| The fish resources are very abundant in the upper Yangtze River, where various fishery modes were presented. The investigation of upper section can not only help us to understand the fishery status in the Yangtze River basin, but also provide powerful scientific bases for the protection of fishery resources. Furthermore, it contributes to evaluate the effects of the Three Gorges hydroelectric project on fish resources and ecological environment. However, in a long time the fishery statistic data of the upper Yangtze River were very few and the statistic data left only were almost simple description. Moreover the cases of evaluating the fish resources in the upper Yangtze River by using basic data were much less. This research evaluates the fishery status in the upper Yangtze River by using commercial fisheries data of Hejiang section from 1999 to 2002.The age, growth and mortality of Rhinogobio ventralis which is endemic to the upper Yangtze River have been studied also. Moreover we have estimated the biomass of Rhinogobio ventralis. The following conclusions were reached.(1)According to the national standard(GB5147-85), the fishing gears in Hejiang section could be divided into eight categories, eight types and seven patterns. Adding up to ten kinds. The number of fishing boat from 1999 to 2002 is 159,100,107 and 116, respectively. The number of different fishing boat and the species composition of different fishing gears were calculated also. Furthermore, the structure of drift trammel net, set longline of baited hooks and jig and their fishing methods were described.(2)The fishing gears in Hejiang section were divided into drift trammel net, set longline and jig according to the fishery status in Hejiang section. 'Number of fishing boat day' was selected as the unit of fishing effort. The annual catch of the four kinds of fishing gears was get from multiplying catch per unit effort (CPUE) by fishing effort. Adding the annual catch of the four fishing gears and then we can get the annual catch in Hejiang section from 1999 to 2002.The value was 104563.464kg, 65564.231kg, 123684.966kg and 107285.272kg, respectively.(3)The capture involved of five age groups. 1-3 year class consisted the majority. The 3-year class represented 61.83% of the catches, which was much more than other age groups. The scales were used for age determining of Rhinogobio ventralis. The relationship between body length and scales radius can be expressed by the equationL=3.2279 R0.8838 (n=372, r=0.9719) .The relationship between body length and body weight can be expressed as the equation W=7.6915 10-6L3.1509(n=445, r=0.9922).The growth of Rhinogobio ventralis can be described by von Bertalanffy growth equation, which is Lt=316.1 (1 - e-0.29847(t+0.1922)) and Wt=578.9 (1 - e-0.29847(t+0.1922') 3.1509.The inflexion of body weight growth curve is at 3.65a and 173.6g.(4)The total mortality coefficient of Rhinogobio ventralis in Hejiang section was estimated to be 1.2617, with a natural mortality coefficient of 0.6151 and a fishing mortality coefficient of 0.6466.The average biomass of Rhinogobio ventralis in Hejiang section was estimated by two methods. One was the methods of fishing mortality coefficient. And the results was 8102.609kg, 10079.553kg, 32323.399kg and 25358.183kg, respectively. The other was the length based cohort analysis and the results was 4832.040kg, 7321.310kg, 19796.090kg and 14562.380kg, respectively. The average fish biomass in Hejiang section was obtained after knowing the proportion of Rhinogobio ventralis in the catch. The results from 1999 to 2002 was 129075.560kg, 87524.737kg, 154217.721kg and 130602.934kg, respectively.
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