Studies On Fishery Resources In Daning River And The Biology Of Discogobio Yunnanensis

The investigation of fish resources and fish samples collecting were carried on in the Daning River in October 2008, May and October 2009. There are 13 sampling points and 3 catch statistics sites were setted, the laboratory datas of fish resources on the Daning River from 2005-2007 were also summarized, and the present situation of the fish on the Daning River were analyzedThere were 99 kinds of fishes in the Daning river, and they belonges 8 orders 16 families,71 genera. Among these fish,Cypriniformes which contains 76 species was the most dominant order, accounting for 76.8% of the total species in Daning river; followed by catfish, which contains 11 species accounted for 11.1%; then, the third was Perciformes which contains 6 and accounted for 6.1%; the other 5 orders accounted for 6.1%.The catches in May were 22 species inWushan,25 species in Dachang,25 species in Wuxi,and Wushan and Dachang had the higher similarity index. The yield of fish were Dachang Section＞Wushan River＞Wuxi River. The catches in October fish were 20 species in Wushan,18 species in Dachang,16 species in Wuxi.Wushan and Dachang had the higher similarity index, and the yield were Dachang＞Wushan＞Wuxi. There were 52 species belonging to 4 orders,10 families and 45 genera in May in total, while only 38 kinds in October. Not only the species number, but also the total yiled weight, in May was bigger than that in October. The similarity of May and October is 0.25.114 random specimens of Discogobio Yunnanensis which were collected from the Daning river were used in the experiment. The age was intestigated using the scals and the vertebra were also used as control. The coinsistence between the two methods is 83.65%. The population include 6 age groups, and groups of age 3 and 4 were. The optimal regression equations can be described by Von Bertalanffy equation as:Lt=10.799 [1-e -0.60128(t+0.017)], Wt=26.25[1-e -0.60128(t+0.017)]2.615.The fast growing period is from the age of one to three. The absolute fecundity (F) ranges from 126～718(average 375) eggs. The relative fecundity (F/m。) ranges from 9.02～65.83(average 21.27) eggs/g and the relative fecundity (F/1) ranges from 1.46～6.62(average 3.74) eggs/mm. The absolute fecundity (F) of Discogobio yunnanensis was positively relate to body length (1), weight (m), net body weight (m。) and age (t). The relative fecundity (F/m。) was negtively relates to the weight (m), net body weight (m。) and the correlation is not significantiy related to other morphological indexs.