Age Comparisons

Lake Champlain Lake Whitefish

Compare age estimates between two readers or from two structures taken from Lake Champlain (VT) Lake Whitefish.
Exercise
Age Comparisons
Whitefish
Author

Derek H. Ogle

Published

Dec 19, 2022

Modified

Feb 13, 2023

Herbst and Marsden (2011) compared the precision, bias, and reader uncertainty of ages estimated from the scales, dorsal fin rays, and otoliths of 151 Lake Whitefish (Coregonus clupeaformis) captured from Lake Champlain in 2009. The initial age estimates from two readers and a consensus age between the two readers from each of the three structures (variables are the structure name with a “1” or “2” appended to denote the reader or “C” for the consensus age) are in WhitefishLC.1

1 See “CSV file” link in “Source” section of linked page.

 

Version A - Otoliths

  1. Use tabular, graphical, and statistical methods to describe any apparent bias in age estimates from otoliths between the two readers.
  2. Describe precision in age estimates between the two readers for otoliths.
  3. Describe any apparent bias between the consensus age estimates from otoliths and scales.

 

Version B - Scales

  1. Use tabular, graphical, and statistical methods to describe any apparent bias in age estimates from scales between the two readers.
  2. Describe precision in age estimates between the two readers for scales.
  3. Describe any apparent bias between the consensus age estimates from scales and fin rays.

 

Version C - Fin Rays

  1. Use tabular, graphical, and statistical methods to describe any apparent bias in age estimates from fin rays between the two readers.
  2. Describe precision in age estimates between the two readers for fin rays.
  3. Describe any apparent bias between the consensus age estimates from fin rays and otoliths.

 

Solution Code:

Available upon request to students not in a class. Contact fishR maintainers.

References

Herbst, S. J., and J. E. Marsden. 2011. Comparison of precision and bias of scale, fin ray, and otolith age estimates for Lake Whitefish (Coregonus clupeaformis) in Lake Champlain. Journal of Great Lakes Research 37:386–389.

Reuse