We are fortunate that explorers and navigators such as Capt. James Cook chose to prepare detailed maps of their journeys. Cook ventured through the Bering Straits, and north of Svalbard. He also sailed south into the Antarctic pack-ice.
His map clearly shows the “Arctic Sea” (generally clear of ice, with the coastline clearly mapped) and the “Frozen Ocean” (north of Canada). Clearly, sea-ice extend in the 1770s aligned with that of today.