Coregonus kiyi
Kiyi are long, thin fish with big silvery scales. They are thin from one side to the other and tallest in the middle. Usually, they are dark on the top, silvery on the side, and white underneath. They have an iridescent pink or purple shine, so they look different colors as they move in the light. They have big eyes, and their lower jaw sometimes sticks out past the top one. Kiyi are 25 cm long on average, but can be anywhere from 12 to 35 cm long. Their head is about a quarter of the size of their body. Their spine has 55 to 58 vertebrae. They have 71 to 91 scales along their lateral line, which is their sensory organ that runs from their head to tail. Kiyi weigh 0.4 and 0.16 kg. They look a lot like other whitefish, but are easy to tell apart by their big eyes and their fins. (Froese, et al., 2011; Hubbs and Lagler, 2004; "Kiyi (Upper Great Lakes Population)", 2008; "Kiyi (Coregonus kiyi)", 2009a)
There are two subspecies of kiyi, which are Upper Great Lakes kiyi in Lake Superior, and Lake Ontario kiyi which lived in Lake Ontario. Upper Great Lakes kiyi had a longer head, and longer paired fins than Upper Great Lakes kiyi. Lake Ontario kiyi were declared extinct in May 2005 from predation, competition, and overfishing. (Froese, et al., 2011; Hubbs and Lagler, 2004; "Kiyi (Upper Great Lakes Population)", 2008; "Kiyi (Coregonus kiyi)", 2009a)
Kiyi are only live in the Great Lakes. They are common in Lake Superior but rare in Lake Huron and Lake Ontario. They are endangered in Lake Michigan, and don't live in Lake Erie. The Committee on the Status of Endangered Wildlife in Canada actually considers kiyi to be gone from all the Great Lakes except Lake Superior. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; Eakins, 2011; Froese, et al., 2011)
Kiyi only live in clear, dark waters of the Great Lakes in North America. They live in freshwater that is 35 to 200 m deep. Although they are occasionally found in shallower waters, they prefer water that is at least 108 m deep. Kiyi are found in water that is 3.7 to 4.6˚C. They have usually been collected by researchers on top of clay or mud bottoms. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; Carlander, 1969; Eakins, 2011; Froese, et al., 2011)
Scientists don't know much about development of kiyi specifically, but it is probably similar to they way lake whitefish develop. Female lake whitefish gain weight faster and are heavier than males, but they are usually about the same length. Lake whitefish eggs take 120 to 140 days to hatch, so they hatch in March or April. By the time they are 3 weeks old, hatchlings are about 13 mm long. About 87% of young lake whitefish die. They grow slowly at first, but start growing faster between June and the end of July. Eggs are less likely to survive as the water gets warmer, but they hatch faster in warmer water. (Carlander, 1969)
Kiyi scatter their eggs over spots in the lake that have gravel bottoms in a process called spawning. Females release the eggs into the water and the males fertilize them. Scientists don't know much about their specific mating systems, but they are probably similar to their close relatives, like lake whitefish. Male lake whitefish arrive at breeding areas before females. Lake whitefish usually scatter their eggs at night. They first move upwards and then release their eggs near the surface of the water. Female lake whitefish release eggs in small batches over 10 days. The eggs are 2 to 3 mm wide, aren't sticky, and float a little bit. One quart could fit 53,000 of them. (Carlander, 1969; Eakins, 2011)
Kiyi spawn in the fall. Females release groups of eggs into the water which males fertilize. In Lake Superior, they spawn from November to December at about 128 m deep in the lake. When they lived in other lakes, they spawned from from September to January at 106 to 165 m deep. When kiyi spawn, females are usually heavier than males of the same length. Eggs hatch in 120 to 140 days. Kiyi are grown up when they are 2 to 3 years old, usually when they are at least 132 mm long. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; Carlander, 1969)
Kiyi don't invest time or effort in their offspring after they spawn. (Carlander, 1969; Eakins, 2011)
The lifespan of kiyi is 7 to 8 years for males and 9 to 10 years for females. Females have been known to live more than 10 years. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; Eakins, 2011)
Scientists don't understand the behavior of kiyi very well. Their close relatives lake whitefish spend most of their time in loose groups (called schools) and don't move around with the seasons. (Dewey, 2008; Tomelleri and Eberle, 1990)
Scientists have not studied movement or home ranges of kiyi very well. Their close relatives lake whitefish have been studied more. In Lake Erie, lake whitefish travel 280 km between deep water and the places where they spawn. In Lake Michigan, they travel 40 to 115 km in a year. (Carlander, 1969)
Kiyi eyes are specially adapted for seeing underwater. They also sense movement with their lateral line, a sensory organ that many fish have that runs form their head to tail. Lake whitefish communicate by touch, and kiyi may do this as well. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; Dewey, 2008)
Kiyi mostly eat small shrimp that live in freshwater. They might also eat opossum shrimp, amphipods, young mayflies, mollusks, zooplankton, benthos, and nonbiting midges. Kiyi eat some kinds of fungi, some shrimp-like crustaceans like Mysis relicta, and some zooplankton. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; "Lake Superior Food Web", 2009; Carlander, 1969; Hubbs and Lagler, 2004)
Kiyi are eaten by burbots and lake trout, and also humans. They may also be eaten by sea lamprey, rainbow smelt, and alewife. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005)
Kiyi eat different kinds of zooplankton and large invertebrates, and are eaten by fish-eating animals. ("Lake Superior Food Web", 2009)
There are no known negative impacts of kiyi on humans. (Froese, et al., 2011)
Kiyi used to be important fish in the Great Lakes that was sold and eaten. Whitefishes in general are sold more than any other fish in the Great Lakes, but people don't buy kiyi very often. Deepwater fishing for kiyi and their relatives still happens in Canadian waters, but fishermen are not allowed to keep very many of them. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; "Coregonus kiyi — kiyi", 2000)
Kiyi are a vulnerable species according to the IUCN Red List. They are a species of special concern according to the the US Fish and Wildlife service, the states of Michigan, Indiana, Minnesota, Wisconsin, New York, and the Ontario Ministry of Natural Resources. They died out in Lake Huron, Lake Michigan, and Lake Ontario mostly from overfishing. They are not fished much any more, but are sometimes caught accidentally along with other fish. They are also threatened by loss of cold deep-water habitat, pollution, and sand accumulating on the bottom. They also compete and are eaten by non-native species like alewife, smelt, Pacific salmon, and sea lamprey. Kiyi are especially vulnerable because they are only found in 1 lake right now. Ways to conserve kiyi are controlling nonnative fish, regulating commercial fisheries, and more research. They might be able to be reestablished in Lake Huron and Lake Michigan. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005; "Coregonus kiyi — kiyi", 2000; "Kiyi (Coregonus kiyi)", 2009a; "Kiyi (Coregonus kiyi)", 2009b)
In 1927, about 52.8% of all cisco fish caught in nets in Lake Ontario were kiyi. In 1942, only 0.01% were kiyi. In 1964, only 1 kiyi was caught in Lake Ontario, but no one has caught one there since. ("Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi", 2005)
Brian Beall (author), Minnesota State University, Mankato, Robert Sorensen (editor), Minnesota State University, Mankato, Gail McCormick (editor), Animal Diversity Web Staff, Catherine Kent (editor), Special Projects.
Committee on the Status of Endangered Wildlife in Canada. Assessment and Update Status Report on the Lake Ontario Kiyi and Upper Great Lakes Kiyi. Ottawa: Her Majesty the Queen in Right of Canada. 2005. Accessed April 22, 2011 at http://dsp-psd.pwgsc.gc.ca/Collection/CW69-14-431-2005E.pdf.
USGS Great Lakes Science Center. 2000. "Coregonus kiyi — kiyi" (On-line pdf). GLSC Fact Sheet 2000-2. Accessed July 09, 2011 at http://www.glsc.usgs.gov/_files/factsheets/2000-2%20Coregonus%20Kiyi.pdf.
Michigan Natural Features Inventory. 2007. "Coregonus kiyi" (On-line). Rare Species Explorer. Accessed April 22, 2011 at http://web4.msue.msu.edu/mnfi/explorer/species.cfm?id=11283.
Wisconsin Department of Natural Resources. 2009. "Kiyi (Coregonus kiyi)" (On-line). Endangered Resources Program Species Information. Accessed April 22, 2011 at http://dnr.wi.gov/org/land/er/biodiversity/index.asp?mode=info&Grp=13&SpecCode=AFCHA01070.
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NOAA. Lake Superior Food Web. Ann Arbor, MI: Great Lakes Environmental Research Laboratory. 2009. Accessed April 22, 2011 at http://www.glerl.noaa.gov/pubs/brochures/foodweb/LSfoodweb.pdf.
Carlander, K. 1969. Handbook of Freshwater Fishery Biology. Ames, IA: The Iowa State University Press.
Dewey, T. 2008. "Coregonus clupeaformis" (On-line). Animal Diversity Web. Accessed May 02, 2011 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Coregonus_clupeaformis.html.
Eakins, R. 2011. "Kiyi" (On-line). Ontario Freshwater Fishes Life History Database. Version 3.95.. Accessed July 09, 2011 at http://ecometrix.ca/fishdb/fish_detail.php?FID=94.
Froese, R., S. Kuosmanen-Postila, R. Reyes, A. Torres. 2011. "FishBase" (On-line). Accessed April 03, 2011 at http://www.fishbase.org/summary/SpeciesSummary.php?id=2672.
Hubbs, C., K. Lagler. 2004. Fishes of the Great Lakes Region. Ann Arbor, MI: The University of Michigan Press.
Tomelleri, J., M. Eberle. 1990. Fishes of the Central United States. Lawrence, Kansas: University Press of Kansas.