Crossbreeding of different populations of sea cucumber Apostichopus japonicus

Development of crossed stockbrood(R×C)of sea cucumber Apostichopus japonicus from Russia(R) and China(C)and early development of the offsprings from crossbreed R×C with different populations of sea cucumber in China were studied.The results showed the first generation offspring(F1) developed to maturity naturally in outdoor ponds or by artificial procedure indoor.The mature F1 had average body weight of(246.5±65.1)g ranging from 140 g to 400 g in 3 years,somatic-gonadal index of(15.7±1.6)%,and the eggs with a diameter of 130-160 μm.The zygotes from the back cross breeding were found between F1(C×R)and C at water temperature of(20.0±0.5)℃,salinity of 31,pH 8.0,and dissolved oxygen concentration of 7.4 mg/L.The growth confirmed the advantage in growth rate in the cross offspring: body length in the auricular larvae,F1(C×R)♀×C♂C♀×F1(C×R)♂F1(C×R)♀×F1(C×R)♂C♀×C♂;body length in the juveniles: 4 months old F1(C×R)♀×F1(C×R)♂C♀×F1(C×R)♂C♀×C♂F1(C×R)♀×C♂;weight in juveniles,F1(C×R)♀×F1(C×R)♂F1(C×R)♀×C♂C♀×F1(C×R)♂C♀×C♂.