This National Geographic video is called Stunning Jellyfish.
From the BBC:
Experts tag jellyfish for study
Barrel jellyfish are found in Carmarthen Bay and Tremadog Bay
Scientists are tagging jellyfish to study their role in marine life off the Welsh and Irish coasts.
Although consisting of 98% water and some being the size of dustbin lids, biologists say they are “tough, robust animals”, making tagging possible.
Experts from Swansea, Belfast and Cork will also examine how long they live.
See also here.
Leatherback turtles’ newly discovered migration route may be roadmap to salvation: here.