I always wonder who these tourists are that complain about the dogs on the beach. I'm a tourist and I go to Sosua beach, and I've never heard other tourist complain about them. I never heard complaints about beach dogs on my trips to Mexico or Costa Rica either. Good grief, there was a beach in Costa Rica where locals and tourists fed a wild baby beach pig and it ran around like a dog and no one cared.
Beach dogs seem to have their own agenda. Don't get me wrong. I'm not one of those people that want to treat a dog as a person, so I don't mess with them or feed them, and they don't approach me.
Of all the things that Sosua could worry about affecting tourists, dogs seems to be the least of concern to me. Sponsoring or subsidizing shows/events, making town more pedestrian friendly, improving street lights in some areas, increasing English speaking police and services, addressing the panhandling and solicitation, etc. would all be more impactful to me.