The General Assembly through resolution 73/292 decided to convene the 2020 United Nations Conference to Support the Implementation of Sustainable Development Goal 14: Conserve and sustainably use the oceans, seas and marine resources for sustainable development. The overarching theme of the Conference is "Scaling up ocean action based on science and innovation for the implementation of Goal 14: stocktaking, partnerships and solutions".
More info available on the UN Ocean Conference website.