褐点石斑鱼不同月龄形态性状的主成分及通径分析

为研究褐点石斑鱼不同月龄形态性状的生长规律特征及形态性状对体质量的影响,采用主成分分析和通径分析方法对3月龄、8月龄和13月龄褐点石斑鱼个体全长(X_1)、体长(X_2)、头长(X_3)、体宽(X_4)、体高(X_5)、尾柄高(X_6)、眼径(X_7)、眼后头长(X_8)和体质量(Y)9个性状进行分析。结果显示,(1)不同月龄褐点石斑鱼各形态性状对体质量的相关系数均达到极显著水平,不同月龄相同形态性状与体质量的相关性存在差异。(2)各月龄第一主成分均指向褐点石斑鱼的生长发育情况;第二主成分均指向眼睛发育情况;但3月龄、8月龄和13月龄第三主成分分别指向尾部发育、体宽发育及体高发育。(3)3月龄阶段,全长、体高、体宽及尾柄高对体质量的直接通径系数达到显著水平;8月龄阶段,全长、体宽、尾柄高及眼后头长对体质量的直接通径系数达到显著水平;13月龄阶段,全长、体高、体宽及体长对体质量的直接通径系数达到极显著水平,并建立了3个月龄组的不同形态性状对体质量最优回归方程。(4)褐点石斑鱼3~13月龄阶段的体长(L)与体质量(W)的关系为W=0.0378L2.873(R~2=0.9596),说明该阶段生长属于等速生长。研究表明,在褐点石斑鱼的不同生长阶段,各形态性状对体质量的影响有所不同,建议以全长(3~13月龄)作为育种工作的目标性状,为褐点石斑鱼早期生长发育阶段的选择育种工作和测量指标提供科学依据。

Principal component and path analysis of morphological traits of Epinephelus fuscoguttatus at different month ages

In order to research growth characteristics and the effect of morphological traits on body mass of Epinephelus fuscoguttatus at different month ages, data of total length (X1), standard length (X2), head length (X3), body width (X4), body depth (X5), caudal peduncle depth (X6), eye diameter (X7), head length after eye (X8) and body mass (Y) were collected at 3 months, 8 months and 13 months of age in this study. The morphological traits were analyzed by principal component and path analysis. The results showed that: (1) the correlation coefficients between all morphological traits at different age phases and body mass were extremely significant. And the correlation coefficients between each trait and body mass differed at different age development stages. (2) The first principal component reflected the growth and development of E. fuscoguttatus at different growth phases. The second principal component reflected the development of eye at different month ages. Thes third principal component was different and reflected the tail development at 3-month-old, body width development at 8-month-old and body height development at 13-month-old. (3) The trait with strongest direct effect on body mass was total length at all the age phases (0.742, 0.776 and 0.840). The path coefficients of four morphometric attributes (X1,X5, X4,X6) for 3-month body mass reached significant difference level. The path coefficients of X1,X4,X6, and X8 for 8-month body mass were also significant. The path coefficients of X1,X5,X4 and X2 for 13-month body mass were highly significant. The multivariate regression equation was Y3-month-old=–36.774+3.992X1+2.295X5+2.759X4+2.186X6,Y8-month-old=–64.569+7.020X1+6.480X4+6.754X6+50.926X8, and Y13-month-old=–302.340+18.128X1+17.688X5–28.463X4+5.928X2. This result suggests that the vital traits that affected body mass at different growth phases were different. (4) The relation equation between standard length and body mass was W=0.0378L2.873 (R2=0.9596) in 3-month to 13-month stages of E. fuscoguttatus, which demonstrated the standard length and body mass growth at similar velocity. We proposed that the total length was the target trait for selective breeding of E. fuscoguttatus at 3–13 month-old stages .This paper provides theoretical evidence and measure targets for breeding of E. fuscoguttatus in the early growth stage in aquaculture.