鸭绿江上游支流细鳞鱼（Brachymystax lenok）的生态环境调查及人工增殖研究

【作者】 高燕；

【导师】 盛连喜；

【作者基本信息】 东北师范大学 ， 环境科学， 2004， 硕士

【摘要】 细鳞鱼(Brachymystax lenok)属鲑形目，鲑科，细鳞鱼属，是名贵的陆封型冷水鱼，世界上只有此一属一种。1988年我国公布的国家重点保护野生动物名录中，被列入国家二级保护动物。细鳞鱼分布范围较广，鸭绿江水系是其主要分布区。近年来天然细鳞鱼分布范围迅速缩小，种群急剧衰退，现已成为鸭绿江的鲜见物种，濒临灭绝状态。在鸭绿江上游支流中选取典型河流十三道沟和十五道沟，对细鳞鱼的生态环境进行了细致的调查。结果表明：（1）该水域属典型的冷水水域，常年水温在16℃以下，pH值6.9～8.3，水中溶氧丰富，明水期溶氧8.10～15.23mg/L，急流处常有过饱和状态，是适宜冷水鱼栖息的水域。（2）有机物营养源丰富，三氮含量充分，总磷含量适宜，利于冷水鱼和饵料生物的生长繁殖。NH4＋-N含量0.034～0.378 mg/L，NO2-N含量0.00064～0.0.0058 mg/L，NO3-N含量在0.11～1.15 mg/L之间。（3）K、Ca、Na、Mg等金属含量能基本满足藻类生物的需要。无重金属污染现象。Pb、Cd、Hg等重金属两次均未检出。（4）浮游生物高峰出现在夏季。浮游植物种类因季节变化而不同，优势种为硅藻，9月份检出量最小，平均为0.325mg／L；浮游动物主要为轮虫类，4月份检出量最小，平均为0.625mg／L。7月份平均浮游植物生物量0.783mg／L，浮游动物3.553 mg／L，高于1985年7月吉林省水产研究所对十三道沟水库的浮游生物检出量。（5）两岸土壤、植被状况良好，土壤类型主要有森林土、白浆土和草甸土。水边植物主要为柳灌丛，在大多数河段对冷水鱼尚能起到掩蔽遮荫的作用。春汛期桃花水的注入，使水域部分指标含量升高，例如NH4＋-N含量最高达0.378 mg/L，可能会影响细鳞鱼的产卵和受精以及受精卵的孵化。其它三个季节，水、土壤和岸边植被状况都非常适合细鳞鱼的生长和发育。驯养的细鳞鱼生长基本正常，比野生种略慢，3年后成活率30％，<WP=4>6年后成活率为26％。成熟细鳞鱼在5月左右产卵繁殖，孵化的鱼苗能适应水泥池的生活。在天然河流中放养细鳞鱼，1年后成活率可达65.1％，放养细鳞鱼摄食、生长正常，性成熟年龄、状况与野生种大体相同。实验结果表明，一些小型水库的水深、溶氧、CODMn、BOD5和营养盐含量都符合冷水鱼的生存条件，相对浮游生物量较多，能满足冷水鱼的摄食要求，水库入水口稍上几十至几百米的河段都适合做产卵场。水库和上游产卵场的范围相对较小，便于保护和管理。人工驯养和放流的初步成功，论证了在鸭绿江上游支流目前的生态环境状况下进行细鳞鱼人工增殖放流的可行性。对拯救这一珍稀物种，保护物种多样性具有重要意义。更多还原

【Abstract】 Brachymystax lenok(Pallas), Salmonidae, Brachymystax, is one of the only inland cold-water fishes. In 1988, it was enlisted as a class II protected specie in China. Brachymystax lenok distributes widely in the world and YaLu River is one of the main areas. Recently, its distribution has been shrinking greatly and population has been decreasing, even more, it is on verge of extinction.Among the upriver anabranches of YaLu River, the 13th and 15th streams were chosen as the typical habitats of Brachymystax lenok to investigate its ecological environment. The results indicated:(1)The cold-water area is fit for the cold-water fishes to live, the perennial temperature is below 16℃, pH 6.9~8.3, and the DO is 8.10~15.23 mg/L at the period of non-frozen, which is very suitable for cold-water fish to live in. (2) The organic nourishment is rich, which is important for both the Brachymystax lenok and the hydrophytes to grow. NH4＋-N：0.034～0.378 mg/L，NO2-N：0.00064～0.0.0058 mg/L，NO3-N：0.11～1.15 mg/L.(3) The metals such as K, Ca, Na, Mg can meet the need of algae, and the content so heavy metals is low which didn’t result in pollution; Pb、Cd、Hg are all below the threshold quota to be monitored.(4) The peak of plankton appeared at summer, the species of phytoplankton changed according to the seasons, the superiority is diatom，the minimum quantity is 0.325mg／L in Sep.; zooplankton mostly is rotifer，the minimum quantity is 0.625mg／L in July. The phytoplankton quantity is 0.783mg／L and the zooplankton quantity is 3.553 mg／L in July, 2003, which are all more than the quantity resulted in July, 1985.(5) The soil and vegetation along the riversides are all right, most of which can provide shelters for zooplankton. What’s more, because of spring flood, some indexes especially NH4+-N was a bit high, maximum is 0.378 mg/L, which might influence Brachymystax lenok’s spawning, fecundation and the development of zygote.The domesticated Brachymystax lenok grew a bit more slowly than the wild ones; the survival rate is 30%.after 3 years, and 26% after 6 year. The matured Brachymystax lenok spawned in May and the fry can adapt the <WP=6>water area in cement-pool. The survival rate of Brachymystax lenok that were released in natural rivers could reach 65.1% in 1 year, they could take food and grow normally, and their mature age and condition were almost the same with the wild population. It is found that: some reservoirs on rhe rives, which conditions such as depth, Do, CODMn、BOD5 and nutrients are more benefit to cold-water fishes, plankton is relative plentiful, and their up-stream of entrances are fit for spawning place,They are easy to manage. The achievements of domestication and manual releasing, demonstrated the feasibility to reproduce and put them into rivers under the existing condition. This is very meaningful for the protection of the scarce species.更多还原