I don't think it's stress, I am not sure what causes the two-tone effect, but it's probably just the fish adapting to it's surroundings, I have caught perch that have been really dark almost black, so dark their stripes are hardly visible, yet some are bright green.
Just my 2p's worth.
The key to this is a line where he says they appear their normal colour in water until you catch them. If that's true it has to be something related to their being caught and removed from the water, so JB could be right.
Sorry - flew into print before I'd read your article properly. If they are two tone in the water, it definitely shoots him down. Can't someone like Bruno Broughton, Paul Garner etc put together a succint scientific reply to this. I can see it's going to run and run...
There has been so many theories put up over the years that I am totally confused!I can't ever remember seeing a two tone from the water I caught most of my big bream from.But did catch one from a water in the valley whilst carping.There is no doubt that it is more common in Bream than other fish though.The straight line bit has IMHO always messed up most of the theories. As for John Bailey he seems to have a habit of trotting out old ,well debated (and often dissproved)theories for a second airing ten years on!
I seem to remember reading a book or article that mentioned a famous carp actually called two tone, anyone remember it? and Duncan Kayes (then the Mid northants?) water had one coz i know a man who caught it!!
No Neil never caught it myself but I have seen two tone Carp out of both Heartbreak and the Waterski but not two tone Bream out of either!Would that not cock up the parasite theory Grayham?As for JB I will quote the great Iberian Barbell debate,the many pictures of 20lb Swedish Pike but couldn't be bothered to take pictures of the 40's,and the ever popular(at least every five years)Barbell bite debate!And there is plenty more where they came from.Maybe the person on the mailling list has not been reading Coarse Fisherman for as long as some of us?
This two tone thing is a great subject though as I have never felt that it has ever been answered 100% in the past.
One thing is pretty clear, if lifting fish from the water causes stress, and stress is causing the two-tone effect then all those thousands of fish caught weekly with no two-tone must be real hard gits!
I can only remember catching three two tone fish in my life. One was a bream of 6 lbs in Ireland ca 1965, the other a pike of about 4 lbs in a Lincolnshire drain ca 1964 and the last an eel of about 11 lbs (Anguilla mossambiqua) in South Africa ca 1975. The eel was dark at the head end almost 1/2 way along its body. Don't ask me what causes two tone fish, I don't know
I haven't actually caught any two tone fish (that I remember) but I have a theory.
Fish have the ability to alter the pigmentation levels to suit their surroundings. A bream caught from a lake that is very coloured is generally very pale, almost silver. One caught from clear water is usually very dark. The same applies to many species of fish, e.g. pike, perch, carp, zander, to name a few.
A two tone fish could just have an area of the body that reacts differently or incorrectly to changing pigmentation, a defect if you like. The area of change is usually very pronounced, a virtual straight line and could very well be a feature of the disorder. It could well be a disorder that can be passed to successive generations, possibly a genetic defect.
I am almost tempted to bet a months salary that it is not caused by stress as the madman Bailey would like us to believe.
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!
Dave ,I have read a very similar theory to yours before and it certainly is the most plausable I have heard.Why is it only with larger fish though? I know that pressure on the skin can affect the changing of pigmentation.Look at how a dead cod always looses its colour more quickly on the side that is touching the shingle.What ever causes it it doesn't seem to affect the fish.I wish that I had given this a bit more thought when I was catching a lot of big bream.It would have been interesting too tag the fish.Be really interesting if some one who was Breaming a lot on a water that produced a lot of two tone fish were to tag them and see if once a two tone always a two tone(and vice verca)was true or not?
Come to think of it, way back in about 1966 I spent a couple of weeks fishing in Ireland. I stayed at Garnafailagh House with Fred Carter on the shores of the Inner Lakes of Lough Ree. I am sure you remember the place Graham.
At that time two-tone bream started making their appearance in catches on Lough Ree. In virtually all cases the head end of the bream was the lighter coloured end.
Fred Carter was absolutely adamant that the two tone colouration was caused by bream that stuck their heads into soft silt or sand during winter months. He claimed he had actually seen them do this. One thing I know is that Lough Ree has an incredible clarity. It's easy to watch fish there even in deep water.
Barrie Rickards also wrote about this strange phenomenon and I think he had an arguement with Fred at the time on this subject. Fred Carter spent virtually a lifetime fishing and watching the fish in the large Loughs of Ireland.
He may have been wrong but I have no reason to doubt his integrity.