the lake is a naturally self-sustaining lake and includes a large variety of fish, such as walleye, northern pike, smallmouth bass, largemouth bass, crappie, bluegill, sunfish, pumpkinseed and perch. the major inlet for bear island lake is the beaver river, which has rapids and beaver dams that limit fish movement. the lake's major outlet is bear island river, which has an old dam that also limits fish movement at low water. aquatic plants grow to a depth of and are sparse along most of the shoreline of bear island lake.