基于形态法的西北太平洋柔鱼种群结构研究

西北太平洋柔鱼是我国鱿钓渔业重要捕捞对象,种群结构是渔业生物学研究的基础内容.文中根据2007年7~10月40°N~45°N,151°E~158°E海域连续采集的1 342尾柔鱼样本,测定其胴长(ML)、腕长等12项形态指标,利用正态线性转化、主成分分析和判别分析等方法研究雌雄个体的种群结构.结果表明,该海域雌、雄柔鱼均存在大小2个种群.均数差异显著性表明,雌性个体2个种群在MW/ML和FW/ML存在显著差异,雄性个体在MW/ML和AL_3/ML存在显著差异,但其形态差异仍属于种内差异.主成分分析和逐步判别分析的判别准确率(雌性60.3%,雄性60.1%),说明所划分的种群在部分形态比指标上差异明显.研究认为,形态学指标可初步区分西北太平洋柔鱼种群,但需结合其他生态学指标和耳石等硬组织进一步划分.

Morphological Analysis on Population Structure of Neon Flying Squid(Ommastrephes bartramii) in the Northwest Pacific Ocean

Neon flying squid (Ommastrephes bartramii) in the northwest Pacific Ocean is an important fishing target in jigging fisheries for China but their population structure has not been well studied. In this paper, a total of 1 342 neon flying squid samples, collected continuously during Jul to Oct, 2007 in the waters bounded by 40°N～45°N and 151°E～158°E were used for population structure analysis and cohort identification. Twelve morphometrics of the samples were measured and analysed using Gaussian mixture, principle component analysis and discriminant analysis for cohort identification. These included mantle length(ML), mantle width(MW), fin length(FL), fin width(FW), head width(HW), tentacular length(TL), tentacular club length(TCL), arms Ⅰ length(AL_1), arms Ⅱ length(AL_2), arms Ⅲ length(AL_3), left arms Ⅳ length(LAL_4) and right arms Ⅳ length(RAL_4). The results indicated that two cohorts of significantly different ML were identified in both the male and female squids in these waters. Moreover, statistical analyses revealed that MW/ML and FW/ML were the two factors that made significant contributions to the differences between the 2 female cohorts (60.3%), in comparison with MW/ML and AL_3/ML for the 2 male ones (60.1%). These findings suggested that the populations of neon flying squid in the northwest Pacific Ocean could be morphologically identified but required further information such as ecological indicators and elemental fingerprint in otolith for validation.