A semi-automated method for daily age estimation in larval populations by discriminant function models
Authors
Quintanilla-Hervás, J.M. (José María); Quintanilla-Hervás, L.F. (Luis Francisco); García-García, A. (Alberto)Date
2014-10-02Type
research articleKeywords
European anchovy larvae Western Mediterranean Daily growth Discriminant functions Age predictive modelAbstract
Discriminant analysis including the best age-correlated variables selected by SMLR’s to construct a predictive
model based on somatic and otolith biometry was applied. Age of anchovy larvae ranging from
10 to 12 mm collected along Western Mediterranean coasts during MEDIAS209 survey were estimated
by otolith microstructure analysis and compared with the number of daily increments estimated by the
model. The model compound by Perimeter2 + Area2 was able to estimate correctly the age of the otoliths
in 75% of the cases assuming
±1 day of error increasing to 90% assuming
±2 days of error with mean
values of APE (3.33%) and CV (4.71%) systematically low. The results indicate the precision of the increment
estimates. Moreover, no differences between the estimated ages from direct readings and those
estimated by the model were observed. The proposed method implies a reduction in the subjectivity
factor and the cost/benefit ratio for ageing studies in fish larvae.
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