雅砻江短须裂腹鱼人工增殖放流群体的生态适应性研究

Stock enhancement is an important measure to protect aquatic animals in China. The ecological adaptability of the released fish acclimating the natural river is the issue paid close attention as well as the research hotspot on the international, while is still short of systematic research in China. Schizothorax wangchiachii is an important fish species for releasing in the Yalong River. In the previous study, it had been revealed that: the condition factor of the released S. wangchiachii decreased firstly and then increased; the released group close to release site had higher quantitative proportions than the group far away; the growth status of the released group was significant different among recapture sites. However, ecological adaptability of the released S. wangchiachii was still unclarified. Accordingly, one hypothesis is put forward in this project: there are significant differences in some ecological characteristics between artificially released and the wild S. wangchiachii, nevertheless, the differences will disappear gradually with the released S. wangchiachii acclimating the natural river. In this project, using the method of “mark-release-recapture”, the difference in the ecological characteristics between the released and the wild group of S. wangchiachii in the Yalong River will be investigated and compared, including feeding, growth, mortality, migration, distribution and population abundance. Afterwards, the feeding ecology, growth status and population dynamic of the released group will be analyzed, and the ecological adaptability will be discussed and clarified. The results will be helpful to reveal ecological adaptability of artificially released S. wangchiachii in the Yalong River, as well as to provide the scientific basis for optimizing stocking strategies and promoting fish conservation in the Yangtze River.

人工增殖放流是我国水生动物保护的重要措施之一。鱼类放流群体在自然河流中的生态适应性，是人们非常关注的问题，也是国际研究热点，但国内研究非常缺乏。短须裂腹鱼是雅砻江的重要放流鱼类。项目前期研究发现：放流后，短须裂腹鱼放流群体的丰满度先降低后上升；放流群体在放流地点附近占比很高；不同回捕地点的放流群体生长水平差异显著；但放流群体的生态适应性尚不清楚。据此，项目假设：人工繁育的短须裂腹鱼在放流后与野生种群在生态学特征上存在差异，但能逐渐适应河流环境，差异逐渐弱化甚至消失。项目拟采用“标记-放流-回捕”方法，分析雅砻江短须裂腹鱼放流群体和野生种群的食性、生长、死亡、迁移与分布、种群丰度等生态学特征，比较它们的差异性，探讨放流群体在摄食生态、生长水平和种群动态上的生态适应性。研究成果不仅有助于揭示短须裂腹鱼放流群体的生态适应性，而且可为优化放流策略提供参考，也可为推进长江鱼类保护工作提供技术支撑。

人工增殖放流是我国水生动物保护的重要措施之一。鱼类放流群体在自然河流中的生态适应性，是人们非常关注的问题，也是国际研究热点，但国内研究非常缺乏。短须裂腹鱼是雅砻江的重要放流鱼类。本项目采用“标记-放流-回捕”方法，分析雅砻江短须裂腹鱼放流群体和野生种群的食性、生长、死亡、迁移与分布、种群丰度等生态学特征，比较它们的差异性，探讨放流群体在摄食生态、生长水平和种群动态上的生态适应性。研究结果显示：人工繁育的短须裂腹鱼在放流到雅砻江自然水体后，先是熟悉野外环境、偶尔摄食，然后逐渐适应用下颌角质刮食砾石上的着生藻，摄食藻类种类和野生群体没有明显差异，但摄食强度很低；放流群体符合匀速生长类型，体长生长速度随年龄增长而下降，体重生长速度则先增长后下降，拐点年龄为7龄，大量个体发育成熟并达到了繁殖年龄，与野生群体接近，但早期的生长速度和加速度略小，放流群体总体生长适应能力较好；放流群体早期死亡率较高，后逐渐下降，体长200mm以上时死亡率较小且稳定，可能是其识别和躲避捕食者能力较弱，需在野外环境中适应；放流群体扩散较快，但主要在放流点下游50km内河段活动，丰度较大，在50km外活动较少，丰度较低；放流群体时间上分布差异的重要原因可能是早期死亡率较高；由于持续多年的大规模放流，放流群体已在研究河段占据绝对数量优势。本研究表明人工繁育的短须裂腹鱼放流到雅砻江后，在摄食、生长、死亡、迁移、种群动态等多个维度上具有很好的生态适应性。本研究不仅揭示了短须裂腹鱼放流群体的生态适应性，而且可为优化雅砻江流域鱼类放流策略提供参考。