REPRODUCTIVE BIOLOGY OF THE FISH, MEGALOBRAMA SKOLKOVII, IN FUQIAOHE RESERVOIR

The fish, Megalobrama skolkovii reaches its sexual maturity at 3 years old for females and 2 years for males in Fuqiaohe reservior.In a spawning season the sex can be identified by examining certain secondary sexual characters such as nuptial tubercles of males.The egg development is of an unsynchoronous type and eggs when spawned are adherent. The spawning takes places from May to June when water temperature ranges from 18 to 28℃ in areas of whirling water in the main river course of the reservoir, and is characteristic of single batch type. A multi-parameter regression analysis shows that the absolute reproduction capacity is positively correlated with body length and body weight,but negatively correlated with egg diameter and body depth.Relative reproduction capacity is only influenced by maturing factor.Egg weight and egg diameters are mainly influenced by maturing factor, and are not correlated to biological indexes of brood fish.