Bolbometopon muricatum (bumphead parrotfish, Valenciennes, 1839) is a conspicuous, iconic and ecologically important coral reef fish species. B. muricatum plays an important role in the bioerosion of the reef framework and as a result has been described as both an ecosystem engineer and keystone species. Here, we assess the abundance, density and size structure of B. muricatum within the world heritage listed Ningaloo Reef, western Australia. We use data obtained from three sources to assess the spatiotemporal distribution and size structure of B. muricatum: (1) historical surveys of the abundance and density of reef fish assemblages at northern Ningaloo Reef (1987–2019); (2) qualitative observations of B. muricatum at northern Ningaloo by expert witnesses (2006–2020); and, (3) targeted timed swim surveys of B. muricatum abundance and size at northern Ningaloo (2021). We discuss the implications of our findings for the ongoing management of this iconic engineer within the world heritage listed Ningaloo Reef