These vessels appeared to trans-ship with Japan-bound refrigerated cargo vessels, known as reefers, some of which were found to be operated by a subsidiary of major Japanese trading house Mitsubishi Corp.

Based on analysis of satellite vessel tracking and testimonies from Indonesian crew members, the EJF concluded that tuna and swordfish had been transferred from Chinese fishing vessels to around 10 Japanese reefers bound for Shimizu port in Shizuoka Prefecture among others. Some crew members testified that they had transferred tuna to a reefer flying the Japanese flag.