Results of the 2004 cod aging exchange using randomly selected samples from the first quarter of the 2002 NEFSC commercial samples. (A) Age-bias plot, showing the average age attained by the DFO age reader versus the ages attained by the NEFSC age reader. Error bars indicate 95% confidence intervals. (B) Age-frequency table, showing each reader'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 DFO age reader; those below the shaded boxes were given higher ages by the NEFSC age reader. Total age frequencies are given by age for both readers. (C) Results summary, indicating results for the NEFSC reader relative to each age for the DFO reader.

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


A. Age-Bias Plot

Cod Age-Bias Plot

B. Age-Frequency Table

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