南海珊瑚礁海域黑缘尾九棘鲈生物学特征初步研究

根据2018—2019年在南沙群岛和西沙群岛珊瑚礁海域采集的礁栖鱼类黑缘尾九棘鲈(Cephalopholis spiloparaea)样本, 对其群体结构、性腺成熟度、摄食强度、肥满度、年龄与生长等生物学特征进行了初步研究, 通过对比分析了南海这两个珊瑚礁海域中黑缘尾九棘鲈生物学特征的地理差异。结果表明: 在南沙海域和西沙海域中黑缘尾九棘鲈的平均体长分别为105.5±10.5mm和110.4±13.1mm, 两海域间的体长和体质量分布均具有极显著的差异(P<0.01); 南沙海域与西沙海域样本体长和体质量关系的异速生长因子b值分别为2.881与2.797; 耳石样本分析结果显示年龄范围为0.58~1.44a, 两个海域间并无显著性差异(P>0.05); 由von Bertalanffy生长方程计算所得的生长参数显示, 南沙海域的黑缘尾九棘鲈比西沙海域的体型相对较小、生长速度相对较快; 两海域黑缘尾九棘鲈的性腺成熟度均以Ⅱ期为主, 且西沙海域样本性腺成熟比例高于南沙海域; 摄食等级以1级为主, 两个海域间的摄食等级分布无显著性差异(P>0.05); 与西沙群岛海域相比, 南沙群岛海域的黑缘尾九棘鲈群体表现出肝体比较低的特征。

Biological characteristics of Cephalopholis spiloparaea of reef waters in the South China Sea

Based on the coral reef fishes of Cephalopholis spiloparaea (Serranidae: Cephalopholis), which were collected from the coral reef waters of the Nansha Islands and Xisha Islands in the South China Sea in September 2018 and May-June 2019, we studied the biological characteristics of C. spiloparaea, including population structure, gonad maturity composition, feeding intensity, fatness index, age, and growth. We compared the geographic variation of the biological characteristics between the two coral reef waters in the South China Sea. The results are as follows. 1) The ranges of the dominant body length were 96~125 mm and 96~115 mm, respectively, in the Nansha reef waters and Xisha reef waters. The distributions of body length and body weight both had significant differences between the two waters (P<0.01). 2) The allometric growth factors (b values) of the body length and body weight relationship from the Nansha reef waters and Xisha reef waters were 2.881 and 2.797, respectively. 3) The result of analysis of otolith samples (May-June 2019) suggests that the age range is 0.58~1.44 a. There were no significant differences in the distribution of age between the two reef waters (P>0.05). 4) The C. spiloparaea in the Nansha reef waters was relatively smaller in size and grew faster than that in the Xisha reef waters. 5) In addition, the gonadal maturation ratio of the Xisha reef waters was higher than that of the Nansha reef waters. 6) The feeding stages of C. spiloparaea from the two reef waters were dominated in Stage 1. Compared with the population of C. spiloparaea in the Xisha reef waters, these results demonstrate that the population in the Nansha reef waters had the characteristics of miniaturization, faster growth rate, and lower hepatopancreas index.