The ship was discovered by the Coast Guard's aircraft on Saturday and, on behalf of the Prosecution Authority, was boarded by the Coast Guard at 8 a.m. on Sunday.
Interviews were held with the commander during the day.
He admits to the crime, saying it was committed through negligence. He is prepared to accept a penalty order, said Håkan Andersson, senior prosecutor on standby at the national unit for environmental and occupational safety cases.
At 1 p.m., the Coast Guard announced that the ship was allowed to leave Sweden.
"The master of the bulk carrier Hui Yuan has admitted to violating the Environmental Code and has deposited money for future fines," the Coast Guard writes on its website.
The bulk carrier Hui Yuan is registered in Panama, according to the Coast Guard. It was en route from Russia to Las Palmas, Spain. The vessel is 225 meters long and 32 meters wide.
This is the fourth time since March that the Coast Guard has boarded a ship. Two of them remain off the southern coast of Sweden. The ships' respective Russian captains are in custody on suspicion of aggravated use of false documents.
