Zoarder Faruque Ahmed, Md. Yeamin Hossein, and Jun Ohtomi (2012) Modeling the growth of silver hatchet chela Chela cachius (Cyprinidae) from the Old Brahmaputra River in Bangladesh using multiple functions. Zoological Studies 51(3): 336-344. The silver hatchet chela Chela cachius, is a freshwater Cyprinidae commercially important for both subsistence and artisanal fisheries in Bangladesh. This small, indigenous fish is widely distributed in Bangladesh, India, Pakistan, and Myanmar. Ages and growth patterns of male and female C. cachius were separately estimated using monthly length-frequency distributions through multiple functions. In total, 2396 specimens were captured from the Old Brahmaputra River in Bangladesh from July 2007 to June 2008. A birth date was assigned to the month when the peak mean gonadosomatic index (GSI) occurred. The age of each cohort was estimated in weeks from the assigned birth date to each sampling month. Growth patterns for both males and females were modeled by fitting 3 different equations between mean standard lengths and the corresponding ages. The growth of C. cachius was best described by the von Bertalanffy model as L-t a 67.26 (1 - exp(-0.024 (t + 20.22))) for males and L-t 69.92 (1 - exp(-0.027 (t + 22.90))) for females based on the coefficient of determination (r(2)), Chi-squared (chi(2)) values, and Akaike's information criterion (AIC), where L-t is the standard length (mm) at age t (wk). Females grew faster than males, and their absolute growth was larger than that of males at any age. The von Bertalanffy growth model, in terms of body weight, provided equations as W-t 3.30 (1 - exp(-0.032 (t + 14.32)))(3) for males and W-t 3.38 (1 - exp (-0.034 (t + 20.42)))(3) for females, where W-t is the body weight (g) at age t (wk). The present study provides a new record of the maximum length of C. cachius from the Old Brahmaputra River and South Asia, which should be useful to fishery managers. http://zoolstud.sinica.edu.tw/Journals/51.3/336.pdf
