Results of the blue whiting otolith exchange
Authors
Meijide-Cameselle, M. (Manuel)Date
1990Type
working paperAbstract
At the Blue Whiting Assessment Working Group, it was agreed
to carry out an otolith exchange programme to solve the
ageing problems pointed out by ACFM.
A sample of 115 otoliths from Division IXa was exchanged, and
seven countries are taking part in the exchange, although it
has not yet been completed. One otolith from each fish was
sectioned and the other preserved in aqueous solution. In
the whole otoliths a tendency to lose one or two early rings
was observed, and in the sectioned otoliths the presence of
false rings was the cause of misreading. A combination of
both methods would probably improve the age determinations,
but is unfortunately time consuming.
The agreement between the readers was in general low, from
both sliced and whole otoliths.The ANOVA with a significance
level of 5% showed that the mean age of the sample is
different for various readers, and the Tukey test showed that
there are no significant differences between three readers,
at the same signif ...
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