Marco,

Great to see you are catching and releasing all the way in Portugal :) This kind of thing happens all the time! So often that it's not even suprising any more. If you have not looked at Fish Chris' page about catch and release, it is at:

http://www.trophybassonly.com/id50.htm

You should have a look. It's a great testament to how well catch and release works. When the world record is caught, any money says that it will be a fish that was caught and released many times before.

Best of luck finding those big Northern strain bass in Portugal.