Effect of adhesives and attachment substrates on Sargassaceae zygote attachment

To address the problem of survival of macroalgal zygote transplants, six adhesives were mixed with Sargassaceae zygotes and incubated to determine their adhesion and germination. The adhesives with the highest zygote survival were selected, and then 4% alginate and 3% CaCl2 were mixed with the zygotes and applied to three adhesion substrates with different levels of roughness. The zygote attachment density was used to determine the combination of adhesives and substrates that was most favorable for zygote adhesion. The results showed that: (1) The zygote attachment density of coated alginate reached 259 ind. cm− 2, with a survival rate of 9.4. Although the attachment density of zygotes encapsulated with hyperbranched polymeric adhesive (HBPA) was low, the material was viscous, adhesive, and slow to dissolve, giving it potential as an outdoor transplant adhesion material. (2) The attachment density of zygotes on brick, cement board, and PVC substrates sprayed with 3% CaCl2 reached 86 ind. cm− 2, 48 ind. cm− 2, and 8 ind. cm− 2, and the survival rate was 52%, 29%, and 5%, respectively. The rougher the substrate, the more zygotes adhered. Therefore, in macroalgae restoration and seaweed farm reconstruction, artificial algal reefs with a rough substrate and granular dents could be used in combination with the application of adhesives. The results of this study will help to address the environmental constraints affecting the artificial transplantation of macroalgae and aid in the development of innovative habitat restoration techniques for macroalgae habitats.