The verb indicates an action on the part of the sea and Death and Hades. They recognize that he “who is seated on the throne” is superior to them and so they must submit and hence surrender the dead temporarily entrusted into their care. They do not own the dead and so cannot keep them. We may see in the verb “give up” an allusion to the general resurrection of all people on the Last Day (Acts 24:15; Daniel 12:2).
13 And the sea gave up the dead who were in it, Death and Hades gave up the dead who were in them, and they were judged, each one of them, according to what they had done.