From Michael Allen, Ottawa, Canada
Whales and dolphins already have enough difficulty communicating because of pervasive human-generated marine noise (7 August, p 15).
Now we learn that humans are going to make life more difficult for them by transmitting their clicks and whistles to hide secret underwater messages. I imagine that for cetaceans it will be akin to us trying to have a conversation with someone in the middle of a crowded, noisy cocktail party.
