The spotted scat (Scatophagus argus), an alien species to the Mediterranean, is spreading in Maltese waters. An escape or deliberate release by an aquarist suspected as the cause. The fish is frequently for sale at Maltese fish markets. The fish has been caught in small numbers around the island since 2007.
Since there are no reports of this species occurring in the wild in the Mediterranean, it does not seem likely that the fish arrived in Malta from elsewhere in the Mediterranean through dispersal or introduction from an established population. Its native range is the Indian Ocean and the tropical to warm temperate Pacific.
Interviews with fish mongers 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.
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.
The spotted scat is considered a trash fish in some parts of its range but as an important food species in others, for example, southern and south-eastern Asia. The species is of commercial importance as a brackish water aquarium fish and juveniles are collected in numbers from the wild for the aquarium trade.