The presence of emperor fishes has been reported in several archaeo-ichthyological studies in Eastern Arabia. The spangled emperor (Lethrinus nebulosus) is one of the main species currently composing annual landings in the central and southern Persian Gulf. Its presence outlines the importance of the coastal environments exploited during different life cycle stages, such as open-water reefs and sheltered embayments, including grass beds. Osteometrical methods for estimating the life-size from bones were developed during the last few decades. Measurements taken from the bones of 32 fresh spangled emperors, collected from a fish market in Umm al-Quwain (United Arab Emirates) in February 2017, were exploited to calculate regression equations (power fits), allowing size estimations from archaeological remains. Because of the difficulties in identifying emperor species using bones, we also tested and discussed the validity of a generic model. The Neolithic site of Akab has provided more than 37 000 fish remains, mostly belonging to kawakawa tunas, trevallies and seabreams, which suggest that fishing was essentially carried out during the winter. Relatively few bones (totalling 100 measurements) were identified as belonging to spangled emperors. However, because of the ecological features of this species, estimated sizes permitted investigations into which fishing grounds were exploited, and even provided new evidence regarding ancient seasonality of coastal occupation in Eastern Arabia.