Brown trout or sea trout?

Dryblob

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Hi guys,

Attaching two images from early this season, first week of march, both fish caught within a cast of eachother. Both long and skinny and well spawned out. Attaching both fish for comparison.

To me, one looks very much like a possible sea trout. Just wondering could any of you offer an opinion?

Cheers

Carl20200323_142759.jpg20200323_141646.jpg
 

scobo

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I can see why you might think the first one could be a sea trout.
Pretty sure the second one is a brownie though.
 

bobmiddlepoint

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I'd go along with the first one being a sea trout. Either a kelt or simply a non spawning finnock that has over wintered in the river and got skinny.


Andy
 

cgaines10

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First one looks more like a sea trout smolt as they’re bigger than salmon smolts. Depends on your river I guess but I wouldn’t call it a ST.

The second looks like some sort of stockie with those big spots?


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Wee Jimmy

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First one looks more like a sea trout smolt as they’re bigger than salmon smolts. Depends on your river I guess but I wouldn’t call it a ST.

The second looks like some sort of stockie with those big spots?


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What utter bollox, ....first it was blue spots definitely a brownie,now its big spots equals stockie.Give me a pint of whatever you're on...:ROFLMAO:
 

cgaines10

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What utter bollox, ....first it was blue spots definitely a brownie,now its big spots equals stockie.Give me a pint of whatever you're on...:ROFLMAO:

I think you need to re read my posts again then as you clearly don’t understand what I’ve wrote. It’s well documented about the blue hue on the gill plate of brown trout.

Likewise irregular spots are most likely found on stock fish. I never said it was, I said it looks like with a question mark for the OP to come back and say something along the lines of “the rivers never been stocked or X club stocks fish etc”.

Hope you’re back up off the floor.


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Wee Jimmy

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I think you need to re read my posts again then as you clearly don’t understand what I’ve wrote. It’s well documented about the blue hue on the gill plate of brown trout.
Blue area on the gill plate is well documented but it certainly doesn’t prove the fish has never been to sea.
Likewise irregular spots are most likely found on stock fish. ....Since when...?




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Cap'n Fishy

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First one looks more like a sea trout smolt as they’re bigger than salmon smolts. Depends on your river I guess but I wouldn’t call it a ST.

The second looks like some sort of stockie with those big spots?


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First one is surely miles too big to be a smolt?

Second one - just looks like a regular wild brownie to me. I've seen plenty with spots that size...

















Col
 

cgaines10

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Yes, only when backed up by scales samples as previously stated.

Since.. stock fish have been used in rivers?


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cgaines10

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First one is surely miles too big to be a smolt?

Second one - just looks like a regular wild brownie to me. I've seen plenty with spots that size...

















Col

Had sea trout smolts upto 12”.

Thanks for all the pics again. Nice variety, as you will know & probably will follow will photos. BT come in many variations & the stocking that went on added further to that mix. Again, I want saying it was a stockie, just that big spots like that can be an indicator along with other visible features. Whether you agree or not is your own perogative.


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Wee Jimmy

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Yes, only when backed up by scales samples as previously stated.

Since.. stock fish have been used in rivers?


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You were clearly inferring the blue spot meant the fish was not a sea trout here no...?
All browns, nice fish too blue gill plate on the first one gives it away.


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Dryblob

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Hi guys

Thank you all for the opinions. The river is a tributary of the river liffey here in Dublin,ireland. Gets a small run of salmon and seatrout that leave the liffey system and head up whats called the rye river. No stocked fish in the system at all.

I put the second picture of the skinny brownie for comparison with the skinny fish (first pic) i believed was possibly a seatrout. I realise scale samples are the only for sure answer but thought i would put it to you gents for opinion.

Thanks for all the opinions, its interesting to hear from guys with lots of experience with seatrout!
 

Cap'n Fishy

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Had sea trout smolts upto 12”.

Going back to this point...

Can I ask how you know they were smolts, rather than fish that move in and out of the river, regularly over the year, or a finnock kelt, mended and turned silver, ready to go back to sea. Here is an example of what we reckoned to be a finnock, well mended and 're-silvered', ready to go back to sea...



The key indicator here was the month - April.

Quoting from this typical description of sea trout life-cycle...

"Young trout of 1 to 3 years old and 5 to 7 inches long will go through some physiological changes which includes the ability to cope with salt water and changing to a silver colour These small silver trout are called smolts. Smolts will shoal together to migrate to sea, usually around late March/April and usually at night.

Going to sea gives the trout access to a much richer source of food, so sea trout will often be substantially bigger than the resident brown trout of the same river."


... I'm thinking if the young trout grows to 12 inches, rather than 5-7 inches, before smolting, that is a helluva lot bigger, requiring really rich feeding. So, if the river has really rich feeding, that is typical of a river that produces mainly brown trout, as there is no need to go to sea to get big (involving all the extra dangers associated with anadromy).

???

Col
 

cgaines10

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Going back to this point...

Can I ask how you know they were smolts, rather than fish that move in and out of the river, regularly over the year, or a finnock kelt, mended and turned silver, ready to go back to sea. Here is an example of what we reckoned to be a finnock, well mended and 're-silvered', ready to go back to sea...



The key indicator here was the month - April.

Quoting from this typical description of sea trout life-cycle...

"Young trout of 1 to 3 years old and 5 to 7 inches long will go through some physiological changes which includes the ability to cope with salt water and changing to a silver colour These small silver trout are called smolts. Smolts will shoal together to migrate to sea, usually around late March/April and usually at night.

Going to sea gives the trout access to a much richer source of food, so sea trout will often be substantially bigger than the resident brown trout of the same river."


... I'm thinking if the young trout grows to 12 inches, rather than 5-7 inches, before smolting, that is a helluva lot bigger, requiring really rich feeding. So, if the river has really rich feeding, that is typical of a river that produces mainly brown trout, as there is no need to go to sea to get big (involving all the extra dangers associated with anadromy).

???

Col

Caught in a smolt trap & inserted with a pit tag. While doing so measurements & weights were carried out. Salmon smolts were on average 4-8” and sea trout smolts 6-12”. Then tracked on their journey downstream & out to sea.


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Cap'n Fishy

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Caught in a smolt trap & inserted with a pit tag. While doing so measurements & weights were carried out. Salmon smolts were on average 4-8” and sea trout smolts 6-12”. Then tracked on their journey downstream & out to sea.


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Interesting stuff. But how do you know the 12 inch ones were first time smolts and not mended finnock kelts on their way back? Or even fish that come and go between salt and freshwater?

Col

PS: Is it a river that is very rich in feeding? Does it produce mostly brown trout or mostly sea trout?
 

cgaines10

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Interesting stuff. But how do you know the 12 inch ones were first time smolts and not mended finnock kelts on their way back? Or even fish that come and go between salt and freshwater?

Col

PS: Is it a river that is very rich in feeding? Does it produce mostly brown trout or mostly sea trout?

Well I suppose you could say the same for the smaller ones unless you monitored them from fry it’s hard to say where they have been, but the distance from estuary is a large distance, so for them to go down and up again would be a huge task.

Definitely not kelts as the average size of sea trout is 4/5lb plus upto high teens.

Mostly sea trout.


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Cap'n Fishy

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... it’s hard to say where they have been...

Sure - I appreciate that is a hard thing to be sure of.

... the distance from estuary is a large distance, so for them to go down and up again would be a huge task.

What sort of mileage? It surprises me when fishing the south end of Loch Hope, we catch 12 oz finnock with sea lice on them - that's 11 Km from the sea in a day or so.

Definitely not kelts as the average size of sea trout is 4/5lb plus upto high teens.

Aye, but that's the average. What's the smallest?

Col
 
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