A manatee researchers had known for more than 20 years was killed by a boat strike over the weekend, leaving her twin calves orphaned and in need of rescue.

Workers with Dolphin Research Center and the Florida Fish and Wildlife Conservation Commission, responded to the bayside of Tavernier in the Upper Keys Sunday to help the baby manatees.

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Their mother, named Bonnie by researchers, had been seen regularly in the area and Dolphin Research Center had helped her get untangled from fishing line on several occasions.

The baby manatees, a boy and a girl, were taken to the Miami Seaquarium for rehabilitation.

While happy to have rescued the manatee calves, personnel at Dolphin Rescue Center were devastated by Bonnie’s death.

“With assistance from her human friends, she was able to continue life in the Florida Keys, including raising other babies before these twins,” the organization said on its Facebook page. “May she rest in peace while her youngest offspring hopefully grow big and strong.”