The Itelmen had a substantial hunter-gatherer and fishing society with up to fifty thousand natives inhabiting the peninsula before they were decimated by the Cossacks conquest in the eighteenth century.
So much intermarriage took place between the natives and the Cossacks that Kamchadal now refers to the majority mixed population, and the term Itelmens at some point became reserved for persisting speakers of the Itelmen language. By 1993, there were less than 100 elderly speakers of the language left, but some 2,400 people considered themselves ethnic Itelmen in the 1989 census. By 2002, this number had risen to 3,180, and there are attempts at reviving the language.
Schurr TG, RI Sukernik, YB Starikovskaya, and DC Wallace. 1999. "Mitochondrial DNA Variation in Koryaks and Itel'men: Population Replacement in the Okhotsk Sea-Bering Sea Region During the Neolithic". American Journal of Physical Anthropology. 108, no. 1: 1-39.