叶尔羌高原鳅对塔里木河水盐碱化的响应机制研究

Triplophysa (Hedinichthys) yarkandensis(Day) is endemic to Tarim river water system,it now becomes the third endangered fish after Aspiorhynchus laticeps and Schizothorax biddulphi because the water environmental degradation. This research include six sampling pionts : Upstream、midstream、downstream 、Aksu River、Khotan River and PaiJian area for four season of Tarim river. We sampled Triplophysa (Hedinichthys) yarkandensis(Day) of different sizes and the oosperm, at the same time, water quality physical and chemical indexes of Tarim River, hydrobiontes and other fishes were sampled. All these were did every season. Though the statistic analysis of fish games,physical and chemical inspection analysis, histology analyses and other experimental methods, combined with the indoor test and field investigation, we tried to study the response mechanism of Triplophysa (Hedinichthys) yarkandensis(Day) population to the water environmental degradation. Under the influence of salinization of water, We found that the behaviour and tolerance of Triplophysa (Hedinichthys) yarkandensis(Day) differ from growth stage. The Baits abundance, spermmotility and survival rate increased first but decreased then with the increase of salinity, flow velocity and flow rate. Behavior changes lead to decline of reinforcing then finally cause population fluctuation.

叶尔羌高原鳅为塔里木河水系特有鱼类，由于塔里木河水体环境劣化，现已经成为塔里木河水系仅次于扁吻鱼和塔里木裂腹鱼之后的第三种濒危鱼类；面对塔里木河水日趋咸化，叶尔羌高原鳅是如何进行响应环境变化的？本项目拟以4个不同季节在塔里木河干流上游、中游、下游3个河段与支流阿克苏河、和田河及灌溉排碱渠等3处共6点采样；通过渔获物分区调查和叶尔羌高原鳅生理生态学试验等途径相结合，对不同水域叶尔羌高原鳅种群数量、水质理化指标、饵料生物调查、残留在咸化河段自然群体的估测分析、不同盐碱条件下鱼类群体鳃及肾脏组织等各方面进行综合研究；揭示塔里木河叶尔羌高原鳅应对河水盐碱化的响应机制，以便为塔里木河叶尔羌高原鳅种群的保护和合理利用提供科学依据。

叶尔羌高原鳅Triplophysa (Hedinichthys) yarkandensis (Day)，地方名：狗头鱼（Dog-head），隶属鲤形目、鳅科、条鳅亚科、高原鳅属、鼓鳔鳅亚属，塔里木河水系土著鱼类。近年来，由于塔里木河盐碱加剧，水量减少，其资源锐减，前景堪忧。2015年32号文，环境保护部和中国科学院联合编制《中国生物多样性红色名录-脊椎动物卷》中叶尔羌高原鳅被定为“易危（VU）”。.鉴于此，本研究发现如下结果：.1、塔里木河叶尔羌高原鳅资源锐减，仅少数存活上游等支流，中游枯水期未发现存活个体。干流水体含沙大，浑浊，盐度20。塔里木河自源头到中下游，盐碱持续升高，台特码湖高达24。.塔里木河中叶尔羌高原鳅多数在3-6龄，个体较大，体色较浅；0-2龄多分布上游支流中，饵料贫瘠。叶尔羌高原鳅在生殖期，短途洄游。选择水较深的坑洼为越冬栖息地，繁殖期洄游到上游支流或上游段水草茂盛的弯道缓流处，约2-3 m水深处产卵。.２、不同盐碱度影响下，叶尔羌高原鳅渗透调节酶活性变化明显。皮质醇、GH/IGF-1、 PRL、甲状腺激素在盐碱高浓度下出现不同变化，除皮质醇外，其他变化不大。盐碱影响下，鳃溃烂，泌氯细胞增多，肠道内皱褶溃烂，微绒毛脱落，肾小球损伤，细胞出现不同程度凋亡。.叶尔羌高原鳅摄食属于日伏夜食型，消化蛋白主要在前肠和中肠，消化淀粉是前肠，消化脂肪是中肠，蛋白酶活性均显著高于脂肪酶和淀粉酶。饥饿可显著影响总抗氧化能力、抗氧化酶活性和自由基含量，并导致肝胰脏氧化损伤。.３、叶尔羌高原鳅受精卵在盐度2-6之间孵化率较高，畸形率则在4和6较低；盐度对仔鱼的安全值为1.5893，碱度为0.5754 g /L。.叶尔羌高原鳅耗氧率/排氮率随盐、碱增大而降低，在盐5和碱0.84 g/L时其呼吸和排泄正常。不同盐碱下，有跳跃、狂躁、急游行为，直至力竭死亡。盐度4和碱度4 g/L环境最喜好。.本项目从野外调查和室内试验相结合，综合揭示塔里木河叶尔羌高原鳅应对河水盐碱化的不同程度的生理生态和种群动态响应，为其资源保护和合理利用提供科学依据。