关键词: 长江下游, 鳊, 年龄, 生长, 繁殖特性

Abstract: To understand the growth and reproduction characteristics of Parabramis pekinensis in the lower reaches of the Yangtze River, we collected 1040 samples from Tongling, Wuhu, Dangtu, Zhenjiang, Jingjiang, and Nantong sections for four consecutive quarters from 2017 to 2018. Body length of the fishes ranged from 84.79 to 305.00 mm. Body weight ranged from 8.50 to 673.39 g. The ratio of male to female was 1∶0.97. The ages ranged from 1 to 6 years. Individuals with 2 and 3 years old dominated the population, with a contribution of 87.9%. Von Bertalanffy growth equations were as follows: L_t=331.09×［1-e^-0.22(t+0.27)］,W_t=589.05×［1-e^-0.22(t+0.27))］^2.964. The inflection point age of growth was t_i=4.67 a, the corresponding body weight was 174.00 g, and the corresponding body length was 219.42 mm. By dissecting 24 samples, we recorded that the absolute fecundity ranged from 1630 to 154247 grains, with an average of 35792±39381 grains. The relative fecundity per unit weight was 10.99-383.70 grains·g^-1, with an average of 120.06±89.68 grains·g^-1. The relative fecundity per unit length was 7.89-598.44 grains·mm^-1, with an average of 142.23±135.78 grains·mm^-1. The absolute fecundity had a linear and exponential relationship with body length and weight, respectively. Our results indicate simple age structure of Parabramis pekinensis in the lower reaches of the Yangtze River, with young individuals predominantly and weak reproductive potential, but a higher level of the growth parameters. Corresponding protective measures should be taken for the sustainable use of Parabramis pekinensis resources.

Key words: lower reaches of the Yangtze River, Parabramis pekinensis, age, growth, reproduction characteristics.