Similar applies to sharks - turn them upside down and they settle quite a lot.
Flip them right way up and they're instantly back to normal.
Once I've extracted the hooks from a ray, I'll flip it right way up and use a gaff or a lump of driftwood to coax it back into the water.
The problem occurs with the really big ones. Flipping a 50kg+ ray is no easy feat, especially as having fought it for an hour or so, one's arms are no longer responding to requests
Sometimes just cutting the trace has to suffice..