Tag-overlap statistic calculation method

The formula to calculate the tag overlap statistic is specified in footnote 3 of CM 41-01 Annex C. This formula is used to compare the length frequency distribution of tagged fish to that of caught fish. However, observers do not measure the lengths of all caught and retained fish which complicates the calculation of this similarity indicator. Here we describe the rationale and preferred method to estimate the length frequency distribution of caught fish.