Tapping into hard-to-get information: the contribution of citizen science campaigns for updating knowledge on range-expanding, introduced and rare native marine species in the Malta-Sicily Channel

Considerable research effort has recently been invested into the reporting of Non-Indigenous Species (NIS) within the Mediterranean Sea, with species' first records from the Basin holding most prestige within the biological community. This invariably leads to a discard of secondary, unpublished records, which represent a vast repository of information. This study documents a total of 49 unpublished records (represented by 89 individuals) of nine Atlantic range-expanding and introduced species, as well as rarely-reported native and cryptogenic species, within the Malta-Sicily Channel, gleaned through citizen science efforts conducted on the islands of Malta and Sicily. The study also represents the second record of Pomadasys incisus (Bowdich, 1825) from Maltese waters, as well as the second record of Selene dorsalis (Gill, 1863) from the Mediterranean.