The first record of the African Sergeant, Abudefduf hoefleri (Perciformes: Pomacentridae), in the Mediterranean Sea

Background Alien fish species are increasing in the Mediterranean Sea, urging closer monitoring of coastal habitats and biodiversity towards achieving timely assessment and management. Among the alien fish species found in Maltese waters there are members of the Abudefduf genus. Methods Research work undertaken with the cooperation of fishermen allows for additional monitoring effort to record the presence of alien species and their possible impacts. One such alien fish specimen collected from Maltese waters in January 2014 was studied through morphological, meristic and genetic analyses. Mitochondrial DNA barcoding analyses were undertaken to confirm the species' identity given that the specimen found belonged to the genus Abudefduf which is composed of a number of congeners that have similar morphological characters. Results and conclusion This research led to the identification of the first record of the African Sergeant, Abudefduf hoefleri (Steindachner 1881) (Perciformes: Pomacentridae), in the Mediterranean Sea. This alien tropical species is native of the East Atlantic and may aggressively compete with native Mediterranean reef species for territories and resources.