Abstract:

Growth and population dynamics of elongate loach （Leptobotia elongata Bleeker） were investigated by using FiSAT II software of FAO on length based data， 1528 specimens of elongate loach were collected from Panzhihua，Yongshan，Shuifu，Juexi，Nanxi，Neijiang，Chishui，Jiangjin，Chengjiang and Wanzhou in the upper reaches of the Yangtze River between September 2010 and August 2012The relationship between the body length（mm） and body weight（g） was expressed as W=1×10－5L3024The growth parameters estimated by length frequency analysis were：〖JP〗asymptotic length （L∞=65610 mm）， growth constant （k=015 year－1） and age at length 0 （t0=－0048 year－1） The natural mortality （M） of elongate loach was 033 year－1 by using Paulys M empirical equation， where the mean habitat temperature was 184 ℃ The total mortality （Z） was 085 year－1 and the fishing mortality （F） was 053 year－1 The exploitation rate （E） was found to be 062 During 2010-2011， the average stock of elongate loach from the upper reaches of the Yangtze River was 1321 tonnes， with a number of 162 862 individuals The MSY was estimated to be 517 t for elongate loach The analysis of related parameters and relative yieldperrecruit suggest that elongate loach in the upper reaches of the Yangtze River is overexploited Corresponding conservative fishery strategies should be carried out to protect the elongate loach in the upper reaches of the Yangtze River