A Study On The Growth Pattern Of Brown Frog (Rana Dybowskii) And Techniques For Discriminating Wild And Captive Individuals

Brown frog (Rana dybowskii) is an important economical species. The wild populationappears to dramatically decline due to the increasing market demand. In recent years,techniques for farm-breeding the brown frog has been developed rapidly and provided aconsiderable portion of market supply. The species showed morphological and physiologicalchanges under farm conditions comparing to their wild conterparts. This makes it possible todevelop a set of techniques to discriminate wild frog and farmed frog to lend experience to theforensic identification of other endangered species in the case that many farmed endangeredspecies are legally used but those wild counterparts are not. We here carried out a comparitivestudy on the growth pattern and morphological and physiological difference between wild andcaptive brown frogs from different regions of Jinlin Province. The results are:1. Brown frog shows distinct dimorphism in the development of body weight, body length,hindlimb length, and forelimb length. The dimorphism inferred from indexs of bodymeasurements sarted from 2 years old, and increases gradually.2. Von Bertalanffy growth model is the optimal model for the description of the growthpattern of brown frog.3. Femur density of brown frog shows significant difference between male and female,and among different regions.4. Both male and female show significant difference in femur density, body-weight/body-length (W/L) and relative fatness (K) between wild and captive brown frogs.5. Between wild and captive brown frogs, a siginificant difference of the area of musclefiber cross-section of 2-year female brown frogs (P＜0.01), but no statistical difference wasobserved for this index in male brown frogs at the same age (P＞0.05).6. Indexs including the relative fatness, body-weight/body-length ratio, bone density andmean area of muscle fiber cross-section was integrated as an index for discriminating wild andcaptive brown frogs. Results showed that the Fisher discrimination equation may achieve avalidity of 93.2% for female frogs, and 95.5% for male frogs.