Age and growth characteristics of S chizopygopsis younghusbandi R egan, 1905 in the Y arlung T sangpo R iver in T ibet, C hina

Summary To better understand the biology of S chizopygopsis younghusbandi R egan, 1905 and its relationship with management considerations, this study describes the relationships between otolith size and fish length and age, verifies annual periodicity of otolith annulus formation, and estimates the S . younghusbandi growth parameters. These age and growth characteristics were studied using 694 specimens collected from A ugust 2008 to A ugust 2009. Otoliths grew asymmetrically throughout the range of standard length ( SL ) studied, showing a clear pattern of alternating translucent and opaque bands. Marginal increment ration ( MIR ) analysis of specimens up to 6 years of age indicated that one opaque band and one translucent band were laid down each year. Maximum observed age was 17 years, corresponding to a female of 35.8 cm SL and 589.1 g body weight ( BW ). The SL ‐ BW relationship was described as BW   = 1.122 × 10 −5 SL 3.030 for sexes combined. The von Bertalanffy growth function was used to model back‐calculated lengths as L t  = 338.4 (1−e −0.233 (t + 0.403) ) for males, and L t  = 433.9 (1−e −0.194 (t + 0.397) ) for females. Growth performance of S . younghusbandi was relatively higher than those of other S chizothoracinaes inhabiting the same river.