Coregonus artedi

Geographic Range

Ciscoes ( Coregonus artedi ) are confined to the Nearctic region. These fish are distributed throughout Canada and the northern United States. Localities include the St. Lawrence Seaway and the Great Lakes. In a north-south direction, ciscoes range from the upper Mississippi drainage in the United States to the Northwest Territories and Alberta in Canada. Ciscoes occur throughout the Great Lakes. In Michigan, most inland lake populations occur in the southern portion of the state, from Oakland County, south to Cass County. Lake Superior is the only lake where ciscoes are abundant; low populations are characteristic of lakes Erie, Michigan, Ontario, and Huron. There are many Coregonus species, and of all of them, ciscoes occur most often in shallow waters and shoals. In Wisconsin, populations tend to be concentrated in northern waters. Specific Wisconsin localities include the Mississippi River, Lake Michigan, and Lake Superior drainage basins. Ciscoes are common in Wisconsin’s northern inland lakes but are rare in Madison-area lakes.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Ciscoes occur in pelagic, cold-water Great Lakes and inland lake environments. During the winter months, they move into shallow coastal waters to spawn, but then return to deeper waters in the spring. Ciscoes are rarely found in waters above 17 to 18ºC. They can live in lakes with surface areas ranging from 20 to 19,000 acres, but are mostly found in lakes with an average surface area of 100 acres and depths of at least 10 m. Cisco-rich lakes tend to be oligotrophic.

• Habitat Regions
• freshwater freshwater

• Aquatic Biomes
• pelagic pelagic
• lakes and ponds

Physical Description

Ciscoes have an average length of 267 mm; they are elongated, nearly round in cross section. They are silvery in color and are usually recognized by their 44 to 52 gill rakers. Their dorsal fins have around 9 to 11 rays and their scales are moderately sized. The lower jaw is either shorter than, or the same length as the upper jaw, and two flaps exist between the nostrils. Identifying ciscoes can be difficult due to the several morphologically similar species within the Coregonus genus; while genetically distinct, the six currently recognized Coregonus species exhibit fewer differences from one another than is typically required to distinguish separate taxa.

• Other Physical Features
• ectothermic ectothermic
• bilateral symmetry bilateral symmetry

Development

Since ciscoes spawn in the winter, their eggs develop slowly and typically hatch in the spring as surface ice begins to thaw. Cisco fry usually live in shallow bays until they are around one month old, and usually mature within 1 to 4 years.

Reproduction

Ciscoes aggregate for spawning as temperatures decrease in the fall. Males typically arrive at the spawning grounds before females and are also the first ones to leave.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Ciscoes usually spawn in late November to mid-December in near-shore waters that are around 5 to 6ºC. Spawning rates tend to peak when temperatures fall below 4ºC. Eggs are deposited at night on top of rocky substrates. While spawning, ciscoes can be seen jumping and splashing.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• sexual sexual

After eggs are deposited in near-shore environments, they are abandoned by the parents.

• Parental Investment
• no parental involvement

Lifespan/Longevity

Ciscoes have an average lifespan of 6 to 10 years, with a maximum age of 13 years. Interestingly, their scales may be used to estimate their age.

Behavior

Ciscoes move constantly. These fish form schools during the day, but disperse during the night. Schools, which are usually around 1 to 2.3 meters tall, tend to form well below the light threshold at which their primary predators, lake trout are able to detect prey. The stomachs of ciscoes are usually fuller during the day, likewise, stomach fullness increases with school size, suggesting schooling aids in predator protection as well as foraging.

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• nocturnal nocturnal
• motile motile
• solitary solitary
• social social

Home Range

Ciscoes usually live their entire life within a few kilometers of where they hatched, though in some cases, individuals may travel about 81 km from where they hatched.

Communication and Perception

Very little is currently known about the methods of communication used among ciscoes. However, their social nature and ability to move as a school implies the use of intraspecific communication.

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

When the waters they inhabit freeze over, ciscoes can perform vertical diurnal movements to feed under the ice at night. As planktivores, they typically feed on algae and small crustaceans ( Cladocera , Copepoda , and Mysis ); infrequently they feed on mollusks , insect larvae, and small fish. Young individuals typically need light in order to find their prey. Fry feed on algae and zooplankton, while adults tend to feed on crustaceans and aquatic insects.

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • eats eggs
  • insectivore insectivore
  • eats non-insect arthropods
• herbivore herbivore
  • algivore
• planktivore planktivore

• Animal Foods
• eggs
• insects
• mollusks
• echinoderms
• other marine invertebrates
• zooplankton zooplankton

• Plant Foods
• algae

Predation

Schooling is the primary means by which ciscoes avoid predators like lake trout . Other predators include northern pike , yellow perch , walleye , sea lamprey , rainbow trout , and burbot .

Ecosystem Roles

As a main source of prey for lake trout , yellow perch , walleye , and northern pike , ciscoes play a key role in the Great Lakes ecosystem. However, between 1930 and 1960, over-exploitation, pollution, and competition with non-native species like rainbow smelt decimated their populations. As the number of rainbow smelt climb in inland lakes, the population of ciscoes plummet and disappear completely in areas where rainbow smelt eat their fry and fingerlings. Great Lake populations, along with native predator-prey relationships have yet to rebound. Around 1963, lake trout were nearly wiped out of the area once cisco populations began their most significant collapse. From 1943 to 1963, lake trout populations declined from around four million pounds to close to zero, while populations of ciscoes declined from 19 million pounds in 1943 to around six million pounds in 1963.

Economic Importance for Humans: Positive

Historically, ciscoes are one of the most commercially important fish in the Great Lakes; in the 1940s, cisco fisheries were producing around 19 million pounds annually.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

There are no known negative impacts of ciscoes on humans.

Conservation Status

Severe over-exploitation of ciscoes from 1930 to 1960, as well as competition with invasive rainbow trout , resulted in dramatic population declines. Other potential competitors include alewives and bloaters . However, rainbow trout populations collapsed in the 1970s, and since that time, ciscoes have been slowly rebounding. The greatest current threat to cisco populations in the Great Lakes is eutrophication. This causes oxygen depletion in lower lake strata, forcing ciscoes into shallower, warmer parts of the water column. These higher temperatures, particularly during the summer months, cause large numbers of the fish to die. Because ciscoes are so sensitive to temperature fluctuations, their responses to eutrophication are thought to be a good indicator of the adverse effects of global warming. In the 1950s, cisco eggs were incapable of hatching in the lower Green Bay due to the incredibly low dissolved oxygen levels (2 mg/L). Currently, cisco egg survival in the Green Bay is around 65%, with a dissolved oxygen level of 11.2 mg/L. These levels are well above the dissolved oxygen needed for cisco eggs to hatch. The St. Mary's River, which runs from Ontario to Michigan, currently exhibits dissolved oxygen levels of 12.7 mg/L, with an egg survival rate of 64%. Recently, the Michigan Department of Natural Resources has implemented a cisco recovery plan for Lake Huron. Since overfishing is no longer a problem, it is thought that competition with rainbow smelt and alewives has kept cisco populations low. One of the motivations for restoring cisco populations is to control alewife populations. Alewives predate on the fry of fish like the economically important lake trout , and it is thought that more abundant cisco populations will help combat this.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Lucas Joel (author), University of Michigan-Ann Arbor, Jeff Schaeffer (editor), University of Michigan-Ann Arbor, Leila Siciliano Martina (editor), Texas State University.

References

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Bailey, R., W. Latta, G. Smith. 2004. An atlas of Michigan fishes with keys and illustrations for their identification. Miscellaneous publications / University of Michigan, Museum of Zoology , 192: 215.

Becker, G. 1983. Fishes of Wisconsin . Madison, WI: University of Wisconsin Press.

Gunderson, J. 2004. "Cisco: Also Known as Lake Herring" (On-line). SeaGrant. Accessed October 28, 2013 at http://www.seagrant.umn.edu/downloads/factsheet_cisco.pdf .

Koelz, W. 1929. Coregonid fishes of the Great Lakes. US Bureau of Fisheries , Part II: 297-643.

Luna, S. 2014. " Coregonus artedi Lesueur, 1818" (On-line). FishBase. Accessed October 28, 2013 at http://www.fishbase.org/Summary/SpeciesSummary.php?ID=235&genusname=Coregonus&speciesname=artedi&AT=Coregonus+artedi&lang=English .

Madenjian, C., E. Rutherford, M. Blouin, B. Sederberg, J. Elliott. 2011. Spawning Habitat Unsuitability: An Impediment to Cisco Rehabilitation in Lake Michigan. North American Journal of Fisheries Management , 31: 905-913.

Milne, S., B. Shuter, W. Sprules. 2005. The schooling and foraging ecology of lake herring ( Coregonus artedi ) in Lake Opeongo, Ontario, Canada. Canadian Journal of Fisheries and Aquatic Sciences , 62: 1210-1218.

Scott, W., E. Crossman. 1998. Freshwater fishes of Canada. Fisheries Research Board of Canada, Ottawa , 184: 966.

Smith, O., J. Van Oosten. 1940. Tagging experiments with lake trout, whitefish, and other species of fish from Lake Michigan. Transactions of the American Fisheries Society , 69: 63-84.

Todd, T., G. Smith. 2011. Environmental and Genetic Contributions to Morphological Differentiation in Ciscoes ( Coregoninae ) of the Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences , 39: 261-267.

Wells, L. 1968. Seasonal depth distribution of fish in southeastern Lake Michigan. US Fish and Wildlife Service Fishery Bulletin , 67/1: 1-15.

Michigan Department of Natural Resources. Distribution and abundance of the lake herring ( Coregonus artedi ) in Michigan. 2014. Ann Arbor, MI: University of Michigan Library. 1995.

2014. "Lake Herring, Coregonus artedi " (On-line). Michigan Department of Natural Resources. Accessed October 28, 2013 at http://www.michigan.gov/dnr/0,4570,7-153-10364_18958-45668--,00.html .

2014. "Lake Herring" (On-line). Monterey Bay Aquarium Seafood Watch. Accessed October 28, 2013 at http://www.montereybayaquarium.org/cr/seafoodwatch/web/sfw_factsheet.aspx?fid=235 .

Lake Huron Technical Committee. Strategy and Options for Promoting the Rehabilitation of Cisco in Lake Huron. 1. Ann Arbor, MI: Great Lakes Fishery Commission. 2007.