饥饿对眼斑双锯鱼(Amphiprion ocellaris)幼鱼形态性状与体质量相关性的影响

本研究运用多变量路径分析技术，分析饥饿7d （饥饿组）和非饥饿状态下（对照组）眼斑双锯鱼（Amphiprion ocellaris）幼鱼的体质量和形态特征之间的相互依赖关系。实验对两种状态下的幼鱼进行体质量（g）和全长（L₁）、体长（L₂）、体高（L₃）、头长（L₄）、头高（L₅）、吻长（L₆）、尾柄长（L₇）、尾柄高（L₈）、背鳍前距（L₉）、胸鳍前距（L₁₀）、腹鳍前距（L₁₁）、臀鳍前距（L₁₂）、眼径（L₁₃）等13个形态性状（mm）的准确测定。采用相关系数、决定系数、通径系数和回归方程等统计方法分析两种状态下眼斑双锯鱼幼鱼的形态性状对体质量的影响。结果显示，两个实验组14个性状间均存在极显著相关关系（P<0.01）；剔除共线性影响后，通径分析筛选出了对照组对体质量影响显著的4个形态性状，直接作用由大到小排序：L₃ > L₂ > L₆ > L₅，间接作用由大到小排序：L₅ > L₆ > L₂ > L₃，单独决定系数由大到小排序：L₃ > L₂ > L₅ > L₆；饥饿组筛选出5个形态性状，直接作用由大到小是L₃ > L₂ > L₁₂ > L₆ > L₇，间接作用由大到小是L₇ > L₁₂ > L₂ > L₆ > L₃，单独决定系数由大到小为L₃ > L₂ > L₁₂ > L₇ > L₆；对照组和饥饿组体质量与形态性状的多元回归方程分别为：W=-0.819+0.106L₃+0.027L₂+0.006L₆-0.050L₅，R²=0.94；W=-0.778+0.078L₃+0.016L₁₂+0.015L₂-0.055L₇+0.018L₆，R²=0.930。结果表明，饥饿影响了形态性状与体质量的相关性，但饥饿和非饥饿状态下体高、体长和吻长都是影响体质量的关键因子，其中体高是最主要的因子，该结果可在眼斑双锯鱼的选育工作中对选育指标的确定提供理论支持。

Effect of starvation on the correlation between morphological characters and body weight in Amphiprion ocellaris

Amphiprion ocellaris is one of the most popular marine ornamental fish species. Its growth performance has been degraded during artificial culture, so selective breeding programs aiming to improve growth is necessary. Some individuals of A. ocellaris may be starved for a relatively long period by some factors during artificial culturing. However, it remains unclear whether starvation has an effect on selecting suitable breeding index. In this study, multivariate path analysis was used to describe the relationship between body weight and morphological characteristics of juvenile A. ocellaris after 7 days of starvation (starvation group) and non-starvation (control group). Body weight (g) and 13 morphological characters (mm) such as total length (L₁), standard length (L₂), body depth (L₃), head length (L₄), head depth (L₅), snout length (L₆), caudal-peduncle length (L₇), caudal-peduncle depth (L₈), pre dorsal length (L₉), pre pectoral length (L₁₀), pre pelvic length (L₁₁), pre anal length (L₁₂), and eye diameter(L₁₃) were measured accurately. The statistical methods such as correlation coefficient, determination coefficient, path coefficient and regression equation were used to analyze the effects of morphological characteristics on body weight under two conditions. The results showed that there was a significant correlation between the 14 personality traits of the two experimental groups (P<0.01); after removing the collinearity effect, the path analysis selected four morphological traits of the control group that had a significant impact on the body weight. The direct effect was ranked from large to small in the order of L₃ > L₂ > L₆ > L₅, and the indirect effect was ranked from large to small L₅ > L₆ > L₂ > L₃, and the order of independent determination coefficient was L₃ > L₂ > L₅ > L₆. For the starvation group, 5 morphological characters were selected, and the direct effect was L₃>L₂>L₁₂>L₆>L₇, the indirect effect was L₇> L₁₂ > L₂ > L₆ > L₃, and the independent determination coefficient was L₃ > L₂ > L₁₂ > L₇ > L₆. The maximum collaborative coefficient of determination to body weight was body height and body length both in the control group and the starvation group. For the control group and the starvation group, the multiple regression equations of body weight and morphological characters were W=-0.819+0.106L₃+0.027L₂+0.006L₆-0.050L₅, R²=0.941; W=-0.778+0.078L₃+0.016L₁₂+0.015L₂-0.055L₇+0.018L₆, R²=0.930. The results showed that starvation affected the correlation between morphological traits and body weight, but body depth, body length and snout length were the key factors affecting body weight under starvation and non-starvation conditions, among which body depth was the most important factor. The results could provide theoretical support for the determination of breeding indexes in the selection and breeding work of A. ocellaris.