A vessel with stolen oil was also recovered.
The Joint Task Force on security in the Niger Delta said it seized a marine vessel and a barge used for bunkering on Sunday, in a crackdown that has netted 76 suspected oil thieves in two weeks.
A spokesperson for the JTF, Lt.-Col. Onyema Nwachukwu, said in a statement issued in Yenagoa that the arrest and seizures were made between April 15 and April 27.
He said the Vessel, MT Shandy, with 12 crew members, was intercepted on Otokomabie Creek near Oloma Community in Rivers.
Eight of the 12 crew members arrested were currently being interrogated in Port Harcourt while the four crew members were left behind to man the vessel in Bonny Island, Mr. Nwachukwu said.
He said the JTF also impounded a barge found at an illegal oil loading point close to Burma Rice Farm between Brass and Obiama waterways in Brass Local Government Area of Bayelsa.
The spokesman explained that the barge was arrested with 50,000 litres of suspected stolen crude oil which had been towed to a terminal for investigation.
He said the task force also intercepted and destroyed 61 boats, conveying suspected stolen petroleum products in some parts of Warri South West Local Government Area of Delta.
The seizures came a week after the force said it impounded a vessel allegedly laden with some 2,500 tonnes of stolen crude at Okuboto creek in Bayelsa.