There is excellent Bass fishing the resevoirs as you say. Any fairly proficient bass fisherman should be sucessful in fishing these areas. I have fished these bodies of water from the shore, small boat and even inner-tube.
The river Ozama and Haina are both great Snook and Tarpon fishing areas. Particularly the upper Ozama.
I have heard of some particularly wealthy individuals stocking some of the highland streams with Trout but I have seen no evidence of this. If they have, the locals probobly decimate them before they get established. Could you just imagine some of the streams near Jarabacoa and Constanza with trout? Paradise!!!
As for Red Carp. I know that some europeans consider it a delicacy but then they liked ABBA. At best it is a trash fish better suited as fertilizer!