sentences:  The Nivkh people populated the Shantar islands until the 1730s.The first recorded exploration of the Shantar Islands was in April 1640, when Russian explorer Ivan Moskvitin allegedly sailed to the mouth of the Amur River with a group of Cossacks and spotted the Shantar Islands on the way back.Moskvitin reported his discoveries to Prince Shcherbatov, the Muscovite voivode in Tomsk.