The story has been blogged here and here. The paper that presents the research touches on a number of identity aspects to the story that I haven't seen discussed elsewhere:
- The whistles actually convey identity, i.e. it's not the sound of the dolphin's voice that others recognize, it's the pattern of the whistle itself.
- A consequence of the previous is that it would be possible for one dolphin to impersonate another by using that dolphin's unique signature whistle. It seems they do this.
- The identifiers are both global (e.g. a dolphin uses the same whistle to identify itself to all other dolphins) and persistent across the lifetime of the animal. Apparently, privacy is not a big concern at the moment. This will likely change as more and more get 'fished'.