Stringray's easily get stressed during and after transport.
First make sure the water quality in your tank is oke. Ray's are highly sensitiv for bad water. Make sure your N03 is less then 25 and your N02 0.
Then i would recommand you to first give the ray's some air in the transport box.
Next let water run from your tank to your transport box. (i normally do this with an string for my air-pomp)
When you want the less stress for your ray's, you should turn of your light in your tank.
And import with wildcatch is that you first put them in quarantine, because they could care parasits with them.
Just remember this... when they start eating in your new tank, they will be ok. Motoro's are normally alot easier than Flowerrays.