Rapid Action Battalion (RAB) members seized 57 turtles from Shankhari Bazar of Old Dhaka.
The mobile court of RAB also detained three traders for selling turtles, said RAB 10 Magistrate Sarwar Alam.
He said the mobile court conducted the raid in the area around 6:30am Friday.
Of the detainees Pradip Chandra Das, 47, Ponir Chandra Das, 39, were sentenced to nine months of simple imprisonment and Kartik Chandra Das was sentenced to three months in jail.
During interrogation, the detainees said they had been selling turtles for eight years collecting those from Khulna, Narshingdi and Munshiganj.