Towards a vitrification-based cryopreservation protocol for the coral Pocillopora damicornis L.: Tolerance of tissue balls to 4.5M cryoprotectant solutions

•Tissue balls of Pocillopora damicornis were used to test cryoprotectant toxicity.•Tissue balls were exposed to cryoprotectant solutions with a molarity up to 5.0M.•Tissue balls tolerated binary cryoprotectant solutions with a 4.0M total molarity.•A 4.5M solution was tolerated when molarity was increased in a stepwise manner.•Ethylene glycol and glycerol were the best tolerated cryoprotectants.