Fishing The Fly Scotland Forum

Sandy Nelson

Blue spots?
« on: 30/06/2015 at 11:19 »
Heres a question to see if anyone is noticing this, or even better has a possible idea why.

I have noticed on quite a few of the fish i have caught recently, both on the Don and other rivers that a fair percentage of the brownies are developing a distinct blue spot on the gill cover aft of the eye, almost like another eye making the head look bigger (one theory) Sometimes it it is very dark and on others it only appears to growing

When i checked through my photo's and others on the forum i have noticed it seems to be quite common, even on some of the FB posts from the north of england, the trout have this blue spot.







So is it a normal part of the trout colouration which i've not noticed before, or are the fish developing a fake eye to make their heads look bigger and fool predators as to their size. Or is it something else? I'm used to the fish having a nice blue sheen on their gill covers but i can't say i've noticed the dense spot before. :z8

I'll be interested to hear people's ideas/experiences

Sandy

Derek Roxborough

Re: Blue spots?
« Reply #1 on: 30/06/2015 at 11:57 »
Is that some sign of a stocking or counting programme,could these trout have been panjetted? I will have to pay attention to our Loch trout , easgach 1

Mike Barrio

Re: Blue spots?
« Reply #2 on: 30/06/2015 at 12:18 »
Is it only appearing on photos taken with flash Sandy?

Sandy Nelson

Re: Blue spots?
« Reply #3 on: 30/06/2015 at 12:28 »
So far these are wild fish so i don't think it is dye, it is the same natural colour as the rest of the blue sheen on the gill plates, just a concentrated area.

Fish were caught from the Annan, the Don and the Deveron, Ricardo had a photo of one as well, the same, off the eden i think, on FB

You can see it quite clearly in real life, the photo's actually hide it a bit, the underwater picture Mike has of the first fish shows the spot really distinctly, much more like real life was. :z16
Some are more intense than others and some fish don't have it all, but it does seem to me to be something i'm noticing more and more, perhaps it is something to do with the season progressing?

Sandy

Rob Brownfield

Re: Blue spots?
« Reply #4 on: 30/06/2015 at 12:37 »
It's normal Sandy. Seen it on fish caught in New Zealand and the US as well as UK.

US fish:



Patagonian fish with two?



New Zealander with faint area


However, as to the cause...I did find this post...the last one...to be interesting and frustrating as I cannot find out anymore.
http://ukflydressing.proboards.com/thread/4032/trout-blue-spot-on-head

Marc Fauvet

Re: Blue spots?
« Reply #5 on: 30/06/2015 at 13:37 »
it's common, Sandy. some are more rounded than others but the blue splotch seems to be everywhere. (but it's not an always... )
interesting 'bigger eye' to scare off predators concept !  :z16
here's a few from here and there:

River Eden, England


Basque region - Pyrenees, France


Northern Sweden


Eastern Pyrenees, France


Derek Roxborough

Re: Blue spots?
« Reply #6 on: 30/06/2015 at 22:28 »
 I will have to pay more attention , promise easgach 1

Sandy Nelson

Re: Blue spots?
« Reply #7 on: 01/07/2015 at 07:23 »
Thanks for the feedback :z18

Amazing how you can spend 30 years catching brownies and not notice this until one evening and then you keep noticing it on every other fish (almost) :X1
Funny the way your brain works, or perhaps its just mine :z4


Sandy

Marc Fauvet

Re: Blue spots?
« Reply #8 on: 01/07/2015 at 09:47 »
Amazing how you can spend 30 years catching brownies and not notice this until one evening and then you keep noticing it on every other fish (almost) :X1
:z4 :z4 :z4

would still be interesting to know why the blue and why there. i'll send this thread over to a biologist buddy to see if he can add info.
cheers,
marc

Derek Roxborough

Re: Blue spots?
« Reply #9 on: 01/07/2015 at 15:28 »
Well, I noticed it this Morning on a small trout from a local loch , I have been fishing more than 50 years and have never noticed it before  :X1 easgach 1 

Allan Liddle

Re: Blue spots?
« Reply #10 on: 02/07/2015 at 22:10 »
Very common Sandy although not all troots have it as prominent than others, as a rule of thumb the more 'leopard' coloured the troot the more prominent it is.
Not just resigned to river troot as loch residents have it as well, although heavy peat stained waters and darker fish often mean it's harder to spot (not always)

Like the big eye theory btw  :z16

And maybe because we spend more time takin troot photies we're noticing the blue spot more? 

Rob Brownfield

Re: Blue spots?
« Reply #11 on: 03/07/2015 at 07:43 »
I can't see the big eye theory being quite on track, sorry. There are plenty of fish both large and small that have "false eyes" on there bodies, and it is always on the tail. Predators tend to strike the head end of a fish, so having a false eye on the tail means a better chance of survival/escape.

There are also a lot of fish that have a "flush" of colour on the gill plate. In some this is because of their diet adding pigmentation to the skin, others, as a form of attractant or warning to other fish. I am leaning towards the latter.

I think :)

Marc Fauvet

Re: Blue spots?
« Reply #12 on: 03/07/2015 at 10:57 »
And maybe because we spend more time takin troot photies we're noticing the blue spot more?

 :z16 :z16 :z16

Sandy Nelson

Re: Blue spots?
« Reply #13 on: 03/07/2015 at 11:45 »
This photo shows why i thought about the eye, not so much to confuse, just to make it look bigger



But you could be right Allan, the more you look, the more you see :z16

Sandy

Marc Fauvet

Re: Blue spots?
« Reply #14 on: 05/07/2015 at 09:57 »
kinda makes it look like a weird flounder...  :z4 :z4 :z4

 




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