匙吻鲟稚鱼形态性状对体重的影响效果分析

Effects of morphometric traits on body weight for juvenile Polyodon spathuln

随机选取30日龄和41日龄匙吻鲟(Polyodon spathuln)稚鱼各120尾,分别测定其体重、全长、头长、吻长、体宽、头宽、眼间距、体高和头高共9个性状指标。采用相关分析、通径分析和多元回归分析方法,分别计算了匙吻鲟以形态性状为自变量对体重(Y)的相关系数、通径系数和决定系数,定量地分析了形态性状对体重的影响效果。结果表明,除41日龄匙吻鲟头长与体重的表型相关系数未达到显著水平外,其余各性状与体重的表型相关系数均达到极显著水平(P<0.01);通径分析显示,全长、体宽、头宽和头高对30日龄匙吻鲟体重的通径系数达到显著水平(P<0.01),全长、体高、头宽、眼间距、体宽对41日龄匙吻鲟体重的通径系数达到显著水平(P<0.01)。可见,不同日龄的匙吻鲟各形态性状对体重的影响有差异,但全长、体宽和头宽对体重的影响均达到显著水平,其中全长对体重的直接影响均最大。通径分析结果与决定系数分析结果的变化趋势一致。应用逐步多元回归分析,将偏回归系数显著的变量对体重建立多元回归方程,30日龄和41日龄匙吻鲟形态学指标对体重的回归方程分别为:LgY=-3.808+1.759 Lg X1+0.235 Lg X5+0.336 Lg X7+0.308 Lg X4和LgY=-3.374+1.328 Lg X1+0.591 Lg X8+0.253 Lg X4+0.231 Lg X6+0.198 Lg X5。两个方程的回归关系均达到了极显著水平(P<0.01)。

The relationships between morphometric traits and body weight of juvenile Polyodon spathuln for 30 d and 41d were analyzed in this study.Nine morphometric traits including total length（X1）,head length（X2）,snout length（X3）,body width（X4）,head width（X5）,interorbital distance（X6）,body depth（X7）,head depth（X8） and body weight（Y） from 120 P.spathuln were measured.The correlation coefficients and path coefficients were calculated by correlation analysis,path analysis and multiple regression analysis.The results showed that all the correlation coeffi-cients of each morphometric trait to body weight were all at extremely significant level（P〈0.01）,excepting for the correlation coefficients of head length to body weight of 41 d P.spathuln.The path coefficients of total length,body width,head width and head depth for 30 d P.spathuln to body weight all achieved very significant level（P〈0.01）.The path coefficients of total length,body depth,head width,interorbital distance and body width for 41d P.spathuln to body weight all achieved very significant level（P〈0.01）.There were some difference in the direct effect of mor-phometric traits to body weight in different years old,but the path coefficients of total length,body width and head width to body weight for 30 d and 41 d P.spathuln all achieved very significant level（P〈0.01）,among which total length was the most predominant variable to affect body weight.The diversification of determinant coefficients analysis was consistent with that of path analysis.The morphometric traits which reached level of significance（P〈0.05） were used to establish the multiple regression equations,which were LgY =-3.808 ＋ 1.759 Lg X1 ＋ 0.235 Lg X5 ＋ 0.336 Lg X7 ＋ 0.308 Lg X4 in 30 d P.spathuln and LgY =-3.374 ＋ 1.328 Lg X1 ＋ 0.591 Lg X8 ＋ 0.253 Lg X4 ＋ 0.231 Lg X6 ＋ 0.198 Lg X5 in 41 d P.spathuln,respectively.