柳江下游江段伍氏华吸鳅早期发育及其资源补充量评估

Early development of Sinogastromyzon wui and its resource supplement in the lower reaches of Liujiang River

  • 摘要: 【目的】观察伍氏华吸鳅早期发育并评估柳江下游江段其资源补充量,为柳江下游江段伍氏华吸鳅的渔业资源开发及可持续利用提供基础数据。【方法】2017年5月16日—8月31日于柳江下游石龙镇进行伍氏华吸鳅的鱼卵及鱼苗采集,对采集到的伍氏华吸鳅鱼卵进行人工培育,重点观察并详细描述其仔鱼时期的形态变化特征;并通过设置断面方法估算伍氏华吸鳅在柳江下游江段的资源补充量。【结果】伍氏华吸鳅卵呈球形,单层卵膜,淡黄色,卵径为4.50±0.10 mm;初孵仔鱼全长5.00±0.21 mm,肌节35对(3+20+12),眼色素和胸鳍原基出现,身体呈淡黄色,卵黄囊前部已有半球形点状色素分布,心跳约165次/min;出膜25 d,全长18.50±0.35 mm,身体呈淡红色,臀鳍、胸鳍和腹鳍均基本形成,完成仔鱼期发育,进入稚鱼阶段。调查期间柳江下游江段采样断面鱼卵和鱼苗的分布系数为0.416,柳江下游江段伍氏华吸鳅鱼卵的群体补充量为2.48×108粒。Spearman相关分析结果显示:伍氏华吸鳅鱼卵密度与流量和水位呈极显著负相关(r=-0.688,P<0.01;r=-0.663,P<0.01),与透明度和溶解氧呈极显著正相关(r=0.667,P<0.01;r=0.297,P<0.01)。【结论】伍氏华吸鳅体长相对其他平鳍鳅科鱼类偏小,其卵为无黏性漂流鱼卵,产卵量与流量和水位呈极显著负相关,与透明度和溶解氧呈极显著正相关,因此柳江下游江段伍氏华吸鳅群体资源补充量可能在大藤峡水库蓄水完成后明显下降。

     

    Abstract: 【Objective】 In order to provide basic data for the resource assessment and sustainable utilization of Sinogastromyzon wui in the lower reaches of Liujiang River,the study observed early development of S. wui and evaluated its resource in the lower reaches of Liujiang River.【Method】 Fish larvaland fish eggs were collected in Shilong Town,lower reaches of the Liujiang River from May 16 to August 31,2017. In this study,the collected eggs were artificially cultivated,and the morphological changes of the larvae were observed and described in detail. The resource supplement of S. wui in the lower reaches of the Liujiang River was estimated by setting a cross section.【Result】 The shape of the fertilized eggs of the fish were ovate with monolayer and yellow colour,which was 4.50±0.10 mm in diameter. The total length of the newly hatched larvae was 5.00±0.21 mm,with 35 pairs of muscle segments 3+20+12. Meanwhile eye pigment and pectoral fin primordia appeared,the heart rate was about 165 times/min and the body was pale yellow with hemispherical spotty pigment distribution in the front part of the yolk sac.Anal fin,pectoral fin and abdominal fin were basically formed and the development of the larvae stage was completed in 25 d after hatching. The total length was 18.50±0.35 mm,and the body was light red. During the investigation period,the distribution coefficient in the sampling section of the lower reaches of the Liujiang River was 0.416 and the resources replenishment of S. wui was estimated to be 2.48×108 eggs during the sampling period in Liujiang River. The Spearman correlation analysis showed that,the density of fish eggs was negatively related to the discharge,and water level significantly(r=-0.688,P<0.01;r=-0.663,P<0.01),while it had significant positive correlation with transparency and the dissolved oxygen(r=0.667,P<0.01;r=0.297,P<0.01).【Conclusion】 Compared with Balitoridae,the length of S. wui is small and its eggs are non-viscous drifting eggs. The spawning of S. wui is significantly negatively correlated with discharge and water level,and significantly positively correlated with transparency and dissolved oxygen. Therefore,the population resource supplement of S. wui in the lower reaches of Liujiang River may decrease after the completion of the Datengxia Reservoir.

     

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