A merchant sailor with Israeli and Ukrainian citizenship had been detained by Russian authorities on Monday, along with his crewmates and ship, the Foreign Ministry said on Friday.
The 50-year-old seaman was released on Tuesday along with the rest of the crew of the Princess Nicole, a Ukrainian bulk carrier.
The Israeli Foreign Ministry and the Israeli embassy in Moscow sent official letters to its Russian counterparts and held talks with them after hearing of the arrest.
On Friday the Princess Nicole was still in the Black Sea, sailing for Constanta, Romania.
Commercial shipping has become perilous in the Black Sea since the Russia-Ukraine War began.
NATO's Shipping Center warned on Wednesday that there was "a high risk of collateral damage on civilian shipping in the northwestern part of the Black Sea," which included mines.
"There are several open-source reports of civilian ships being hit directly or indirectly as a result of the acts of war in the northwestern Black Sea within Ukrainian territorial waters and adjacent international waters," NATO said. "Civilian shipping is encouraged to exercise caution and be on high alert in the area."
The Russian Black Sea Fleet was accused by the Armed Forces of Ukraine on Wednesday of using the civilian general cargo ship Helt as a human shield. The Estonian-owned ship sank on Thursday, the cause of the damage unclear. Of the six crew members, four were missing as of Thursday evening, and two had made it into a life raft.
The same day a Bangladeshi vessel was hit by a missile or bomb at another port.