Age determination of trachinotus ovatus (L.)‎ based on otolith weight

Abstract EN

Age determination of fish, from a population having a considerable variation in size at age, has been investigated using the relationship between otolith weight (Wo) and fish length (Lf), which has been described by many authors to be influenced by growth rate.

In such a population of Trachinotus ovatus (L.), an index of age can be obtained for individual fish by estimating the equivalent otolith weight (We) at a particular fish length (Lf) and the appropriate value of modal length (Lm), using the otolith weight-fish length relationship determined for each age group.

This index of age can be calculated from the formula : We = 0.29 (Lm – Lf) + Wo It is concluded that this model not only permits a much greater proportion of fish to be assigned ages than is possible with otolith alone, but also enables these age groups to be verified as year classes.