can improve a country's trading opportunities.

As a turning point in the fight against illegality in the fishing sector, the PSMA is a concrete step towards healthier seas, as called for by Goal 14 of the new 2030 Agenda for Sustainable Development.

At the FAO, we are convinced that sustainable development requires an integrated effort and relies on network effects — which in turn can catalyse a positive feedback loop. The port state controls envisaged, for example, can indirectly bring other global problems to light, such as undeclared labour in the fishing industry, the illicit trade in endangered species and non-compliance with Marine Protected Areas.