Well, first off, make sure your trolling in the right place. If you continue trolling, you should end up where you started in the Frigid Ocean. The route makes a slightly rectangular, counter-clockwise loop around the Frigid Ocean. Also, make sure your either using the white or orange bait. I caught two with orange and one with white. And if you still can't get it, remember that it is really rare so it might take a while to get it.