MOSCOW — Almost 100 captive whales seized by the Russian government in the country’s Far East before they could be exported to Chinese marine parks will be evaluated as a first step toward freeing them, officials said on Thursday.

The mammals have been held in what became known as the “whale jail” — watery pens in Srednyaya Bay near the Russian city of Vladivostok. The whales, which can fetch millions of dollars depending on the species, had been captured off Sakhalin Island last summer and fall by four companies linked to one businessman.

Dmitri N. Kobylkin, Russia’s minister of natural resources, said the sheer number of whales in need of release was unprecedented. In the past couple of decades, captured whales have been released only individually or in small numbers.



“There has never been such a situation before in the world,” Mr. Kobylkin said at a news conference, adding that a summer release would increase the animals’ chance of survival.