Bulgarian shipping company Balgarski Morski Flot reported on Monday another missing sailor on its ships.
Hristo Hristov, a mechanic on the ship "Vitosha", now in the Riga Gulf of the Baltic Sea, was found missing around noon on Monday, the company said.
Local authorities are now searching the sea for his whereabouts.
Hristov, 54, lives in Burgas. He is married and the father of two.
Hristov is the second sailor on a ship owned by Balgarski Morski Flot to be reported missing in the last two days.
Earlier on Monday, Ukrainian authorities said they put an end to the search for Ventsislav Ivanov, 40, the second mate on the ship Milin Kamak.
His disappearance was noticed at the weekend when the ship was due to enter the port of Feodosia in southern Ukraine.