We wouldn't want to use whistles that will have a negative effect. The dolphins recognize the whistles as a form of communication, but it is a new kind of language to them. The creation of a cross-species auditory language has never been done before. The reason it has taken biologists so much longer to establish communication with dolphins than with apes is that dolphins are logistically so much harder to work with. Apes are physically more similar to us.
Dolphins are almost purely acoustic.
And research at Project Delphis is not as sophisticated as ape sign language. My hesitation is that dolphins are primarily acoustic animals while humans are primarily visual animals. We believe that communication this way is a viable possibility. We'll be able to ask questions and they will be able to answer in very simple terms. Marten, who has been working with three dolphins at the park, says the dolphins already recognize and repeat the artificial whistles he has devised.