| 英文摘要 |
Histological techniques were used to evaluate the reproductive dynamic of black marlin Makaira indica in the waters off eastern and southwestern Taiwan and in the South China Sea. Random samples of 5,188 length-weight data and 626 gonad specimens (124 males, 502 females) were collected during September 2004 to April 2007 at Shinkang and Tungkang fish markets. The eye-to-fork lengths (EFL) range from 110.9 to 382.0 cm. Based on the monthly gonadosomatic index (GSI), oocyte diameter (OD), proportion of maturing stages, OD distributions and the macroscopic observation of ovaries, black marlin did not spawn in the waters off eastern Taiwan, but mature females were observed in waters off southwestern Taiwan and in South China Sea. The estimated size at 50% maturity was 194.92 cm EFL for females, the EFL at first maturity was 158 cm for male. The proportion of mature females with ovaries containing postovulatory follicles was 0.18 on average during the spawning season of March to April, suggesting that on average, the black marlin spawns every 1.89 day. Average batch fecundity for 19 females was 1.52 !O 0.2 (mean !O S.E.) million eggs, and the relative batch fecundity was 105.72 !O 11.96 eggs per gram of body weight.The relationship between batch fecundity in millions (BF) versus eye fork length (EFL, in cm) was BF=2!N10^-12 EFL^8.05 (R^2 = 0.43; n = |
