The observation of an all-dark Pseudobulweria petrel in the Bismarck Sea, Papua New Guinea, in April 2017, is described, together with a review of similar at-sea observations. The affinity of these birds to Fiji Petrel P. macgillivrayi is discussed and some suggestions made as to how knowledge of this population might be advanced so that, ultimately, its conservation can be facilitated along with a suite of imperilled Pacific petrels that urgently require safeguards.