【作者】 季强；

【导师】 谢从新；

【作者基本信息】 华中农业大学 ， 湿地资源与资源， 2008， 硕士

【摘要】 6种裂腹鱼类(异齿裂腹鱼、拉萨裸裂尻鱼、尖裸鲤、巨须裂腹鱼、双须叶须鱼和拉萨裂腹鱼)具有重要的渔业经济价值,其资源量有限,部分属于珍稀鱼类。随着西藏地区经济的发展,对水产品的需求量增大,局部地区出现捕捞过度的趋势,因此有必要对西藏鱼类资源及可持续利用问题进行深入的科学研究和分析。本文对6种裂腹鱼类的消化道形态进行了比较解剖观察,对6种裂腹鱼类的饵料种类组成以及食物竞争的状况进行分析研究。主要结果如下:1.6种裂腹鱼类的消化道形态消化道分为口腔、咽部、食道和肠四部分。①6种鱼的口裂大小为尖裸鲤＞拉萨裸裂尻鱼＞双须叶须鱼＞巨须裂腹鱼＞拉萨裂腹鱼＞异齿裂腹鱼;下颌角质程度不一,异齿裂腹鱼和拉萨裸裂尻下颌具锐利角质,其它下颌具角质但不是锐利的边缘或下颌正常无角质;口型除尖裸鲤为端位口其他五种鱼类均为下位口。②口内无颌齿、口腔齿和游离舌;下咽骨下咽齿变异特殊。③6种鱼的食道与肠界限明显,其粘膜褶均为纵褶:除尖裸鲤外其它五种鱼的比肠长均大于1,肠粘膜褶均为Z型。2.6种鱼类的食性及食物竞争①异齿裂腹鱼和拉萨裸裂尻鱼主要摄食着生藻类,尖裸鲤主要摄食小型鱼类和裂腹鱼类幼鱼,巨须裂腹鱼、双须叶须鱼、拉萨裂腹鱼主要摄食水生昆虫和底栖无脊椎动物。②根据各饵料成分的重量百分比,计算出各鱼种间的饵料重叠系数和食物多样性指数,结果显示:6种鱼类有一定程度的摄食分化以减少彼此间的食物竞争,但在雅鲁藏布江这样食物基础相对匮乏的环境中,异齿裂腹鱼和拉萨裸裂尻鱼、巨须裂腹鱼和双须叶须鱼、双须叶须鱼和拉萨裂腹鱼、巨须裂腹鱼利拉萨裂腹鱼的食物竞争比较严重;6种裂腹鱼利用食物的种类多样性差异较大。③着生藻类和底栖无脊椎动物是主要饵料生物,其丰度是决定各种鱼类种群数量最关键的生物因子,因此对其资源监测具有重要意义。④6种裂腹鱼类消化道的形态结构与其摄食方式和食性是一致的,主要表现在下颌角质的有无、发达与否,咽齿的形态和肠的长短等方面。更多还原

【Abstract】 All the six Schizothoracinae fishes(Ptychobarbus dipogon,Oxygymnocvpris stewarti, Schizopygopsis Younghusbandi,Schizothorax o ’connori,Schizothorax macropogon and Schizothorax waltoni) have an importantly economic value,however,the resource is limited,some species are trasuralbe.Along with the ecnomic development of Tibet region,the need for the aquatic products becomes larger,there exsits over-fishing trend in some areas,therefore,it is necessary to further study and analyze for the sustainable utilization of Tibet fish resourece.167 individuals of six Schizothoracinae fishes were collected in Rikeze reach of Brahmaputra Rive from May to July.Comparative morphological structure of the digestive tract in six Schizothoracinae fishes were observed in this study,measured and calculated the correlative data.The food species of six Schizothoracinae fishes and feeding competition among them were studied.The main results are as follows:1.The morphological structure of digestive tract of Six Schizothoracinae fishes The digestive tract includes oral cavity,pharynx,esophagus and intestine.①The magnitude of the horny sheath of lower jaw and the mouth cleft in six Schizothoracinae fishes are different,Oxygymnocypris stewarti＞Schizopygopsis Younghusbandi＞Schizothorax o’connor＞Schizothorax macropogon＞Schizothorax waltoni＞Ptychobarbus dipogon.And the position of mouth of six fishes except Oxygymnocypris stewarti is inferior②There are not jaw teeth,oral cavity teeth,and mobile lingua in these fish species. The special variations in pharyngea bone and pharyngeal teeth were observed.Most of pharyngea bones show arc in shape.Except that the pharyngeals of Schizothorax o ’connori presents oblique-truncate,the pharyngeal teeth in other fishes are tip.③There is a distinct dividing line between the esophagus and the intestine.All of the mucosal folds of esophagus show vertical-drape.Except for Oxygymnocypris stewartii, the ratios of gut length to body length of the other five fishes are all beyond 1 The mucosal folds of intestine are displayed in Z shape in six fishes.2.Feeding habit and Feeding competition of six Schizothoracinae fishes①Schizothorax o’connori and Schizopygopsis Younghusbandimainly feed on periphytic algae.Oxygymnocypris stewartii mainly feeds on small fishes.While,aqutic insects and benthic invertebrates are the primary diets of Schizothorax macropogon, Ptychobarbus dipogon,and Schizothorax waltoni.Six fishes display the feeding preference to a certian extent.②The dietary overlap coefficient and food diversity indices among them was caculatcd using weight percentage of each food species.The results suggested that the degree in feeding competition among the four pairs was very high.It was observed that six fishes might reduce the degree in feeding competition through feeding partitioning. There are greatly differences in the extent of food utilization among six Schizothoracinae fishes.③Periphytic algae and benthic invertebrate are main food of six fishes.The abundance of food is the most key biological factor to determine the population amount, which has great significance in supervising the fishery resources.④The morphological structures in the alimentary canal of six Schizothoracinae fishes have adapted well to the feeding types and feeding habits.The adapted characteristics primarily exhibit whether the horny sheath exists and developes,the morphological structure of pharyngeal teeth,the length of intestine,and so on.更多还原