Shortjaw cisco COSEWIC assessment and status report: chapter 9
Habitat
In Lakes Superior, Michigan, and Huron, the shortjaw cisco generally inhabits waters 55 to 144 m in depth, although they have been recorded from as deep as 183 m and occasionally in more shallow water (Scott and Crossman 1973). Seasonal differences were noted in Lake Superior with movement into shallower water during spawning, and the fish inhabited 110-114 m in spring, 55-71 m in summer, and 73-90 m in winter (Dryer 1966). Hoff and Todd (2004) noted during 1999-2001 that Lake Superior shortjaw ciscoes were most abundant at the maximum depths at which they were collected in the 1920s, suggesting a shift to deeper water in the intervening decades. In Lake Nipigon, shortjaw ciscoes inhabit depths between 10-60 m, although the occasional individual has been captured deeper than 60 m (Turgeon et al. 1999).
Habitat preferences in smaller lakes are poorly known. Captures in George Lake, Manitoba from gillnets set in August 1996 between 36-57 m revealed that shortjaw ciscoes inhabited the very deepest stratum of the lake--occurring mostly in gillnets set at 45-47 m, but not in sets shallower than 42 m (Murray and Reist 2003). Likewise, shortjaw ciscoes were found to inhabit the deepest portions of Sandybeach Lake, Ontario, at depths ranging 22-38 m along with sympatric lake herring (Wain 1993). Certainly, once the lakes stratify, the fish will be found in the deeper waters of the hypolimnion. In contrast, shortjaw ciscoes were found quite shallow at depths of 2-16 m in Barrow Lake, Alberta (maximum depth=24 m; Steinhilber et al. 2002).
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