The study on otolith and growth in Juvenile of the four domestic fishes from hukou section of the Yangtze River
长江湖口水域四大家鱼幼鱼的耳石与生长研究

The daily ages of 23 juvenile black carps, 111 juvenile grass carps, 73 juvenile silver carps and 70 juvenile bigheads collected from hukou section of the Yangtse River in July and August, 2009, were determined by observing the daily increment of 1apillus. Average age of juvenile black carps, grass carps, silver carps and bigheads were 52.4±5.6d, 57.1±10.6d, 49.8±4.7d and 57.5±7.1d, respectively. Regression analysis shows that, short radius of lapillus of the four domestic fishes were all in a linear correlation with the daily age and body length and weigh. Daily age were also in a linear correlation with body length and weigh. Calculated based on the daily age, growth rate of body length of juvenile black carps, grass carps, silver carps and bigheads were 0.1651 cm/d, 0.1426cm/d, 0.0928 cm/d and 0.0997 cm/d, growth rate of body weigh were 0.9412 g/d, 1.0211g/d, 0.4978 g/d and 0.7292 g/d.