I'll bet that many Domincans come into the US under pretense of being Puerto Ricans. Have you heard of this? It wouldn't be too hard to travel from Dominica to Puerto Rico since they are close, and then hopping on a plane from Puerto Rico to the US.
I have done the math. At the company I work for a lot of the cafeteria workers are from East Boston and Lawrence, and they seem to be mostly Dominicans. Can’t say why. Very decent people, but I only see the ones with jobs and W-2’s.