I don;t think you guys are being very realistic about collecting rays in Brazil. Even with 'connections' it is not that easy, nor cheap, nor particularly pleasant for most of the time.
They will take one look at any of you and KNOW that you are a foreigner and the price of everything will immediately be X10. Also Brazilian rays are quota'd to ad to your complications. You may have better luck in Peru, if you want ugly motoros or giant tigers.
Go to the Amazon on a nice vacation, but not a specific collecting trip,then come back and purchase a ray from a reputable person like Mike at H2O and save yourself $$thousands.