Studies On The Biological Characteristics And The Evaluation Of Genetic Resource Of Onychostoma Rara

The paper deals with the bioligical characterictics and genetic resource of Onychostoma rara. From February 2004 to October 2004,198 speciemens of Onychostoma rara were collected respectively from the Qingshui River and the Duliu River in Guizhou, China.198 specimens were aged by scale.It is showed that the new annuli in the scales of Onychostoma rara are mostly formed yearly in May. The analysis of composition of the catches show that those of dominant age groups from 1 to 2 years.With electronic computer,the correlative formula and the most fitted Von-Bertalanffy equation,for "radius"of the scale(R,mm) and body-length(L,mm), body-weight(W,g) are selected as follows:L=41.095+62.374R,W=1.5×10^-5L^3.1229.L_∞=508.141, W_∞=4232.6215, k=0.1812,t₀=-0.824, t_i=5.456((?) ). Lt=508.141(1-e^{-0.1812(t+0.824)}), Wt= 4232.6215(1-e^{-0.1812(t+0.824)})^3.1229.The instantaneeous growth rate equationsdepending on the growth equation are as follows:dl/dt=92.0751e^{-0.1812(t+0.824)}, dW/dt=2395.1113e^{-0.1812(t+0.824)}(1-e^{-0.1812(t+0.824)})^2.1229.The instantaneeous rate growth equation of the weight have an inflexion:d²l/dt²=-16.684e^{-0.1812(t+0.824)},d²W/dt²=433.9942e^{-0.1812(t+0.824)}(1-e^{-0.1812(t+0.824)})^1.1229(3.1229e^{-0.1812(t+0.824)} -1).According to the analysis of the food intestine, Onychostoma rara feeds mainly on phytoplankton.The absolute fecundity of Onychostoma rara varies from 2745 to 22373,with the average of 7059.2.The relative fecundity based on body-weight varies from 7.96to 20.31,with the average of 11.11.Onychostoma rara reproduces yearly from May to August.The composition of nutrition of muscle are as follows:the percentage of protein is 16.73%,the ratio of fat,ashes is 2.05%,0.98%,separately.In addition,we evaluated germ plasm of Onychostoma rara by age and growth,fecundity,food,nutrition of muscle. Onychostoma rara is a good kind of freshwater fish.