Keyes [2004, p. 15] says: “In the post-truth era we don't just have truth or lies but a third category of ambiguous statements that are not exactly the truth but fall short of a lie”. In this paper about Hector's and Maui dolphin management in New Zealand, we argue that some scientific knowledge about these species presented and disseminated in ways that equate to this third category and as such may be classed as ‘post-truth type communication’. This generates citizen mistrust in science, scientists and government agencies and inflames conflict among informed stakeholders. We argue trust may be rebuilt by a combination of deliberative approaches to environmental governance, transparency about uncertainties, information gaps and divergent scientific opinions, and reformulation of normal scientific approaches and assumptions to those advocated by post-normal science.