Results of the 2011 haddock ageing exchange
using randomly selected age-stratified samples from the 2010 NEFSC autumn survey.
(A) Agreement plot, showing the ages attained by the Canadian age reader versus the ages attained by the U.S. 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 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 U.S. age reader; those below the shaded boxes were given higher ages by the Canadian age reader. Total age frequencies are given by age for both readers. (C) Results summary, indicating results for the Canadian reader relative to each age for the U.S. reader.
2011 U.S./Canada Ageing Exchange
2010 Autumn Survey (201004)
DK vs. SJS
*The Canadian age reader is listed first; this is not meant to imply that either reader's ages are expected to be more reliable.
²Two samples (aged 3 & 6) may have been accidentally switched. If these samples are excluded, the precision levels increase to 89.6% agreement and 2.23% CV.