Between October 1956 and January 1971, the Institute of Oceanography and Fisheries (IOF, Croatia) performed a series of trawl-surveys in the Croatian coastal waters between Split and Šibenik (central-eastern Adriatic, Mediterranean) in the area of the Jabuka Pit with two motorboats, “Bios” (300 HP; LOA = 26 m) and “Predvodnik” (200 HP; LOA = 19 m).