Leave scientists to our own devices and we will build ever more complex models that describe our understanding of the way the world works. Leave decision-makers alone and they will build policies unencumbered by scientific realities. And yet, when the two meet, elegant models capable of addressing real-world problems on politically viable timeframes can and do emerge. People expect a lot from marine and coastal environments -- plentiful seafood from fisheries and aquaculture, beautiful places for recreation, renewable energy, and protection from storms. In a marine spatial plan, a wide range of uses of the marine environment are put on one map. But we have yet to understand how such plans are likely to yield changes in the delivery of services people care about and expect to derive from the ocean. This brief symposium will present cutting-edge advances in the modeling and mapping of marine ecosystem services and the ways in which this work is actually being used to inform policy. We will give special attention to how services are likely to change under alternative management scenarios and the trade-offs that result. We will then focus on how these advances are being incorporated into decision-making by national and regional governance bodies. We will conclude with a discussion about information flowing both ways from management to science and back again, highlighting how to most effectively do science that matters.