Otolith development and daily increment formation in redbreast tilapia Tilapia rendalli larvae and juveniles

抄録

Otoliths of the laboratory-hatched Tilapia rendalli were investigated for 29 days after hatching. The sagitta and lapillus were observed at hatching. They were round-shaped until 10th and 3rd day and becoming oval-shaped thereafter. Increments in the sagitta and lapillus were discernible throughout their development. Increment counts for both coincided with the number of days after hatching. The asteriscus only appearing in the fish larger than 8.00 mm of standard length was oval-shaped with an ambiguous core and invisible increments. These results revealed that the sagitta and lapillus were appropriate for determining the age in days while the asteriscus was unsuitable.