The Morphological Basis of Fish Age Estimation Methods Based on the Otolith of Nemadactylus macropterus

Abstract

Relationships between the anatomy of the endolymphatic sac, sac otoconia, sagitta and astericus of Nemadactylus macropterus (Cheilodactylidae: Teleostei) are described and the variation in opaque and hyaline zones, sulcal checks, and daily microincrement widths along different growth axes of the otolith measured. The quantitative morphology of the otolith is used to compare the different age estimation techniques for N. macropterus that are based on opaque and hyaline zones, sulcal checks, and daily microincrements. Comparison of the different methods shows that at the present state of knowledge daily microincrements present the most credible age estimation method for N. macropterus.