The black jewfish (Protonibea diacanthus) occur in tropical coastal waters throughout the central Indo-Pacific. They have long been valued as an important recreational and artisanal species in fisheries, but have become increasingly targeted by commercial fisheries due to demand for their swim bladder. This rise in targeted fishing has led to uncertainty around the sustainability of some stocks, and in Queensland waters it resulted in the implementation of highly restrictive management arrangements. To better understand how changes in fishing pressure may impact the sustainability of P. diacanthus populations throughout Eastern Australia, we evaluated the population biology of the species. The results provide new insights into the spawning periodicity, fecundity, age and growth, and connectivity of P. diacanthus populations, which will help improving the assessment and management of the species.