On the opening day of a global science conference, French fishery scientist Clea Abello presented research showing that marine protected areas could protect commercially valuable fisheries.By Teresa TomassoniNICE, France—More than 2,000 scientists, advocates and policymakers from at least 100 countries convened this week at the One Ocean Science Congress, warning of a mounting marine crisis and promising recommendations to solve it—not only for the sake of life below the surface, but for the entire planet.