2017 Volume 83 Issue 2 Pages 174-182
Age and growth of red tilefish Branchiostegus japonicus caught from June to December, 2012 in western Wakasa Bay, Japan, were investigated based on otolith analyses using the cross-section and surface methods. Assuming annual formation of ring marks and a hatching date of September 1, which was inferred based on observed monthly change in the proportion of mature females (GSI≥2.5), ages were assigned to individuals according to the number of ring marks in the sectioned otoliths. Since there were almost no one- or two-year-old fish specimens sampled, back-calculated length data of these fish were complemented using otoliths of ring groups 1-3 by the surface method. Briefly, the first and second ring radii of each specimen were substituted into relational expressions between otolith radius and standard length of females and males. Length-at-age data were fitted to the von Bertalanffy growth equations by a non-linear least squares method. The equations were estimated as follows: Lt=276(1−exp−0.490(t−0.215)) for females and Lt=389(1−exp−0.320(t−0.0483)) for males, where Lt is the standard length (mm) at age t. The maximum ages observed were 18 and 14 years for females and males, respectively.