These form another clue, a clue to the Indians who mined copper on the island. The Indians came to the island only in mild seasons, taking what resources they could, and leaving before winter. The Indians mined here by about 2000 B.C., continuing for 1,000 years, and Isle Royale and Superior area copper made its way by trade as far as New York, Illinois, and Indiana. Indians were probably most active here from 800 to 1600. By the 1840s, the only Indian encampments white miners encountered were a maple sugaring camp on Sugar Mountain and a seasonal fishing camp on Grace Island.
Aquatic environments abound both on and around the island.
In fact, some 80 percent of the national park is underwater, as shallow warm water ponds, streams, and rivers, and the deep, cold, foreboding Lake Superior waters. Commercial fishing has been one of the mainstay economic activities on the island throughout historic times. It began before 1800, to feed the fur traders. Since about 1840, it has been a largely individual enterprise. The major economic species were lake trout, whitefish, and herring lurking in the range of water depths and bottoms along kilometers of Isle Royale shoreline.