Difference between stock and wild browns

kingf000

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My club has just asked us to differentiate between stocked and wild trout in our catch returns. I've never really bothered before as I don't kill any river trout I catch. I've always assumed that stocked trout have no or very few red spots, but using this recognition I seem to be catching many times more stocked fish from the same stretch that the majority of fish caught are reported wild. The only thing I can think of is that I am thinking fish with very few red spots are stocked, whereas others regard them as wild. Another thing is that many of the fish are about the same size, whereas I would have thought wild trout would vary considerably in size. Other differences such as shape of mouth and markings on the fins seem to be much more subtle to detect, especially as I normally unhook trout in the water without touching it by grasping the fly and giving it a quick twist. So does anyone have any comparative pictures of stockies vs wild?
 

grandad keith

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Maybe your club should have dye marked the stock they bought,although i think it fades over time.Also stock fish do have imperfect fins sometimes compared to wild bred.
 

baca157

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Lack of red spots means nothing. Most of Clyde trout have no red spots and they are all wild.

Some stocked trout will be marked in some way. Either with a clipped fin or a small tatoo (usually a dot on the belly). I am not sure this is a rule though?

Cheers,
Sebastian
 

sean freeman

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There are always a couple of tells with stocked fish, pigmentation and colouration in comparison to the native fish, an awful lot have a crumpled looking dorsal or poorly formed fins. Scale adhesion is usually quite poor. The clubs upstream of ours put in fairly convincing stocked fish sometimes but there’s always a tell. As above the dye marks help too.

Out of interest why does your club stock if wild fish are so prevalent? You’d probably find if they stopped that wild trout recruitment would increase.
 

sewinbasher

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The dye marking of stockies is at the request of the buyer and adds a little to the cost. My club has been dye marking since 2003 and we found that the marks generally last at least 12 months, sometimes up to 24 months, the best we had was 36 months. We know this because we placed the mark in different locations to differentiate the year of stocking.
 

Mrtrout

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I’d ask your club to stop stocking at all, I pulled the plug seven years ago on our club and it helped the wild trout to regain a good resurgence in the Eden. We also never see wild trout with red spots.
S.
 

kingf000

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There are always a couple of tells with stocked fish, pigmentation and colouration in comparison to the native fish, an awful lot have a crumpled looking dorsal or poorly formed fins. Scale adhesion is usually quite poor. The clubs upstream of ours put in fairly convincing stocked fish sometimes but there’s always a tell. As above the dye marks help too.

Out of interest why does your club stock if wild fish are so prevalent? You’d probably find if they stopped that wild trout recruitment would increase.
The club used to dye mark but don't any more, I think mainly because after a few months it faded. You'd also have to net the fish and turn them over, which I don't like doing unless the hook is deeper down in the mouth. My concern is that the number of wild fish is being grossly, grossly overestimated. If there were lots of wild fish around 12-14 inches upwards, the size of most of the fish I catch, than shouldn't there be even more wild fish under 12 inches being caught? I reckon I catch 1 trout under 12 inches (with red spots!) for every 10 trout I catch over and that is mirrored in the catch returns.
Yes, a few years ago you could tell a stockie from the poor state of the fins, but with better rearing practices in many hatcheries, this seems to be getting much more difficult to tell without a direct side-by-side comparison. When the stocked fish are first introduced they are of a different colour, but rapidly change to that similar to the wild.
As they stock with trout around 12-14 inches, I automatically assume that any fish I catch around that size is probably stocked, unless there is a good reason to think otherwise.
 

raphael

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Red spotting pattern depends on the strain... and you have so many different brownies ones. We have there some catchments with different strains, with isolated or mixed populations, some with red spots, some without, some with little dark cross, some with big marks, some with three large stripes, some without, some with dense spotting, some with very few spots, some brown, some greenish, some golden, some grey, etc... all wild (most of the time, provided the wild stock is still well preserved, genetics show that there is no or little stocked fish introgression!).
If there's never been red spotted fish, where you are then it can be an indicator, but...

Marking can be a good idea, getting rid of stocking is a better one...

R
 

ejw

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As a Club we used to mark stock fish, initially the "Dot" but then moved to clipping the fin. Dodn't make much difference, never had returns to show, most in one year 7 fish ! Once we stopped stocking, numbers went up, Grayling numbers grew and the size of the "wild" fish, beat all the previous stockies !
Habitat improvement is the key. Get that right and fish stocks improve. EA still class the river as "non breading" as they cannot find small fish - they should come out with me sometime !!!!
 

Overmiwadrers

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As some of the posters say red spots aren’t an absolute as I have seen grown on stockies develop them also colours vary a lot within a short length of river I put a record of a trip on my local a week ago it’s the last post in the Yorkshire reports all those fish caught within 2 miles of same river and all quite different the river hasn’t been stocked in living memory
 

kingf000

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As some of the posters say red spots aren’t an absolute as I have seen grown on stockies develop them also colours vary a lot within a short length of river I put a record of a trip on my local a week ago it’s the last post in the Yorkshire reports all those fish caught within 2 miles of same river and all quite different the river hasn’t been stocked in living memory
Whether to stock or not is not so simple as saying it has worked in river X. You have to be sure that the conditions are suitable for sustaining a good population of wild trout and not just relying on wild trout making their way downstream, if they can. For example this stretch of the river has a large head of barbel, which reportedly eat trout eggs. In the last couple of years, with the heavy floods, the stretch of the river has lost nearly all of its weed and much of the suitable gravelly trout spawning areas. So whether it could sustain a wild trout population at this moment is very doubtful. We are at the most downstream and of the trout fishing. Just a couple of miles downstream, it is a coarse fishing river and trout are few and far between. Yes, you could throw away hundreds of years tradition of trout fishing in this stretch of river.
I did actually support a proposal a couple of years ago at the AGM to reduce stocking, but the proposal was roundly rejected by the majority of members.
 

rabmax

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There is one club i fish who have stocked a few this year.Fairly easy to tell the stocked fish.Just look at the condition of the fish.Normally the fins or tail are a bit stunted & a give away.
 

BobP

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The easiest way to differentiate between wild & stocked is to clip the adipose fins off the stock fish. Unmistakeable and doesn't grow back. Takes a few seconds per fish. It is a method used in many parts of the world, eg to distinguich between wild steelheand and hatchery reared.
 

Cap'n Fishy

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As others have said, I would ignore colour and spots, which can be highly variable in both wild and stocked browns.

If a brown has been stocked, its fins usually give it away. Its dorsal is never quite as 'square-cornered' as a wild fish, and its tail is never as 'jaggy-pointed' as a wild fish. The pectorals of a wild fish can be rounded due to parasites nibbling them, but very often a stocked trout does not have a dead straight leading edge bone to its pectorals. We often refer to them as "Harry Lauder's walking stick." 😜

I'll have a dig through my photos - I have hunners of wild browns, but not many of stockie browns!

Col
 

Cap'n Fishy

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This is a stocked brown...

Menteith30Jul20_0245.jpg


Pectoral fin is a bit ragged-edged to the rear, but it doesn't have the 'Harry Lauder's walking stick' leading edge. The dorsal fin is not prominent, but hopefully you can see the leading edge is rounded. Pelvic and anal fins also ragged-edged.

In common with some stocked browns, the spots are 'lumps of coal' type, though I would not call that a diagnostic - just something we often see.

Another stocked brown (one of a two's up with a rainbow!)...

Menteith28May19_3955.jpg


While its pectoral is not Harry Lauder's walking stick, you can see it is not dead straight, like a wild fish. The tail is quite rounded.

Another stockie brown...

Menteith22May19_2957.jpg


Another lumps of coal spots one. Dorsal is distorted. And this one does have a Harry Lauder's walking stick pectoral.

Compare with any wild brown...

Shinness-Jun18_7496.jpg


Shinness-Jun18_8050.jpg


Shinness-Jun18_8193.jpg


SutherlandJun2016_4951.jpg


Orkney2012_1777-crop.jpg


Orkney2013_2362.jpg


Orkney2013_2440.jpg


Orkney2013_2458.jpg


Shin2015_8798.jpg


And many more...

Col
 

Whinging pom

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We use to stock and tried to differentiate which was which … it’s nigh on impossible. It’s really an unrealistic request .

Whoever stocks your trout will have the genes and markings of whatever wild strain they originated from. The chances are they are pretty similar to the wild ones in your waters.

There was a thought that most stockies were loch Leven strain. The strain that are supposed have also gone on to colonise the Himalayas, Australia and New Zealand with their bright red spots.Whether this is true or not I don’t know.. but your stockies genes would come from fish that originally had been eggs and milt stripped from wild British fish.
The only obvious give away were some deformaties to the tails and pectorals from the fish farm … that’s no basis for research of what proportion of caught fish are wild and how your stocking management is going. ( and the investment in stocking !!). Wild females that had dug redds also can get some wear and tear to the fins and tail too.
We tried marking, but fish farm decided to do it as they were releasing into the stream and we saw the stress it was putting on the fish and the slow recovery. So we stopped that.


If you have wild fish, try and talk the club into stop stocking even just for a season or two to see the effect.
The behaviour of stocked fish really damages your wild fishes chances and ability to thrive. The stockies do not adapt to behaving like wild fish, they aggressively seek food and have little or no predator awareness. By the end of winter you will probably have lost the fast majority of the investment in stocked fish . ( we reckoned on losing around 90% of stocked fish each year and less than10% were taken by anglers . Thats 80% stock just lost to the stream a ludicrous return on any investment).

Wild fish fear things coming down from above or passing over… stocked fish see it as feeding time. Wild fish from hatching actively avoid each other except at spawning time and hold onto the best food places available by sizing up and backing off. Stock fish have been crammed together from hatching and aggressively take over areas for food and upset the whole pecking order and balance of the stream… in the equation of energy used to protein taken the smaller wild fish don’t stand a chance and lose condition.
i wonder if the barbel could have as much impact on the Wild trout as the stockies?

We are what would be described as a chub and Dace water. Wild trout manage to keep a hold and we help them with some habitat management by the members. We are not a pristine trout stream !

Within a season of ceasing stocking our catch returns for the anglers more than doubled! Stretches of stream that once gave up 2 or 3 stocked fish in an evening, became an area with 10+ rising fish … and ok most of these were 6-8 inches they’re was still 3 or 4 1lbs plus fish to be had too .


There are many good papers written on the studies of the impact of stocked fish in wild populations it’s not anecdotal or hearsay … and talk to the Wild trout trust .

Try to push to Stop stocking and put your resources instead into improving the river for your wild population. It’s a leap of faith for many people who just want to pay subs and catch a few fish, They will fear it will be too hard to find fish, but once they see the difference,if it’s anything like our club, you’ll soon get them on board . Good luck with it!
 
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BobP

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Where on earth did the idea that wild fish fear things coming from above them? Explain, if you can, the browns on a river like the Teign in Devon feasting on caterpillars dropping from oak trees alongside the river. An imitation needed to drop onto the water with a "plop" and was immediately seized. Anywhere there are trees lining the river you will find trout waiting for something to drop from above whether it be a beetle, caterpillar or some other bug. The only fear those fish will have is that of some other fish getting it first.

You are telling us that trout are terrified of mayflies landing on the water which they often do in their attempts to take off. Same with daddy long legs. Explain too, how it is that wild trout are not merely attracted to the plop of things like sweetcorn hitting the water, but will engage in a feeding frenzy with several others. Trout, whether brown or rainbow, wild or stocked, are programmed to react to that "plop".

That theory is like the old saying that nymph fishing is unfair because it teaches the fish to bottom feed. Total rubbish.
 
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