| This paper dealed with the annuli characteristics, age, growth, reproduction strategies and histology of the gonad development of spawning stocks for G. przewalskii. The main results are as follows:1. There are two patterns of annuli characteristics on anal scale. One is the pattern of zones of wildly and closely-spaced circuli and the circuli forms ridge, and the outer edge of the ridge is the annuli. The other has no evident zones of wildly and closely-spaced circuli, but possesses some obvious circles which are annuli at interval on the scale. Lapilus and asteriscus can both be used for ageing and the percent agreements within the error of ?1 annuli for annulus readings between it and lapillus were 100%, but sagitta is not suitable for ageing because it is fragile. Observed in perspective light, wide opaque zones and close translucent zones arrange alternately on sectioned otolith, sectioned dorsal fin spine and vertebra. The joints between the wide zones and close zones are the annulis.2. The interpretability of four kinds of ageing materials are as follows: sectioned dorsal fin spine>sectioned lapillus>scale>vertebra. Sectioned dorsal fin spine is the best material in ageing of the fish less than eight years. As for the fish elder than eight years sectioned lapillus is the reliable ageing material that had more annulus readings than scale, dorsal fine spine and vertebra.3. The formation period of annuli is mainly from April to June every year.4. The condition factor of G. przewalskii decreased in reproduction seasons. The sexual ratio of spawning stocks was 1.66 : 1, and the age composition was from 4 to 11. The mean body length and body weight of female were bigger than those of male.5. The relationship of body length and body weight of female is W=0.000174 L2.49899, while that of male is W=0.0000402 L2.75382, and there is significant difference between female and male. The growth of G. przewalskii can be described with Von Bertalanffy factions of It=551.9301[l-e-0.07112(t+0.3044)] (female) and Lt=682.8688[l-e-0.05304(t+0.4240)] (male).The growth inflexion of female and male are 12.57 and 18.67,respectively.6. G. przewalskii migrates to rivers for reproduction from May to August, and the main reproduction sites are the three rivers of Shaliu River, Buna River and Heima River. The three spawning stocks had no significant differences in mean body length, mean bodyweight and mean age.7. The sex can be identified base on the shape of anal fin, and there are some obvious pearl organs on anal fin of male individuals during reproduction seasons. In the whole spawning stocks the body length, body weight and age of the minimum male individual were 130.0 mm, 28.0g and 4 years respectively, and those of the minimum female individual were 175.0mm, 58.0g and 6 years respectively.8. The gonadosomatic index (GST) of ovaries and testises of adult G. przewalskii exhibited only one peak during one year from June to July. The mean maturity egg's radius was 2.33mm, and it had no significant relationship with length or GSI. The mean absolute fecundity was 4337.81 2541.26, and the mean relative fecundity was 27.09 11.09. The absolute fecundity increased with the increase of body length, body weight, somatic body weight and gonad weight, while there was no significant relationship between relative fecundity and body length, body weight or somatic weight.9. The gonad development of G. przewalskii can be divided into 6 stages. The development of oocytes from phase 3 to phase 4 was synchronous, the histological structure of the ovary and testis came back to stage II after reproduction. The ovary of G. przewalskii would develop to stage IV in winter, and the ovary matured only once in a year.
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