Occurrence of larval Elopichthys bambusa and its relationship with hydro-logical conditions in the middle and lower reaches of Pearl River

For studying Elopichthys bambusa resource status in the middle and lower reaches of Pearl River, which could be used to guide fish resources protection and ecological restoration, larval Elopichthys bambusa were surveyed at Zhaoqing section in 2005 and 2006. Sampling was conducted continuously by Jiang net. The result show that reproduction period of E. bambusa lasted 105 days, and the larval was mainly occurred from May to July, accounted for 0.29% of the total fish larvae in 2006. The larval E. bambusa were 8.89?0.25 mm in total body length, and ranged from melanoid eye stage to yolk-exhausted stage. The density of E. bambusa and total fish larvae regularly changes with day and night. The density was higher at night than day time. Correlation and cross-covariance function analysis show that it was significantly correlated between density of E. bambusa larvae, discharge and water level in Guanliang hydrometric station (P<0.05, n=126), Luoding River was one of the main rivers that affected E. bambusa reproduction. It was also inferred that Luoding River and from Luoding River estuary to Wuzhou section were the main spawning grounds, which were contributing about 41.4% of the total E. bambusa larvae in the middle and lower reaches of Pearl River.