基于DNA条形码技术的浔江桂平段漂流性鱼卵鉴定

Identification of drifting fish eggs in Guiping section of Xunjiang River based on DNA barcoding technology

  • 摘要: 【目的】基于DNA条形码技术鉴定浔江桂平段漂流性鱼卵,揭示浔江桂平段鱼类早期资源状况,为浔江鱼类产卵场调查及鱼类资源保护提供数据支撑。【方法】2024年5—8月于大藤峡产卵场、前进产卵场和东塔产卵场下游25~50 km处的桂平市江口镇江段采集鱼卵,带回实验室用于DNA提取。采用DNA条形码技术,对鱼卵样本进行物种鉴定。【结果】在江口镇江段断面共采集鱼卵646粒,经测序获得565条有效序列,93.98%可鉴定到种,6.02%可鉴定到属。共鉴定出18种已分类鱼类,隶属于1目3科8亚科16属。其中,鲤科鱼类15种,对应557条有效序列,占总有效序列数的98.58%;鳅科鱼类2种,对应2条有效序列,占总有效序列数的0.35%;平鳍鳅科鱼类1种,对应6条有效序列,占总有效序列数的1.06%。在565条有效序列中,黄尾鲴有效序列数最多,为183条,占32.39%;其次为赤眼鳟,为135条,占23.89%;银鮈(113条,占20.00%)、银鲴(29条,占5.13%)、鲮(21条,占3.72%)和南方拟䱗(18条,占3.19%)的有效序列数相对较多。在鉴定到种的18种鱼类中,典型产漂流性鱼卵鱼类有15种。种内和种间遗传距离分析结果显示,种间遗传距离平均值是种内遗传距离平均值的28.74倍。系统发育树显示,鉴定出的鱼卵样品聚为19个独立支系,多个同属物种聚为同一分支。【结论】大藤峡水利枢纽蓄水后浔江桂平段产漂流性鱼卵鱼类物种组成虽未发生明显变化,但“四大家鱼”等大中型经济鱼类占比降低,小型鱼类逐渐占据优势。水利工程运行可能导致鱼类群落结构向小型化演替,应在鱼类主要繁殖期加强栖息地保护并实施生态调度。

     

    Abstract: 【Objective】DNA barcoding technology was used to identify drifting fish eggs in the Guiping section of Xunjiang River, and reveal the early resource status of fish, which could provide data support for the investigation of fish spawning grounds and fish resource conservation in Xunjiang River.【Method】Fish eggs were collected from May to August of 2024 in Jiangkou Town section of Guiping City, located 25-50 km downstream of the Datengxia spawning ground, Qianjin spawning ground, and Dongta spawning ground. The samples were transported to the laboratory for DNA extraction. DNA barcoding technology was used to identify the fish egg samples.【Result】A total of 565 valid sequences were obtained from the 646 collected fish eggs in Jiangkou Town section, of which 93.98% of the samples could be identified to the species level, and 6.02% could be identified to the genus level. A total of 18 species were identified, belonging to 1 order, 3 families, 8 subfamilies, and 16 genera. Among them, there were 15 species of Cyprinidae, corresponding to 557 valid sequences, accounting for 98.58% of the total valid sequences; there were 2 species of Cobitidae, corresponding to 2 valid sequences, accounting for 0.35% of the total valid sequences; and there was 1 species of Gastromyzontidae, corresponding to 6 sequences, accounting for 1.06% of the total sequences. Among the 565 valid sequences, Xenocypris davidi had the highest number of sequences (183 sequences, accounting for 32.39%), followed by Squalibbarbus curriculus (135 sequences, accounting for 23.89%). Relatively high numbers of sequences were also obtained for Squalidus argentatus (113 sequences, accounting for 20.00%), Xenocypris argentea (29 sequences, accounting for 5.13%), Cirrhinus molitorella (21 sequences, accounting for 3.72%), and Pseudohemiculter dispar (18 sequences, accounting for 3.19%). Among the 18 species identified to multiple species level, 15 were typical drifting egg spawners. Analysis of intraspecific and interspecific genetic distances revealed that the average interspecific genetic distance was as 28.74 times as that of the average intraspecific genetic distance. The phylogenetic tree showed that the identified fish egg samples clustered into 19 independent clusters, and multiple species in the same genus clustered into the same branch.【Conclusion】The species composition of drifting fish eggs in the Guiping section post-impoundment remain consistent with pre-impoundment conditions of Dateng Water Control Hub. However, there is a noticeable decline in the proportion of medium and large fish (such as Ctenopharyngodon idellaAristichthys nobilisHypophthalmichthys molitrixMylopharyngodon piceus), while small-sized fishes have gradually become dominant. The operation of water conservancy projects may lead to a trend of miniaturization in fish community structure. Therefore, it is imperative to strengthen habitat protection and implement ecological regulation during the critical reproductive periods of fish.

     

/

返回文章
返回