Comparison of scales, pectoral fin rays, and otoliths for estimating age, growth, and mortality of lake whitefish, Coregonus clupeaformis, in Great Slave Lake / Xinhua Zhu ... [et al]. : Fs70-5/2016-115E-PDF

“It has been well documented that otoliths are the preferred hard structure for estimating the age of Coregonids. Additionally, the slower growth due to short growing seasons experienced in populations from the sub-arctic may alter the utility of alternative, non-lethal structures for estimating ages. In this study, scales, pectoral fin rays and otoliths from Great Slave Lake (GSL) Lake Whitefish Coregonus clupeaformis (Mitchill, 1818) were compared for differences in processing time efficiency, annular assignments, precision biases and reader uncertainty. Among the three ageing structures, pectoral fin rays took longest to process followed by scales and then otoliths. Readers’ confidence was highest for otoliths, followed by pectoral fin rays and then scales. Annuli in ground and baked otoliths appeared as dark, narrow lines with regular spacing; however, annuli in pectoral fin rays and scales were more variable in appearance. Readings of pectoral fin rays had the highest and largest uncertainty while readings of otoliths had the lowest uncertainty. Within-reader precision was highest for age estimates from otoliths, followed by scales and pectoral fin ray sections. Reader confidence, within reader precision and age estimates themselves, were all affected by age structure and age class”--Abstract, p. iv.

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