Abstract
These case studies endeavor to report incidences of caudal fin deformities in several commercial fishes living in natural populations in the Saudi Arabian coastal waters of the Arabian Gulf. Two groups of anomalies were observed, slight and severe. The carangid species, Parastromateus niger (Bloch) and the soleid species, Euryglossa orientalis (Bloch & Schneider), had slight cases of caudal fin abnormalities, while the species Oreochrromis mossambicus (Peters), Epinephelus stoliczkae (Day), Diagramma pictum (Thunberg), Cephalopholis hemistiktos (Rüppell), Lethrinus nebulosus (Forsskål), and Lutjanus sanguineus (Cuvier) had severe deformities. The abnormalities were assessed by morphological diagnosis. None of the cases was fatal as they occurred in adult individuals. The possible causes for these deformities as well as the suitability of this kind of case study for environmental monitoring are discussed. Further studies should be conducted from the perspective of pollution.