Fur trade marten furs could generate in international markets spurred a "fur fever" in which many Russians moved to Siberia as independent trappers. From 1585 to 1680, tens of thousands of sable and other valuable pelts were obtained in Siberia each year. The primary way for the Muscovite state to obtain furs was by exacting a fur tribute from the Siberian natives, called a "yasak". "Yasak" was usually a fixed number of sable pelts which every male tribe member who was at least fifteen years old had to supply to Russian officials. Officials enforced "yasak" through coercion and by taking hostages, usually
Maritime fur trade piece. The other furs that were sent to Europe and America were changed to 'coat collars or hats'. Due to this great demand and worth of the sea otters pelt, the Russian-America Company (RAC) annual expenses was around 1000,000 rubles each year and profited over 500,000 rubles per year. The fur of the Californian southern sea otter, "E. l. nereis", was less highly prized and thus less profitable. After the northern sea otter was hunted to local extinction, maritime fur traders shifted to California until the southern sea otter was likewise nearly extinct. The British and American maritime fur traders