A swordfish, Xiphias gladius, behaviour, movements, biology and trophic ecology was studied off Reunion Island (southwestern Indian Ocean) within framework of EU-funded project PESCARUN. The project includes experimental fishing with buoy fishing gear, stomach content analysis and tagging with a pop-up satellite electronic tag (PSATs). Here we present preliminary results of the project including tagging of 5 individuals, results of night fishing trials and stomach content analysis performed to date.