Fish that made a leap in evolution

That was the name of an article in the Toronto Star's science section yesterday.

First few lines:

" Biologists have found that salmon in a lake in the northwest U.S. developed into two genetically different populations in only 13 generations - much faster than expected. In effect, it was evidence of a small but rapid step in salmon evolution."

Comments? Questions?

P.S. I do not mean to start another long argument with this. Please do all the arguing inside your own head and not with other people, thank you; I'm sure everyone's tired enough from the last one.