Evaluation of the growth and heterosis of hybrids among three commercially important sea urchins in China: Strongylocentrotus nudus, S. intermedius and Anthocidaris crassispina

In the present study, we investigated growth, development and viability at the larval, juvenile and adult stages of Strongylocentrouts nudus (Sn), Strongylocentrotus intermedius (Si), Anthocidaris crassispina (Ac) and their hybrids. We achieved improvements of traits related to growth in hybrid F1 via hybridization among the three commercially important sea urchins in China. The obtained results reveal that the average performance traits from fertilization to the 3-month-old juvenile stage (i.e., fertilization rate, larval survival rate, metamorphosis, juvenile survival rate) of heterospecific crosses were significantly inferior to those of conspecific crosses. After 22 months of lab culturing, we measured the growth characteristics (i.e., diameter, height, wet body weight and gonad weight) and evaluated heterosis. The Si×Ac group showed clear heterosis in all characteristics compared to conspecific controls (4.00–59.40%). The Si×Sn and Ac×Sn groups showed limited heterosis, and the hybrids produced few or no gametes. The heterosis of Si×Ac, Si×Sn and Ac×Sn obtained in this work will have significant implications for the development of sea urchin aquaculture.