Lake Herring, Coregonus artedi
Identifying characteristics: (Native Fish) To dorsal fins including one adipose fin, pointed snout with long lower jaw, long cylindrical body.
Lake herring or "ciscoes," are small slender school fish that generally inhabit the midwater regions of the Great Lakes. This member of the trout/salmon family resembles the lake whitefish. Both are slender and silvery, and each has two flaps on the septum dividing the nostril. However, the lake whitefish has a rounded, blunt snout, while the lake herring has a pointed snout with a longer lower jaw.
As water temperatures drop in the fall, the lake herring forms large spawning schools. In the Great Lakes region, this occurs in late November or early December, a week or two after the lake whitefish has spawned. Spawning may occur at a variety of depths-from shallow water three to 10 feet deep, to much greater depths. These fish may even spawn pelagically in midwaters 30 to 40 feet below the surface in water 210 feet deep. Males move onto the spawning grounds first, and either leave before the females do, or remain behind for a few days. Eggs are deposited on the bottom and abandoned by the parents. The eggs develop slowly in the lower winter temperatures, and studies indicate that they hatch after the breakup of spring surface ice. Lake herring fry feed on algae and zooplankton: adults add crustaceans and small aquatic insects to their diet. In general, males and females grow at about the same rate, although females tend to live longer and may reach a larger size. The average adult weighs 2.4 to 12 ounces, and may live from six to 10 years.
Since lake herring are preyed upon heavily by lake trout, northern pike, yellow perch, and walleye, they are an important part of the food chain in the Great Lakes ecosystem. During the 19th and early 20th centuries lake herring made up a significant part of the Great Lakes commercial fishery, but their numbers have since dropped drastically. They are most readily caught by anglers when they gather into spawning schools in the fall.