VALUES OF EIGHT STRUCTURES AS AGE DETERMINATION OF PTYCHOBARBUS DIPOGON, TIBET AUTONOMOUS REGION

The morphology and annulus characteristics of Ptychobarbus dipogon were described by eight aging materials in Tibet Autonomous Region, China, and then the suitable aging materials were determined in term of structures and annuli characteristics of eight aging materials. Hip scale was seriously specialized, annulus characteristics of chest scale, lateral-line scale, back scale were not obvious. Compared with the lapillus, the average percentage error was 41.63% for hip scale, 51.26% for chest scale, 50.50% for lateral-line scale, and 51.26% for back scale. The average percentage errors of asteriscus (12.28%), vertebrae (15.67%), and opercular bones (17.81%) were little different from lapillus. Below 23 years old fish, the average age of lapillus was 14.39 years that was similar with asteriscus (13.13 years) and vertebrae (13.20 years), but it was significantly higher than opercular bones and four scales (P<0.05). Above 23 years old fish, the average ages of seven aging materials were significantly lower than that of lapillus (P<0.05). The maximal age was 49 years for lapillus, 35 years for asteriscus, 34 years for vertebrae, 34 years for opercular bones, 22 years for hip scale, 19 years for chest scale, 16 years lateral-line for scale, and 17 years for back scale. The relationship between the age of lapillus and body length was logarithm function (P<0.01). Therefore, the lapillus was the suitable age determination material for Ptychobarbus dipogon.