SeaWorld Orlando transferred four manatee calves to an Ohio aquarium for rehabilitation, freeing space to treat more of the threatened sea mammals that have been dying in Florida at an alarming rate.

SeaWorld said DHL Express transported the manatees from its rescue and rehabilitation center to the Columbus Zoo and Aquarium on Saturday.

DHL donated its services, including the flight. SeaWorld said it has been getting a record number of manatees needing treatment at its center, one of only five critical care facilities for manatees in the U.S.

More than 1,000 manatees died in Florida in 2021.

DHL transported the manatees in custom-built containers and they were monitored throughout the flight by a Columbus Zoo veterinarian.