中国鲎人工繁育及1龄稚鲎形态性状对体质量的影响

Effects of Morphological Characters on Body Weight of Artificially Bred the First Instars of Horseshoe Crabs (Tachypleus tridentatus)

中文关键词: 中国鲎  人工繁育  形态性状  相关分析  通径分析

英文关键词: Tachypleus tridentatus  Artificial propagation  Morphological trait  Correlation analysis  Path analysis

中文摘要:

      2018年5~9月，在广东湛江对中国鲎(Tachypleus tridentatus)进行人工繁育技术初步研究。在水温为28℃~32℃、盐度为26~30、pH为7.4~7.8条件下，9对中国鲎共产卵8.713×104粒，受精率为56%~68%；受精卵历时约45 d后，胚胎发育孵化成1龄稚鲎，孵化率达92%，共获得1龄稚鲎4.827万尾。随机取样人工繁育1龄中国鲎500尾，测量头胸甲长(X1)、头胸甲宽(X2)、头胸甲高(X3)、腹部长(X4)和体质量(Y) 5个形态性状，应用相关分析、多元回归、通径分析、决定系数分析等方法，分别计算得出各个形态性状对体质量的相关系数、通径系数和决定系数，进一步分析形态性状对体质量的直接和间接作用。结果显示，所有形态性状与体质量的相关系数均达到极显著水平(P<0.01)。各形态性状对体质量的通径系数均达到极显著水平(P<0.01)，其中，通径系数最大的是头胸甲宽，说明头胸甲宽对体质量的直接作用最大。决定系数分析结果与通径分析结果一致，各表型性状对体质量的总决定系数Σd=0.863，表明所选形态性状是影响体质量的主要性状。通过逐步回归分析方法，经偏回归系数显著性检验，建立了以体质量为因变量，以头胸甲长、头胸甲宽、头胸甲高和腹部长为自变量的多元回归方程：Y=‒0.228+0.248X1+ 0.073X2+0.333X3+0.073X4。本研究表明，1龄中国鲎的头胸甲宽对体质量的影响最大，种质评价和放流苗种筛选应以头胸甲宽度为首选依据。

英文摘要:

      Tachypleus tridentatus is a rare marine living fossil with immense economic and scientific research value. However, recently, over fishing and indiscriminate killing have led to a sharp decline in the number of horseshoe crabs. Artificial release proliferation is not only an important way to recover horseshoe crab populations, but also to protect biodiversity and promote the sustainable development of fishery. We conducted a preliminary study on artificial breeding of horseshoe crabs T. tridentatus in Zhanjiang, Guangdong Province from May to September 2018. When the water temperature was 28℃~ 32℃, salinity was 26~30, and pH was 7.4~7.8, 9 pairs of T. tridentatus laid 87130 eggs with a fertilization rate of 56%~68%. After 45 days, the embryos hatched into the first instars of juvenile T. tridentatus. The hatching rate was 92%, and 48268 T. tridentatus larvae were obtained. To study the correlation between phenotypic traits and body weight, five quantitative traits (carapace length X1, carapace width X2, carapace height X3, abdomen length X4, and body weight Y) of the first instars of T. tridentatus, 500 individuals were measured, and subjected to correlation analysis, multiple regression analysis, path analysis, and determination coefficient analysis. The results showed that there were considerable correlations (P<0.01) among the five measured traits. Path coefficients of various morphological traits for body mass reached a highly significant level (P<0.01), and the largest path coefficient was used in analyzing the width of the head and chest armor. This indicated that the width of the head and chest armor had the greatest direct effect on body mass. The trend of determination coefficient analysis was comparable to that of path analysis. The elevated total determination coefficient (Σd=0.863) between phenotypic features and body weight indicated that the selected traits were practically useful. The multiple regression equation for estimating body weight was Y=‒0.228+0.248X1+0.073X2+0.333X3+0.073X4. It indicates that the carapace width of the first instars of T. tridentatus has the greatest influence on body mass. Therefore, the width of cephalothorax should be the first choice in germplasm evaluation and seedling screening.