三峡水库产漂流性卵鱼类繁殖现状及水文需求研究

NATURAL REPRODUCTION AND HYDROLOGIC REQUIREMENTS OF PELAGOPHIL FISH IN THE THREE GORGES RESERVOIR

  • 摘要: 为了解三峡库区产漂流性卵鱼类的自然繁殖对三峡水库调蓄的响应, 研究于2016和2017年5—7月在三峡库区忠县江段进行鱼类早期资源调查。结果表明, 三峡库区鱼类早期资源物种多样性较高, 共采集到鱼类60种, 其中产漂流性卵鱼类30种。鱼卵中贝氏䱗Hemiculter bleekeri、银Squalidus argentatus数量占优势, 仔鱼中鲌亚科的䱗属和飘鱼属数量占优势。三峡库区鱼类早期资源量丰富, 2016年和2017年调查期间流经忠县断面鱼卵的估算总量分别为70.41和34.54亿粒; 仔鱼总量为1037.63和344.27亿尾; 四大家鱼卵苗总量分别为29.09和21.17亿粒/尾。产漂流性卵鱼类在三峡库区忠县至涪陵江段的繁殖高峰在6月中旬至7月中旬, 即三峡水库调蓄至防洪限制水位145 m之后的时段, 而在6月上旬之前仅有少量繁殖活动发生; 在涪陵以上, 尤其是长寿以上江段5月中旬即有较大规模的繁殖。通过对三峡库区忠县至涪陵江段产漂流性卵鱼类繁殖水文需求的分析, 表明四大家鱼仅在有持续涨水的条件下繁殖, 而贝氏䱗和银对涨水的依赖程度很小。研究表明, 三峡水库的鱼类早期资源物种多样、资源丰富, 产漂流性卵鱼类在库区涪陵以下江段的繁殖时间主要在6月上旬以后, 且产卵规模较小, 而库尾及上游江段是三峡库区鱼类早期资源的主要来源地。在金沙江下游梯级开发的形势下, 需要加强对三峡库尾及上游江段产漂流性卵鱼类繁殖所需水文条件的维护以及对产卵场的保护。

     

    Abstract: To reveal the relationships between spawning activities of pelagophil fish and environmental factors in the Three Gorges Reservoir (TGR), fish eggs and larvae were sampled at Zhongxian section, from May to July in 2016 and 2017. 60 fish species including 30 pelagophil fishes were sampled. Hemiculter bleekeri and Squalidus argentatus were the dominant species in eggs, and Hemiculter and Pseudolaubuca were abundant in larvae. In 2016, 7.041 billion eggs and 103.763 billion larvae drifted through the sampling section, and in 2017, 3.454 billion eggs and 34.427 billion larvae drifted through the sampling section. The amount of eggs and larvae of the four major Chinese carps reached 2.909 billion in 2016 and 2.117 billionin in 2017. Spawning activities of pelagophils fish varies temporally in different river reaches, which mainly occurred after early-June in the river reach from Zhongxian to Fuling but begun in mid-May in the river reach upstream of Changshou. Fish eggs and larvae from the river reach upstream of Changshou provided a large resource for recruitment to the fishery in TGR. Classification and regression trees (CART) analysis explored that spawning activities of the four major Chinese carps were favord when water discharge was rasing. But, spawning activities of Hemiculter bleekeri and Squalidus argentatus had no relationship with water discharge. In order to protect the spawning grounds and meet environmental requirements for natural reproduction of pelagophils fish, we propose ecological regulation of the cascade hydro-power projects in the Jinsha River and maintenance of large free-flowing stretches upstream of TGR.

     

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