The men stand accused of condemning the victims to their deaths by forcing them to stay in the ship's broiling, fume-filled hold. They were identified by survivors of the sinking after they were all brought to Catania in Sicily on Monday.
The alleged traffickers were three Moroccans, including the 20-year-old captain of the ill-fated vessel, four Libyans and a 17-year-old Syrian.
The 13-metre vessel left Libya overnight Friday-Saturday with 362 people onboard - so overcrowded that the traffickers were desperate to ensure those in the hold remained there to keep it stable.
"Anyone who tried to get a bit of air was punched, kicked and hit with sticks or belts to keep them in," Catania prosecutor Michelangelo Patane told a press conference.
Of the more than 300 migrants who survived the sinking, 116 were Moroccan nationals who are to be repatriated in the next few days. The others, mostly from sub-Saharan Africa, Bangladesh and Pakistan, will be moved to reception centres across Italy pending possible asylum requests.