Broodstocks management, fecundity and the relationship between egg size and embryo survival ability of Sinocyclocheilus grahami

Broodstock management, fecundity and egg size of the golden-line barbel Sinocyclocheilus grahami were studied from 2007 to 2010. The induced spawning success of female S. grahami was 25.2% in 2007 and dramatically increased to 91.3% in 2010. The nucleus deviation rate and hatching success were 61.5% and 30.4%, respectively, in 2007 and increased to 85.2% and 44.5%, respectively, in 2010. Providing nutritious food for broodstocks of S. grahami can ensure optimum breeding conditions as well as high-quality eggs and fingerlings. There also seems to be a relationship between absolute fecundity (F) and standard length (SL), as described by the power-exponent function F=0.0004826SL3.166 (R2=0.6424，P<0.05). The average of number of spawn egg was 2118.4±899.1 from 2007 to 2010, the average of absolute fecundity was 2402.9±881.9 from 2007 to 2010, and the average of relative fecundity was 70.4±20.8 from 2007 to 2010. The number of spawn egg, absolute fecundity and relative fecundity increased in individuals with a longer body length. Additionally, egg size contributed to the survival rate of embryos. The different batches reached an asymptotic, low or stable embryonic mortality during the first two days; the balance was broken in the subsequent seven days, as high embryonic mortality was observed in smaller eggs. The mortality of embryos from eggs larger than 2.0 mm was, contrastingly, rather stable. Embryos from bigger eggs have stronger survival potential, as bigger eggs can provide more energy and thus, a more favorable environment for early development.