From June 2007 to May 2008,511 specimens of Mystus macropterus were collected from the middle reaches of the Chishui River for age determination and growth study.New annuli on the pectoral spine were formed mainly in June and July.The age of specimens ranged from 1 to 7,and age groups of 2 and 3 constituted the main part,accounting for 38.9% and 31.3% of the total,respectively.The correlation formula for body length(L) and body weight(W) was:W=6×10-5L2.638(R=0.937).The correlation formula for radius of the ...