A Review of the Age, Growth Characteristics, and Population Resources of Ptychobarbus dipogon in the Middle and Upper Reaches of the Yarlung Zangbo River

Abstract

This paper applies the von Bertalanffy growth equation to study the age structure and growth characteristics of 210 Ptychobarbus dipogon collected in September 2019 in the middle and upper reaches of the Yarlung Zangbo River and employs FISAT II software to estimate the population characteristics’ parameters. Its aim is to provide a basis for the conservation of the population resources of the Ptychobarbus dipogon. In this study, the length of the catch ranged from 137 mm to 475 mm, the weight ranged from 44.04 g to 1142.80 g, the minimum age was 5 years, and the maximum age was 47 years. The body length–weight relationship was W(♀) = 4.1738 × 10−5L2.7687 (n = 86, R2 = 0.901); W(♂) = 2.7784 × 10−5L2.8434 (n = 100, R2 = 0.918). The growth equation was Lt(♀) = 505.000[1 − e−0.048(t−1.992)]; Lt(♂) = 452.254[1 − e−0.069(t−4.233)]; Wt(♀) = 1296.576[1 − e−0.048(t−1.992)]2.7687; Wt(♂) = 1001.872[1 − e−0.069(t−4.233)]2.8434. The inflection point ages of the female and male Ptychobarbus dipogon were 7.95 and 6.05, respectively. The exploitation rate of Ptychobarbus dipogon was 0.61, which exceeds the optimum exploitation rate of resources (0.57). The population resources are overfished. It is suggested to strengthen the conservation of Ptychobarbus dipogon population resources and the protection of native fish on the Qinghai–Tibet Plateau.