Life History Variations of Anadromous Cisco (Coregonus artedii), Lake Whitefish (C. clupeaformis), and Round Whitefish (Prosopium cylindraceum) Populations of Eastern James–Hudson Bay

Abstract

Differences in life history among three species of anadromous coregonines from La Grande River, James Bay, were significant with lake whitefish (Coregonus clupeaformis) and round whitefish (Prosopium cylindraceum) displaying reproductive patterns more typical of harsh northern environments and characteristic of "K-selection," relative to cisco (Coregonus artedii). Interspecific differences at La Grande River were more apparent than intraspecific differences in life history traits of cisco and lake whitefish over the James–Hudson Bay range. Although cisco exhibit decreasing reproductive effort independent of growth over the North American range, thus conforming to life history theory, both growth and reproductive effort are reduced northwards over their James–Hudson Bay range. The observations suggest that physiological constraints related to the shorter growing season at the northern limit of cisco's coastal Hudson Bay range may overwhelm expected coadapted life history traits. Lake whitefish exhibit reduced reproductive effort independent of variations in growth northwards over their North American and James–Hudson Bay coastal range; this suggests coadaptation of life history traits that permit survival at northern sites.Key words: reproduction, growth, life history theory, anadromous coregonines, James–Hudson Bay