Cisco (Lake Herring), Coregonus artedi

Lake herring

Identifying characteristics: (Native Fish) Cisco (formerly known as Lake Herring) are members of the trout and salmon family that inhabit the midwater regions of the Great Lakes and high quality inland lakes. Cisco have slender, elongate bodies with two dorsal fins, a pointed snout with long lower jaw, and in side view are decidedly elliptical. Cisco are silvery with faint pink to purple iridescence on the sides, blue-green to gray backs and white below. Fin colorations vary, but in general the outer portions of the dorsal and caudal fins are darkly pigmented.

As water temperatures drop in the fall, Ciscoes form spawning schools. In the Great Lakes region, this occurs in late November or early December, when surface ice begins to form. 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. Cisco 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. Although the average adult weight is less than a pound, the cisco can reach larges sizes in some waters and may exceed five pounds.

Since Cisco 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 Cisco 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.

Cisco graphic courtesy of Joseph R. Tomelleri and copyrighted.