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Vol. 48 No. 5, 2009
Validation of Annular Deposition in Scales and Otoliths of Flathead Mullet Mugil cephalus
Chih-Chieh Hsu1 and Wann-Nian Tzeng1,2,*
1Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei 106, Taiwan
2Department of Life Science, College of Life Science, National Taiwan University, Taipei 106, Taiwan
Chih-Chieh Hsu and Wann-Nian Tzeng (2009) Age
estimation of fish is essential for understanding their life history
and population dynamics, and for assessing and managing stocks.
The periodicity of age marks of both scales and otoliths of flathead
mullet Mugil cephalus was
validated using cultured fish of known ages, and these were compared to
those of wild ones. Annuli in scales were characterized by dense
circuli in the basal area, merged circuli in the lateral-basal area,
and interrupted circuli in the lateral area of the scale. Annuli
in whole otoliths were characterized by an opaque zone under both
reflected and transmitted light. In acid-etched sectioned
otoliths, annuli were defined by dense concentric rings. Annuli
of both scales and otoliths of M. cephalus
were coincident and were deposited once a year during winter.
Scales are convenient for age estimation because there is no need for
special treatment. Preparing otolith sections for etching is
time-consuming and costly, but the otolith microstructure and
microchemical analyses can provide additional life-history information.
Key words: Mugil cephalus, Otolith, Scale, Annulus, Age estimation.
*Correspondence: Tel: 886-2-33662887. Fax: 886-2-23639570. E-mail:wnt@ntu.edu.tw
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