In order to explore the feasibility of the north-south relay aquaculture model for S.intermedius between Fujian and Shandong Province,raft aquaculture experiments were conducted in the Qida sea area of Lianjiang,Fujian and Yandunjiao sea area of Rongcheng,Shandong from March 2021 to April 2022.Using abalone raft aquaculture facilities,regular feeding of kelp (Laminaria japonica) and asparagus (Gracilaria lemaneiformis) were carried out.After 13.5 months of breeding,the shell diameter of large-size S.intermedius had reached (61.97±2.38) mm,the body mass had reached (93.13±9.84) g,and the gonadal index had reached 17.69%±1.84%.The shell diameter of the middle-size S.intermedius had reached (58.20 ± 3.03) mm,the body mass had reached (68.43±8.88) g,and the gonadal index had reached 15.38%±1.44%.The shell diameter of the small-size S.intermedius had reached (51.39±2.41) mm,the body mass had reached (53.28±8.71) g,and the gonadal index had reached 13.45%±1.39%.The experimental results showed that according to the seasonal differences in seawater temperature between Fujian and Shandong,S.intermedius sea raft relay aquaculture could greatly improve the growth rate of sea urchins,shorten the breeding cycle,and was an efficient breeding model with good promotion value.Using the north-south relay aquaculture model;choosing large-size S.intermedius seedlings to breed could bring higher economic benefits.

In order to explore the feasibility of aquaculture of purple sea urchin (Anthocidaris crassispina) in raft, a raft culture experiment of purple sea urchin was carried out in Qida sea area of Lianjiang, Fujian Province from April 2021 to September 2022.In the existing abalone culture sea area, the raft culture facilities were used to feed kelp (Laminaria japonica) and asparagus (Gracilaria lemaneiformis) regularly.After 17 months of breeding, the diameter of the purple sea urchin had reached ( 47.10 \mathrm{} \pm \mathrm{} 4.07 ) mm, the body mass had reached ( 43.40 \mathrm{} \pm \mathrm{} 8.80 ) g, and the gonadosomatic index was 4.45 \mathrm{\%} \mathrm{} \pm \mathrm{} 2.97 %.The test results showed that it was feasible to use the existing abalone marine raft culture facilities to carry out the marine raft culture of purple sea urchins, but it was necessary to improve the culture facilities according to the characteristics of purple sea urchins such as long thorns.