Length-weight relationship and biological data of a threatened fish, Ptychobarbus chungtienensis (Tsao, 1964) in Bita Lake of Shangri-La, Yunnan, China

Authors

  • W. S. Jiang,

    1. State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, The Chinese Academy of Sciences, Yunnan, China
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  • Y. P. Zhao,

    1. State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, The Chinese Academy of Sciences, Yunnan, China
    2. University of Chinese Academy of Sciences, Yunnan, China
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  • W. Y. Wang,

    1. State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, The Chinese Academy of Sciences, Yunnan, China
    2. University of Chinese Academy of Sciences, Yunnan, China
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  • J. X. Yang,

    1. State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, The Chinese Academy of Sciences, Yunnan, China
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  • X. Y. Chen

    Corresponding author
    • State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, The Chinese Academy of Sciences, Yunnan, China
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Author's address: X. Y. Chen, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, the Chinese Academy of Sciences, 32 East Jiaochang Road, Kunming, Yunnan, 650223, China.

E-mail: chenxy@mail.kiz.ac.cn

Summary

This paper provides the length-weight relationship (LWR) and other biological information of a threatened plateau freshwater fish species Ptychobarbus chungtienensis in the subfamily Schizothoracinae of the family Cyprinidae, from the Bita Lake of Shangri-la, in Yunnan, China. The LWR was BW = 0.00954 TL2.95 for a total of 392 individuals, where the coefficient b was close to 3.0, suggesting a near-isometric growth in this species. The total length: standard length relationship was TL = 0.399 + 1.151 SL. Fitting a von Bertalanffy growth function to the observed length-at-age data resulted in L(t) = 53.1 (1-e−0.08(t−0.2)). The natural mortality rate (M) was 0.20 year−1. Length at first maturity (Lm) was 20.57 cm, and 6.3 years the theoretical estimated age at first maturity (Am). Ptychobarbus chungtienensis mature gradually beginning in May, reaching a reproduction peak around August, with most individuals completing reproduction by October. The gonadosomatic index (GSI) was highest in August (GSI = 0.1351) and lowest in October (GSI = 0.0467). The male index (GSI = 0.0866) was lower than in females (GSI = 0.1466) (P < 0.05). Mean condition factor (Km) of P. chungtienensis was 0.8500, and not significantly different between sexes (P = 0.124), but differing significantly between seasons. In October the condition factor (Km = 0.9211) was significantly higher than in May (Km = 0.8379) or in August (Km = 0.8412) (P < 0.05).

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