| 英文摘要 |
Age and growth of black marlin (Makaira indica) in the waters off eastern Taiwan were studied from counts of growth bands on cross sections of the third spine of the first dorsal fin. Length and weight data and the dorsal fin spines were collected monthly at the fishing port of Shinkang (southeast of Taiwan) from July 2004 to April 2006. In total, 923 dorsal fins were collected, of which 874 (95%)(187 males and 687 females) were aged successfully. Trends in the monthly mean marginal increment ratio indicated that growth bands formed once a year. Two methods were used to back-calculated the length of presumed ages, and growth was described by using the standard von Bertalanffy growth function and the Richards function. The most reasonable and conservative description of growth assumes that length-at-age follows the standard von Bertalanffy function for male Lt = 305.8〔1 – e-0.125 (t +2.274)〕 and female Lt =396.7〔1 – e-0.094 (t + 1.825)〕, and that the relationship between spine radius and lower jaw fork length (LJFL) follows a power function. Growth differed significantly between the sexes; females grew faster and reached larger sizes than did males. The maximum sizes in our samples were 368.2 cm LJFL for females and 261.5 cm LJFL for males. |
