Daily growth increments in the lapillus of the otoliths of one-year-old mpasa,
Opsaridium microlepis, were investigated to estimate the early growth and
breeding period. Lapillus increment counts, as age in days, revealed the breeding
period to be from May to October. A logistic curve was fitted to total length (L, mm)
at age (T, days) data as L = 182.30/(1+e-((T-151.39)/43.46)). Another model that
explains lapillus radii (Am)total length and age/lapillus radii relationships was
formulated as L = 202.63/(1+e-((430.74 Ln(T)-2160.52)/155.62)). Estimated growth
rates from hatching to 75, 76-225 and 226-300 days of age based on above models
were about 0.30, 0.90 and 0.30 mm total length per day, respectively. This growth
pattern illustrates that mpasa could reach 20 cm total length within a year of hatching.