北部湾口眼镜鱼年龄与生长

Age and growth of moonfish, Mene maculata from mouth of the Beibu Gulf, South China Sea

摘要:

2010年5月至2011年4月, 对北部湾口海域作业的灯光围网和拖网渔船渔获物中的眼镜鱼进行逐月(除6、7月)采样, 通过生物学测定(1 025尾)及292枚(雌性: 148枚, 雄性: 144枚)脊椎骨的年龄鉴定, 对眼镜鱼年龄和生长进行研究。结果表明, 眼镜鱼脊椎骨上的年轮由宽窄相间的明带和暗带组成, 边缘增长率 (marginal growth increment, MGI)计算结果显示年轮形成时间主要在8—10月, 同期性腺成熟指数 (gonadosomatic index, GSI)也最高, 表明年轮形成时间与繁殖期时间同步, 即1年1个年轮。北部湾口眼镜鱼GSI高峰期(8—10月)与中上层水温高峰趋势相符, 表明眼镜鱼的产卵高峰期与中上层水温关系密切。北部湾口灯光围网和拖网渔获物中眼镜鱼的年龄组成为雌性0⁺~5⁺龄6个年龄组、雄性0⁺~4⁺龄5个年龄组。雌雄个体间生长差异不显著, 叉长与体质量的关系为W=6.00×10^-5L2.8415(n=1025, r²=0.94, P>0.05), 年龄生长方程为L_t=334.85[1-e^{-0.17(t+0.92)}]。北部湾口眼镜鱼在3⁺龄之前生长迅速, 之后生长逐渐减缓。

Abstract:

Fish age and growth are key biological parameters for the assessment of fisheries resources. By the purse seiners and trawlers catch sampling, a total of 1 025 individuals of moonfish, Mene maculata were collected monthly in the mouth of the Beibu Gulf, South China Sea from August 2010 to May 2011. The samples ranged from 83 to 256 mm with fork length (FL). By biological measurement and age identification of 292 (female: 148, male: 144) pieces of vertebrae section, the age and growth of M. maculata were studied. Results showed that the annuli was composited of opaque wide band and transparent narrow band which indicated they were formed once a year, from August to October by monthly changes in the Marginal Growth Increment (MGI). Moreover, the Gonadosomatic index (GSI) designated that the time of reproduction period and formed annuli were similar. Both the GSI and the pelagic water temperature peaked from August to October, which indicated the close relationship of M. maculata spawned periods and pelagic water temperature. Age was determined by reading annuli on vertebrae, and the estimated age ranges from 0⁺ to 5⁺ years for female and from 0⁺ to 4⁺ years for male. The females and males moonfish showed similar ages structure and growth patterns, and the body weight and fork length data fitted the function W=6×10^-5L2.8415 (n=1025, r²=0.94, P>0.05). The fork length and age data fitted the von Bertalanffy growth function L_t=334.85[1-e^{-0.17(t+0.92)}]. It can be safely concluded that moonfish grows faster before age three, and then slows down.