Explorative analysis on red mullet (Mullus barbatus) ageing data variability in the Mediterranean

The uncertainty in age estimation by otolith reading may be at the root of the large variability in red mullet (Mullus barbatus) growth models in the Mediterranean. In the MEDITS survey, red mullet age data are produced following the same sampling protocol and otolith reading methodology. However, ageing is assigned using different interpretation schemes, including variations in theoretical birthdate and number of false rings considered, in addition to differences in the experience level of readers. The present work analysed the influence of these variations and the geographical location of sampling on red mullet ageing using a multivariate approach (principal component analysis). Reader experience was the most important parameter correlated with the variability. The number of rings considered false showed a significant effect on the variability in the first age groups but had less influence on the older ones. The effect of the theoretical birthdate was low in all age groups. Geographical location had a significant influence, with longitude showing greater effects than latitude. In light of these results, workshops, exchanges and the adoption of a common ageing protocol based on age validation studies are considered fundamental tools for improving precision in red mullet ageing.

Keyword(s)

Mullus barbatus, age variability, MEDITS, Mediterranean, reader effect, false rings, date of birth

How to cite
Carbonara Pierluigi, Zupa Walter, Anastasopoulou Aikaterini, Bellodi Andrea, Bitetto Isabella, Charilaou Charis, Chatzispyrou Archontia, Elleboode Romain, Esteban Antonio, Follesa Maria Cristina, Isajlovic Igor, Jadaud Angelique, Garcia-Ruiz Cristina, Giannakaki Amalia, Guijarro Beatriz, Kiparissis Sotiris Elias, Ligas Alessandro, Mahe Kelig, Massaro Andrea, Medvesek Damir, Mytilineou Chryssi, Ordines Francesc, Pesci Paola, Porcu Cristina, Peristeraki Panagiota, Thasitis Ioannis, Torres Pedro, Spedicato Maria Teresa, Tursi Angelo, Sion Letizia (2019). Explorative analysis on red mullet (Mullus barbatus) ageing data variability in the Mediterranean. Scientia Marina. 83 (S1). 271-279. https://doi.org/10.3989/scimar.04999.19A, https://archimer.ifremer.fr/doc/00591/70320/

Copy this text