Reserch Of Growth Characteristic And Population Management Of Culter Alburnus Basilewsky In Nianyushan Reservoir

We collected 885 individuals of Culter alburnus Basilewsky from NianYuShan reservoir during April, 2007 to April, 2008. We studied the age and growth characteristics, estimated the annual population size and built Beverton-Holt model. The study opened out the growth rules and characteristics of Culter alburnus in NianYushan reservoir, built the model of population management, provided the scientific bases to make rational capture age and standard, indicated strategies and measures for explore and management of Culter alburnus Basilewsky in NianYushan reservoir reasonably. The results were summarized as follows:1. The age of Culter alburnus Basilewsky were identified by Scale and Operculum, the agreement rate was larger than 80 percent by analysis results. Both of them can be used for age identification.2. There were 7 age groups in the age configuration from 1-7, the preponderant groups were 1 to 3, 96.95 percent in total; The average body length was 29.91±6.61cm, the preponderant groups were 20 to 35cm, 79.66 percent in total; The average body weight was278.76±215.51g, the preponderant groups were 200 to 600g.3. The relationship between body length and total length can be expressed by the equation y=1.4574x+1.1892 (R²=0.9429) ; The relationship between body length and scales radius can be expressed as the equation y=78.354x-0.9154 (R²=0.7178) ; The relationship between body length and body weight can be expressed by the equation W=0.0098L^2.9947 (R²=0.9521) ; The growth of Culter alburnus Basilewsky can be described by von Bertalanffy growth equation, which is L_t =113.2956 (1-e^{-0.2331(t-0.4347)}and W_t = 13898.8183(1 -e^{-0.2331(t-0.4347)2.9947}; As follows the growth parameter were: L_∞is 113.2956cm, W_∞is 13898.8183g, k is 0.2331, t₀ is 0.4347; The inflexion point is 5.14 years, and the body length and body weight in this point were 75.46cm and 4107.24g.4. The condition factor of male and female Culter alburnus Basilewsky were 1.9083 and 1.9458, female's was larger than male's. The pinnacle of condition factor formed in March and July in female stocks, and male's changed with a rise at the first and a fall later. The condition factor increased with the rise of age.5. The total mortality coefficient Z of Culter alburnus Basilewsky in NianYushan reservoir was estimated to be 1.2617, the total mortality rate A was 0.6237, the natural mortality coefficient M was 0.4654, the natural mortality rate v was 0.2863, the fishing mortality coefficient F was 0.5485, the fishing mortality rate u was 0.3374, the E was 0.5410. The biomass of Culter alburnus Basilewsky was estimated to be 228954.78 Kg by the length based cohort analysis.6. The B-H model was built for population management. When the t_c was 2, M is 0.4654, F was 0.5485 and k was 0.2331, the average body length L_y was 29.91cm, the average body weight W_y was 278.76g and the average age T_y was 2.05a. The yield per unit recruitment was 467.2851 g/ind.7. We suggest the age of Culter alburnus Basilewsky in NianYushan reservoir must be increased to 3, so that the mature population can be protected and the population size can be recriut better. In this capture intensity the capture weight arrive at the max, so we can get the most economy benefit.