泥鳅入侵对碧塔海中甸叶须鱼种群数量的影响研究

Bitahai Lake is one of the only 46 “international important wetlands” in China; the core scenic spot of “5A” class National Forest Park, Potatso National Forest Park, an important tourism hotspot in China even in the world which receiving 1.2 million tourists from home and abroad every year; the core area of the Bitahai Provincial Nature Reserve; and part of the “Three Parallel Rivers of Yunnan Protected Areas” Natural Heritage of the world, . Ptychobarbus chungtienensis is the only native fish in the Bitahai Lake and one of the most important components in the Bitahai Lake ecology system. The “One Lake One Fish” phenomenon is unique in the world. Besides, Ptychobarbus chungtienensis is identified as “Endangered” species according to the China Species Red List. The population of mud fish (Misgurnus anguillicaudatus) is increasing rapidly since it is found for first time in August of 2009, and now it is very large. Meanwhile, the Reproductive population of Ptychobarbus chungtienensis is decreasing obviously. This project aims to make clear how and to what extent mud fish influences the Ptychobarbus chungtienensis population. The project will be carried out from these 3 aspects: if they compete in food or habitat, if mud fish prey on eggs and offspring of Ptychobarbus chungtienensis and how about the interannual variation of populations of mud fish and Ptychobarbus chungtienensis. Answers to these questions will enlighten the protection of Ptychobarbus chungtienensis, the ecology system of Bitahai Lake and the sustainable developent of Potatso National Park.

碧塔海是我国仅有的46个“国际重要湿地”之一；为5A级国家森林公园——普达措国家森林公园的核心景区，是我国乃至世界的旅游热点；是碧塔海云南省级自然保护区的核心区；也是滇西北三江并流区世界自然遗产地的一部分；其独特的“一湖一鱼”现象世界罕见。中甸叶须鱼是碧塔海分布的唯一土著鱼类，是碧塔海生态系统的最重要组成成分之一，被《中国物种红色名录》认定为濒危（EN）物种。自2009年8月在碧塔海首次发现外来物种——泥鳅以来，泥鳅数量持续增加；与此同时，中甸叶须鱼繁殖群体数量则呈明显减少趋势。本项目旨在通过碧塔海野外调查实验，明确泥鳅以何种方式影响中甸叶须鱼的种群数量及影响程度，主要从食物、栖息地竞争，泥鳅对中甸叶须鱼卵、苗捕食强度、泥鳅及中甸叶须鱼的年际变化等三个方面展开研究。这些问题的揭示将为中甸叶须鱼及碧塔海生态系统的保护提供理论依据，从而为普达措国家森林公园的可持续发展提供保障。

2019年8月、2020年9月、2021年7-11月，在碧塔海开展了中甸叶须鱼、鲫鱼、泥鳅、大鳞副泥鳅四种鱼类食性、时间、空间分布的研究。新冠疫情影响了2020年大部分的野外划，致使目前项目仅完成了野外采样及标本统计工作。已取得的成果主要有以下几方面：1）三种外来鱼类与中甸叶须鱼有较为相似的食谱，可能导致了本土鱼类种群数量的下降；2）大鳞副泥鳅食物中发现有卵、苗，还不能确定是中甸叶须鱼的卵苗；3）大鳞副泥鳅、泥鳅、鲫鱼与中甸叶须鱼时空分布差异较大，并没有专门捕食中甸叶须鱼卵苗的习性；4）中甸叶须鱼种群总数的95%置信区间为3119±936尾；雌鱼95%置信区间506±344尾；雄鱼95%置信区间393±344；性别不清个体95%置信区间293±149尾；5）碧塔海四种鱼类中只有鲫鱼感染了绦虫，其感染率为23.91%，平均感染强度为14.24，四种鱼类对绦虫的敏感性有极大的差异，鲫鱼较易感，而其他鱼类较不易感。