Pyotr Mikheichik, 53, was traveling in the Italian Thetis ship when it was rammed by the Panama-registered Heleni vessel in heavy fog about 6.5 kilometers (4 miles) off Sicily.
The other 13 people on board, including eight researchers studying marine flora near the Mediterranean island, were rescued and taken to hospital.
Russia's Consul General in Palermo, Sicily's largest city, confirmed the report, saying that "retrieving the body will take some time, as all corridors in the boat are blocked by debris."
Alexander Gusev said divers had swum down to the ship several times Sunday, but could not enter the vessel. On Monday morning, they resumed their efforts and spotted the body near the vessel's kitchen.
Prosecutors and marine authorities are investigating the cause of the collision.
