The researchers studied the fish diversity at Saya de Malha and Nazareth Banks in Mauritius using different methods like trawls, traps, and video. They found Myctophidae in pelagic waters, Gobiidae, Triglidae, and Synodontidae in bottom trawls, and Lethrinidae in demersal waters. The main catch was Lethrinus mahsena at 21m depth. This study provides new information on fish families at these banks beyond just commercial species.