A World Trade Organisation (WTO) agreement aimed at reducing overfishing took effect on Monday, requiring countries to reduce subsidies doled out to fishing fleets and aiming to ensure sustainability of wildlife in the world’s seas and oceans by helping limit the depletion of fish stocks.

The Geneva-based trade body touts the deal as its first focusing on the environment, and the first broad and binding agreement on ocean sustainability. It formally took effect on Monday after four more countries (Brazil, Kenya, Tonga and Vietnam) adopted it.