Hugo Verlomme’s novel, Mermere (1978-2020), depicts a conflict between two humanities, the earthlings, who represent a world devastated by pollution and hypertechnology, and the « noés », oceanized humans who attempt to rebuild their relationship with nature through respect for marine ecosystems. The paper aims at showing to what extent this novel is an ecotopia in the tradition of Ernest Callenbach’s Ecotopia, an ecological utopia based on the maritime world, which is an original space compared with traditional utopian places. In the wake of the « oceanic turn » taken by the humanities, the article draws on what Laura Winkiel calls « hydrocriticism », a geocriticism adapted to the maritime world, which aims to study literary and artistic productions as spatially and temporally intertwined with the geography and agency of the ocean.