An overlooked and unexpected introduction? Occurrence of the spotted scat Scatophagus argus (Linnaeus, 1766) (Osteichthyes: Scatophagidae) in the Maltese Islands

The spotted scat Scatophagus argus (Linnaeus, 1766) is recorded for the first time from Malta and the Mediterranean from fish offered for sale at a Maltese fish market. Interviews with fish sellers and fishermen showed that this fish is caught occasionally in small numbers in trammel nets from shallows on seagrass meadows in the southeast of Malta and that it has been present since at least 2007. The native range of the species is the Indian Ocean and the tropical to warm temperate Pacific but the species is commercially available as a brackish water aquarium fish. Given that this species has also been regularly imported into Malta by the aquarium trade since at least 1986, an escape or deliberate release by an aquarist seem to be the most probably mode of introduction. It is surprising that this euryhaline species which requires brackish water to complete its life cycle should have become established in Malta where there is a dearth of such habitats.