Ummm,madman bailey?I have to dissagree there mr cooper,odd and off the well worn track perhaps but madman?methinks not.The man makes me think hard most times i read his stuff,isnt that what he's about?
I agree that pigment changes are most unlikely following capture,lets face it,we would know by now if them sorts of shennanigans were occuring.I agree with your defect theory,for what its worth,it seems the most believable explanation,until the broughtons of the world come up with scientific stuff on the subject, my moneys with you.Are any areas more prone to this than others?Are bream from meres more susceptible than say gravel pit fish?Do river fish show the same % of two tones?This is fascinating stuff,we should know!