Distinctions Between the Broad Whitefish, Coregonus nasus, and Other North American Whitefishes

Abstract

176 specimens of C. nasus and 121 of "humpback" whitefish (allied to C. clupeaformis) were examined from 15 North American localities where the two kinds occurred sympatrically. No previously published criteria were effective in separating the two kinds at all sizes in all localities, but combinations of certain pairs of measurements chosen to compensate for non-isometric growth allowed identification of all individuals examined. Length of longest gill raker was less than 20% of the interorbital width in all C. nasus, more in all "humpbacks". Means of 15 other proportional or meristic characters differed consistently between sympatric species pairs. C. nasus is a distinct and widespread species. Its distribution and nomenclature are reviewed.