Multi-generational selective breeding for high fertility in the marine copepod Bestiolina amoyensis

Copepods are a group of marine plankton that play an essential role in the energy transfer of marine ecosystems. They serve as vital prey for the larvae of numerous economically important species of fish, shrimp, and crabs. Bestiolina amoyensis , a copepod species inhabiting nearshore warm waters, possesses numerous commercial advantages for fishing, including small size, rapid reproduction, and strong adaptability. These make it an ideal live feed for aquaculture. In this study, a breeding plan for high fertility was conducted with B. amoyensis. The samples were breed five generations using the total egg production as breeding index. A circular mating strategy were applied by randomly selected offspring from the 4th day eggs of different pairs both in selected and control groups. The stability of selection also were investigated for another 5, 10, 15 generations. After multiple generations of selection, there was a gain of 23.99% in total egg production in the fifth generation (G5) with a heritability (h ² ) of 0.46 ± 0.11. The population densities of the selected and control groups were 9075.00 ± 193.18 ind/L and 7200.33 ± 249.18 ind/L, respectively. After the passage of another 5, 10, and 15 generations without selection, there was a decrease in total egg production in the selected group. However, significant differences remained in the total egg production of females and population sizes between the selected and control groups. The results showed that the reproductive capacity of Bestiolina amoyensis has could be improved by continuous selection, which may provide technical support for large-scale and high-density cultivation.