Valery Rybkin and Sergei Mestnikov, the captains of the Russian Grot and the Ukrainian SUAR-2 fishing boats, both of which were seized and towed to the Georgian port of Poti January 10, were also remanded in custody for two months by the court last week pending trial.
The captains were denied bail late last week. The crews of eight and 10 people respectively were released on bail of $1,100 each earlier.
Authorities said earlier the sailors could be charged with illegally crossing the maritime border, illegally fishing in Georgian territorial waters and violating international maritime regulations. They could face up to five years in prison.
The Georgian border police earlier claimed to have discovered six metric tons of illegal catch on board the Grot, which is registered at Russia's southern port of Novorossiisk.
Both vessels were fishing off the coast of Abkhazia, which has proclaimed its independence from Tbilisi but has not been recognized as a state by the international community.
Georgian law says Abkhazian ports and coastal waters are closed to international navigation, except for vessels with humanitarian cargoes.
The incident could mark a further escalation in the already tense relations between the two ex-Soviet neighbors.
Russia's Foreign Ministry called Saturday on Georgian authorities' understanding and restraint in their handling of the case.
"We expect the Georgian side to treat the incident with understanding, to show restraint in its statements and actions, and to free the captain of the fishing boat," official Foreign Ministry spokesman Mikhail Kamynin said.
