The Nigerian Navy said it arrested two Ghanaians, 50 Nigerians and seven Sri-Lankans in several operations during Yultide.
Channels TV quoted Commander of NNS Beecroft, Ibrahim Shettima, as saying that officials of the Economic and Financial Crimes Commission as well as those of the Department of Petroleum Resources have been brought in to collect data for further investigation.
One of the vessels trapped in the navy net is MV Zebrugge.
The ship, which was carrying seven Sri-Lankans, had petroleum products without proper documentation.
Its captain denied knowledge of the source of the fuel, saying he was contracted to take the product to Ghana.
Another vessel, MT Jonko, was arrested on December 21 with 11 Nigerians onboard and 1077 metric tonnes of crude oil.
It was gathered that samples of the product on board had been collected from various compartments of the tanker for further analysis.