The officially permitted crab catch in Russia is 57,000 metric tons, but the real take amounts to some 350,000 tons a year.
"For two years since the latest trawling research of the western Kamchatka shelf [since the summer of 2005] the number of Kamchatka crab has dropped by 40.6%," the spokesperson for the Pacific scientific research centre of fisheries and oceanography said.
Scientists said the ban should apply to the industrial catch of Kamchatka crab, and limit the catch of blue crab on the western Kamchatka shelf.
The initiative was announced earlier this month by the Russian Federal Fisheries Agency chief, Andrei Krainy, at a news conference held by RIA Novosti.
January 2, a Cambodian fishing boat was detained near the Kamchatka Peninsula for alleged poaching of some 25 metric tons of crab on board.
In August 2006, the captain of a Japanese vessel was arrested near the Kuril Islands, off Russia's Pacific Coast, suspected of illegally fishing for valuable crab in Russian waters.
Kamchatka crabs live in the Sea of Japan and Okhotsk and in the southern part of the western shore of the Kamchatka Peninsula.