Center has been tagging the orcas to learn more about where they roam in the
winter...
So, the agency has been putting tags on a fin or two and tracking the whales via satellite. They use a pneumatic dart gun from about 4-12 meters that penetrates the fin tissue with a transmitter’s “retention petals,” the center writes."
http://blog.seattlepi.com/thebigblog/2013/01/16/ever-wonder-where-the-killer-whales-go-during-the-winter/