Results of the 2004 cod ageing exchange using randomly selected samples from the first quarter of the 2002 NEFSC commercial samples. (A) Agreement plot, showing the ages attained by the U.S. age readers versus the ages attained by the Canadian age reader. A small amount of noise was added to the data to improve visibility of overlapping data points. (B) Age-frequency table, showing each country's ages. Numbers in the shaded boxes indicate agreement between the two ages. Numbers above this diagonal indicate fish which were given higher ages by the Canadian age reader; those below the shaded boxes were given higher ages by the U.S. age readers. Total age frequencies are given by age for both countries. (C) Results summary, indicating results for the U.S. readers relative to each age for the Canadian reader.

Species: Cod Test Type: 2004 U.S./Canada Ageing Exchange
Sample Source: 2002 Commercial Samples (Q1) Stock Area: Georges Bank
Age Reader*: NM/NS vs. BH Date Completed: Winter 2003-2004
Number Tested: 46²    
CV: 2.40% Agreement: 89.1%
Bowker's test: Not significant
  *The U.S. age readers are listed first; this is not meant to imply that any reader's ages are expected to be more reliable. Both U.S. age readers worked together to age these samples.
  ²For 22 fish sampled in January, one year was added to each of the Canadian ages because of the different birthdates applied by each laboratory.


A. Agreement Plot

Cod Agreement Plot

B. Age-Frequency Table

Age Age (BH)
(NM/NS) 0 1 2 3 4 5 6 7 8 9 10 Total
Total 6 11 22 2 2 1 2 46
0
1
2
3
4 6 2 8
5   9 9
6 21 1 22
7 2 2
8 2 1 3
9    
10 1 1 2


C. Results Summary

Age (BH) N N Agreed Percent Agreed Average Age (NM/NS)
4 6 6 100 % 4.00
5 11 9 82 % 4.82
6 22 21 95 % 6.18
7 2 2 100 % 7.00
8 2 2 100 % 8.00
9 1 0 0 % 8.00
10 2 1 50 % 8.00


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