Post-season Review

Last modified on Feb 25, 2019

1. Another reader ages a set percentage from each project (20%–30%).

  • Most locations use some type of multiple independent reads to assess precision. For example, both Oregon Department of Fish and Wildlife (ODFW) and Idaho Fish and Game (IDFG) have two trained readers conduct initial reads independent of one another. Reads are blind with no knowledge of biological data. Only basin, date, species, and stock information are known.

2. Review differences and discuss.

  • Once completed, the two readers review the disagreements and confirm the age.

3. Plot data to identify outliers, examine length versus age.

  • After all ages are assigned, data are plotted to identify outliers, and body lengths are plotted against the age estimates.
  • Sometimes change age.
  • Most often, results in potential data discrepancy.
  • Once completed, they validate age estimates by checking for CWTs. This does not validate the ages or check for accuracy, because the ages of the fish are not known.

4. Validate ages, check for CWTs, if available.

5. Difficult ages and projects.

  • May read higher percentage of scales in areas where reads conflict.