壮体沙鳅早期发育及红水河来宾江段资源补充量评估
EARLY MORPHOGENESIS AND ESTIMATION OF RESOURCES OF BOTIA ROBUSTA IN THE LAIBIN SECTION OF HONGSHUIHE RIVER
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摘要: 2017年4月中旬至8月底于红水河来宾江段进行鱼卵、鱼苗监测, 发现壮体沙鳅Botia robusta (Wu, 1939)为所采集鱼卵中的主要优势种。研究对壮体沙鳅卵进行培育、观察并详细记录了14个重要发育期的形态特征。卵膜无黏性, 卵膜径平均为6.8 mm; 鳔一室期, 鱼苗体长为7.1 mm, 身体肌节数为33对。孵出后第20日, 鳍条完全形成、体表色素整体形成, 进入稚鱼阶段。该江段壮体沙鳅的产卵繁殖主要集中在5—6月, 当年补充群体总量估计达2.23×108颗, 然而伴随下游大藤峡水利枢纽的建成其年际补充量将受到严重威胁; 将壮体沙鰍卵的单位捕捞努力量与主要环境因子进行相关性分析, 发现仅水温变动与其产卵动态呈显著性相关(P<0.05), 现场水温记录表明:水温达到20℃时开始产卵, 水温超过28℃时产卵量明显减少, 且最适产卵温度为22℃。Abstract: We investigated larval and eggs resource of Botia robusta at Laibin section in the Hongshuihe River from mid of April 2017 to August, and found that Botia robusta was the dominant species of collected eggs. We studied the ontogeny of Botia robusta from the Tail bud to Juvenile phase and described the features of 14 developmental stages respectively. The egg membrane was non-adhesive, averaging 6.8 mm. One chamber air bladder was 7.1 mm in total length and the muscle nodes were about 33 pairs. It took 20d to finish the Yolk-sac larva phase stage, spawning mainly from May to June. The total number of the eggs laid at Laibin section in 2017 was about 2.23×108. The correlation analysis between oviposition and major environmental factors found significant correlation between the water temperature with the spawning dynamics (P<0.05).