FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

A total of 26,330 fork length measurements (FL) of Coryphaena hippurus collected daily from January 2004 to July 2005 at Shingkang fish market, Taitung were used to fit von Bertalanffy growth curves by using the MULTIFAN. The estimated von Bertalanffy growth parameters for female were: growth coefficient (K) = 0.605 yr^-1, asymptotic length (L∞) = 134.6 mm, and estimated FL at ages 1 and 2 were FL1 = 66.77 cm, and FL2 = 97.56 cm respectively; and K = 0.707 yr^-1, L∞ = 143.1 mm, FL1 = 77.95 cm, FL2 = 110.96 cm for males. Two age classes were distinguished and their age composition were: age class 1(85.5 %), age class 2(14.5 %) for females and age class 1(85.1 %), age class 2(14.9 %) for males. The landings were mainly composed of age class 1 and age class 2 fish. Mortality estimates were as follows: Z = 1.46 yr^-1, M = 0.82 yr^-1, and F = 0.64 yr^-1 for females and Z = 1.51 yr^-1, M = 0.89 yr^-1, and F = 0.62 yr^-1 for males. Exploitation rates were 43.9% and 41.1% for females and males, respectively.