Lake Ontario and Great Lakes kiyi COSEWIC assessment and status report: chapter 9

Special Significance of the Species

Of the six cisco species identified as ‘endemic’ in the Laurentian Great Lakes (bloater, blackfin cisco, deepwater cisco, kiyi, shortjaw cisco, shortnose cisco ) by Koelz (1929), the kiyi is one of only three species (other species are C. hoyi and C. zenthicus) known to be extant. The ciscoes are the most notable of the few species endemic to the relatively young waterbodies of northern North America, and are believed to be one of few examples of the incipient species flock concept in North America (Smith and Todd 1984). As ‘endemic’ species, these ciscoes represent unique evolutionary and ecological processes. The Laurentian Great Lakes are no more than 18,000 years old (Dyke and Prest 1987); therefore, the ‘endemic’ ciscoes have likely evolved in the Great Lakes within the last 18,000 years (Smith and Todd 1984). Changes in gill raker morphology (e.g. number, length) over time, have minimized competition between the endemic ciscoes (Smith and Todd 1984). In addition to these unique processes shared by the endemic ciscoes, the kiyi exhibits unique adaptations to its deepwater habitat including enlarged eyes and pectoral fins.

The deepwater ciscoes were once a commercially important species in the Great Lakes and several species, including kiyi, are still harvested in the Canadian waters of Lake Superior. All six have been previously assessed by COSEWIC; the shortnose cisco was originally listed as Threatened in 1987 (re-assessed as Endangered in 2005), as was the shortjaw cisco (re-confimed in 2003); the deepwater (Extinct since 1953, re-confirmed in 2000), and blackfin (Threatened) were listed in 1988. The kiyi was first assessed as Special Concern in 1988, as was the bloater, the only Great Lakes cisco Not at Risk (COSEWIC 2004).

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