Adaptability of gorgonians to temperature, salinity and light after branch-cut transplantation

Gorgonians serve as crucial natural spawning substrates for Sepiella japonica. Given the decline in gorgonian resources, restoring their populations and reconstructing the key habitats for squids is of urgent importance. In July 2021, 80 strains of white and red gorgonian corals were collected from the Zhongjieshan Archipelago Marine Special Reserve. This study analyzed the survival rates and openness levels of Menella sp. and Suberogorgia sp. under four different time periods (7:00, 11:00, 15:00, 19:00), five different temperature gradients (10, 15, 20, 25, 30 °C), six different salinity gradients (10, 15, 20, 25, 30, 35), and four light types (blue light, blue and white light, white light, indoor natural light) using the two-point and Duncan methods. The adaptability of transplanted gorgonians to three key environmental factors was explored. Results indicated that both Menella sp. and Suberogorgia sp. were most active at 19:00. The optimum survival temperature and salinity for Menella sp. were 21.9–26.9 °C and 17.7–24.4, respectively, with survival rates of 90.8% and 85.1%. Menella sp. was sensitive to blue and white light, with 57.9% and 40.2% of individuals achieving grade III or higher openness under these light conditions. For Suberogorgia sp., the optimal survival salinity was 24.4-34.6, with a survival rate of 95.4%, and sensitivity to white light. The proportion of individuals achieving grade III or higher openness for salinity and light was 23.4% and 54.1%, respectively. Both gorgonian species demonstrated adaptability to different environmental factors following branch-cut transplantation. The survival rate and openness grade of Menella sp. were significantly higher than those Suberogorgia sp. These findings provide a theoretical basis for ecological restoration and resource conservation of gorgonian corals.